ML060810160

Hydrogeological Characterization of Rancho Seco

ML060810160
Person / Time
Site:	Rancho Seco
Issue date:	03/15/2006
From:	Redeker S Sacramento Municipal Utility District (SMUD)
To:	Document Control Desk, NRC/FSME
References
MPC&D 06-036
Download: ML060810160 (77)

Text

• SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT 9

The Power To Do More."

P.O. Box 15830, Sacramento, CA 95852-1830; 1-888-742-SMUD (7683)

MPC&D 06-036 March 15, 2006 U.S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555 Docket No. 50-312 Rancho Seco Nuclear Generating Station License No. DPR-54 HYDROGEOLOGICAL CHARACTERIZATION OF RANCHO SECO Attention: John Hickman Attached is a copy of the hydrogeological characterization report for Rancho Seco. The purpose of the characterization was to determine the site-specific geological, hydrological, and hydrogeological physical parameters required to develop a mathematical model to calculate soil derived concentration guideline levels (DCGLs) for potential radiological contaminants.

As they become available, we will submit additional technical basis documents in anticipation that the review of these documents will facilitate NRC review and approval of the License Termination Plan to be submitted later this year.

Members of your staff with questions requiring additional information or clarification may contact Bob Jones at (916) 732-4843.

Sinc Ielv eve Redeker Manager, Plant Closure and Decommissioning Attachment Cc w/ attachment:

B.S. Mallett, NRC, Region I S50 RANCHO SECO NUCLEAR PLANT

• 14440 Twvin Cities Road, Herald, CA 95638-9799; (209) 333-2935

iii Az Mu JD7Ji7'T~hTT

4 URS L

March 7, 2006 LL

.-1, Mr. Einar Ronningen Rancho Seco Nuclear Generating Station d

14440 Twin Cities Road Herald, California 95638

Subject:

Submittal of Hydrogeological Characterization

Dear Mr. Ronningen:

We are pleased to submit with this letter, 12 copies of the Hydrogeological Characterization of the Rancho Seco Nuclear Generating Station.

If you have questions concerning this report, please contact Tom Cudzilo (679-2290) or me (679-2247).

Sincerely, Michael Thomas Project Manager URS Corporation Crown Corporate Center 2870 Gateway Oaks Drive, Suite 150 Sacramento, CA 95833 Tel: 916.679.2000 Fax: 916.679.2900 K:\\Vprocess\\2561 2\\Rancho Seco\\lydro Asscssment\\Text.doc

Hydrogeological Characterization of the Rancho Seco Nuclear Generating Station Prepared for:

Rancho Seco Nuclear Generating Station 14440 Twin Cities Road Herald, California 95638 Prepared by:

URS URS Group, Inc.

2870 Gateway Oaks Drive, Suite 150 Sacramento, California 95833 March 2006

RANCHO SECO Table of Contents Section Page Acronyms and Abbreviations.....................

iii Section 1.0 1.1 1.2 1.3 1.4 1.5 Section 2.0 2.1 2.2 2.3 2.4 Ilydrogeological Characterization.........................

1-1 Purpose.................................................................................................................

1-1 Site Description.......................

1-1 1.2.1 Location......................

1-1 1.2.2 Site Description......................

1-1 1.2.3 Operating History......................

1-1 1.2.4 Post-Operation Activities......................

1-4 1.2.5 Potential Radiological Contaminant Sources........................................... 1-4 1.2.6 New Site Construction.................................................

1-5 Demography......................................................................................................... 1-5 Topography.......................................................................................................... 1-6 Meteorology......................................................................................................... 1-6 Hydrogeological Conceptual Model.....................

2-1 Previous Geologic Investigations

........................... 2-1 2.1.1 Initial Siting Investigation.................................................

2-1 2.1.2 Geotechnical Investigation for Proposed Evaporation Ponds.................. 2-1 2.1.3 2005 Update Investigation................

................................. 2-3 Geology and Physical Parameters 2-5 Hydrology..................................................

2-9 Hydrogeology.................................................

2-11 Section 3.0 3.1 3.2 Section 4.0 4.1 4.2 Section 5.0 Groundwater Evaluation..................................

3-1 Sampling for General Minerals in Groundwater.................

................. 3-1 Data Interpretation..................................

3-5 Conclusions and Recommendations....................................

4-1 Conclusions.......................................................................................................... 4-1 Recommendations................................................................................................ 4-1 References..................................

5-1 LIST OF APPENDICIES Appendix A: 2005 Drilling Logs and Well Construction Details Appendix B 2005 Physical Parameter Laboratory Results Appendix C 2005 Groundwater Sample Laboratory Results KAVprocess\\2561 2\\Rancho Seco\\dlydro Assessment\\Text.doc i

March 2006

RANCHO SECO Table of Contents LIST OF TABLES 2-1 Construction and Water Elevation Data........2-4 2-1 onstucton ad Waer levaion ata.............................................................

24 2-2 Physical Property Data Status for RSNGS............................................................. 2-8 3-1 General Minerals Results from Analyses of Groundwater.............................................. 3-2 LIST OF FIGURES 1-1 Location of Rancho Seco Nuclear Generating Station.................................................... 1-2 1-2 Details of Rancho Seco Property Owned by Sacramento Municipal Utility District...... 1-3 2-1 Locations of Borings Drilled and Sampled at Rancho Seco NGS................................... 2-2 2-2 Geologic Map of Area from Rancho Seco to Galt, California...................

..................... 2-6 2-3 Topography and Surface Water Features Surrounding RSNGS................

.................... 2-10 2-4 Geologic Cross Sections, Rancho Seco NGS Site......................................................... 2-12 2-5 Groundwater Elevation Contours Measured in 2003, Southern Sacramento County... 2-14 2-6 Potentiometric Surface Map for Groundwater Beneath RSNGS, December 2005.......

2-15 3-1 Piper Diagram for Groundwater Concentrations Beneath RSNGS..............

................... 3-3 3-2 Stiff Diagrams of Cation and Anion Concentrations in Groundwater Beneath and Upgradient from RSNGS.............................................................

3-4 K:\\%Wrrocess\\25612\\Rancho Seco'llvdro Asscssment\\Text.doc ii Mlarch 2006

HYDROGEOLOGICAL CHARACTERIZATION Acronyms and Abbreviations bgs below ground surface cm/sec centimeters per second District Sacramento Municipal Utility District meq milliequivalent(s) mg/L milligram(s) per liter RSNGS Rancho Seco Nