ML062920340

(E-Mail) Appendix 3 to 316a Demonstration

ML062920340
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Site:	Vermont Yankee
Issue date:	08/25/2006
From:	Dewald L Entergy Nuclear Vermont Yankee
To:	Flemming J Office of Nuclear Reactor Regulation
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Richard Emch- Appendix 3 to 316a Demonstration " '"Page 1 From: "DeWald, Lynn" <Idewald@entergy.com>

To: <jlf2@ nrc.gov>

Date: 08/25/2006 12:04:03 PM

Subject:

Appendix 3 to 316a Demonstration Jason, Attached is Appendix 3 (hydrothermal report) to the April 2004 316a demonstration. You will receive the other documents Monday via UPS.

Lynn Lynn DeWald Entergy Nuclear Vermont Yankee, LLC 320 Governor Hunt Road Vernon, VT 05354 802-258-5526 (phone) 802-258-5865 (fax) 802-380-4493 (cell)

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Appendix 3 to 316a Demonstration Creation Date 08/2512006 12:02:43 PM From: "DeWald, Lynn" <Idewald@entergy.com>

Created By: ldewald@entergy.com Recipients nrc.gov OWGWPOO2.HQGWDOO1 JLF2 (Jason Flemming)

Post Office Route OWGWPOO2.HQGWDOO1 nrc.gov Files Size Date & Time MESSAGE 317 08/25/2006 12:02:43 PM TEXT.htm 3878 Final Appendix 3 Hydrothermal Report 30-Apr-2004.pdf 3617118 Mime.822 4956970 Options Expiration Date: None Priority: Standard ReplyRequested: No Return Notification: None Concealed

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No Security: Standard

Prep~rd for Normandeau Associates, Inc., Bedford, NH as Appendix 3 to their report: 316(a) Demonstrationin Support of a Requestfor IncreasedDischargeTemperatureLimits at Vermont Yankee NuclearPo Station DuringMay Through October

'It Hydrotherinal Modeling of the Cooling Water Dis arge from the Vermont Yankee Power Plant to the Connecticut River ASA Repor 02-088 Final Report April 2004 (I~evision)

Craig Swanson Hyun-Sook Kim Sankar Subbayy1 I

Paul Hall

\ Jiganesh Patel

-\

/1 FA 'A I

'A Applied cience Associates, Inc.

70 Dean nauss Drive Narraga ett, RI 02882

/I 165 tlb4irt.

Executive Summary The Vermont Yankee Nuclear Power Station (Vermont Yankee), an electric-generating station, is located on the Connecticut River in Vermont above the Vernon Dam. Vermont Yankee uses a sophisticated cooling system that varies from an open cycle, once-through cooling water configuration to a closed cycle, cooling tower configuration that recirculates the cooling water. In support of a request to increase discharge temperature limits during the summer period pursuant to a 316(a) of the Clean Water Act, Applied Science Associates, Inc.

(ASA) was contracted to .assess the thermal discharge from the plant and its effects on the River using a state-of-the-art, boundary fitted computer simulation model accepted by the United States Environmental Protection Agency and numerous state regulators.

The model was calibrated and confirmed to data collected from a set of continuous monitoring thermistors as part of a field program from May through October 2002. The data also included river flows and water temperatures obtained from permanently deployed instruments used in Vermont Yankee's operations. The model calibration and confirmation exercises used data sets acquired in August and June - July 2002, respectively. The August calibration period was chosen to be representative of warm river temperatures and low river flows. The June - July confirmation period was chosen to include warm river temperatures occurring during fishway operations.

Results of the calibration and confirmation indicated that the model predicted both flows and temperatures well. The flow predictions for the calibration and confirmation periods were very successful, exhibiting RME and ECV values less than 3% and 4%, respectively, which were smaller (better) than U. S. EPA guidance levels (30% and 10%, respectively).

Correlations between the prediction and observations were excellent, with r 2 values of 0.92 and 0.98 for the calibration and confirmation periods, respectively, which were larger (better) than the guidance level of 0.88.

The calibration results indicated that temperature predictions were also good. Best results were obtained at the upper layer, but they became somewhat reduced with depth. Squared correlation coefficients at the surface were usually larger (better) than the U. S. EPA guidance level of 0.71, and the correlations became smaller with depth. However, RME and ECV for all three layers ranged between 0 and 5.6%, showing that they were smaller (better) than the EPA guidance levels (25% and 45%, respectively) and suggesting that the predictions throughout the water column were acceptable.

The confirmation results indicated that the model performed excellently in simulating the thermal conditions of June - July 2002. The surface temperature predictions showed RME values ranging between 0.6% to 3.0% compared to the guidance level of 25%, ECV values between 2.6% and 8.1% compared to the guidance level of 45%, and r 2 greater than 0.66 compared to the guidance level of 0.71. Similar variations in model error statistics were found at the middle and bottom layers. Based on the successful calibration and confirmation, the model could then be used for predictions under selected plant and river conditions.

i

Two sets of scenario simulations were performed for the August and June - July periods separately, to investigate the effect of proposed new temperature limits within the portion of the lower Vernon Pool affected by the Vermont Yankee discharge during the summer permit compliance period and during the period of fishway operation, respectively. For the August period, a I'F (0.6°C) increase from 20F (I.1IC) to 30F (1.70C) resulted in a marginal increase in the temperature of the water column or on the bottom. For worst conditions occurring only 1% of the time, 30% of the bottom area increased by at least 0.3°C (0.5°F) and 20%

increased by a maximum of 0.4°C (0.7'F). For typical conditions occurring 50% of the time, 30% of the bottom area increased by at least 0.1 0 C (0.2 0 F), 20% increased by at least 0.2 0 C (0.4 0 F) and 10% increased by a maximum of 0.6C (I.10 F). Similar results were obtained for changes in water column volume.

Temperature predictions during June and July when the fishway was operating with warmest river temperatures indicated that a I°F increase in temperature rise generally resulted in similar increases (0.4°C) [0.7 0 F] in water temperature regardless of whether conditions were worst (1% of the time), infrequent (10% of the time) or typical (50% of the time). There was a slight increase in effects under typical conditions of higher river flow and therefore higher plant flow. Results also indicated that the ambient water temperature primarily influenced the temperature in the fishway rather than Vermont Yankee's rejected heat.

Based on the hydrothermal modeling results, a 1 F (0.6°C) increase in the permit limit from 2 0F (1.1°C) to 30F (1.7 0C) resulted in de minimus changes in the thermal structure of the Vernon Pool.

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Table of Contents

1. Introduction ....................

to...................................................................................................... 1

2. Description of Study Area ................................................................................................ 2

3. Thermal Plume Mapping .................................................................................................. 4 3.1 Historical Studies .......................................................................................................... 4 3.2 2002 Field Data ............................................................................................................ 4 3.2.1 Data Descriptions ................................................................................................... 4 3.2.1.1 Vernon Pool Temperature ................................................................................ 4 3.2.1.2 River Flow and Temperature ............................................................................. 7 3.2.1.3 Plant Operations ................................................................................................ 8 3.2.1.4 Meteorological Conditions ............................................................................... 8 3.2.2 August 2002 10 3.2.2.1 Lower Vernon Pool Temperatures .................................................................. 10 3.2.2.2 River Flow and Temperature ........................................................................... 18 3.2.2.3 Vermont Yankee Station Operations ............................................................... 19 3.2.2.4 Meteorological Conditions ............................................................................. 19 3.2.3 June - July 2002 ..................................................................................................... 20 3.2.3.1 Vernon Pool Temperatures ............................................................................. 20 3.2.3.2 Plant Operations .............................................................................................. 24 3.2.3.3 Meteorological Conditions ............................................................................. 24

4. Hydrothermal Model ..................................................................................................... 25 4.1 Model Description - WQMAP .................................................................................. 25 4.2 WQMAP System ....................................................................................................... 27 4.3 Application to the Vernon Pool .................. ... 28 4.3.1 Grid Generation ..................................... ........ 28 4.3.2 Bathymetry ........................................ ........ 31 4.3.3 Boundary Conditions ................................. ........ 31 4.3.3.1 Model Calibration and Confirmation ......... .................................................... ...... 32 4.3.3.2 Scenario Simulations ....................................................................................... 36 4.4 Model Calibration and Confirmation ........................................................................ 40 4.4.1 Calibration to August 2002 Period ....................................................................... 43 4.4.2 Confirmation to June - July 2002 Period ............................................................. 53 4.4.3 Discussion ............................................................................................................. 62

5. Thermal Plume Simulations ............................................................................................ 65

6. C onclusions ......................................................................................................................... 73

7. R eferences ........................................................................................................................... 75 Appendices Appendix A August 2002 Data Appendix B June - July 2002 Data Appendix C Hydrodynamic Model Description (Muin and Spaulding, 1997)

Appendix D Development of an Estuarine Thermal Environmental Model in a Boundary-Fitted, Curvilinear Coordinate System (Mendelsohn, 1998).

Appendix E WQMAP Description iii

List of Figures Figure 3-1. Location of thermistor stations for long-term thermistor deployment. The lower image is a detailed view of lower Vernon Pool immediately upstream of Vernon Dam.. 6 Figure 3-2. Location of Orange Municipal Airport met station relative to Vermont Yankee. 9 Figure 3-3. A comparison of air temperature and atmospheric pressure at Orange, MA and Vermont Yankee for the August survey period. Pressure records have been corrected for the difference in elevation between the two locations ................................................. 10 Figure 3-4. Temperature profiles for the C stations on 8/05/02 17:00 ............................. 12 Figure 3-5. Temperature profiles for the D stations on 8/05/02 17:00 .............................. 12 Figure 3-6. Temperature profiles for the E stations on 8/05/02 17:00 .............................. 13 Figure 3-7. Temperature profiles for the C stations on 8/06/02 17:00 ............................. 13 Figure 3-8. Temperature profiles for the D stations on 8/06/02 17:00 ............................. 14 Figure 3-9. Temperature profiles for the E stations on 8/06/02 17:00 .............................. 14 Figure 3-10. Temperature profiles for the C stations on 8/10/02 17:00 ........................... 15 Figure 3-11. Temperature profiles for the D stations on 8/10/02 17:00 ........................... 15 Figure 3-12. Temperature profiles for the E stations on 8/10/02 17:00 ............................. 16 Figure 3-13. Temperatures recorded by surface thermistors of C (top), D (middle) and E (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an across-channel transect at the surface of Vernon Pool at the given location ..................................................................................................... 17 Figure 3-14. Temperatures recorded by surface thermistors of '1/2' (top), '3/4' (middle) and

'5/6' (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an along-channel transect at the surface of Vernon Pool at the given location ............................................................................... 18 Figure 3-15. Temperatures recorded by surface thermistors of C (top), D (middle) and E (bottom) stations during the June-July survey period. Each of the above plots therefore represents the time evolution of an across-channel transect at the surface of Vernon Pool at the given location ..................................................................................................... 22 Figure 3-16. Temperatures recorded by surface thermistors of '1/2' (top), '3/4' (middle) and

'5/6' (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an along-channel transect at the surface of Vernon Pool at the given location .............................................................................. 23 Figure 4-1. Model grid for the Vernon Pool study area: Blue shaded cells represent downstream boundary and green shaded cells represent intake, discharge and upstream river boundary ............................................................................................................ 30 Figure 4-2. Model bathymetry of the lower area of the study domain ............................... 32 Figure 4-3. Vermont Yankee Station operations with computed rejected heat for the calibration period from 1 to 24 August 2002 ............................................................ 34 Figure 4-4. Vermont Yankee Station operations with computed rejected heat for the confirmation period from 25 June to 9 July .............................................................. 35 Figure 4-5. Typical daily variations of air temperature and solar radiation for the August and June-July periods ......................................................................................................... 37 Figure 4-6. Downstream flow comparison between the prediction and observations ..... 44 Figure 4-7. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string C3 ...................................................................... 46 iv

Figure 4-8. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string D3 ...................................................................... 47 Figure 4-9. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string E3 ...................................................................... 48 Figure 4-10. Comparison of observed (thick) and simulated temperatures (thin) for monitoring stations 7 (top) and 3 (bottom) .................................................................. 49 Figure 4-11. Comparison of the observed (thick) and predicted flows (thin-dashed) across the V ernon D am .................................................................................................................... 54 Figure 4.12 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station C3 ................................................... 56 Figure 4.13 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station D5 ................................................... 57 Figure 4.14 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station El ..................................................... 58 Figure 4-15. Comparison of predicted and observed temperatures at the fishway during the confirm ation period ..................................................................................................... 62 Figure 5-1. Predicted surface temperature distribution for August scenario 50%-3°F ..... 65 Figure 5-2. Predicted middle-layer temperature distribution for August scenario 50%-3°F.. 66 Figure 5-3. Predicted bottom-layer temperature distribution for August scenario 50%-3°F. 66 Figure 5-4. Model grid area (shaded in purple) used for the computation of the thermally effected area ....................................................  :................................................................ 68 Figure 5-5. Mean percent bottom area coverages versus temperature for the four August scenarios .......................................................................................................................... 69 Figure 5-6. Mean percent water column volume coverages versus temperature for the four A ugust scenarios .......................................................................................................... 69 Figure 5-7 Maximum percent bottom area coverages versus temperature for the four August scenarios .......................................................................................................................... 70 Figure 5.8 Maximum percent volume coverages versus temperature for the four August scenarios .......................................................................................................................... 71 Figure 5-9. Percent time coverages of mean surface-layer temperature at the fishway ......... 72 v

List of Tables Table 3-1. Location and total water depth for field study thermistor stations .................... 7 Table 3-2. Therm istor depths by station ............................................................................. 7 Table 3-3. Statistical analysis of meteorological data for the summer survey period ..... 20 Table 3-4. Statistical analysis of meteorological data for the summer survey period ..... 24 Table 4-1. Summary of parameters for August scenarios. Vermont Yankee Temp denotes the plant discharge temperature ......................................................................................... 38 Table 4-2. Summary of parameters for the June -July scenarios. Vermont Yankee Temp denotes the plant discharge temperature .................................................................... 39 Table 4-3. Summary of model parameters used in the calibration and testing ................. 40 Table 4-4. Model calibration and confirmation guidance (McCutcheon et al., 1990) ..... 43 Table 4-5. Quantitative comparisons of predicted and observed surface temperatures for the calibration period from 1 to 24 August 2002 .............................................................. 51 Table 4-6. Quantitative comparisons of predicted and observed temperatures at the middle layer for the calibration period from 1 to 24 August 2002 .......................................... 52 Table 4-7. Quantitative comparisons of the predicted and observed bottom temperatures for the calibration period from 1 to 24 August 2002 ........................................................ 53 Table 4-8. Quantitative comparisons of the predicted and observed temperatures at the surface layer for the confirmation period from 25 June to 9 July 2002 ...................... 59 Table 4-9. Quantitative comparisons of the predicted and observed temperatures at the middle depth for the confirmation period from 25 June to 9 July 2002. N/A stands for no data available ................................................................................................................... 60 Table 4-10 Quantitative comparisons of the predicted and observed temperatures at the bottom layer for the confirmation period from 25 June to 9 July 2002 ....................... 61 Table 4-11. Vernon Pool hydrothermal model calibration and confirmation evaluation in comparison with EPA guidance (McCutcheon at al., 1990) ....................................... 63 vi

1. Introduction Entergy Nuclear Vermont Yankee, LLC (Entergy VY) owns the Vermont Yankee Nuclear Power Station (Vermont Yankee), an electric-generating station located in Vermont, on the Connecticut River (River) above the Vernon Dam, a hydroelectric facility owned by PG&E National EnergyGroup. Vermont Yankee uses a sophisticated cooling system that varies from an open cycle, once-through cooling water configuration to a closed cycle, cooling tower configuration that recirculates the cooling water. In support of a request to increase discharge temperature limits during the summer period pursuant to a 316(a) of the Clean Water Act, Applied Science Associates, Inc. (ASA) was contracted through Normandeau Associates, Inc. to assess the thermal discharge from the plant and its effects on the River using a state-of-the-art, boundary fitted computer simulation model accepted by the United States Environmental Protection Agency and numerous state regulators.

The purpose of this study was to determine what effects, if any, the increased Vermont Yankee thermal discharge would have on the thermal structure of the River, particularly during the late summer period of low River flow and warm River temperatures. The study included a field program (i.e., collection) component to characterize the physical thermal regime in the Vernon Pool. A hydrothermal modeling study designed to characterize the circulation and temperature distribution in the River followed. The modeling study was designed to evaluate the potential effects of Vermont Yankee's proposed increase on the temperature distribution in the River under expected and worst-case conditions.

This report documents the hydrothermal model application, calibration and confirmation, which then provided predictions of the thermal regime in the Vernon Pool under relevant scenarios. Section 1 provides an introduction to the study, including background and purpose, and structure of the report. Section 2 describes the study area, the Vernon Pool, on the Connecticut River above the Vernon Dam and the relevant information about dam and plant operations and layout. Section 3 describes the thermal plume mapping and other field studies and data used in the modeling study. Section 4 describes the hydrothermal model (BFHYDRO) and the Water Quality Mapping and Analysis Package (WQMAP) system, of which the model is a part. This section also describes the application of the model to the Vernon Pool and the results of the calibration and confirmation procedures. Section 5 presents the thermal plume simulations for a series of selected environmental and plant operating conditions. Section 6 presents a summary and conclusions. Section 7 lists references. Presentations of the environmental, dam and plant data during selected periods are included as appendices as are descriptions of the BFHYDRO model and the WQMAP system.

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2. Descriptionof Study Area Vernon Pool is located on the Connecticut River and situated on the border of Vermont and New Hampshire. The entire pool is 41.8 km (26 mi) long and 770 m (0.48 mi) in maximum width, with a total volume of 49.3x 106 m3 (1.7x 109 ft3). The area of interest for this study is the lower portion of the pool including the area from the Vernon Dam at the southern extent to 7.2 km (4.5 mi) north.

Vermont Yankee is located about 840 m (0.5 mile) north of the Vernon Dam on the west shore (Vermont). The plant discharges heated water with a maximum heat rejection of 1,100 megawatts (MW) thermal (in June 2002, for example), by taking relatively cool river water from an intake structure 570 m (1,870 ft) north of the discharge.

The Connecticut River flows, and therefore the flows through the Vernon Pool past Vermont Yankee, are highly regulated by hydroelectric generation activities both upstream and downstream from Vermont Yankee. Five hydroelectric dams and three storage dams exist on the main-stem Connecticut River upstream from Vernon Dam, and there are three hydroelectric dams and one pumped-storage facility downstream. The U. S. Geological Survey (USGS) operated a Connecticut River gauging station located just below Vernon Dam from 1936 until 1973. Operation of the Northfield Mountain Pumped Storage generating facility (downstream from Vernon Dam) and modification of the next downstream dam at Turner's Falls reduced the efficacy of the stage height-discharge rating and USGS ceased use of the gauging station in 1973.

Vernon Station, a 26 MW hydroelectric generating facility located on the west (VT) side of the 366 m (1,200-ft) long Vernon Dam, passes about 283 m3/s (10,000 ft3/s) of generation flow. When river discharge exceeds this capacity, the station generates continuously and the surplus flow is spilled from crest gates or deep gates. When River discharge is less than Vernon Station's capacity, all of the river discharge past Vernon Dam is controlled by the facility. The stipulated minimum flow at Vernon Station is 35 m3/s (1,250 ft3/s) or inflow if it is less than 35 m3/s (1,250 ft3/s). This situation leads to two characteristic patterns of regulated discharge: one of high and gradually varying flow, and one of daily cycling between minimum and capacity flows characterized by rapid transitions.

Vernon Station owns and operates for certain periods during each year a fish ladder and a downstream fish passage conduit to facilitate both the upstream and downstream passage of anadromous fishes, including Atlantic salmon and American shad. The fishway was installed and became operational in 1981, and the downstream fish conduit (pipe) was first operated in 1991. The fishway, located near the western bank of the Connecticut River, is typically run between mid-May and early July of each year. The fishway is a concrete structure consisting of a vertical slot ladder from the tailrace leading up to a fish trap and viewing gallery, and an ice harbor style ladder that provides passage from the trap up to Vernon Pool. The fish ladder is supplied with a continuous flow of 1.8 m3/s (65 ft3/s) during the period of operation, and an attraction flow of 1.1 m3/s (40 ft3/s) is also discharged near the foot of the ladder. The "pipe" supplying the additional attraction flow was converted in 1994 into a "fish pipe".and 2

is presently used as an alternate downstream fish passage device. The primary downstream fish passage conduit (fish tube) is located in the center of the powerhouse, and 9.9 m3/s (350 ft3/s) of bypass flow is supplied through a 2.7 m (9-ft) by 1.8-m (6-ft) gate and tube that constricts to a 1.2-m (4-ft) by 1.5-m (5-ft) opening at the discharge end. The downstream fish passage conduit and the fish pipe are operated continuously from April through July and from September through October of each year.

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3. Thermal Plume Mapping 3.1 HistoricalStudies Prior to the present survey, a joint hydrological-biological study of Vernon Pool was conducted between 1974 and 1977 (Binkerd et al., 1978). The hydrological study featured a thermal survey of Vernon Pool using both a long-term deployment of in situ temperature probes and a series of short-term surveys using a towed temperature probe. The towed device was used to determine temperatures at a given depth along a series of across-channel transects. In addition, the towed probe was used to obtain profiles of temperature with depth at fixed locations around the pond.

This study concluded that discharge of cooling water from Vermont Yankee results in two distinct flow patterns within Vernon Pond. During periods of relatively high river flow the strong river currents shear the plume as it emerges from the Vermont Yankee discharge and is deflected to flow along the Vermont shore. In contrast, during periods of low river flow the plume extends far into the river channel before being swept downstream. In both of these flow regimes, warm plumes were found to sink if the ambient water temperature in the river was less than 4 'C (39.2 °F), the temperature at which water attains its maximum density.

3.2 2002 FieldData Data considered here derive from a field survey conducted by Normandeau from May through December of 2002. The data presented here come from two periods during-this survey: 1-23 August and 25 June - 9 July. The August period was determined by a joint Normandeau-ASA review to be representative of low flow, high temperature summer conditions in the river. The June - July period was chosen by Normandeau as period during which both the fishway was in active operation and the river temperatures were warm. Data available for review included temperature data from a long-term thermistor network deployed in the study area by Normandeau, meteorological data, and information on river flow and the flow of cooling water through Vermont Yankee.

3.2.1 Data Descriptions 3.2.1.1 Vernon Pool Temperature Spatial and temporal variations in the thermal structure of the study area were monitored using the state-of-the-art temperature acquisition system deployed during 2002 to obtain thermal data for calibration of the hydrothermal model. Onset StowAway TidbiT 32K, temperature data loggers were deployed to measure the thermal regime of lower Vernon Pool of the Connecticut River during June through November 2002. These temperature loggers have a manufacturer's reported measurement range of-4°C to +370 C, and a reported accuracy of +0.4 0 C. All of the temperature loggers were set to record data at simultaneous five-minute intervals. Two strings of temperature data loggers were deployed in close proximity to each other at each of 11 stations in Lower Vernon Pool for redundancy.

4

Stations, shown in Figure 3.1, are referred to by transect (F was the most upstream; C, D, E were the most downstream, respectively) and by station number (1-6). Station numbers were also assigned systematically, with stations 1 and 2 being the pairs of temperature loggers located proximate to the Vermont shore, stations 3 and 4 were in the center of the channel, and stations 5 and 6 were proximate to the New Hampshire shore. Upstream control stations (F1I/F2 and F3/F4) were located upstream from the influence of the discharge, while the remaining transects were at or downstream of the Vermont Yankee discharge. For example, Station E5/E6 included the pair of temperature strings located on transect E proximate to the New Hampshire shore on the most downstream transect below the discharge. All station locations were marked with GPS latitude and longitude coordinates (Table 3-1).

Nine of the 11 stations were established along three bank-to-bank transects in the Lower Vernon Pool at locations representing the expected exposure to the thermal gradient from the Vermont Yankee discharge. One transect (C) was perpendicular to the river flow, located immediately downstream of the discharge weir, and had samplers deployed at quarter points along this transect (25%, 50% and 75% of the distance from the Vermont shore). A second transect (D) was also perpendicular to the river flow, located downstream from the discharge weir one-third of the distance towards Vernon Dam, and had samplers deployed at quarter points along the transect (25%, 50% and 75% of the distance from the Vermont shore). A third transect (E) was also perpendicular to the river flow, located downstream from the discharge weir two-thirds of the distance towards Vernon Dam, and had samplers deployed at quarter points along the transect (25%, 50% and 75% of the distance from the Vermont shore).

The remaining two of the 11 stations were established as an upstream control station transect (F). These stations were located within the Vernon Pool upstream from the influence of the thermal gradient along a transect perpendicular to the river flow, with samplers deployed at 25% and 50% of the distance from the Vermont shore.

Three temperature data loggers were attached to each string and arrayed from surface to bottom (Table 3-2). One temperature data logger was deployed at the surface depth (1 foot below the surface, referred to as surface or "S"when used as a suffix to Station number), a second logger was deployed at mid-depth (halfway between the surface and bottom =."M"),

and a third logger was deployed at one foot above the river bottom (bottom or "B") at each station. Therefore, a total of 66 temperature data loggers were deployed for this study (2 pairs per station x 11 stations x 3 depths). All depth measurements were relative to the total water column depth observed at a station at the time of deployment (Table 3-1).

Data from the thermistor arrays were downloaded on a weekly basis. These raw data were then filtered with a 3-hour low-pass filter and subsampled at hourly intervals. The 3-hour low-pass filter is a centered 3-hour moving average. This is an appropriate data conditioning step because the model input data is on a one-hour timestep and the model therefore cannot simulate processes that occur at frequencies less than one hour. The model-data comparison is thus more accurate. Resulting time series are shown in Appendix A, Figures A1-A33; (August 2002) and Appendix B, Figures B I-B22, (June - July 2002).

5

Data from the thermistor arrays, which were set to record temperatures at 5-minute intervals, were downloaded on a weekly basis. These raw data were then filtered with a 3-hour low-pass filter and subsampled at hourly intervals. The 3-hour low-pass filter was a centered 3-hour moving average. This is an appropriate data-conditioning step because the model input data is on a one-hour timestep and the model therefore cannot simulate processes that occur at frequencies less than one hour. The subsequent model-data comparison is thus more accurate. The resulting time series are shown in Appendix A, Figures A1-A33, and Appendix B, Figures B 1-B22.

Figure 3-1. Location of thermistor stations for long-term thermistor deployment. The lower image is a detailed view of lower Vernon Pool immediately upstream of Vernon Dam.

6

Table 3-1. Location and total water depth for field study thermistor stations.

Station Latitude Longitude Depth (N) MW (m (ft))

C1/C2 420 46.636' 720 30.598' 5.2 (17)

C3/C4 420 46.628' 720 30.499' 5.2 (17)

C5/C6 420 46.623' 720 30.395' 4.3 (14)

D1/D2 420 46.527' 720 30.620' 6.1 (20)

D3/D4 420 46.493' 720 30.499' 4.3 (14.1)

D5/D6 420 46.475' 720 30.427' 7.0 (23)

El/E2 420 46.411' 720 30.680' 11.9(39)

E3/E4 420 46.369' 720 30.598' 4.0 (13)

E5/E6 420 46.336' 720 30.510' 1.5 (5)

Fl/F2 420 47.399' 720 31.316' 4.0(13)

F3/F4 420 47.437' 720 31.258' 6.4 (21)

Table 3-2. Thermistor de ths by station.

Station Surface (S) Middle (M) Bottom (B)

Thermistor Thermistor Thermistor Depth (m (ft)) Depth (m (ft)) Depth (m (ft))

CI/C2 0.3(1) 2.6(8.5) 4.9(16)

C3/C4 0.3(1) 2.6(8.5) 4.9(16)

C5/C6 0.3 (1) 2.1 (7) 4.0 (13)

D1/D2 0.3 (1) 3.1 (10) 5.8 (19)

D3/D4 0.3(1) 2.1(7) 4.0(13)

D5/D6 0.3(1) 3.5 (11.5) 6.7(22)

El/E2 0.3(1) 5.9(19.5) 11.6(38)

E3/E4 0.3(1) 2.0(6.5) 3.7(12)

E5/E6 0.3 (1) 0.8 (2.5) 1.2 (4)

F1/F2 0.3(l) 2.0(6.5) 3.7(12)

F3/F4 0.3 (l) 3.2 (10.5) 6.1 (20) 3.2.1.2 River Flow and Temperature Measurements of river flow at the Vernon Dam were provided by Vermont Yankee, based upon information obtained from the dam owner. River flow was reported at hourly intervals throughout the deployment period. This raw hourly data was processed with a 3-hour low-pass filter (Appendix A, Figures A34-A36; Appendix B, Figures B23-B24).

Water temperatures both upstream and downstream of the study area are also monitored and were reported by Vermont Yankee. Temperature upstream of the study area was measured at Monitoring Station 7 (420 49.364' N, 720 32.745' W) and downstream temperature was measured at Monitoring Station 3 (420 45.921' N, 720 30.400' W), shown in Figure 3.1.

Temperatures were recorded at hourly intervals at both locations and are presented here without any additional processing (Appendix A, Figures A34-A36; Appendix B, Figures B23-B24).

7

During the period from May to July each year, water temperatures were monitored during fishway operations at the Vernon Dam. Measurements were taken at hourly intervals. Figure B27 and B28 show a portion of the observations for 25 June to 9 July 2002.

3.2.1.3 Plant Operations Cooling water flow and temperature data for Vermont Yankee were calculated based on the actual station operating conditions, upstream river water temperature at Station 7, and total river discharge at Vernon Dam using the thermal compliance equation. The temperature and volume flux of water discharged from the station into the river were reported at hourly intervals for the duration of the study period. These data are reported here without any additional processing (Appendix A, Figures A37-A39; Appendix B, Figures B25-B26).

3.2.1.4 Meteorological Conditions Atmospheric forcing can affect the hydrothermal model via two distinct mechanisms:

mechanical and thermal. First, wind induces a shear stress on the surface of the water, which can cause the water, particularly near the surface, to move in the general direction of the wind. Wind energy can also cause mixing in the upper layers of the water column that tends to homogenize the distribution of water properties with depth. The magnitude of these effects is a function of both the speed and direction of the wind. Second, transfer of heat between the water and the atmosphere can modify the thermal structure of the water body.

This process is driven by solar radiation, which is a measure of the thermal energy reaching the surface of the water, with ancillary factors such as air and dew point temperatures also of importance.

Meteorological data for this study derive from two separate sources. Wind speed and direction were measured at a meteorological tower located at Vermont Yankee.

Measurements were taken at 15-minute intervals at a height of approximately 11 m (36.1 ft) above the ground. Since the meteorological data was not reported exactly on the hour, a cubic spline curve fit was applied to the observations (passing exactly through the surrounding four data points) to generate one-hour estimates. These data were then filtered with a centered 3-hour moving average. The resulting time series are shown in Appendix A, Figures A40-A42, and Appendix B, Figures B29-B30.

Observations of air temperature, dew point temperature, relative humidity and atmospheric pressure, some of which (i.e., dew point temperature, relative humidity) were not available at Vermont Yankee, were obtained from the National Climate Data Center for the weather station at the Orange Municipal Airport in Orange, MA, the nearest such site to Vermont Yankee. The station is located approximately 30 km (18.6 mi) SE of Vermont Yankee at 420 34' N, 72' 17' W (Figure 3-2). The station sits at an elevation of 169.2 m (555.1 ft) above sea level. For comparison, the normal average elevation of the surface of Vernon Pond is approximately 66.7 m (218.8 ft). The validity of approximating meteorological conditions at Vermont Yankee with those at Orange, MA is born out by a comparison of air temperature and atmospheric pressure records from the two locations (Figure 3-3). Data from the Orange, MA station was reported at hourly intervals. Cubic splines were used to synchronize this data to the wind data from Vermont Yankee. The splined data were then filtered with a 3-hour low-pass filter (Appendix A, Figures A43-A45; Appendix B, Figures B31-B34).

8

In addition, calculated values of solar radiation at Orange, MA were obtained from the Northeast Regional Climate Center. Solar radiation is reported hourly and the data are presented here with no additional processing (Appendix A, Figures A46-A48; Appendix B, Figures B31-B32).

Figure 3-2. Location of Orange Municipal Airport met station relative to Vermont Yankee.

9

50 40 LD.30A 20 E

10 At-0 90 8/1 8/8 8/15 8/22 Date (2002)

Figure 3-3. A comparison of air temperature and atmospheric pressure at Orange, MA and Vermont Yankee for the August survey period. Pressure records have been corrected for the difference in elevation between the two locations.

3.2.2 August 2002 The August survey period covers the period from 1 to 24 August 2002 and is representative of low flow, high temperature conditions. Survey data for this period are presented in Appendix A.

3.2.2.1 Lower Vernon Pool Temperatures Temperatures at the C stations (Figures Al1-A9), arrayed across the Vernon Pool at the outfall location (Figure 3-1), ranged from a low of just under 24 °C (75.2 0F) (C6 bottom, 1 August) to approximately 29.5 °C (85.1 0F) (C4 surface, 18 August). Note that shortly after noon on 15 August the surface thermistor at C4 comes online. This is related to the weekly downloading of data from the thermistor strings. Surface thermistors at the C stations exhibit a diurnal variation in temperature of 1-2 °C, while thermistors at mid-depth show a variation of at most 1 Deep thermistors JC. show no diurnal variation. This diurnal variation may be due to variations in the temperature and volume flux of water discharged from the station as well as solar heating.

10

Missing data between 1-15 August 2002 for the thermistor located at the surface at Station C4 in lower Vernon Pool is seen in Figures A4-A5. Data loggers were downloaded on 14 and 15 August 2002, during which three files were irretrievable. The loggers were sent to Onset where data sets from two of the loggers were retrieved by the instrument manufacturer.

The data from the station C4S logger could not be retrieved due to instrument failure, resulting in a loss of data for that point from 31 July to 15 August 2002. Station C3S, the duplicate of C4S, was downloaded without data loss during that period. Because all thermistor loggers were deployed in redundant pairs, there was no effective loss of relevant data. Even though the C4S temperature data logger failed out of the 66 deployed, the success rate of 65/66 or 98.5% is, in the experience of the consultant team (ASA and Normandeau),

exceptionally good. Losses of data are fairly routine when loggers are deployed in situ, and, because of redundant deployment design, this loss did not affect the usefulness of the data for the study.

Thermistors at the D stations (Figures A IO-A 18), arrayed across the river several hundred meters downstream of the outfall (Figure 3-1), recorded temperatures ranging from a low of just under 24 'C (75.2 'F) (D6 bottom, 12 August) to approximately 29.3 'C (D5 surface, 17 August). Overall, temperatures at these stations resemble those of the C stations. Diurnal temperature variations at the D stations are on the order of 1-1.5 °C for the surface thermistors and 1 'C for the middle thermistors. No diurnal variation is evident in the deep thermistors.

Thermistors at the E stations (Figures A19-A27), arrayed across the river just upstream of the dam (Figure 3-1), recorded temperatures ranging from a low of just under 24.4 °C (75.9 'F)

(E2 bottom, 1 August) to approximately 29.8 °C (85.6 'F) (E5 surface, 17 August). The individual E stations exhibit a wide range of behavior, reflecting the differences in the depth of the water column (and the thermistors) at each location. Diurnal variations at these stations fall in the range of 1.5 - 2 *C for the surface thermistors.

Temperatures recorded at the C, D and E stations indicate that water column stratification is similar at each of these locations. For example, temperatures show considerable stratification at all stations from 1-5 August, with the deep thermistors recording significantly lower temperatures than the surface and middle thermistors (Figures 3-xx-3-xx). However, on 6 August this temperature difference decreases at almost all stations and the water column becomes well mixed for a period of several days (Figures 3-xx-3-xx). Stratification is then re-established around 10 August at all stations (Figures 3-xx-3-xx). This stratification lasts until 21 August, when it begins to break down again. Some small deviations from the larger trend are apparent at some of the E stations. For example, Station El/E2 shows the same pattern of stratification breaking down and re-establishing as do the C and D stations.

However, while the station is very deep, the total temperature difference between the top and bottom thermistors is only approximately 2 'C (3.6 'F), substantially less than the difference seen at stations upstream, particularly given that the water column is much deeper here.

Station E3/E4 behaves similarly to station El/E2, except that stratification is somewhat weaker. This reflects the fact that the deep and middle thermistors are deployed at much shallower depths than at Station El/E2 (Table 3-2). Station E5/E6, located in extremely 11

shallow water, exhibits almost no stratification at all, with no more than approximately 1.5 °C difference between the surface and deep thermistors.

Temperature Profiles at the C Thermistor Stations on 815102 17:00 Temperature (*C) 25.0 25.5 26.0 26.5 27ý0 27.5 28.0 28.5 29.0 29.5 30.0 0

2 3-4-

Figure 3-4. Temperature profiles for the C stations on 8/05/02 17:00.

Temperature Profiles at the D Thermistor Stations on 815/02 17:00 Temperature (*C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0 I..-

-3 4.

5 6

7 Figure 3-5. Temperature profiles for the D stations on 8/05/02 17:00.

12

Temperature Profiles at the E Thermistor Stations on 815/02 17:00 Temperature (*C) 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 29.5 30.0 0

2A 3

-E I 4 E "4E3 5 E4 7

8 9

10 11 12 Figure 3-6. Temperature profiles for the E stations on 8/05/02 17:00.

Temperature Profiles at the C Thermistor Stations on 8/6/02 17:00 Temperature (IC) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0

-0C2

-41C3 2 ~-C4 cl3 Figure 3-7. Temperature profiles for the C stations on 8/06/02 17:00.

13

Temperature Profiles at the D Thermistor Stations on 816/02 17:00 Temperature (*C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0 f-2 3

04 Figure 3-8. Temperature profiles for the D stations on 8/06/02 17:00.

Temperature Profiles at the E Thermistor Stations on 8/6/02 17:00 Temperature (*C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 2

3 0 ... . .. .. .

4 20 .....

5 r-10 i 1 I1 I 1

~11 12 Figure 3-9. Temperature profiles for the E stations on 8/06/02 17:00.

14

Temperature Profiles at the C Thermistor Stations on 8/10102 17:00 Temperature (°C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0 t-2 a=.

0 3

4 5 ' I I Figure 3-10. Temperature profiles for the C stations on 8/10/02 17:00.

Temperature Profiles at the D Thermistor Stations on 8/10102 17:00 Temperature (°C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0 ......

-3 a06 4 04 5

6 Figure 3-11. Temperature profiles for the D stations on 8/10/02 17:00.

15

Temperature Profiles at the E Thermistor Stations on 8110/02 17:00 Temperature (*C) 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 0

2 3

4 5

7 8

9 10 11 12 Figure 3-12. Temperature profiles for the E stations on 8/10/02 17:00.

Thermistors at the F stations (Figures A28-A33), located upstream of the station intake (Figure 3-1), measure temperatures during this time ranging from a low of 23.8 'C (74.8 'F)

(F4 bottom, 1 August) to a high of 28.8 'C (83.8 °F) (F3 surface, 19 August). Both the F1/F2 and the F3/F4 stations exhibit trends similar to those seen at the C and D stations downstream. However, the stratification at the F stations is generally weaker than at the other stations. Temperature differences between surface and deep thermistors at the F stations can be as much as approximately 3 'C, but appears to be more typically on the order of 1.5 'C. Note that the surface and mid-depth thermistors at Station F4 go offline shortly before noon on 14 August and remain inactive for the remainder of the period. Diurnal temperature variations at the F stations are as much as 1 'C at the surface, less than 0.5 °C at mid-depth and essentially non-existent in the deep water.

Spatial variations in the temperature of the surface water in Vernon Pool can be investigated by considering across-channel and along-channel transects of temperature with time. During the August survey period, temperatures along the across-channel transects defined by the C, D and E thermistor stations (Figure 3-13) show little spatial variation. In general, temperatures for a given transect are within approximately 1 'C (1.8 'F) of each other at any given time, and the temperature record is dominated by a diurnal signal associated with a combination of solar heating and plant operations. The C 1/C2 station has slightly higher temperatures than the C3/C4 or C5/C6 stations throughout most of the survey period, while the D5/D6 and E5/E6 stations consistently report the highest temperatures along their respective transects. A consideration of along-axis transects (Figure 3-14) reveals similar 16

I trends. Temperatures stay within approximately 1 'C (1.8 'F) of each other at any time along a given transect.

i3 25 E S28 ao15 .L------1 - 1 8/6 8/13 8/20 30 301 25

• 25

• 2oý 15-8/6 8/13 8/20 Fiue313Tmeatrsrcoddb surfac thritoso1C(o)20 mdden 2002 Dat Figure 3-13. Temperatures recorded by surface thermistors of C (top), D (middle) and E (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an across-channel transect at the surface of Vernon Pool at the given location.

17

30 Q

025 7 F (U

E E20 I,-

15 8/6 8/13 8/20 3O S25 E 20 8/2 15 8/6 8/13 8/20 30 EE S25 S20 15 8/6 8/13 8/20 Date (2002)

Figure 3-14. Temperatures recorded by surface thermistors of '1/2' (top), '3/4' (middle) and '5/6' (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an along-channel transect at the surface of Vernon Pool at the given location.

3.2.2.2 River Flow and Temperature River flow, as measured at the Vernon Dam, fluctuated considerably between 1 and 17 August and then remained relatively constant from 17 to 24 August (Figures A34-A36).

Flow during the earlier period exhibited a diurnal variation, with flow generally reaching a maximum in the late afternoon/early evening and a minimum in the early morning. The 18

period of 17-24 August stands in marked contrast to this, with a mean flow of 42 m3 /s (1,483 ftO/s) that remained nearly constant throughout the entire week (Figure A36). Overall, flow during the August period ranged from 36 to 194 m 3/s (1,271 to 6,851 fR 3/s), with an average 3

value of 66 m /s (2,331 ft /s).

Section 3.1.2 of the Demonstration details the nature of flow regulation at Vernon Dam. As discussed therein, Connecticut River flow is highly regulated by numerous upstream storage and hydroelectric stations. Although storage in the Vernon headpond provides some flexibility of flow release from Vernon Dam independent of inflow, the upriver hydro stations and Vernon Station are generally operated more or less in unison to maximize power output during times of peak power demand. The hourly flow record for Vernon Dam provides (Figures A34-A36) direct evidence of the highly regulated nature of the whole River.

Measured Upstream Station 7 Temperatures are slightly cooler (approximately 1.6 'C (2.9 °F) on average) than Measured Downstream Station 3 Temperatures (Figures A34-A36). The Measured Upstream Station 7 Temperature shows no evidence of a diurnal temperature variation, and in general correlates well with the deepest thermistor readings from Stations Fl-F4 for this period. For the August period, Measured Upstream Station 7 Temperatures ranged between 23.8 and 25.7 'C (74.8 and 78.3 'F), averaging 24.8 'C (76.6 'F).

The Measured Downstream Station 3 Temperature shows a marked diurnal variation of approximately 1 'C (1.8 'F) during the period from 1-15 August and a somewhat less prominent diurnal variation thereafter. During the August survey, Measured Downstream Station 3 Temperatures ranged between 24.9 and 28.0 'C (76.8 and 82.4 *F) with an average temperature of 26.4 'C (79.5 'F).

3.2.2.3 Vermont Yankee Station Operations The flow of cooling water discharged from the station varied considerably and sharply between I and 17 August, while flow varied less dramatically between 17 and 24 August (Figures A37-A39). Overall, flow varied between 0.2 and 19.9 m3 /s (7.1 and 702.8 ft3/s) for the period, with an average flow rate of 8.8 m3/s (310.8 ft3/s).

The temperature of the discharged cooling water averaged 31.6 °C (88.9 'F) for the August survey period. The maximum discharge temperature during this period was 36.1 'C (97.0 'F) while the minimum discharge temperature was 25.7 'C (78.3 'F).

3.2.2.4 Meteorological Conditions Winds were generally light during this period (Figures A40-A42), with a maximum speed of 6.7 m/s (15.0 mph). The average wind speed for the period was 1.9 m/s (4.3 mph). Winds were predominantly from the west for the period, with an average wind direction of 2 09'.

The air temperature record at this time is dominated by a diurnal signal with amplitude typically in excess of 10 'C (18 'F) (Figures A43-A45). Dew point temperature, in contrast, shows very little diurnal variation during this period, and little variation at all between 1 and 5 August. Relative humidity, which is a function of both air and dew point temperatures, 19

consequently displays a strong diurnal variation. In general, relative humidity achieves a minimum value at midday, when air temperatures are at their highest, and a maximum value around midnight, when air temperatures reach their lowest values. Atmospheric pressure during the study period changed smoothly over periods of days and remained bounded within a relatively narrow range of approximately 20 mbar. A summary statistical analysis of the data records for this time frame is presented in Table 3-3.

Solar radiation during this period exhibits a regular diurnal variation with a maximum peak magnitude of approximately 941.8 W/m2 (1 August), a minimum peak magnitude of 621.1 W/m 2 (23 August), and a mean peak magnitude of 839.7 W/m 2 (Figures A46-A48).

Irregularities in the peaks are due to local variations in atmospheric conditions (e.g., cloud cover).

Table 3-3. Statistical analysis of meteorological data for the summer survey period.

Air Temperature Dew Point Relative Humidity Pressure IC (OF) I °C (OF) I I mbar I Mean 22.3 (72.1) 15.9 (60.6) 0.71 997.8 Minimum 8.0 (46.4) 6.6 (43.9) 0.29 988.5 Maximum 35.0 (95.0) 23.3 (73.9) 1.00 1006.8 3.2.3 June - July 2002 The June - July survey period spans from 25 June to 9 July 2002. Survey data for this period are presented in Appendix B.

3.2.3.1 Vernon Pool Temperatures Temperatures at the C stations (Figures B 1-B6), arrayed across the river at the outfall location (Figure 3-1), ranged from a low ofjust under 19.5 °C (67.1 'F) (Cl bottom, 1 July) to approximately 27.5 'C (81.5 'F) (Cl surface, 4 July) during this period. All C stations display episodes of stratification during theperiod, during which deep thermistors register temperatures as much as 3.5 'C (6.3 'F) lower than those recorded at the surface. The Cl/C2 station appears most inclined towards stratification, remaining stratified almost without interruption for the period of 1-9 July. Surface thermistors at the C stations exhibit diurnal variations in temperature on the order of 0.5 'C (0.9 'F) during periods with little water column stratification. This signal appears to propagate throughout the entire depth of the water at these locations.

Thermistors at the D stations (Figures B7-B 12), arrayed across the river several hundred meters downstream of the outfall (Figure 3-1), recorded temperatures ranging from a low of 19.6 "C (67.3 "F) (D I bottom, 25 June) to approximately 28.3 "C (82.9 "F) (D5 surface, 3 July). Overall, the water column at the D stations appears to be more regularly stratified than at the C stations. The Dl/D2 station, in particular, shows regular stratification throughout the June-July period, with temperature differences across the water column of approximately 2.5

'C (4.5 "F). The D3/D4 and D5/D6 stations exhibit more intermittent stratification during 20

this period. Diurnal temperature variations at these stations are on the order of 0.5 'C (0.9 *F) at the surface for periods with no stratification (e.g., D3/D4, 28 June - 1 July).

Thermistors at the E stations (Figures B 13-B 18), arrayed across the river just upstream of the dam (Figure 3-1), recorded temperatures ranging from a low of 19.3 'C (66.7 'F) (E2 bottom, 25 June) to approximately 27.7 'C (81.9 *F) (E5 surface, 5 July). The individual E stations exhibit a wide range of behavior, reflecting the differences in the depth of the water column (and the thermistors) at each location. Station El/E2 shows substantial stratification throughout the June-July period. However, while the station is very deep, the total temperature difference between the top and bottom thermistors is only approximately 2 'C, substantially less than the difference seen at stations upstream, particularly given that the water column is much deeper here. Station E3/E4 exhibits weak stratification between 25 June and 1 July, but is relatively well mixed after that. The mid-depth thermistors were not operational at this station during this period. Station E5/E6, located in extremely shallow water, exhibits almost no stratification at all. Diurnal variations at these stations fall in the range of 1 'C (1.8 'F) for the surface thermistors at these stations.

Thermistors at the F stations (Figures B 19-B22), located upstream of the station intake (Figure 3-1), measure temperatures during this time ranging from a low of 19.5 'C (67.1 °F)

(Fl bottom, 25 June) to a high of 25.0 'C (77.0 'F) (Fl surface, 5 July). Both the F1/F2 and the F3/F4 stations show little stratification during the study period. Diurnal temperature variations at the F stations are as much as I 'C (1.8 'F) at the surface. This signal attenuates with depth.

Spatial variations in the temperature of the surface water in Vernon Pond can be investigated by considering across-channel and along-channel transects of temperature with time. During the June-July survey period, temperatures along the across-channel transects defined by the C, D and E thermistor stations (Figure 3-15) show significant spatial gradients in temperature for much of the survey period. Temperatures across channel can vary by as much as 3 to 4

'C (5.4 to 7.2 'F) at a given instant in time. The CI/C2 station reports higher temperatures than the C3/C4 or C5/C6 stations throughout most of the survey period. The exception to this is the period between 28 June and 1 July, during which all C stations report nearly identical temperatures. This period corresponds to a period of particularly strong river flow

(> 300 m3/s (10,594 ft3/s)) (Figure B23). Temperatures along the D and E transects show substantial gradients between 25 June and 4 July, but are homogenous after 4 July. A consideration of along-axis transects (Figure 3-16) reveals a similar degree of structure.

While there are periods of homogeneity, in general gradients of 2 to 3 °C (3.6 to 5.4°F) exist along a given transect.

21

25 E20 15 6/25 7/2 7/9 30 E 2 25 7/

E D 15 6/25 7/2 7/9 S0~

-779 Date (2002)

Figure 3-15. Temperatures recorded by surface thermistors of C (top), D (middle) and E (bottom) stations during the June-July survey period. Each of the above plots therefore represents the time evolution of an across-channel transect at the surface of Vernon Pool at the given location.

22

0625 E 0 30 25 a

E 20 EE 15

• 0 I.-

6/25 7/2 7/9 Date (2002)

Figure 3-16. Temperatures recorded by surface thermistors of '1/2' (top), '3/4' (middle) and '5/6' (bottom) stations during the August survey period. Each of the above plots therefore represents the time evolution of an along-channel transect at the surface of Vernon Pool at the given location.

Measured Upstream Station 7 Temperatures are cooler than Measured Downstream Station 3 Temperatures by an average of 2.4 'C (4.3 °F) for the period (Figures B23-B24). The Measured Upstream Station 7 Temperature shows little evidence of a diurnal temperature variation during this period, and in general correlates well with the deepest thermistor readings from Stations F l-F4. Overall, Measured Upstream Station 7 Temperatures ranged between 18.7 and 23.8 °C (65.7 and 74.8 OF), averaging 21.5 'C (70.7 OF).

23

The Measured Downstream Station 3 Temperature shows a diurnal variation of approximately 1 'C (1.8 'F) during the period from 2-9 July. Measured Downstream Station 3 Temperatures for the period ranged between 20.7 and 26.2 'C (69.3 and 79.2 'F) with an average temperature of 23.5 °C (74.3 °F).

During the June-July survey period a thermistor was deployed to record water temperatures at the Fishway at hourly intervals (Figures B27-B28). Fishway temperatures during the study period ranged from a minimum of 20.8 °C (69.5 'F) to a maximum of 27.1 'C (80.8 °F),

averaging 23.8 'C (74.8 °F).

3.2.3.2 Plant Operations The flow of cooling water discharged from Vermont Yankee averaged 18.0 m3/s (635.7 ft3/s) for the June-July study period (Figures B25-B26). The maximum flow rate achieved during the period was 30.8 m3/s (1087.7 ft3 /s).

The temperature of the discharged cooling water averaged 32.7 'C (90.9 'F) for the June-July survey period. The maximum discharge temperature during this period was 35.7 °C (96.3 °F) while the minimum discharge temperature was 28.2 °C (82.8 °F).

3.2.3.3 Meteorological Conditions The maximum wind speed during the June-July study period was 5.4 m/s (12.1 mph)

(Figures B29-B30). The average wind speed for the period was 1.7 m/s (3.8 mph). Winds were predominantly from the west for the period, with an average wind direction of 222'.

The air temperature record at this time is dominated by a diurnal signal with amplitude typically in excess of 10 'C (18 'F) (Figures B31-B32). Dew point temperature shows very little diurnal variation during this period. Relative humidity, which is a function of both air and dew point temperatures, consequently displays a strong diurnal variation. In general, relative humidity achieves a minimum value around midday, when air temperatures are at their highest, and a maximum value around midnight, when air temperatures reach their lowest values. Atmospheric pressure during the study period changed smoothly over periods of days. A summary statistical analysis of the data records for this time frame is presented in Table 3-4.

Solar radiation during this period exhibits a regular diurnal variation with a maximum peak magnitude of approximately 988.9 W/m 2 (30 June), a minimum peak magnitude of 759.2 W/m 2 (5 July), and a mean peak magnitude of 882.2 W/m2 (Figures B31-B32). Irregularities in the peaks are due to local variations in atmospheric conditions (e.g., cloud cover).

Table 3-4. Statistical analysis of meteorological data for the summer survey period.

Air Temperature Dew Point Relative Humidity Pressure 0C (F) °C (OF) mbar Mean 23.0 (73.4) 16.5 (61.7) 0.71 995.1 Minimum 10.7 (51.3) 6.6 (43.9) 0.28 985.3 Maximum 34.4 (93.9) 23.9 (75.0) 1.00 1004.1 24

4. HydrothermalModel The hydrothermal model used to predict the velocity and temperature structure of the lower Vernon Pool is part of a modeling system known as WQMAP. The model calculates the circulation and thermal characteristics in the area known as the far field where the initial plume momentum has dissipated and the plume is affected only by the ambient currents. If needed, a near field model can optionally be used to predict plume dilution in the vicinity of the discharge in the relatively small area where the discharge plume is primarily influenced by its own momentum. Since the focus of the study was on the lower Vernon Pool and not the immediate area around the discharge, the use of such a near field model was not considered necessary. In any event, the geometry of the Vermont Yankee discharge did not lend itself to the use of such a model (i.e. CORMIX3). The CORMIX3 model could not directly simulate the plant discharge geometry since there is a built-in model limitation that the discharge depth to width ratio be at least 0.05. The Vermont Yankee discharge geometry has a depth to width ratio of 0.005 (depth of 0.54 ft, width of 100 ft), 10 times less than the minimum, making CORMIX3 an inappropriate model.

4.1 Model Description- WQMAP A state-of-the-art, boundary-fitted computer model (Swanson et al, 1989; Muin and Spaulding, 1997; Huang and Spaulding, 1995b) was used to predict pool elevations, flow, velocities and temperature distributions in the Vernon Pool. The boundary-fitted model matches the model coordinates with the shoreline boundaries of the water body, accurately representing the study area. This system also allows the user to adjust the model grid resolution as desired. This approach is consistent with the variable geometry of shoreline features of the Connecticut River. Development of the boundary fitted model approach has proceeded over the last decade (Spaulding, 1984; Swanson et al., 1989; Muin, 1993; and Huang and Spaulding, 1995a). The model may be applied in either two or three dimensions depending on the nature of the problem and the complexity of the study.

The boundary fitted method uses a set of coupled quasi-linear elliptic transformation equations to map an arbitrary horizontal multi-connected region from physical space to a rectangular mesh structure in the transformed horizontal plane (Spaulding, 1984). The three dimensional conservation of mass and momentum equations, with approximations suitable for lakes, rivers, and estuaries (Swanson, 1986; Muin, 1993) that form the basis of the model, are then solved in this transformed space. In addition a sigma stretching system is used in the vertical to map the free surface and bottom onto coordinate surfaces. The resulting equations are solved using an efficient semi-implicit finite difference algorithm for the exterior mode (two dimensional vertically averaged) and by an explicit finite difference leveled algorithm for the vertical structure of the interior mode (three dimensional) (Swanson, 1986). The velocities are represented in their contra-variant form. A sigma stretching system is used to map the free surface and bottom to resolve bathymetric variations.

25

A detailed description of the basic model being used for the Vernon Pool study with associated test cases is included as Appendix C (Muin and Spaulding, 1997). The publication was originally part of a Ph.D. dissertation (Muin, 1993), which extended the boundary fitted model capabilities, applying a contra-variant velocity formulation to the transformed momentum equations. A brief description of the model follows.

The basic equations are written in spherical coordinates to allow for accurate representation of large model areas. The conservation equations for water mass, momentum (in three dimensions) and constituent mass (temperature [heat] and salinity) form the basis of the model. It is assumed that the flow is incompressible, that the fluid is in hydrostatic balance, the horizontal friction is not significant and the Boussinesq approximation applies.

The boundary conditions are as follows:

• At land the normal component of velocity is zero.

• At open boundaries the free surface elevation must be specified and temperature and salinity specified on inflow.

• On outflow temperature (heat) and salinity is advected out of the model domain.

• A bottom stress or a no slip condition is applied at the bottom. No temperature (heat) is assumed to transfer to or from the bottom.

• A wind stress and appropriate heat transfer terms are applied at the surface.

• The surface heat balance includes all of the primary heat transfer mechanisms for environmental interaction. These include evaporative and sensible heat exchange with the air just above the water surface, and long wave radiation exchange between the water surface and the sky, and net short wave solar radiation between the loss due to reflection and the gain due to absorption at the water surface.

There are a number of options for specification of vertical eddy viscosity, Av, (for momentum) and vertical eddy diffusivity, Dr, (for constituent mass [temperature and salinity]). The simplest formulation is that both are constant, A,. and Do, throughout the water column. They can also be functions of the local Richardson number, which, in turn, is a function of the vertical density gradient and vertical gradient of horizontal velocity. A more complex formulation adds the dependence on mixing length and turbulent energy.

Details can be found in Appendix C.

The set of governing equations with dependent and independent variables transformed from spherical to curvilinear coordinates, in concert with the boundary conditions, is solved by a semi-implicit, split mode finite difference procedure (Swanson, 1986). The equations of motion are vertically integrated and, through simple algebraic manipulation, are recast in terms of a single Helmholtz equation in surface elevation. This equation is solved using a sparse matrix solution technique to predict the spatial distribution of surface elevation for each grid.

The vertically averaged velocity is then determined explicitly using the momentum equation.

This step constitutes the external or vertically averaged mode. Deviations of the velocity field from this vertically averaged value are then calculated, using a tridiagonal matrix technique. The deviations are added to the vertically averaged values to obtain the vertical 26

profile of velocity at each grid cell thereby generating the complete current patterns. This constitutes the internal mode. The methodology allows time steps based on the advective, rather than the gravity, wave speed as in conventional explicit finite difference methods, and therefore results in a computationally efficient solution procedure (Swanson, 1986; Swanson et al., 1989; Muin, 1993).

The environmental heat transfer model at the water surface contains a balance of the important terms governing the flow of heat including:

• short wave solar radiation

• long wave atmospheric radiation

• long wave radiation emitted from the water surface

• convection (sensible) heat transfer between water and air

• evaporation (latent) heat transfer between water and air A detailed description of the equations used for the environmental heat transfer model is given in Appendix D.

4.2 WQMAP System ASA personnel have developed and applied many computer modeling tools. In conducting aquatic environmental analyses we have developed a PC-based system, which integrates geographic information (land use, watersheds, etc.), environmental data (water quality parameters, surface elevations and velocities, stream flows, bathymetry, etc.) and models (analytical and numerical, hydrodynamic, pollutant transport, etc.). The power of such a system, called WQMAP (Water Quality Mapping and Analysis Program) (Mendelsohn, et al., 1995), is that it allows the user to model conditions and analyze alternatives to determine the optimal solution to a particular problem. A graphical user interface simplifies user inputs and allows a graphical display of model output. In addition, one of the modeling components within ASA's WQMAP has been specifically developed for application to the study of thermal effluents in coastal waters. More details on WQMAP can be found in Appendix E.

The geographic information component of WQMAP holds user-specified layers of data appropriate for the task. For instance, in this project such layers might include shorelines, intake locations, thermal diffusers or canals, monitoring data locations, etc. Each data layer can be easily input, either directly into WQMAP with a mouse and screen forms or through import from existing geographic information systems such as ARC/INFO, MAPINFO or AUTOCAD. Data can be exported as well. Each layer can be displayed separately or in any combination. Graphics can be generated and sent directly to a printer (color or black and white) or stored for later use in a computer driven slide show.

The environmental data component of WQMAP stores and displays actual environmental data, which are needed for analysis or used in model input or calibration. This component links to standard PC software such as databases, spreadsheets, and data contouring packages.

Importing to and exporting from other systems is also possible.

A suite of tools in WQMAP can be used to import, export and manipulate environmental data. Time series of data at single or multiple stations can be imported, processed and 27

displayed. Other measuring systems (e.g., moored current meters, sea surface radars, acoustic Doppler current profilers) can also be accessed and provided into the model.

Another feature of WQMAP is its display capabilities. Color or black and white hard copies of any geographic, environmental, or model data screen display can be made. In addition, WQMAP is a powerful tool to inform audiences, both lay and technical, about project goals, methodology, and results. WQMAP is typically installed on Pentium class PCs and can be used to drive large screen monitors (for small audiences) or projector displays (for larger audiences).

4.3 Application to the Vernon Pool 4.3.1 Grid Generation The first step in generating a grid is to define the study area of interest, e.g., the Vernon Pool in the Connecticut River above the Vernon Dam. Experience with previous model applications suggests that open boundaries should ideally be located away the specific area of interest at natural constrictions, since there will be no significant lateral variability. This principle suggests that the model boundaries be located at the Vernon Dam and Bellows Falls (Figure 4-1).

The WQGRID component of WQMAP consists of a set of tools to generate a boundary fitted grid. The grid is specified by locating grid points along shorelines and bathymetric features.

Each point has assigned grid counters to keep track of how each grid point relates to its neighbors. The grid spacing in the domain is roughly determined by grid spacing at land boundaries. Finer grid resolution is specified for increased flow resolution of the thermal discharge from Vermont Yankee. Once the boundary grid points along the shoreline have been specified, and any interior bathymetric feature grid points located, the gridding model generates all the remaining interior points. These points are constrained to obey a Poisson equation and their locations are solved iteratively by a Poisson solver. Technical details can be found in the WQMAP User's Manual (ASA, 1996).

Figure 4-1 shows the model grid. Here the full grid covers a 42 km (26 mile) extent of the Connecticut River known as the Vernon Pool, with a total of 3131 water grid cells in each of 11 layers. The grid is finer (20 m x 20 m [65 ft x 65 ft]) in the area near the Vermont Yankee discharge to better resolve the circulation and thermal plume. The grid upstream from the lower Vernon Pool is purposely coarse to minimize the model computations required yet still provide accurate downstream predictions.

In general the grid aspect ratio reflects a prioriestimates of expected flows. This means that the longer grid dimension, if any, is oriented along the major axis of the flow. This approach is necessary because the hydrodynamic model has inherent time step restrictions based on the ratio of grid size to flow speed. Faster model runs are possible when the grid is optimized in this manner.

The 11-layer grid covers the entire modeled area, regardless of the pool depth. In shallow areas, the local cell thicknesses are smaller (thinner), while in deeper areas the local cell 28

thicknesses are larger (thicker). The local cell thickness is always 1/11 of the local water depth. The advantage of this type of approach is that, regardless of the water depth, the model effectively resolves the vertical structure finely with I1 layers given the relatively shallow depth of the River in Vernon Pool. This can be contrasted with models that are limited to constant local cell thicknesses (i.e., 1 m [3 ft] everywhere) resulting in lower resolution in shallow areas.

29

Figure 4-1. Model grid for the Vernon Pool study area: Blue shaded cells represent downstream boundary and green shaded cells represent intake, discharge and upstream river boundary.

30

4.3.2 Bathymetry A depth value must be assigned to each cell in the model grid. Two methods were combined to create the array of grid depths. First, the bathymetric soundings from a field study conducted by Normandeau in June 2002 with associated latitude and longitude for the area were combined into a digital data set. Each grid cell was automatically assigned a depth value by interpolation from the data based on a distance-weighting algorithm for soundings close to the grid location. Once the bathymetric measurements were applied, the WQGRID result was generated.

The second method to assign depths is based on the experience of the modeler to more accurately specify depths. Tools from WQGRID were used to select individual cells or groups of cells and specify depth values. This procedure is necessary to accurately represent bathymetry in an area where the automatic interpolation may not capture the actual depth or no data is available, for example just upstream of the Vernon Dam.

Figure 4-2 shows a plan view of the resulting model bathymetry in the lower Vernon Pool.

Most immediately noticed is the deep water-depth along the river axis (- 5 m [16 ft]),

becoming deeper approaching the Vernon Dam (-412 m [40 ft]). Also seen is a somewhat deeper area near the intake. These are important features controlling the flow in the area.

Another notable feature is the shallow, relatively flat area in the eastern portion of the Pool.

4.3.3 Boundary Conditions There are three steps involved in any thermal dispersion modeling study: calibration, confirmation and simulations. The 11-layer, 3-dimensional boundary fitted hydrodynamic model (BFHYDRO) employed to determine the circulation and thermal distribution requires a set of boundary forcing conditions for each step. River flow, surface elevation and winds are major forcing functions important in driving the circulation, and solar radiation and auxiliary parameters such as air and dew temperature, relative humidity and pressure play an important role in determining the thermal field.

The model calibration was conducted for August 2002, while the confirmation was performed for late June and July 2002. For the modeling, flow observed at Vernon Dam and temperature at upstream station 7 was specified at the upstream river boundary. All the data were collected at hourly intervals (as described in Section 3). This section documents boundary forcings including river flow and temperature, environmental conditions and plant operations, required for model simulations each period.

It was assumed that the discharge from the Bellows Falls Dam, upstream of the Vernon Pool, is well-mixed, an appropriate assumption given that water passing through hydroelectric facilities is well mixed as is confirmed by the Vernon Dam tailrace temperature data. Thus the upstream boundary condition should have no significant vertical structure, except that atmospheric heat transfer can and does cause periodic stratification of the water column as the water moves downstream through the Vernon Pool. The Station 7 temperature is indicative of the well-mixed water column Bellows Fall Dam discharge, since it is less affected by diel atmospheric effects due to its depth. These assumptions were corroborated during the model calibration process.

31

Figure 4-2. Model bathymetry of the lower area of the study domain.

4.3.3.1 Model Calibration and Confirmation Two periods were chosen for the model calibration and confirmation, based on warm environmental conditions with low river flow (calibration) and fishway operation (confirmation). The calibration period extended from 1 through 24 August when air temperature was in general warmer than any other month and river temperatures were warmest. The confirmation period extended from 25 June to 9 July, which was the latter portion of the fishway operation period (mid May through early July) to capture the time of warmest river temperatures.

Figures A40 through A48 show environmental conditions for the August period, including two major heat-flux parameters (air temperature and solar radiation). Mean air temperature for the August period was O.80 C (1.4°F) warmer than the second warmest month (July), and ranged from 8 (46°F) to 35TC (95°F) (Figures A43 - A45). Diurnal variations were apparent 32

during the period, showing a maximum range of 19.4AC (35°F) on 9 August. Temperature at night occasionally dropped to 100 C (500F). Solar radiation was almost constant during the period, except when more cloud coverage occurred on 20 and 24 August, with maximum radiation lower by about 240 W/ m2 than the peak radiation.

Figures B29 through B34 shows atmospheric forcing parameters for the June-July period. Air temperature varied between 9VC (48 0F) and 34TC (93 0F) showing a mean temperature of 23TC (73 0 F). Diurnal variation of the temperature was similar as that in the August period.

Solar radiation was also the same magnitude as the August period.

River environmental conditions were quite different for these two periods, however. Figures A35-A36 and Figures B23-B24 present river flow and upstream and downstream water temperatures. The flow for the August period was relatively low at 50 m3/s (1,766 ft3/s) with occasional high flows as large as 200 m3 /s (7.063 ft3/s), whereas the flow for the June-July period was greater than 200 m/s (7.063 ft/s) for most of the period. Mean flows were 66 m3 /s (2,317 ft/s) and 266 m3/s (9,394 ft3/s) for the August and June-July periods, respectively.

Based on information presented in the Demonstration (Table 3-1, page 7), August median flow at North Walpole is about 106 m3/s (3,735 ft3/s) while the 9 5 1h percentile flow (August flow that exceeds this flow 95% of the time) is 51 m3/s (1,797 ft3/s). Flows during the August modeling period were therefore substantially below "normal", but well within the historic range. The average flow during the August modeling period has an exceedance value of about 85% and that the lowest flow (50 m3/s) would be expected to be exceeded more than 95% of the time. Similarly, based on Table 3-1, the median flow during the June/July modeling was about 167 m3/s (5,900 ft3/s). The 95 th percentile flow is expected to be about 79 m3/s (2,800 ft3/s) during the same period. This means that average flow during the modeling period was considerably higher than historic median flow (-25% exceedance value), but still well within historic ranges. The minimum flow during this period was very low, exceeded nearly 95% of the time. Thus, flows that occurred during the time periods used for model calibration and verification were often well below historic median flows, but all were well within recorded ranges.

While the measured upstream temperature was almost constant at 25TC (77°F) for the August period, the temperature for the June-July period gradually increased from 190C (66'F) to 24TC (75'F) and finally leveled off from 6 through 9 July.

The power plant operations were also different for the periods. Figures 4-3 and 4-4 show the variation of plant discharge flow, AT and rejected heat for the August and June-July periods, respectively. In August, rejected heat was at 200 MW for the most of period, except times when the discharge flow was high with relatively high AT. The maximum flow and AT were 20 m3/s (706 ft3/s) and 1I C (20'F), respectively. For the June-July period, the plant discharge flow was constant at 20 m3/s (706 ft3/s) from 25 June to 2 July, and showed large daily variations. A similar response was seen for AT and rejected heat. AT and heat for the first six days were at 13TC (23°F) and 1,100 MW, respectively. For the rest of the period, AT 33

varied between 5'C (9°F) and 13'C (23°F), and reject heat changed between 200 MW and 1,100 MW.

Flow 30I 320 ..

10 ... ..

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug New AT 15 10 1..34..67.. 10 1 2 13 14 5

..... ....... 1 ....... 21... 4.......

I--

5

- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug Rejected Heat I Nf1f) 1000 ..................

....... 4...................

500 ....... ... ... ....... .......

lJ 1 2 3. 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug 2002 Figure 4-3. Vermont Yankee Station operations with computed rejected heat for the calibration period from 1 to 24 August 2002.

34

Flow Jun Jul Temperature Rise I-- I 5 ....... ... .....

25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul Rejected Heat 50

• o ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i. . . . . . . . . . . . . . . . . . . . . . . . . . . . !. ..

I..

0 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul 2002 Figure 4-4. Vermont Yankee Station operations with computed rejected heat for the confirmation period from 25 June to 9 July.

35

4.3.3.2 Scenario Simulations A total often scenarios were developed by Normandeau with combinations of various hypothetical Vermont Yankee Station operations and river conditions. Four scenarios were chosen for the August period, and six scenarios were selected for the June-July period.

Tables 4-1 and 4-2 summarize the scenarios. The scenarios for the August period included both a worst case (low river flow and high river temperature conditions occurring less than 1% of the time) and an average case (river flow and temperature conditions occurring 50% of the time. Both the existing permit AT of 2°F and the proposed new permit AT of 3°F were evaluated for each case (Table 4-1). The scenarios for the June-July period included both the worst and average cases plus a case where low flow and high temperature conditions occurred less than 10% of the time. Again both the existing permit AT of 2*F and the proposed new permit AT of 3°F were evaluated for each case (Table 4-2). The period of record from which 1% and 50% occurrences of low flow and high temperature were derived for both the July-August and mid-May-mid-July periods of evaluation was the most recent five year period, 1998 - 2002.

Atmospheric forcing for the scenario simulations used monthly mean values for all parameters except air temperature and solar radiation. Because the heat exchange varied dramatically over a 24-hr period due to variations in air temperature and solar radiation, typical daily profiles were determined for these parameters. Figure 4-5 shows the daily variations of air temperature and solar radiation for the August and June-July periods obtained by taking an average for each hour in the day for 30 days between 1 to 30 August, and between 15 June to 15 July, respectively. The mean air temperature for August varied between 15°C (59'F) and 27°C (81 0 F), and the radiation peaked at 765 W/m 2. Mean values used for dew temperature, pressure and relative humidity were 14.9'C (58.8'F), 999 mbar and 73%, respectively. For the June-July period, air temperature and solar radiation were 0.7'C (1.3*F) lower and 31 W/m 2 higher than those in August, respectively. All monthly mean values of the atmospheric forcing functions, as well as the mean daily variations in air temperature and solar radiation used for the modeling scenarios were based on actual data from the 1-30 August and 15 June - 15 July periods of 2002, consistent with the calibration and confirmation periods.

36

Air Temiperature 25i-20 i 0 2 4 6 8 10 12 14 16 18 20 22 24 SoWerRaedftbon 600/

~400-200-0 2 4 6 8 10 12 14 16 18 20 22 24 Figure 4-5. Typical daily variations of air temperature and solar radiation for the August and June-July periods.

37

Table 4-1. Summary of parameters for August scenarios. Vermont Yankee Temp denotes the plant dischar e temperature.

Scenario River Vermont Intake Vermont Vermont Heat Description Flow Yankee Temp Yankee Yankee Flow Temp AT In m3/S 0C °C °C MW (ft 3/s) (ft 3/s) (OF) (OF) (OF) 1%-2°F rise 36.1 3.4 26.1 37.8 11.7 168 1% occurrence of (1,275) (121) (79) (100) (21) low flow and high temperature conditions with existing permit AT of 2°F 1%-3'F rise 36.1 5.2 26.1 37.8 11.7 253 1% occurrence of (1,275) (182) (79) (100) (21) low flow and high temperature conditions with proposed new permit AT of 31F 50%-2'F rise 96.8 7.3 23.1 37.8 14.7 449 50% occurrence (3,420) (258) (73.5) (100) (26.5) of low flow and high temperature condition with existing permit AT of 20 F 50%-3'F rise 96.8 11.0 23.1 37.8 14.7 673 50% occurrence (3,420) (387) (73.5) (100) (26.5) of low flow and high temperature condition with proposed new

__permit AT of 30F 38

Table 4-2. Summary of parameters for the June -July scenarios. Vermont Yankee Temp denotes the plant discharge temperature.

Scenario River Vermont Intake Vermont Vermont Heat Description Flow Yankee Temp Yankee Yankee Flow Temp AT m3/s m /s -C 0C 0C MW (ft3/s) (ft3/s) (OF) (OF) (OF) 1%-2'F rise 45.2 3.6 (128) 23.9 37.8 13.8 208 1% occurrence of (1,660) (75.1) (100) (24.9) low flow and high temperature conditions with existing permit AT of 20 F 1%-3°F rise 45.2 5.4 (192) 23.9 37.8 13.8 323 1% occurrence of (1,660) (75.1) (100) (24.9) low flow and high temperature conditions with proposed new permit AT of 3 0F 10%-2'F rise 47.6 3.4 (120) 22.6 37.8 15.2 217 10% occurrence of (1,685) (72.6) (100) (27.4) low flow and high temperature conditions with existing permit AT of 20 F 10%-30 F rise 47.6 5.2 (184) 22.6 37.8 15.2 329 10% occurrence of (1,685) (72.6) (100) (27.4) low flow and high temperature conditions with proposed new permit AT of 3'F 50%-2°F rise 156.8 9.2 (325) 18.8 37.8 18.9 726 50% occurrence of (5,558) (65.0) (100) (34.1) low flow and high temperature conditions with existing permit AT of 20 F 50%-3'F rise 156.8 13.8 18.8 37.8 18.9 1,090 50% occurrence of (5,558) (488) (65.0) (100) (34.1) low flow and high temperature conditions with proposed new permit AT of 3°F 39

4.4 Model Calibrationand Confirmation The calibration or confirmation of numerical models is a complex process. Much literature has been published over the past few decades describing various approaches (McCutcheon et al., 1990; Hess and Bosley, 1992; Lynch and Davies, 1995). In general the calibration process is an organized procedure to select model coefficients to best match observations.

The calibration should be based on two principles (McCutcheon et al., 1990):

• the simplest model formulation should be used to solve the problem at hand, and

• the model coefficients and parameters should be uniform in space and time unless there is strong evidence in the experimental data that they should change.

The calibration procedure (McCutcheon et al., 1990) can be summarized as follows for the Vermont Yankee hydrothermal application:

• reproduce velocities and flows at selected locations by adjusting bottom friction, eddy viscosity coefficients and open/river boundary specifications.'

• reproduce temperature distributions by adjusting eddy diffusivities, flux rates to the atmosphere and the plant heat loading rates.

For the calibration application a matrix of computer runs were executed to determine the sensitivity of the model to variations in model parameters and find the set that gave the best model results in comparison with observations. The resulting hydrodynamic model parameters ultimately chosen included a quadratic bottom friction coefficient of 0.005 and a vertical eddy viscosity of 0.005 m2/s (0.0 16 ft2/s). The horizontal and vertical eddy diffusivities for temperature were 1 m2/s (3.28 ft 2/s) and 0.7x 10 m/s 9

(0.2x 10.4 ft2/s),

respectively. These are summarized in Table 4-3 indicating the range of values tested as well as a comparison to literature value ranges. The calibration process tested values over a range from at least one half to at least twice the ultimate value used. This extensive testing provided confidence that the calibration' process used the optimum set of parameters Table 4-3. Summary of model parameters used in the calibration and testing.

Parameter Units Value Range of Literature Values Used Values Tested Quadratic bottom n/a 0.005 0.0025- 0.0002-0.016* in friction coefficient 0.03 Ambrose et al. (1988)

Vertical eddy viscosity m/s 0.005 0.001-0.01 0.0-0.2 in Cole and Wells (undated)

Horizontal eddy diffusivity m2/s 1.0 0.5-2.0 0.0001 - 100 in Bowie et al. (1985)

Vertical eddy diffusivity m/s 70* 510"- 2*106 - 10' in Bowie et 10.2 al., 1985 Based on a range of Manning coefficients given as 0.01 to 0.08.

The upstream river boundary forcings used actual flow and temperature. The downstream open boundary forcing used zero relative elevation. The net surface heat fluxes were computed using observed solar radiation and other environmental parameters (air 40

temperature, dew temperature, winds and relative humidity). During the confirmation period, the computed net heat flux varied between -94 W/ m2 for a cloudy day and 88 W/ m2 for a sunny day.

These hydrodynamic and temperature parameters were selected to minimize the difference between model predictions and observations, using the qualitative and quantitative evaluation metrics described below.

The sensitivity study showed that the currents and flows were generally insensitive to bottom friction. Progressively increasing the horizontal and vertical diffusivities systematically reduced the horizontal and vertical gradients of temperature, with lower values resulting in stronger gradients and stratification. Decreasing the heat transfer coefficient increased heating in the shallow water areas, and 98% of the coefficient suggested in Thomann and Mueller (1987) was chosen for simulation.

Qualitative Comparisons The comparison of model results and observations depends on data dimensionality. For example, a time series of data collected at a particular site can be plotted together with model output to provide a visual comparison. This comparison can provide information on the suitability of the model to simulate the range of variability evident in the observations. Each process that affects the observations has a characteristic frequency or set of frequencies. The data can be filtered to remove low, mid or high frequencies, as an aid in understanding the important physical processes and their time scales. No model can simulate the entire range of frequencies since neither the forcing functions (e.g. winds) are known with sufficient precision nor is the model grid fine enough to resolve the small scales. It is often necessary to filter the observations (i.e., remove the high frequencies) when comparing to model results.

Care must be taken to avoid removing any important frequencies, however.

The most direct way to provide a qualitative comparison is to plot the model predictions and the observed data for each variable over the time of the simulation. This can be done with time series plots of the variables of interest or contour plots when looking at spatially varying patterns.

QuantitativeComparisons Quantitative comparisons are statistical measures that can be applied to the model predictions and field data sets that provide a numerical assessment of the comparison. These statistical measures can be grouped into two major components: those measures that describe an individual set of data (e.g., a time series of one variable) and those that relate the degree of difference (error) between two data sets (e.g. time series of model predictions and field observations). Individual statistical measures include the mean, standard deviation, percentiles, minimum, and maximum. The independent variable can be time, depth or distance in these data. The quantitative comparisons between data sets include relative error, root mean square error, linear regression, comparison of means and correlation coefficient.

McCutcheon et al (1990) describes these quantitative comparisons in detail and provide guidance on acceptable values. Each statistical measure is briefly discussed below.

41

Relative Mean Error (RME)

The relative error measures the difference between calculated and observed mean values and can be defined in a variety of ways. The relative mean erroris the relative difference of the means rme =- -

x where x is the mean of the observation values and c is the mean of the model-predicted or calculated values. Evaluation of this statistic over space and time can be made to provide a cumulative frequency of error (median error, percentile exceedances). The relative error is expressed as a percentage. This statistic can be unreliable for small values of the mean and does not provide information on the variability in the data but is a useful indicator for general model performance.

Error Coefficient of Variation (ECV)

The error coefficient of variation is the ratio of the root mean square error to the mean. It is defined as:

Y N and expressed as a percentage.

2 Square of Correlation Coefficient (r )

The correlation coefficient (r) relates to the linear interdependence of the predictions to observations. It is defined as the ratio of the covariance and the standard deviations of predicted and observed values.

The squared correlation coefficient is the square of r, and lies between -1 and 1. A value of zero indicates no correlation between two observations and predictions, I represents perfect.

positive correlation and -1 implies perfect negative correlation.

The U. S. EPA has published guidance on the acceptable statistical measure values for model calibration/confirmation (McCutcheon et al., 1990). Table 4-4 shows a summary of the guidance for different measures and properties. The statistical measures have been defined above and the properties include flow and temperature. There is a unique value presented for each property. McCutcheon, et al. (1990) state that these guidance values are representative of a mean level of calibration/confirmation among multiple comparisons and are not to be considered an upper limit (RME, ECV) or lower limit (ri) for individual comparisons.

42

Table 4-4. Model calibration and confirmation guidance (McCutcheon et al., 1990).

Error Measure Property Value Relative Mean Error, RME Flow 30%

Temperature 25%

Error Coefficient of Variation, ECV Flow 10%

Temperature 45%

Squared Correlation Coefficient, r2 Flow 0.88 Temperature 0.71 4.4.1 Calibration to August 2002 Period The primary focus of the calibration process is to adjust appropriate model parameters to optimize the comparison to a data set of observations. The parameters, as discussed in the previous sections, include bottom friction, horizontal and vertical dispersion, and atmospheric exchange rates. A period from 1 through 24 August was chosen for calibration because the river was in a low flow, high temperature regime.

The observed data used for the model calibration are hourly flow measurements at Vernon Dam and temperature data from the thermistor string array. Each thermistor station had three thermistors at different depths, 0.3 m (1 ft) below the surface, mid-depth and 0.3 m (I ft) off the bottom. Results of the comparison with the model predictions are presented below.

Flow Comparisons Figure 4-6 shows predicted flow at Vernon Dam (dash - dot), together with the observed flow (solid). The predicted flow is highly correlated with the observations, showing a squared correlation coefficient of 0.96. Mean values for the predictions and observations are 67 m3/s (2,366 ft3/s) and 66 m 3/s (2,331 ft3/s), respectively. The RME is 3%, the ECV is 0%

and r2 is 0.92. The model calibration results show that the model predictions of flow agree well with observations, exhibiting statistical measures with values well within U.S. EPA guidance levels of 30% for RME, 10% for ECV and 0.88 for r2.

Between predictions and observations, however, there is a time lag of 1.5 hrs, which is due to the travel time of a parcel of water between the upstream and downstream boundaries. There also exists an oscillation at a period of about 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, especially seen after a large change in flow amplitude.. The overshoots and artificial oscillations in the modeled flow predictions are typical for an under-damped system responding to step inputs. The step inputs are due to the regulated flow in the River attributable to the hydroelectric project operations, as discussed above and in Section 3.1.2 of the Demonstration. The large, almost instantaneous change in flow, often by a factor of four from 50 to 200 m3/s (1760 to 7060 ft3 /s), is sufficient to generate an overshoot response followed by a damped oscillation. The period of oscillation is approximately 5 hrs, which corresponds to the natural frequency of the Vernon Pool. Conservation of water mass is preserved during these transient events. These small variations have no appreciable effects on temperature predictions.

43

100V 50 r ~ .-

0 I L4 I L'_ _L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug 2002 Figure 4-6. Downstream flow comparison between the prediction and observations.

Temperature Comparisons Temperature comparisons between the predictions and observations are shown as time series for each of the three thermistor depths on a string. Figures 4-7 to 4-9 show the surface, middle and bottom layer temperatures for representative strings (C3, D3 and E3) located in the center of the pool from discharge to the dam. Quantitative comparisons (statistical measures) are presented for all the thermistors in Tables 4-5 through 4-7. The locations of the thermistor strings are shown in Figure 3-1. String C3 is located 278 m (910 ft) east of Vermont Yankee, and Strings D3 and E3 are located 384 m (1,258 ft) and 517 m (1,695 ft) southeast of the station, respectively.

The model predictions and observations for the surface layer at String C3 compare well for the entire simulation period (Figure 4-7), exhibiting RME of 1%, ECV of 1.9% and r 2 of 0.82 (Table 4-5). The maximum difference for the layer is 0.6°C (1. 1F) occurring on 11 August, but the mean difference is only O.3°C (0.5°F). The mid-depth temperatures agree well with the observations (0.9% RME, 2.5% ECV and 0.7 r2) except 1 - 5 August and 11 - 15 August when the observed bottom temperatures are higher than the mid-depth temperature. The bottom comparison diverges somewhat more than that for the mid-depth.

The observed temperatures at String D3 exhibit a large diurnal variation at both the surface and middle layers, but less at the bottom layer (Figure 4-8). The predictions at the surface agree well with the observations, with r2 'f 0.82, RME of 1.1% and ECV of 2.0% (Table 4-5).

However, the model slightly under predicts the mid-depth temperature for most of the period, except 14 - 16 August, showing a 0.3°C (0.5°F) difference in temperature. The model error 44

statistics for this layer are 1.3% for RME, 2.2% for ECV and 0.74 for r2 (Table 4-6). The bottom comparison is good except under predictions of peaks.

Figure 4-9 shows the temperature comparisons at String E3. The surface observations exhibit relatively large temperature peaks on 1 - 2, 4 -5 and 13 August, which are probably due to the heated flow from Vermont Yankee. The model predicts the peaks well but sometimes under predicts (8 - 9 August) or over predicts (14 - 16 August). The statistics for the layer show low RME, ECV and r2 (0.1%, 2.7% and 0.57, respectively). The predictions for the mid-depth agree well with the observations, especially predicting the long-term variation.

However, the model under predicts the temperature peaks both at mid depth and bottom. The r2 value decreases with depth. The RME values decrease from 0.8% for the middle layer to 0.5% for the bottom layer, whereas the ECV values increase from 2.6% for the mid-depth to 2.9% for the bottom.

The temperature comparisons show that the model sometimes predicts a larger amplitude of the diurnal temperature variation at the surface. This may be due to the fact that the source of air temperature data was the weather station at the Orange Municipal Airport in Orange, MA, which is 35 km (22 mi) southeast of Vermont Yankee. Although some meteorological parameters were available at Vermont Yankee, the surface heat transfer submodel of the hydrothermal model required additional meteorological parameters not measured at Vermont Yankee, so the data from Orange were used. Some differences exist in parameters from the two stations. For instance, the daily air temperature variation at Orange has an amplitude of 1 to 3°C (1.8 to 5.4°F) larger than at Vermont Yankee. From previous model applications, the surface water temperature variation is typically one-half of the air temperature variation, which would result in a amplitude 0.5 to 1.51C (0.9 to 2.71F) larger than the observations.

Thus the model calibration would have been even better using the local Vermont Yankee temperatures. In any event, the model was shown to be well calibrated, indicating the Orange data was suitable for use.

Figure 4-10 shows predicted temperatures at upstream and downstream stations 7 and 3, superimposed on the measurements. Stations 7 and 3 are located 6.4 km (4 mile) north and 1.8 km (1.1 mile) south of Vermont Yankee, respectively. Since station 7 is located far north of the plant, there should be no impact by the rejected heat from the plant. The measurements at stations 7 and 3 are used as an indicator of background water temperature and the effects of plant operation, respectively.

The predicted temperatures at station 7 agree well with the observations. The maximum difference found between the two data sets is only 0.7°C (1.3°F) occurring on 6 August (model underprediction). Temperature comparisons at station 3 also show good agreement with a maximum difference in temperature of IVC (1.8°F). This occurs on 15 August during a 6-day over prediction period (14 - 19 August). Since such an over prediction for the period is also observed at the same layers for other stations, it may be related to an under prediction of vertical stratification but is not significant.

45

C3 @surface 28 o_., *.***'*.a"........ .......

24-1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug C3 @middle 32.

3 0 - . ... .. . ... ... '

J328 24 221 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug C3 @bottom 32 -r- . I model

-data 30 ...

4. 26 22 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug Figure 4-7. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string C3.

46

D3 @surface 32 30 306 . . . . . ....

.......... _4....... i........... ....

26 1 2 43 5 6 7 8 910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug D3 @middle 3 20 .. , ! , * . ! . = . * . ! . t . ! * . = .- .- .....

& 28 E

026 24 - .... . . .. .. . . . . .. . . . . . . . ... . .

22' 1

Aug D3 @bottom 32 Aug Figure 4-8. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string D3.

47

E3 @surface Aug E3 @Middle Aug E3 @bottom Aug Figure 4-9. Comparison of observed (thick) and simulated temperatures (thin) at the surface, middle and bottom layers for string E3.

48

j*Monitor Station 7 32 Model

-Data 30 . . .. . ... . . . . . ..

. . . . .. .. .. . . . . . . .. . . .. .. : .. . .. ; .. . . . . .. . . .. .. . . . . ... . . .. . . .. .. :. . . . ...!:i . . .. . . .. . . .. . . . . . . . . ..

0628 0.

E

• . 26 24 z

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 2*4 Aug

@Monltor Station 3

• 1

___ Model

- Data 30 628 I!

24 22 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug AT

&3 E

02 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Aug Figure 4-10. Comparison of observed (thick) and simulated temperatures (thin) for monitoring stations 7 (top) and 3 (bottom).

49

The river AT can be defined as the temperature at downstream station 3 minus the temperature at upstream station 7. The predicted river AT for this period ranges between 0.5'C (0.9'F) and 3.4'C (6.1 F), whereas the measured AT varies from 0.4'C (0.7°F) to 2.9°C (5.2'F). Mean values for river AT are 1.8'C (3.2'F) and 1.5°C (2.7°F) for model and data, respectively, exhibiting only a O.3TC (0.57F) over prediction compared to the measurements.

This is mostly due to the difference existing during the over prediction period (14 - 19 August).

Quantitative comparisons for all the thermistors are summarized in Tables 4-5 to 4-7.

Parameters presented in the tables are model and data statistical measures: mean, relative mean error (RME), error coefficient of variance (ECV), and squared correlation coefficient,

?. Also presented in each table is U. S. EPA guidance levels for each statistical measure.

Tables 4-5 through 4-7 present statistics for surface-, middle- and bottom-layer temperature predictions at all 22 thermistor strings, respectively. Squared correlation coefficients for the surface temperature prediction vary from 0.46 (String F4) to 0.86 (String C2) with an average for all surface thermistors of 0.74, slightly higher than the U. S. EPA guidance level of 0.71.

RME for the surface temperature predictions ranges between 0% (String Cl) and 3.5%

(String C4) with an average of 1.1%, and ECV varies from 1.1% (String C4) to 2.9% (String D5) with an average of 2.2%. Compared to the U. S. EPA guidance levels of 25% (RME) and 45% (ECV), the RME and ECV values are much smaller, implying that the model predicts the surface temperature well. Tables 4-6 through 4-7 show similar results except that the r2 values become smaller with depth. However, excellent comparisons in terms of RME and ECV are found for these layers. Average values of RME and ECV for the middle layer are 1.5% and 2.5%, respectively, and the values for the bottom layers are 1.9% and 3.3%.

The calibration for temperatures hence is acceptable, according to the guidance levels.

50

Table 4-5. Quantitative comparisons of predicted and observed surface temperatures for the calibration period from 1 to 24 August 2002.

Thermistor Model - Mean Data 7 Mean RME ECV r2 (oc) (oc) (0) (%)

Cl 27.2 27.2 0.0 1.5 0.84 C2 27.8 27.5 1.0 1.6 0.85 C3 26.6 26.9 1.0 1.9 0.82 C4 26.6 27.6 3.5 1.1 0.86 C5 26.5 26.9 1.7 2.6 0.76 C6 26.5 26.8 1.4 2.4 0.77 DI 27.1 26.9 0.7 1.8 0.80 D2 27.0 27.0 0.1 1.6 0.79 D3 26.7 27.0 1.1 2.0 0.82 D4 26.5 27.0 2.0 2.5 0.80 D5 26.6 27.3 2.4 2.9 0.81 D6 26.6 27.1 1.9 2.6 0.78 El 27.0 27.0 0.1 1.9 0.77 E2 27.0 27.0 0.1 1.9 0.77 E3 26.7 26.7 0.1 2.7 0.57 E4 26.7 27.0 1.0 2.4 0.72 E5 26.7 27.3 2.1 2.8 0.80 E6 26.7 27.2 1.7 2.8 0.74 Fl 26.1 26.3 0.8 2.6 0.61 F2 26.1 26.3 0.8 2.6 0.61 F3 26.1 26.3 0.7 2.7 0.58 F4 26.1 25.9 0.6 2.3 0.46 Average 1.1 2.2 0.74 Guidance 25 45 0.71 51

Table 4-6. Quantitative comparisons of predicted and observed temperatures at the middle layer for the calibration period from 1 to 24 August 2002.

Thermist Model - Mean Data - Mean RME ECV r, or (C) (%) (%)

C1 27.0 26.6 1.4 2.9 0.57 C2 27.6 27.1 2.0 2.7 0.72 C3 26.0 25.8 0.9 2.5 0.70 C4 26.0 26.2 0.6 1.8 0.76 C5 26.2 26.6 1.3 2.2 0.77 C6 26.2 26.6 1.6 2.4 0.77 D1 26.8 26.1 2.9 4.2 0.33 D2 26.8 27.5 2.5 1.0 0.59 D3 26.5 26.8 1.3 2.2 0.74 D4 26.3 27.5 4.3 1.2 0.69.

D5 26.0 26.2 0.6 2.9 0.47 D6 26.0 26.2 0.4 2.9 0.47 El 26.5 26.1 1.5 3.2 0.43 E2 26.5 26.1 1.5 3.2 0.43 E3 26.3 26.5 0.8 2.6 0.52 E4 26.3 26.4 0.6 2.6 0.52 E5 26.7 27.1 1.6 2.6 0.76 E6 26.7 27.1 1.4 2.7 0.72 F1 25.6 26.1 2.0 2.6 0.73 F2 25.6 26.0 1.7 2.4 0.73 F3 25.4 25.5 0.4 1.8 0.67 F4 25.4 25.1 1.2 1.5 0.27 Average 1.5 2.5 0.61 Guidance 25 45 0.71 52.

Table 4-7. Quantitative comparisons of the predicted and observed bottom temperatures for the calibration period from I to 24 August 2002.

Thermistor Model - Mean Data - RME ECV (jC) Mean ('C) (%) M%)

Cl 26.5 25.3 4.8 5.6 0.36 C2 27.2 25.8 5.6 6.0 0.42 C3 25.9 25.8 0.4 2.5 0.49 C4 26.6 26.0 2.4 2.9 0.66 C5 25.7 25.5 0.6 2.3 0.60 C6 25.7 25.5 0.9 2.4 0.59 DI 26.6 25.5 4.4 5.3 0.39 D2 26.6 25.5 4.5 5.4 0.39 D3 26.1 26.1 0.0 2.4 0.55 D4 26.9 26.8 0.5 2.0 0.40 D5 25.9 25.4 1.9 4.0 0.26 D6 25.9 25.3 2.2 4.0 0.34 El 26.4 25.7 2.5 3.7 0.45 E2 26.4 25.7 2.5 3.8 0.44 E3 26.1 26.0 0.5 2.9 0.41 E4 26.1 25.9 0.6 2.9 0.41 E5 26.1 26.8 2.8 3.7 0.63 E6 26.1 26.8 2.7 3.6 0.68 Fl 25.3 25.5 1.1 1.9 0.73 F2 25.3 25.5 1.0 1.9 0.72 F3 25.2 25.1 0.5 1.8 0.62 F4 24.7 24.6 0.3 1.9 0.23 Average 1.9 3.3 0.49 Guidance 1 25 45 0.71 4.4.2 Confirmation to June - July 2002 Period The primary focus of the confirmation process is to compare the model predictions with observations for a different period, keeping the model coefficients the same as that arrived at during the calibration process. The model predicted flows across the Vernon Dam and the predicted temperatures at all stations were compared with the observed data. Quantitative evaluation of the model predictions with the observations are given in terms of the RME, ECV and r2 , as was done for the calibration period results.

Flow Comparisons The model-predicted flows through the Vernon Dam compare well with the observations as shown in Figure 4-11. The correlation for the flows is high (r2 of 0.99). The mean value of observations and predictions are 266 m3/s (9,394 ft3 /s) and 273 m3/s (9,641 ft3/s),

respectively. The RME and ECV are 2.5% and 3.6%, respectively, lower than U. S. EPA guidance levels of 30% and 10%. The r2 is 0.98, above the U.S. EPA guidance level of 0.88, implying that the prediction is successful.

53

26 27 28 29 30 1 Jul 2002 Figure 4-11. Comparison of the observed (thick) and predicted flows (thin-dashed) across the Vernon Dam.

Temperature Comparisons Figure 4-12 through 4-14 shows comparisons of temperature predictions and observation at Strings C3, D5 and El respectively. The observed temperatures at String C3 show little variations with depth, except on 4 June when the surface temperature appears high. The model predicts the temperatures well for all three layers, exhibiting high correlation coefficients (r2 ) of 0.80, 0.94 and 0.95 for the surface, middle and bottom layers, respectively (see Tables 4-8, 4-9 and 4-10). RME and ECV values for the surface comparison are 2.2%

and 4.1%, respectively. The values are somewhat lower for the two deep layers (see Tables 4-9 and 4-10). At String D5 located 298 m (979 ft) southwest of String C3, observed surface temperature exhibits a strong diurnal variation, which does not exist at String C3. The model predicts the variation and also the long-term trend well. As the diurnal variation diminishes in the observations, the model still predicts the variation persistently, but the predicted amplitude is smaller with depth. Squared correlation coefficients, r1, are 0.89 for the surface layer (Table 4-8), 0.87 for the middle layer (Table 4-9) and 0.89 for the bottom layer (Table 4-10). RME and ECV values are smaller with depth, 1.4% and 3.2% for the surface layer, respectively. Good comparisons are found for all three layers at String El, showing r 2 values of 0.89, 0.92 and 0.91 for the surface, middle and bottom layers, respectively.

54

The statistical evaluations of the model predictions are summarized in Tables 4-8 through 4-

10. For the surface temperature, RME values for all strings are less than 4.5% (String E2),

with an average of 1.89%. Range for the ECV values is between 2.6% (String Dl) and 8.1%

(String Fl), showing an average of 4.2%. Both the RME and ECV are much lower than U. S.

EPA guidance levels of 25% and 45%, respectively. The lowest r2 of 0.66 is found to occur at String Fl and for all other stations r2 is higher than U. S. EPA guidance level of 0.71. The model predictions show excellent comparison with observations. Tables 4-9 and 4-10 show the statistical evaluation of the model temperature predictions at mid-depth and bottom, respectively. The model predicted temperatures show excellent comparisons, with the r2 exceeding 0.71 at all stations, except at String Fl. Average RME values for the two layers are 1.6% and 2.7%, respectively, lower than 25% U. S. EPA guidance level. The ECV comparison shows a similar result with the RME. The average r? values were 0.87 and 0.91 for the lower layers, better (larger) than the guidance level of 0.71. Therefore, the model temperature predictions are acceptable, based on the statistical measures.

Figure 4-15 shows a comparison of the model predictions for the fishway temperature with the observations. The model predicts temperatures well for the first three days and for the second half of the simulation period (1 - 9 July), exhibiting an r 2 of 0.86, comparing well to the U. S. EPA guidance of 0.71. The model, however, under predicts temperatures by 1.50C (3.2°F) on average for the period between 28 and 30 June, when the river flooded (see Figure B-23). Mean predicted temperature is 0. IC (0.2 0F) larger than the observed mean (23.8°C

[74.8 0F]). RME and ECV values between model predictions and observations are only 0.67%

and 3.15%. These are smaller than the 25% and 45% U. S. EPA guidance levels, respectively, suggesting that the predictions are very good.

55

• 'JP'I C3 @surface 30 28 E

18L 25 26 27 28 29 30 1 2 3 4 5 6 7 8 Jun Jul C3 @middle 32 30 I I...... .II.. I.

28 o 26 4"24 22 20 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul C3 @bottom iA . .

[ model 30 - data 28 - ....

26-E 4) 22 - i. . .. . . .......... ...... ...

20 , I , b , I , I , l , i ,

25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul Figure 4.12 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station C3.

56

D5 @surface o 26 E.

Ee 24 I--

18 L 1 1 1.-.-. I1 .- 1 ' 1 ' 1 - 1 - 1 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul D5 @middle 30 30 .. ..... ..... I  !

28 - ........

03.

E 0.

24 0 ................! ...........................

i.............. -

26 -

25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul D5 @bottom 32 ii - model-30 ....... ... a............a...

28 c 26 E 24 22 ....... . ....... .. . ...

20 i i L i i i i i i I i I i i I i I I i i i i rl

• i i i i i 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul Figure 4.13 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station D5.

57

El @surface 32 30 28 oO 26 a-E 24 ......... . . I 22 20 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul El @middle 32 30 ............

28 ............... ...

o 26 E 24 22 20 . .... . . . ..

22i . I 33 . I 4 5I I 66 I 7I . 8I 182255 26I 27 , 28 2I , 29I 303I 1I 1 9

Jun Jul El @bottom 32 model 30 -data 28

. . . ... * . . . . . . . . . . . . . . . .... . .i........ . . .. . . . . . .i. . .... ... . . . . . . ... . ....

........ *. . . . . d t 26 E 24 22 20 182 I I I I 2I I 1 I I I 3 5 9 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 Jun Jul Figure 4.14 Comparison of the observed (thick line) and predicted (thin-dashed) temperatures at the surface, mid and bottom layers at station El.

58

Table 4-8. Quantitative comparisons of the predicted and observed temperatures at the surface layer for the confirmation period from 25 June to 9 July 2002.

Thermistor Model - Mean Data - Mean RME ECV r2 i(oc) (oC) (%) (%)

Cl 24.1 23.9 1.0 3.6 0.89 C2 24.1 23.8 1.1 3.4 0.89 C3 23.4 22.9 2.2 4.1 0.80 C4 23.4 23.0 1.7 3.7 0.81 C5 23.4 22.9 2.3 4.3 0.77 C6 23.4 .22.8 2.8 4.6 0.77 D1 24.3 24.3 0.3 2.6 0.77 D2 24.3 24.0 1.6 3.1 0.78 D3 23.1 23.7 2.4 4.3 0.89 D4 23.1 23.6 2.4 4.1 0.90 D5 23.5 23.8 1.4 3.2 0.89 D6 23.5 23.4 0.6 3.3 0.85 El 24.3 23.9 1.5 2.9 0.89 E2 24.3 23.2 4.5 5.9 0.81 E3 23.6 24.3 3.0 3.9 0.87 E4 23.6 24.3 2.9 4.0 0.86 ES 23.7 24.1 1.6 4.1 0.81 E6 23.7 23.9 0.8 4.0 0.81 Fl 23.1 23.7 0.5 8.1 0.80 F2 23.1 22.6 2.3 4.6 0.71 F3 23.1 22.7 1.8 4.3 0.73 F4 23.1 22.4 2.9 5.2 0.66 Average 1.9 4.2 0.82 Guidance 1 25 45 0.71 59

Table 4-9. Quantitative comparisons of the predicted and observed temperatures at the middle depth for the confirmation period from 25 June to 9 July 2002. N/A stands for no data available.

Thermistor Model - Mean Data - Mean RME ECV (oc) (OC) (%) (%

C1 23.6 23.3 1.0 3.1 0.90 C2 23.6 23.4 0.7 2.9 0.91 C3 22.2 22.6 1.7 2.4 0.94 C4 22.2 22.5 1.2 2.2 0.94 C5 23.1 22.6 2.1 3.9 0.80 C6 23.1 22.7 1.8 3.7 0.80 D1 24.0 23.1 3.9 4.8 0.83 D2 24.0 23.0 4.2 5.0 0.83 D3 22.8 N/A N/A N/A N/A D4 22.8 23.3 2.3 3.8 0.90 D5 22.6 22.8 1.2 2.9 0.87 D6 22.6 22.8 1.0 2.8 0.87 El 23.3 23.0 1.7 2.8 0.92 E2 23.3 22.9 1.9 3.3 0.90 E3 22.7 N/A N/A N/A N/A E4 22.7 N/A N/A N/A N/A E5 23.7 24.0 1.1 4.0 0.82 E6 23.7 23.9 0.5 4.0 0.81 F1 22.8 22.6 0.9 3.5 0.77 F2 22.3 22.5 1.0 2.5 0.88 F3 22.2 22.3 1.9 2.6 0.94 F4 22.2 22.4 1.0 2.4. 0.94 Average 1.6 3.3 0.87 Guidance 1 1 25 45 0.71 60

Table 4-10 Quantitative comparisons of the predicted and observed temperatures at the bottom layer for the confirmation period from 25 June to 9 July 2002.

Thermistor Model - Mean Data - Mean RME ECV r, (OC) (2c) 2.0 24.

C1 22.5 22.4 0.6 2.4 0.92 C2 22.5 22.4 0.6 2.4 0.92 C3 22.0 22.4 1.7 2.4 0.95 C4 22.0 22.3 1.7 2.3 0.95 C5 22.2 22.5 1.3 2.2 0.93 C6 22.2 22.4 0.8 2.0 0.93 D1 23.3 22.5 3.2 3.8 0.91 D2 23.3 22.5 3.3 3.9 0.91 D3 22.3 22.7 1.9 2.9 0.91 D4 22.3 22.7 1.7 2.8 0.91 D5 22.3 22.6 1.1 2.5 0.89 D6 22.3 22.3 0.0 2.4 0.88 El 23.2 22.6 2.3 3.1 0.91 E2 23.2 21.5 7.6 7.9 0.91 E3 22.3 23.4 4.6 5.4 0.84 E4 22.3 23.4 4.6 5.4 0.86 E5 22.7 23.9 5.3 6.6 0.86 E6 22.7 23.7 4.5 5.9 0.88 F1 21.9 22.5 2.8 3.2 0.94 F2 21.7 22.5 3.2 3.5 0.94 F3 21.6 22.4 3.4 3.8 0.94 F4 21.6 22.4 3.5 3.9 0.94 Average 2.7 3.7 0.91 Guidance 25 45 0.71 61

Temperatures @Fishway Jun Jul Figure 4-15. Comparison of predicted and observed temperatures at the fishway during the confirmation period.

4.4.3 Discussion Model results were compared to water temperature and river flow data for two different periods to provide model calibration and confirmation. The August 2002 period served as the model calibration period and the June 2002 period served as the model confirmation period. Both calibration and confirmation of the model were successful, particularly when compared to target EPA guidance values for statistical measures as shown in Table 4-11.

62

Table 4-11. Vernon Pool hydrothermal model calibration and confirmation evaluation in comparison with EPA guidance (McCutcheon at al., 1990)

Error Measure Property Guidance Calibration Confirmation Value Relative Mean Flow 30% 3.0 2.5 Error, RME Temperature (avg) 25% 1.1 1.9 Error Coefficient Flow 10% 0 3.6 of Variation, ECV Temperature (avg) 45% 2.2 4.2 Squared Flow 0.88 0.92 0.98 Correlation Coefficient, r2 Temperature (avg) 0.71 0.74 0.82 The calibration period was characterized by relatively low flow rates and high water temperatures. A number of model parameters, including bottom friction, horizontal and vertical dispersion, and atmospheric exchange rates, were adjusted to provide an optimal comparison to the observational data. Predicted flow rates for the calibration period compare very well to observational data. Predicted and observed flows are highly correlated, with statistical measures of correlation well within the target guidance levels provided by the U.S.

EPA. Further, small differences between predicted and observed flows, where they occurred, can largely be attributed to two factors. First, there is a time lag of 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> between the predicted and observed flows, which is due to the travel time for water between the upstream and downstream boundaries. Second, there is an expected oscillation in the model predictions with a period of approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> following large changes in flow amplitude, as a result of resonance at the natural frequency of the Vernon Pool. Neither of these differences effect overall calibration.

Predicted and observed temperatures also compare verywell overall for the calibration period. The comparison is generally slightly better for the surface layers than for the bottom layers, where the model tends to attenuate higher frequency temperature variations (e.g., diel variations). One source of disagreement between predictions and observations may be the occasional underprediction of vertical stratification. In general, however, the temperatures throughout the study area compare very well with target guidance criteria as set forth by the U.S. EPA.

The June 2002 period, which featured high flows and low temperatures relative to the August calibration period, served as the model confirmation period. Model parameters were set at the values determined for the calibration period. Comparison of model predictions to observations for this period therefore provides an independent check on the validity of parameter values chosen for this system. Overall, predicted values of flow and temperature 63

compare very well with observations for the confirmation period. This may be due to the fact that the overall thermal pattern is more uniform during the June period, and flow rates are higher, with somewhat less abrupt variations, producing less overall variability in the system.

64

5. Thermal Plume Simulations A total of ten scenarios were analyzed, four during the August warm river temperature, low flow period (Table 4-1) and six during the June-July fishway operation period (Table 4-2).

Each simulation was run for seven days in order to bring the system to a quasi-steady state, which started on the third simulation day. Boundary forcings and environmental conditions used for the simulations were described in Section 4.3.3.2. This section presents results of the ten scenario simulations: four August scenarios (Table 4-1) and six June-July scenarios (Table 4-2).

Figures 5-1 to 5-3 show plan views of the predicted thermal fields at the surface, middle and bottom layers, respectively, in the lower Vernon Pool for one of the August scenarios, 50%-

3°F rise (which had the highest thermal load) as an example of the three dimensional nature of the predicted thermal distribution. Temperature contours are color coded in 0.5 'C (0.9°F) increments as shown in the left portion of the figures. The contours show a maximum near the Vermont Yankee discharge with the plume of elevated temperatures attached to the western shore in all figures. The surface temperatures (Figure 5-1) are warmest, both in the plume and upstream of Vermont Yankee. The thermal plume is in a concentric elliptic shape, having larger extent downstream. The middle-layer temperatures (Figure 5-2) show a similar temperature at the center of plume as the surface layer, but the plume is smaller in size. The bottom temperatures (Figure 5-3) are coolest and show the smallest plume size.

20., 205 2(15. 21 21, 215 2.5 1 22 22, 275 2751 20 2301215 O[25 205 24 20,5 25 25, 255 Figure 5-1. Predicted surface temperature distribution for August scenario 50%-30 F.

65

0 20ft . .

Figure 5-2. Predicted middle-layer temperature distribution for August scenario 50%-

30 F.

Figure 5-3. Predicted bottom-layer temperature distribution for August scenario 50%-

3 0 F.

To compare the effects of the thermally impacted area for the different scenarios, the model output was post-processed to compute water volume and bottom area coverage for different temperatures. This analysis was performed for the lower Vernon Pool, since there was no 66

thermal impact north of the plant. Figure 5-4 shows the model grid cells used for the analysis.

The total bottom area and water column volume based on these grid cells are 1.3x 106 m2 (14x10 6 ft2) and 5.5x10 6 m3 (194x>10 6 ft 3), respectively.

Figure 5-5 shows the mean bottom area coverage as a function of temperature for all four August (low river flow and high river temperature) scenarios. The mean is calculated over a daily cycle. The figure shows total bottom area (y-axis) that equals or exceeds a given temperature (x-axis). Thus at low temperatures (e.g. 221C) 100% of the bottom area exceeds this temperature. At high temperatures (e.g. 35°C) 0% of the bottom area exceeds this temperature. The results show that the mean bottom areas for scenarios 50%-2°F rise and 50%-3 0 F rise, with the highest river flow and lowest river temperature, begin to drop below 100% between 22 and 23°C, drop rapidly to 13 and 16 % of the bottom area exceeding 23.5°C for both the scenarios, and then gradually drop further to below 1% of the area above 27°C. The largest area and volume coverages occur for scenario 1%-3°F rise, although the rejected heat (253 MW) is about 40% smaller than scenario 50%-30 F rise (673 MW). Both scenario 1%-2 0 F rise and 1%-3 0F rise have the same background conditions and same Vermont Yankee discharge temperature rise (3.9°C [1 1.7°F]), except the 1%-2°F rise scenario has a higher discharge volume (5.2 m 3/s [182 ft3 /s] compared to 3.4 m 3/s [121 ft3/s]

for the 1%-3°F rise scenario). Similarly, the 50%-3°F rise scenario discharges more heated water volume by 4.6 m3/s (162 ft3/s) than 50%-2°F rise scenario. Figure 5-5 indicates that the higher discharge flow scenarios result in higher bottom area coverage.

67

Figure 5-4. Model grid area (shaded in purple) used for the computation of the thermally effected area.

Figures 5-6 shows the mean water column volume coverage as a function of temperature for the four production August scenarios. The results are similar to those for bottom area with the relative position of each scenario in the figure the same.

68

Mean Bottom Area Coverage 2

(Total Area - 1,312,W99 mn )

100 1 90 80 70 80 40 30 20 10 0 II I I >

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Temperature (CC Figure 5-5. Mean percent bottom area coverages versus temperature for the four August scenarios.

Mean Volume Coverage (Total Volume - 5,483,801 m) 100T 90 80 70 60 a

150 40 30 20 10 01..... .......

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 0

Temperature ( C Figure 5-6. Mean percent water column volume coverages versus temperature for the four August scenarios.

69

Figures 5-1 through 5-3 show the model-predicted plume at different layers taken at 11:30 AM to illustrate the horizontal and vertical distribution of temperature. The data presented in Figures 5-5 and 5-6 represent averages computed over a 24-hr period. The peak temperature values in each layer occur at different times during the day, with deeper layers in the water column lagging behind the surface layers by several hours. Figures 5-7 and 5-8 show the peak bottom area coverage and peak volume coverage, respectively, as functions of temperature for all four August (low river flow and high river temperature) scenarios. It is seen that there are only minor differences compared to the mean coverages presented in Figures 5-5 and 5-6.

Max Bottom Area Coverage (Total Area = 1,312,899 M2 )

100 80

• 50 40 30 20 10 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Temperature (*C)

Figure 5-7 Maximum percent bottom area coverages versus temperature for the four August scenarios.

70

Max Volume Coverage (Total Volume = 5,483,801 m3) 100 90 80 70 60 50 40 30 20 10 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Temperature (CC)

Figure 5.8 Maximum percent volume coverages versus temperature for the four August scenarios.

Another comparative measure of the scenarios is the amount of time that the mean fishway temperature at the Vernon Dam exceeds a specified temperature. Figure 5-9 shows percent time coverages of the mean surface-layer temperature at the fishway for the six June-July scenarios (Table 4-2). The temperatures were calculated as the mean value of the predictions for the top three layers (layers 11 to 9) of the western-most model cell located at the fishway.

Because of its high ambient water temperature (23.9°C [75.1 'F]), the scenario 1% -3°F rise shows the largest impact on the fishway temperature, exhibiting 100% at 23TC (73.4°F) and 0% at 24.80 C (76.6 0 F), and scenario 10% -3'F rise shows the least effect, dropping from 100% at 20.8°C (69.4°F) to 0% at 22.2°C (72.0°F). A I°F increase in temperature rise results in the same time coverages but at 0.40 C (0.7°F) higher temperatures. The scenario 1%-2 0F rise showed 100% time coverage for temperatures less than 22.6'C (72.7°F), 50% coverage at 23.3°C (73.9 0F), and 0% coverage for temperatures greater than 24.40 C (75.9°F), whereas the scenario 1%-3°F rise exhibited 100% coverage for temperatures less than 23°C (73.4 0 F), 50%

coverage at 23.6°C (74.5°F), and 0% coverage for temperatures greater than 24.8°C (76.6 0 F).

A similar variation in coverage was observed for the 10% occurrence set and the 50%

occurrence set.

The temperature increase due to a IF rise in the permit limit was constant at 0.4°C (0.7°F) for the 1% and 10% scenarios. However, for the 50% scenario the temperature increase was generally somewhat larger, ranging between 0.43°C (0.77°F) and 0.550 C (1IF).

71

Percent Time Coverage of Mean Temperature at Fishway 100-w*A 80 707 60 --- 1%3 60 go 50 20 16 16 17 l8 19 20 21 22 23 24 25 26 27 28 29 30 Temperature (@0)

Fig ure 5-9. Percent time coverages of mean surface-layer temper ature at the fishway.

72

6. Conclusions A state-of-the-art, boundary-fitted, three-dimensional hydrothermal model was applied to the Vernon Pool on the Connecticut River to investigate the effects of the discharge from Vermont Yankee on the temperature distribution in the lower portion of the Pool. The model was calibrated and confirmed to data collected from a set of continuous monitoring thermistors as part of a field program from May through October 2002. The data also included river flows and water temperatures obtained from permanently deployed instruments used in Vermont Yankee operations. The model calibration and confirmation exercises used data sets acquired in August and June - July 2002, respectively. The August calibration period was chosen to be representative of warm river temperatures and low river flows. The June - July confirmation period was chosen to include warm river temperatures occurring during fishway operations.

Results of the calibration and confirmation indicated that the model predicted both flows and temperatures well. The flow predictions for the calibration and confirmation periods were very successful, exhibiting RME and ECV values less than 3% and 4%, respectively, which were smaller (better) than U. S. EPA guidance levels (30% and 10%, respectively).

Correlations between the prediction and observations were excellent, with r2 values of 0.92 and 0.98 for the calibration and confirmation periods, respectively, which were larger (better) than the guidance level of 0.88.

The calibration results indicated that temperature predictions were also good. Best results were obtained at the upper layer, but they became somewhat reduced with depth. Squared correlation coefficients at the surface were usually larger (better) than the U. S. EPA guidance level of 0.71, and the correlations became smaller with depth. However, RME and ECV for all three layers ranged between 0 and 5.6%, showing that they were smaller (better) than the EPA guidance levels (25% and 45%, respectively) and suggesting that the predictions throughout the water column were acceptable.

The confirmation results indicated that the model performed excellently in simulating the thermal conditions of June - July 2002. The surface temperature predictions showed RME values ranging between 0.6% to 3.0% compared to the guidance level of 25%, ECV values between 2.6% and 8.1% compared to the guidance level of 45%, and r2 greater than 0.66 compared to the guidance level of 0.71. Similar variations in model error statistics were found at the middle and bottom layers. Based on the successful calibration and confirmation, the model could then be used for predictions under selected plant and river conditions.

Two sets of scenario simulations were performed for the August and June - July periods separately, to investigate the effect of proposed new temperature limits within the portion of the lower Vernon Pool affected by the Vermont Yankee discharge during the summer permit compliance period and during the period of fishway operation, respectively. For the August period, a IF (0.6°C) increase from 2°F (1.1C) to 3°F (1.7°C) resulted in a marginal increase in the temperature of the water column or on the bottom. For worst conditions occurring only 1% of the time, 30% of the bottom area increased by at least 0.3°C (0.5°F) and 20%

73

increased by a maximum of 0.4'C (0.7°F). For typical conditions occurring 50% of the time, 30% of the bottom area increased by at least 0.1°C (0.2°F), 20% increased by at least 0.2°C (0.4OF) and 10% increased by a maximum of 0.6°C (1.1°F). Similar results were obtained for changes in water column volume.

Temperature predictions during June and July when the fishway was operating with warmest river temperatures indicated that a IT increase in temperature rise generally resulted in similar increases (0.4°C) [0.7°F] in water temperature regardless of whether conditions were worst (1% of the time), infrequent (10% of the time) or typical (50% of the time). There was a slight increase in effects under typical conditions of higher river flow and therefore higher plant flow. Results also indicated that the ambient water temperature primarily influenced the temperature in the fishway rather than Vermont Yankee's rejected heat.

Based on the hydrothermal modeling results, a IF (0.6°C) increase in the permit limit from 2°F (1.1°C) to 3°F (1.7°C) resulted in de minimus changes in the thermal structure of the Vernon Pool.

74

7. References Ambrose, R.B, T.A. Wool, J.P. Connolly, and R.W. Schanz, 1988. WASP4, a hydrodynamic and water quality model - model theory, user's manual, and programmer's guide.

EPA 600/3-87/039, Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens, GA, January 1988.

Applied Science Associates, Inc., 1996. WQMAP User's Manual.

Binkerd, R.C., W. D. Countryman, R. M. McNeer and D. J. Marx, 1978. 316 Demonstration, Vermont Yankee Nuclear Power Station, Connecticut River, Vernon, Vermont, Engineering, hydrological & biological information and environmental impact assessment, submitted to Vermont Yankee Nuclear Power Corporation. Aquatec, Incorporated.

Bowie, G.L., W.B. Mills, D.B. Porcella, C.L. Campbell, J.R. Pagenkopf, G.L. Rupp, K.M.

Johnson, P.W.H. Chen, S.A. Gherini, and C.E. Chamberlain, 1985. Rates, constants, and kinetics formulations in surface water quality modeling. EPA 600/3-85/040, Environmental Research Laboratory, Office of Research and Development, U.S.

Environmental Protection Agency, Athens, GA, June 1985.

Cole, T.M. and S.A. Wells, undated. CE-QUAL-W2: a two-dimensional laterally averaged, hydrodynamic and water quality model, version 3.1, user manual. Instruction Report EL-03-1, U.S. Army Corps of Engineers, Washington, DC.

Hess, K. and K. Bosley, 1992. Methodology for validation of a Tampa Bay circulation model. 2 nd ASCE Coastal and Estuarine Conference, Tampa, Florida, 1992.

Huang, W. and M.L. Spaulding, 1995. A three dimensional numerical model of estuarine circulation and water quality induced by surface discharges. ASCE Journal of Hydraulic Engineering, 121:(4) April 1995, p. 300-311.

Lynch, D. R., and A. M. Davies, 1995. Quantitative skill assessment for coastal ocean models. Coastal and Estuarine Studies No. 47. American Geophysical Union, Washington, DC.

McCutcheon, S. C., Z. Dongwei, and S. Bird, 1990. Model calibration, validation, and use, Chapter 5 in Technical Guidance Manual for Performing Waste Load allocations. In:

Book III: Estuaries, Part 2: application of estuarine waste load allocation models, J.J.,

Martin, R.B. Ambrose, and S. C. McCutcheon (eds.), US Environmental Protection agency, Office of Water, March 1990.

75

Mendelsohn, D., et al, 1995. WQMAP in a Windows environment, published in proceedings of: 4th International Conference on Estuarine and Coastal Modeling, ASCE, San Diego, October 26-28, 1995.

Muin, M. and M.L. Spaulding, 1997. A 3-D boundary-fitted circulation model.

Journal of Hydraulic Engineering, Vol. 123, No. 1.

Muin, M., 1993. A three-dimensional boundary-fitted circulation model in spherical coordinates, Ph.D. dissertation, Univ. of Rhode Island, Narragansett Bay Campus, Narragansett, RI.

Spaulding, M. L., W. Huang, and D. Mendelsohn, 1989. Application of a boundary fitted coordinate hydrodynamic model. Estuarine and coastal modeling: Proceedings of a conference, Sponsored by the Waterways, Port, Coastal and Ocean Division of the American Society of Civil Engineers (ASCE), Newport, Rhode Island, November 15-17, 1989, p. 27-39.

Spaulding, M.L., 1984. A vertically averaged circulation model using boundary fitted coordinates. Journal of Physical Oceanography, May, pp. 973-982.

Swanson, J.C., D. Mendelsohn, 1993. Application of WQMAP to upper Narragansett Bay, Rhode Island. Estuarine and Coastal Modeling III. Proceedings of the 3rd International Conference, sponsored by the Waterway, Port, Coastal and Ocean Division of the ASCE, Oak Brook, IL, September 8-10, 1993.

Swanson, J.C., M. Spaulding, J-P. Mathisen and 0. 0. Jenssen, 1989. A three dimensional boundary fitted coordinate hydrodynamic model, Part I: development and testing. Dt.

hydrog, Z.42, 1989, p. 169-186.

Swanson, J.C., 1986. A three-dimensional numerical model system of coastal circulation and water quality, Ph.D. Dissertation, Univ. of Rhode Island, Kingston, R.I.

Thomann, R. V., and J. A. Mueller, 1987. Principles of Surface Water Quality Modeling and Control. Harper Collins, 644pp.

Wallace, J.M, and P. V. Hobbs, 1977. Atmospheric Science: An Introductory Survey.

Academic Press, 467 pp.

76

Appendix A: August 2002 Data List of Figures Figure Al. Temperature time series data for stations CI and C2 from 8/01/02 to 8/07/02.

• ---..... o.... ,,.......oo..... *ooo............... .... ...... o...-..... .... *......o...1 Figure A2. Temperature time series data for stations CI and C2 from 8/08/02 to 8/16/02.

................................................... 1 Figure A3. Temperature time series data for stations CI and C2 from 8/17/02 to 8/23/02.

................................................ 2 Figure A4. Temperature time series data for stations C3 and C4 from 8/01/02 to 8/07/02.

-.......... *..°°... °*°°°*oH°°°°°°°H**.........****oH*...........

..... *......°°°*

..-.. 2 Figure A5. Temperature time series data for stations C3 and C4 from 8/08/02 to 8/16/02.

.. ooooo.... -°oo *** .... *.........

- . .******OO..**OH..OOOOOO.O... *...........

• -*-----...... ..... *3 Figure A6. Temperature time series data for station C3 and C4 from 8/17/02 to 8/23/02.

................................................ 3 Figure A7. Temperature time series data for stations C5 and C6 from 8/01/02 to 8/07/02.

S................ .... .................... **oooo*ooo...... Hoo..o.. 4 Figure A8. Temperature time series data for stations C5 and C6 from 8/08/02 to 8/16/02.

.................................... .......... 4 Figure A9. Temperature time series data for stations C5 and C6 from 8/17/02 to 8/23/02.

... ...... .............................. ........ 5 Figure AlO. Temperature time series data for stations DI and D2 from 8/01/02 to 8/07/02 ........................................................................................................................ 5 Figure All. Temperature time series data for stations DI and D2 from 8/08/02 to 8/16/02 ........................................................................................................................ 6 Figure A12. Temperature time series data for stations DI and D2 from 8/17/02 to 8/23/02 ........................................................................................................................ 6 Figure A13. Temperature time series data for stations D3 and D4 from 8/01/02 to 8/07/02 ........................................................................................................................ 7 Figure A14. Temperature time series data for stations D3 and D4 from 8/08/02 to 8/16/02 .. ..................................................................................................................... 7 Figure A15. Temperature time series data for stations D3 and D4 from 8/17/02 to 8/23/02 ........................................................................................................................ 8 Figure A16. Temperature time series data for stations D5 and D6 from 8/01/02 to.

8/07/02 ........................................................................................................................ 8 Figure A17. Temperature time series data for stations D5 and D6 from 8/08/02 to 8/16/02 ......................................................................................................................... 9 Figure A18. Temperature time series data for stations D5 and D6 from 8/17/02 to 8/23/02 ........................................................................................................................ 9 Figure A19. Temperature time series data for stations El and E2 from 8/01/02 to 8/07/02 ...................................................................................................................... 10 Figure A20. Temperature time series data for stations El and E2 from 8/08/02 to 8/16/02 ....................................................................................................................... 10 Figure A21. Temperature time series data for stations El and E2 from 8/17/02 to 8/23/02 ....................... ... .. .................................. 11 Figure A22. Temperature time series data for stations E3 and E4 from 8/01/02 to 8/07/02 ...................................................................................................................... 11 i

Figure A23. Temperature time series data for stations E3 and E4 from 8/08/02 to 8/16/02 ...................................................................................................................... 12 Figure A24. Temperature time series data for stations E3 and E4 from 8/17/02 to 8/23/02 ...................................................................................................................... 12 Figure A25. Temperature time series data for stations E5 and E6 from 8/01/02 to 8/07/02 ...................................................................................................................... 13 Figure A26. Temperature time series data for stations E5 and E6 from 8/08/02 to 8/16/02 ...................................................................................................................... 13 Figure A27. Temperature time series data for stations E5 and E6 from 8/17/02 to 8/23/02 ...................................................................................................................... 14 Figure A28. Temperature time series data for stations Fl and F2 from 8/01/02 to 8/07/02 ...................................................................................................................... 14 Figure A29. Temperature time series data for stations Fl and F2 from 8/08/02 to 8/16/02 ...................................................................................................................... 15 Figure A30. Temperature time series data for stations F1 and F2 from 8/17/02 to 8/23/02 ...................................................................................................................... 15 Figure A31. Temperature time series data for stations F3 and F4 from 8/01/02 to 8/07/02 ...................................................................................................................... 16 Figure A32. Temperature time series data for stations F3 and F4 from 8/08/02 to 8/16/02 ...................................................................................................................... 16 Figure A33. Temperature time series data for stations F3 and F4 from 8/17/02 to 8/23/02 ...................................................................................................................... 17 Figure A34. Upstream and downstream temperature and river flow measured at Vernon D am ........................................................................................................................... 18 Figure A35. Upstream and downstream temperature and river flow measured at Vernon D am ........................................................................................................................... 19 Figure A36. Upstream and downstream temperature and river flow measured at Vernon D am ........................................................................................................................... 20 Figure A37. Water temperature and flow at the VYNPS discharge .......................... 21 Figure A38. Water temperature and flow at the VYNPS discharge ........................... 22 Figure A39. Water temperature and flow at the VYNPS discharge .......................... 23 Figure A40. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north .......................................................... 24 Figure A41. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north .......................................................... 25 Figure A42. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north .......................................................... 26 Figure A43. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA .................................................................................. 27 ii

Figure A44. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA ................................................................................. 28 Figure A45. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, M A .................................................................................. 29 Figure A46. Solar radiation at Orange, MA ............................................................... 30 Figure A47. Solar radiation at Orange, MA .............................................................. 30 Figure'A48. Solar radiation at Orange, MA ............................................................... 30 iii

Temperature Time Series Data at Thermistor Stations CI and C2 30-29 225 28PA S27 25 24 23 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure Al. Temperature time series data for stations C1 and C2 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations Cl and C2 30 C-.8 ...... ..

29 M 28 -

- 27 I-IE 26  ::: ::..

25 23 08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A2. Temperature time series data for stations C1 and C2 from 8/08/02 to 8/16/02.

A-1

Temperature Time Series Data at Thermistor Stations Cl and C2 30 i i i i i i. . . .. i i 29 A ..............

08 10108/

ii!i![' ! i i M 0

I-.0.3 T e m e ra u r Tim Se ie ..................................

20 1L ii ~~~ ~ ~ ~ ~ ~

............... ~~ 1 - 303 rni 29 26 .:==,*

25iii~iii~i*!

2408/0 080 08/02ii 080 0&03*;*i~ 0-8-03 080 OG 0/5 OW5 080 0/6 080 0/7 0:0 12:0 0:0 0:0 1 :0..0120.:0.20..0 .... .. 200...... 00 2:0 00

= 12=*

i(2002)i ==Da 08/01 08/017 08/02 08/02 08/03 08/03 08/204 08/204 08/21 08/25 08/06 08/06 08/07 08/03 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Figureiii~

A4 eprtr im seisdt o ttosC n 4fo /10 o80/2 Date (2002)

Figure A3. Temperature time series data for stations C3I and C4 from 8/017/02 to 8/07/02.

A-2

Temperature Time Series Data at Thermistor Stations C3 and C4 30 29 28 27 E 26 I.-

25 24 23, , , , .. . . . * , . .. 4 , t ,

08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A5. Temperature time series data for stations C3 and C4 from 8/08/02 to 8/16/02.

Temperature Time Series Data at Thermistor Stations C3 and C4 30 29 28 27 E 26 25 24 08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A6. Temperature time series data for station C3 and C4 from 8/17/02 to 8/23/02.

A-3

Temperature Time Series Data at Thermistor Stations C5 and C6 30 29 28 S27 25 24 23 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A7. Temperature time series data for stations C5 and C6 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations C5 and C6 30 29 C53.6 28 26 25 A 24

23. ..

08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A8. Temperature time series data for stations C5 and C6 from 8/08/02 to 8/16/02.

A-4

Temperature Time Series Data at Thermistor Stations C5 and C6 30 1 C-.13

- S21

-C639mM 29 C6-2.13 m 28 27 25 24 23 08117 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08121 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A9. Temperature time series data for stations C5 and C6 from 8/17/02 to 8/23/02.

Temperature Time Series Data at Thermistor Stations D1 and D2 30 29 -Do-3.05 027 I,-

25 24  : '  :.....

23 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A10. Temperature time series data for stations Dl and D2 from 8/01/02 to 8/07/02.

A-5

Temperature Time Series Data at Thermistor Stations D1 and D2 30 29- 0M D1-57 m E 26 25 23 08/08 08/08 08/09 08/09 08110 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure All. Temperature time series data for stations DI and D2 from 8/08/02 to 8/16/02.

Temperature Time Series Data at Thermistor Stations DI and D2 30 28  :

08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08121 08/22 08/22 08/23 08/23 08124 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A12. Temperature time series data for stations D1 and D2 from 8/17/02 to 8/23/02.

A-6

Temperature Time Series Data at Thermistor Stations D3 and D4 30 E 26 08/01 08/01 08/02 08/02 08/03 08/03 08104 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0.00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A13. Temperature time series data for stations D3 and D4 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations 03 and 0:4 30 . . .

29 28 E 26 25 V 24 08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08115 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 000 1200 000 1200 000 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A14. Temperature time series data for stations D3 and D4 from 8/08/02 to 8/16/02.

A-7

Temperature Time Series Data at Thermistor Stations D3 and D4 30 .

i*~~~~~339 m6:..........

D40.3.

\

2 25 08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A15. Temperature time series data for stations D3 and D4 from 8/17/02 to 8/23/02.

Temperature Time Series Data at Thermistor Stations D5 and D6 30 29

-67m 28 ...... ..... N ....

27 24 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A16. Temperature time series data for stations D5 and D6 from 8/01/02 to 8/07/02.

A-8

Temperature Time Series Data at Thermistor Stations D5 and D6 30 28 A E26 25 24 23 08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08115 08/16 08/16 08117 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A17. Temperature time series data for stations D5 and D6 from 8/08/02 to 8/16/02.

Temperature Time Series Data at Thermistor Stations D5 and D6 30 D m 29

- 635 28 25 24-23 08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A18. Temperature time series data for stations D5 and D6 fromn 8/17/02 to 8/23/02.

A-9

Temperature Time Series Data at Thermistor Stations El and E2 29 E-15 28 E 26 * ..... **

24 23 .. . . .... N ;

08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A19. Temperature time series data for stations El and E2 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations El and E2 30.

29 E- 5 25 24 ***[

23 . . .

08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A20. Temperature time series data for stations El and E2 from 8/08/02 to 8/16/02.

A-10

Temperature Time Series Data at Thermistor Stations El and E2 30 .

E m 29 28 E-15m 23 1 23 08/17 08/17 08/18 08/18 08119 08119 08/20 08/20 08/21 08/21 08/22 08/22 08123 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure 27 A21. Temperature time series data for stations ElI and E2 from 8/17/02 to 8/23/02.

Temperature Time Series Data at Thermistor Stations E3 and E4 25  :::

30-

2. 4 . . . . ............... ..... I*

29 24* E.-1.8.

23 '. . ... . ..

08/017 08/1 08/02 08/02 08/03 08/03 08/204 08/204 08/05 08/05 08/08 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 27 Date (2002)

Figure A21. Temperature time series data for stations E31 and E4 from 8/017/02 to 8/07/02.

E 26 25 23 08/01 08/01 08/02 08/02 08103 08/03 08/04 08104 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A22. Temperature time series data for stations E3 and E4 from 8/01/02 to 8/07/02.

A-1I

Temperature Time Series Data at Thermistor Stations E3 and E4 30 29 J 2 *; 2 0 27 26 E419 IE 23 24  : ;.:

08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08112 08/13 08/13 08/14 08/14 08/15 08/15 08116 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A23. Temperature time series data for stations E3 and E4 from 8/08/02 to 8/16/02.

Temperature Time Series Data at Thermistor Stations E3 and E4 30 28 26-.9 27*w 722:

2i-25-24 23 08/17 08/17 08/18 08/18 08119 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A24. Temperature time series data for stations E3 and E4 from 8/17/02 to 8/23/02.

A-12

Temperature Time Series Data at Thermistor Stations E5 and E6 30 - 7- iii- i-i 1 1ii 29 E.-.-.2.m 28 ýE&......

e 27 E26 0%

25 i 24 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A25. Temperature time series data for stations E5 and E6 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations E5 and E6 30 7 m . ....

29 28 M L 27 1-25 24 23 08/08 08/08 08/09 08/09 08110 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A26. Temperature time series data for stations E5 and E6 from 8/08/02 to 8/16/02.

A-13

Temperature Time Series Data at Thermistor Stations E5 and E6 30 07 29 28 E 26 24 23-08117 08117 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 000O 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A27. Temperature time series data for stations E5 and E6 from 8/17/02 to 8/23/02.

Temperature Time Series Data at Thermistor Stations Fl and F2 30-F-.8 29-28 F-.6 25 24-23 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A28. Temperature time series data for stations F 1 and F2 from 8/01/02 to 8/07/02.

A-14

Temperature Time Series Data at Thermistor Stations Fl and F2 30 1..

29 ... .. . .... F l- 6 m........

i_:F 27-27-25 24 23 .

08108 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A29. Temperature time series data for stations F 1 and F2 from 8/08/02 to 8/16/02.

Temperature Time Series Data at Thermistor Stations Fl and F2 30 29 FI36

- 98

• F 28 27-25 24--

23 i!ii  !;t!

08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A30. Temperature time series data for stations F I and F2 from 8/17/02 to 8/23/02.

A-15

Temperature Time Series Data at Thermistor Stations F3 and F4 30 29 28 F46 0 m S27-  ;;2;; T T:2::

E 28 24 23 08/01 08/01 08/02 08/02 08/03 08/03 08/04 08/04 08/05 08/05 08/06 08/06 08/07 08/07 08/08 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A31. Temperature time series data for stations F3 and F4 from 8/01/02 to 8/07/02.

Temperature Time Series Data at Thermistor Stations F3 and F4 30 29 80 24 E 26 23 08/08 08/08 08/09 08/09 08/10 08/10 08/11 08/11 08/12 08/12 08/13 08/13 08/14 08/14 08/15 08/15 08/16 08/16 08/17 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A32. Temperature time series data for stations F3 and F4 from 8/08/02 to 8/16/02.

A-16

Temperature Time Series Data at Thermistor Stations F3 and F4 30 E25 23 ......

08/17 08/17 08/18 08/18 08/19 08/19 08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure A33. Temperature time series data for stations F3 and F4 from 8/17/02 to 8/23/02.

A-17

2 26 0.24 E

22 20 8

88.3 150 -1 53.0 E 100 -V__ . __ _ - - 35.3 U.

IJ.

l 1TWL.LJ I I . I I I I I I I l I I I . I I . I I I I r I I I I I t I 8/1 8/2 8/3 8/4 8/5 8/6 8/7 8/8 Date (2002)

Figure A34. Upstream and downstream temperature and river flow measured at Vernon Dam.

A-18

28 28 L--- Station 73 (upstre l.,-*.Station .am)

(downstream) 26 E

22 201 1 1I1 I 1 i.ll I .LWI .L.I . I

.L.LIL.L+/- LLI. I I I II LL.LL.L.

8/8 8/9 8/10 8/11 8/12 8113 8/14 8/15 8/16 8/ 17 I-250 200 0

150

.gL ,.0 100 8/8 8/9 8/10 8/11 8/12 8/13 8114 8/15 8/16 8/17f.

Date (2002)

Figure A35. Upstream and downstream temperature and river flow measured at Vernon Dam.

A-19

LD 22 26 0.24 E

22 20 8 8124 250 , ,  ::.3 0

150 53.0 0 0

LL 0

LC. 100 35.3 50 17.6 8/17 i7 8/18

, 7 I8/19 iL " .i L..

8/20 I .(L 8/21 I.I 8/22 i I I I 8/23 8/24 n-Date (2002)

Figure A36. Upstream and downstream temperature and river flow measured at Vernon Dam.

A-20

WY] __ _ -~____

I" KP~' f ,h 4) 35 0.

(i)

KIJV I.-

Our FJ LL I.II .. ..I I ... L..L.L I .I I.LI.. I I I 1L .. 1 f ri.l.... .. L +/-.L .LJ .... I II. W

,8/1 812 8/3 814 8/5 8/6 8/7 8/8 0;- 0 LJL Date (2002)

Figure A37. Water temperature and flow at the VYNPS discharge.

A-21

35 8 2

E 818 8/9 8110 8/11 8/12 8/13 8/14 8/15 8/16 8/1 7 20 15 10 0

8/8 8/9 8/10 8/11 8/12 8/13 8/14 8/15 1 Date (2002)

Figure A38. Water temperature and flow at the VYNPS discharge.

A-22

4 UI

• i

• i z i i i

• i i i i i i i i

& 35 0

a-E 0

I-24 0 U 0

Date (2002)

Figure A39. Water temperature and flow at the VYNPS discharge.

A-23

10 Fi C

180 - HN J A 1 0f 90- __

A 8/2 8/3 8/4 8/5 816 8/7 8/8 Date (2002)

Figure A40. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north.

A-24

lIl

-5 0 Ze z.ý

-59 1 8/8 819 8/1 81 8/2 83 814 8/15 8/16 8/17.

5 (10 0

-5

-10 iL.Li

.LLL.i i L.Liil l [ t

.LLLi i . i i i i L .I I II.

8/8 8/9 8/10 8/11 8/12 8/13 8/14 8/15 8/16 8/1 7 C

C 0

Date (2002)

Figure A41. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north.

A-25

10 In

-5

-10 L I I I I t I I I I I I I I I I I I I I I t I I I 8/17 8/18 8/19 8/20 8/1 8/22 8/23 8/24 360 C

Date (2002)

Figure A42. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north.

A-26

• 1'*

- Air Temperature J) I I ýuI . . I I 1I I I I . 1 -1 1 . I .

Dew Point Temperature 30 8/1 8/2 8/3 8/4 8/5 8/6 817 8/E o lO LLLLJ 1LLL LL.L L ,LW..L/ -.LL..L.L.

0.6 0.2 8/1 812 M/ 8A4 8/5 8W6 8V7 8/E LD 98C 1010 1 1 . . . . .. . .....

oo99o0"

980 970 =

811 8/2 813 814 8/5 816 8/7 8/8 Date (2002)

Figure A43. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA.

A-27

I Air Temperatur S--- Dew Point Temperature]

40 1. . . . . . . . . . .

E 20 . t ~. IAJ, 4,

8/8 810 8/10 8/11 8/12 8/13 8/14 8/15 8/16 8/ 17 U.

2 E, 0.

I~ I 1.- -LLyL LII .LL. .L .L+/-

. L .

L.... J . IW..

I. I....J 1 9 11 1 A

0.

8/8 8/9 8/10 8/11 8/12 8/13 8/14 8/15 8/16 8/17 2 990 Co 980 970 I ' I I f i l i f l l I fI 8/8 8/9 8/10 8/11 8/12 8/13 8/14 8/15 8/16 8/17 Date (2002)

Figure A44. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA.

A-28

- Air Teperature

--Dew Point Temperature I

401 a

C, E

12 DI I .I ,I ij I i I I I J-' iiiiiiii1 8/17 8/18 8/19 8/20 8/21 8/22 8/23 8/24 0.8

2 0.6 EC 0.4V 0.2 8/17 8/18 8/19 8/20 8/21 8/22 8/23 &124 IUIU (C

1000

.0 2 990 C) 0.

980 970 8/17 8/18 8/19 8/2 8/21 8/22 8/23 8/24 Date (2002)

• Figure A45. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA.

A-29

luL oo)/

0/ '

0 2 60 0o 8/ i1 8/ i 8/3 8/4i i i i ii 8/5

(/1 4C 2

o0 _'_t 8/1 8/2 a13 8/4 8/5 8/6 8/7 8/8 Date (2002)

Figure A46. Solar radiation at Orange, MA.

Ei8000 2 600 400 200 841 818 8/9 8/10 8/11 8/12 8113 8/14 8/15 8/16 8/17 Date (2002)

Figure A47. Solar radiation at Orange, MA.

I . I ý I . I . I I . I . . . . . I ý I I . ý . ý .

I

. . g g , . ý I I-iii __________ -

I

~ -I-Al UV N80 A

.2 60

- 40 0 20 0-8/17 8/18 8/19 8/20 8/21 8/22 8/23 8/24 Date (2002)

Figure A48. Solar radiation at Orange, MA.

A-30

Appendix B: June - July 2002 Data List of Figures Figure BR. Temperature time series data for stations C1 and C2 from 6/25/02 to 7/01/02.

• • -**....... ,- ...... ............................................... 1 Figure B2. Temperature time series data for stations CI and C2 from 7/02/02 to 7/08/02.

-....... . .......... 1 Figure B3. Temperature time series data for stations C3 and C4 from 6/25/02 to 7/01/02.

...... **.°°°°.....* ......... ...... ............. ... . ........ ...... . ............................................... 2 Figure B4. Temperature time series data for stations C3 and C4 from 7/02/02 to 7/08/02.

- . . . . . . . . ......... . . . . . . . . ..... .................................. 2 Figure BS. Temperature time series data for stations C5 and C6 from 6/25/02 to 7/01/02

-........................... ................................................... 3 Figure B6. Temperature time series data for stations C5 and C6 from 7/02/02 to 7/08/02.

............................... ....... ............................ 3 Figure B7. Temperature time series data for stations DI and D2 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 4 Figure B8. Temperature time series data for stations Dl and D2 from 7/02/02 to 7/08/02 ........................................................................................................................ 4 Figure B9. Temperature time series data for stations D3 and D4 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 5 Figure B10. Temperature time series data for stations D3 and D4 from 7/02/02 to 7/08/02 ........................................................................................................................ 5 Figure B11. Temperature time series data for stations D5 and D6 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 6 Figure B12. Temperature time series data for stations D5 and D6 from 7/02/02 to 7/08/02 ........................................................................................................................ 6 Figure B13. Temperature time series data for stations El and E2 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 7 Figure B14. Temperature time series data for stations El and E2 from 7/02/02 to 7/08/02 .. ..................................................................................................................... 7 Figure B15. Temperature time series data for stations E3 and E4 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 8 Figure B16. Temperature time series data for stations E3 and E4 from 7/02/02 to 7/08/02 ........................................................................................................................ 8 Figure B17. Temperature time series data for stations E5 and E6 from 6/25/02 to 7/0 1/02 ........................................................................................................................ 9 Figure B18. Temperature time series data for stations E5 and E6 from 7/02/02 to 7/08/02 ......................................................................................................................... 9 Figure B19. Temperature time series data for stations Fl and F2 from 6/25/02 to 7/0 1/02 ...................................................................................................................... 10 Figure B20. Temperature time series data for stations Fl and F2 from 7/02/02 to 7/08/02 ...................................................................................................................... 10 Figure B21. Temperature time series data for stations F3 and F4 from 6/25/02 to 7/0 1/02 ...................................................................................................................... 11 Figure B22. Temperature time series data for stations F3 and F4 from 7/02/02 to 7/08/02 ...................................................................................................................... II i

Figure B23. Upstream and downstream temperature and river flow measured at Vernon D am ............................................................................................................................ 12 Figure B24. Upstream and downstream temperature and river flow measured at Vernon D am ........................................................................................................................... 13 Figure B25. Water temperature and flow at the VYNPS discharge ........................... 14 Figure B26. Water temperature and flow at the VYNPS discharge ........................... 15 Figure B27. Water temperature recorded at the Fishway ........................................... 16 Figure B28. Water temperature recorded at the Fishway ........................................... 16 Figure B29. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north .......................................................... 17 Figure B30. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north .......................................................... 18 Figure B31. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA ................................................................................ . 19 Figure B32. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA .................................................................................. 20 Figure B33. Solar radiation at Orange, MA .............................................................. 21 Figure B34. Solar radiation at Orange, MA ............................................................... 21 ii

Temperature Time Series Data at Thermistor Stations Cl and C2 30 28 26 e

• 24 E

12 22 20 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure Bi. Temperature time series data for stations C I and C2 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations Cl and C2 30 28 26 2

• 24 E

22 20 18 ' . . . .. I I I......i I... 1 -4I 07/02 07/02 07/03 07/03 07/04 07/04 07105 07/05 07/06 07/06 07/07 07/07 07/06 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B2. Temperature time series data for stations C 1 and C2 from 7/02/02 to 7/08/02.

B-1

Temperature Time Series Data at Thermistor Stations C3 and C4 30 28 . . ...8. . .

26 20 18 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B3. Temperature time series data for stations C3 and C4 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations C3 and C4 30 .. ...

26 22 20* .... ..

18 .... ... . . "

07/02 07102 07/03 07/03 07/04 07/04 07105 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B4. Temperature time series data for stations C3 and C4 from 7/02/02 to 7/08/02.

B-2

Temperature Time Series Data at Thermistor Stations C5 and C6 30 aC5-0.33 m 20 18 06/25 06125 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B5. Temperature time series data for stations C5 and C6 from 6/25/02 to 7/01/02 Temperature Time Series Data at Thermistor Stations C5 and C6 30 26-&

04 A C0 I-183 Da20202 Figure B6. Temperature time series data for stations C5 and C6 from 7/02/02 to 7/08/02.

B-3

Temperature Time Series Data at Thermistor Stations Dl and D2 30 287/01/0 26 22 20 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07101 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B7. Temperature time series data for stations D I and D2 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations Dl and D2 30 26 22 20 20at (2002)9 Figure B8. Temperature time series data for stations DlI and D2 from 7/02/02 to 7/08/02.

B-4

Temperature Time Series Data at Thermistor Stations D3 and D4 30 28 D m 26 S241 1 0 E

22 20 18 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07102 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B9. Temperature time series data for stations D3 and D4 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations 03 and D4 30 26 m i-D324.1* m 1!20 07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B10. Temperature time series data for stations D3 and D4 from 7/02/02 to 7/08/02.

B-5

Temperature Time Series Data at Thermistor Stations D5 and D6 301 28 26 D667 m S24 22 207 1.

18 .

06125 06125 06/26 06126 06/27 06/27 06/28 06128 06/29 06/29 06/30 06130 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B 1I. Temperature time series data for stations D5 and D6 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations D5 and D6 30 D5. m.

20 22 11 2 18 07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B12. Temperature time series data for stations D5 and D6 from 7/02/02 to 7/08/02.

B-6

Temperature Time Series Data at Thermistor Stations El and E2 30-28 El1.58 m 26 ... ........ ..... . . .58 m 0 26 22 20 18 06/25 06/25 06/26 06/26 06/27 06/27 06128 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B13. Temperature time series data for stations ElI and E2 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations El and E2 07024 0/02 07/03 07/03 0 4 0 4 0~7/0 07/05 .

0:00 2 002

0:00 2 :002 0:007 612:0 0:0012 00/

0:00/ 2 :002 0:030 12:00 0:0012:0701 26 .

• 0:/00 Date (2002) 20 Figure E B14. Temperature time series data for stations El and E2 from 7/025/02 to 7/08/02.

07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B14. Temperature time series data for stations El and E2 from 7/02/02 to 7/08/02.

B-7

Temperature Time Series Data at Thermistor Stations E3 and E4 30E303m 28 E06325 m2 18~

26 22 E4- .98 18 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06130 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B15. Temperature time series data for stations E3 and E4 from 6/25/02 to 7/01/02.

E Temperature Time Series Data at Thermistor Stations E3 and E4 30 28E403m 26 E20 18 07/02 07/02 07/03 07/03 07/04 07104 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B16. Temperature time series data for stations E3 and E4 from 7/02/02 to 7/08/02.

B-8

Temperature Time Series Data at Thermistor Stations E5 and E6 30 28 26 p

' 24 E

22 20 18 I .. ...........

. I I 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 06/29 06/30 06/30 07101 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B17. Temperature time series data for stations E5 and E6 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations E5 and E6 30 28 E S24 2WM 20 07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07106 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B18. Temperature time series data for stations E5 and E6 from 7/02/02 to 7/08/02.

B-9

Temperature Time Series Data at Thermistor Stations Fl and F2 30 F m 28 26 a 24

=

0.

0 22 20 18 06/25 06125 06/26 06/26 06/27 06127 06/28 06/28 06/29 06/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B19. Temperature time series data for stations F1 and F2 from 6/25/02 to 7/01/02.

Temperature Time Series Data at Thermistor Stations Fl and F2 30 28 F13?

26 24 22 20 18 07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B20. Temperature time series data for stations F I and F2 from 7/02/02 to 7/08/02.

B-10

Temperature Time Series Data at Thermistor Stations F3 and F4 30 26  :; iN**:

20-320m

.* 24 a.

22 41N 26 18 F 06/25 06/25 06/26 06/26 06/27 06/27 06/28 06/28 06/29 08/29 06/30 06/30 07/01 07/01 07/02 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B21. Temperature time series data for stations F3 and F4 from 6/25/02 to 7/01/02.

a.

Temperature Time Series Data at Thermistor Stations F3 and F4 22 N 24 20 18 i 07/02 07/02 07/03 07/03 07/04 07/04 07/05 07/05 07/06 07/06 07/07 07/07 07/08 07/08 07/09 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00 Date (2002)

Figure B22. Temperature time series data for stations F3 and F4 from 7/02/02 to 7/08/02.

B-11

JU ý, , , I E

6/25 6126 6127 6128 6/29 6/30 7/1 7/2 E

I-, 600 . . . r . . . . . . . . . . . . . . . . . . 21.2 CD CD 0D 200 07.1 100 03.5 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I I - I 00.0

.6/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 Date (2002)

Figure B23. Upstream and downstream temperature and river flow measured at Vernon Dam.

B-12

30 0

V E

V I-7/9

-4 n' 500 17.6 400 14 1 lvv 0

CD 0

3001.

U.)

200_____ 0 10C13.

7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 Date (2002)

Figure B24. Upstream and downstream temperature and river flow measured at Vernon Dam.

B-13

40

.35 L-25 6/ 25 6/26 6/27 6/28 6/29 6/30 7/1 7//2 At' r -.-- r--r-r--r r I- I  !---r-r* r -r I I r-r- r -rrrrr 1 V I y-rr V I I I I . 1Uo 883

-20 ~1_____ ___ 706 530 0 LL.

LL 353 177 0 LL L L L .. .. . .L..L...L....

. .+/-L.L.

. .L.L.L .. .~J. .. L. .. L. 0 6/25 6/26 6/27 6/28 6/29 6/30 7/1 77/2 Date (2002)

Figure B25. Water temperature and flow at the VYNPS discharge.

B-14

40 .~l. . .

-M A

O 2

-v 0-i-

7/2 Ar 7/3 I

7/4

\rv \If 7/5 7/6 7/7 7/8 A<1l 7/9 30Ll 25 io

.1 i.t 1 15

-883

-706

.Z 153 LL 0,

LA.

1035 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 Date (2002)

Figure B26. Water temperature and flow at the VYNPS discharge.

B-15

25 I-20L 6125 6/26 6/27 6/28 6/29 6/30 7/1 7/ 2 Date (2002)

Figure B27. Water temperature recorded at the Fishway.

LD25 ___ ___

.2 9

E 20 _____ _____

712 7/3 7/4 7/5 7/6 7/7 7/8 7/9 Date (2002)

Figure B28. Water temperature recorded at the Fishway.

B-16

-I0 r i 1I 1 ,1i 11 *Trrr rrrrr -Tr -Irir"rr 6/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 10

-5 615 6/26 6/7 6;28 629/3717/

CO 3 10 . .. . .. . . . .. . . . . . . . .

2780 IA A l 180 i1 a 1 6/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 Date (2002)

Figure B29. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north.

B-17

IL-rr-- fl l1 TIfl -Iy-IIl I fi ll -rr iirl-r-5

-105 9

V) 7/2 7/3 7/4 7/5 716 7/7 7/8 7/

9 C

a*

Date (2002)

Figure B30. Wind stick plot and wind speed and direction as observed at the VYNPS.

In the top figure, each stick points in the direction the wind is blowing to and stick length is proportional to wind speed. The bottom figure shows the direction the wind is blowing from relative to true north.

B-18

Irr -i--i--i-, r r, , r

" Air Temperature Dew Point Temperature 40 G2° - - -___

I- 20:/ ._, vI.. j, 6125 6/26 6/27 6/28 6/29 6/30 7/1 M

>' 0.8 0.6

". 0.4 __-

0.2 6/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 1010 1 . . . . . . .. . . . .

LD990 IL 980 iA W/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 Date (2002)

Figure B31. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA.

B-19

401--Dew Point Temperature 40 20 ,.

712737475767/7/7I 10.

7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/M 0.6 .L .. L . .. .

0.4 -

0.2 FiueB2, i n e oittmeauerltv huidt an tmshri resr 7/2 7/3 7/4 7/5 716 7/7 7/8 7/g E

10 10 . . . . . . . . . . . . . . . . . .

1000 L0 980 07n I I I I 1 I I I I I I I t I 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 Date (2002)

Figure B32. Air and dew point temperatures, relative humidity and atmospheric pressure as observed at Orange, MA.

B-20

I ULMF iI I A

n A .-ta E 8O0

.* 60

11 Fl 1111 104 nJ * *- =,

Co20 0 6/ 6j'28 6/29 6 '30 7 '11 7 /2 25 6/26 27 Date (2002)

Figure B33. Solar radiation at Orange, MA.

000 600 400- -

CIU 200 - --

0 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 Date (2002)

Figure B34. Solar radiation at Orange, MA.

B-21

Appendix C: Hydrodynamic Model Description (Muin and Spaulding, 1997)

THmEE-DnMENsIoNAL BOUNDARY-FITTED CIRCULATION MODEL 1 2 By Muslim Muln and Malcolm Spaulding ADSTRACT A spherical coodinate. thuee-dimensional, nonorthogonal, bound*y-fined circulation model (con-travauiant formulation) for application to estuarine. coastal sea. and continental shelf watme is presented. The model employs a split mode technique where the equations are decomposed into exterior and interior modes.

The exterior mode (vertically averaged) described in an earlier paper (Muin and Spaulding 1996) Is solved using a semiimplicit solution technique. The interior mode (vertical structure) Is solved explicitly, except for the vertical diffusion terms that are solved implicitly. The tmnporally and spauialy varying eddy viscosity and diffuitvity are determined from a turbulent kinetic energy equation and an empirically specified length scale. A series of tests are presented to evaluate model performance where analytical solutions or other numerical solutions am available for compatison. The model's ability to predict the point vertical structure of tidal flow is tested against analytic solutions employing (I) const*nt viscosity; and (2) an eddy viscosity varying linearly with depth with a no-slip bottom boundary condition. The ability of the model to simulate three-dimensional tidal flow was tested against an exact solution for an annular section channel with quadratically varying bathymetry. The model was also tested against analytic solutions for steady residual flow generated by density gradient. wind, and river flow in a channel. The model predicted turbulent energy distributions generated from a bottom boundary were compared to those from a previous numerical study by Davies and Jones (1990). No-slip and bottom stress formulations at the sea bed, and their effect on the vertical structure of the flow are analyzed. The model was used to predict the salinity distribution in a simple rectangular channel Identical to the Rotterdam Waterway.

The computational method is very economical. stable, and accurate with the CFL stability condition up to 100.

INTRODUCTION the equations of continuity, momentum, and conservation of substance can be written as Numerical modeling techniques are routinely msed to study circulation and pollutant tansport in eswarne mnd coastal wa- Contlnulty tems. The majority of models employ finite-difference tech-niques on square grid systems. While this has proven usl I Ou + _ l r-w in various applications, it becomes expensive whcn the study r cos 8 ; rae r r";a-"f (1) region is geometrically and bathymetrically complex. Such difficulties motivate the use of alternative solution approaches Momentum that allow flexibility in the grid specification, for example fi-nite elements (Lynch and Werner 1987) and boundary-fined Ii-direction coordinates (Johnson 1980; Spaulding 1984; Sheng 1986; au +" uau O T u uL uuw

+ n 1 Swanson 1986; Muin and Spaulding 1996).

This paper presents the extension of a two-dimensional (2D) 7.0.: 74KBO +O7 7ra Oe vertically averaged, boundary fitted, spherical coordinate cir- LOp + i / u\

culation model developed by Muln and Spaulding (1996) to P.rCosOO +r O (2)

Or) three dimensions. The paper first presents the governing equa-tions in spherical coordinates with appropriate assumptions 0-direction and boundary conditions. The equations arm further trans-formed to a o-coordinate. This is followed by pres.entations of av + -" +-- ftanB

-v + -+=+

the governing equations in a generalized curvilinear coordinate ar rcos-'e rO+B r Or+'

system, turbulence parametrization, the solution methodol-ogy, and model testing for which analytic (linear problems) IpO(A.On solutions or other numerical solutions arc readily available. (3)

Testing emphasizes calculations of the vertical structure of the r-direction flow. Testing of the 2D vertically averaged version of the model for a series of horizontal flow problems (sec Lynch and Op (4)

Gray 1978) was presented in Muin and Spaulding (1996).

GOVERNING EQUATIONS Conservation of Substance Using a spherical coordinate system, where 4 = longitude positive east; 8 - latitude positive north, and r = positive up, +P.F alI . + g]'

'Jurusan Telailk SipIl Institut Teknologi Bandung. Bandung. Indone- + r-T L" - ' " '-

sia.

'Prof. and Chair., Dept. of Oc. Enars.. Univ. of Rhode Island, Narra-(5) pawn Bay Campus, NarragnseI. RI 022.

Note. Discussion open until June 1.1997. Separate discussions should Equation of State of Sea Water be submited for the Individual papes in this symposium. To extend the p -A(S' 8) (6) losing date one month, a written request must be filed with the ASCE Manager of JournaiL 7U manuscript for this paper was submitted for -where t a time; u, v and w = velocity components in fi, 8, and review and possible publication on January 10. 1994. This paper is part of the Jamsa/ o/fildraw Eagiarssdg. Vol. 123. No. 1. January. 1997. r directions. res*pectively;f= Coriolis parameter p = pressure; CASC., ISN 0733-9429/97=0014)002-00121,4.00 + $.50 per page. g - gravity;, p - water density; p. - basi-averaged water den-Paper No. 7655. sity; A. = vertical eddy viscosity; D, = vertical eddy diffusiv-21 JOURNAL OF HYDRAULIC ENGINEERING / JANUARY 1997

ity; D. = horizontal eddy diffusivity; 6 =C; temperature S= Momentum salinity (ppt); and q = concentration of a conservative sub-stance such as 0 or S. 4ire-tion The equations described previously assume the following-the flow is Incompressible, density differences are neglected auD + I a-OD I au.- 2uvD +u-D unless multiplied by gravity (Bousslnesq approximation), the at. r Cos +r a6 r tan + AfvD vertical acceleration is very small compared to gravity (hydro--

- static-as-umpion);-and the-horizontal- ree aneglcted. . + - - D, 2p..rcos.l 0 t__ +4,( -2 (

Soundary Conditions t4 a a 8u%

The land boundaries are assumed impermeable where the +(4p-2pe<r+D- + - IioA-normal component of velocity is set to zero N a~ aj D11 \80/ý (16)

T.= 0 (7) O-direction On river boundaries, the velocities are specified and the pres- avDI "D +1 aD -uu JV"D an e sure gradient is set to zero. At open boundaries the water el-evation or vertically varying velocity as a function of time is at rCosaf a+ r as known from field observations or otherwise specified. avwD D At closed boundaries the transport of substance is zero. At + ;--+ AD=--L-- 1YX + (p - 2pXl - N L an open boundary the concentration must be specified during 2pxi f a an inflow. On outflow the substance is advected out of the model domain according to ae aej Du .. A, Lv (17) 21 21.0(842)

+ oq.direcon at r cos 0 a4 aq +*

+ ;*=. Lq . (sb)

( 8b (18) at r ae D Baa At the surface, the wind stress is specified as

• .,-= C.c Nw,, -+w.. ',- p.c.w.'/ W

_+w2 (9) Conservation of Substance where W. and W4 = wind speeds in the + and e directions, aq + aq + ! q aq .1 4 _L [D aq\

respectively; p. = density of air; and C. = drag coefficient at at *rcos 0a4. raI B-V Da'a. a)./

the surface.

The kinematic free surface boundary condition is given as + IR a'q +alq\

ac w'*+r*'**

u a2 + 7*(10)

! L( (19) 7: rcos 04~ r a where Two options are available to specify the bottom boundary condition X=fl pdo' (20a)

1. Bottom stress condition

" - p.C.U.Nr4 +v", r&.- p.C.Vbv' +_ V. 0(1) + a) + -Y, + -Y.+ 2 (20b) where Cj, = bottom drag coefficient; and u. and %*=

velocity components at the bottom in the 4. and 0 direc- -Y* [Ia(1 o'c +)

tions. respectively.

2. No-slip condition (20c)

D rc-os 01_ -U_ rcsa.j u=4O and vj,=O (12) 1 1 -aah l+ aacl (20d)

At the bottom boundary, no momentum flux is allowed and [co-sOB r 6 77-O 3-o70-j the kinematic condition is specified 1 8h I ah where D = h + C= total water depth.

w = -ub-r os e Z7b7ý (13) The horizontal velocities and independent variables are next transformed to a curvilinear coordinate system. The equations The governing equations are transformed to a a-coordinate of motion and continuity equation in a curvilinear coordinate system to resolve bathymetric variations with a constant num- system (E.i, in terms of the contravariant velocity compo-ber of grids. The transformation is defined as nents, are as follows:

• ,'. 80=0'. r=R+C+(cr-I XC+h)2, :-e (14)

The governing equations now become (dropping the primes Continuity for convenience)

+ t (cos atOJu-D) + Ian (cos OJr D)

Continuity ac 1 BuD 1 BuD uD -oD

+ Jr cos "5-B=0 a, atr Cos 0 a4ý + r aO _ r tan e + a 0 (15)

Ba'21 (21)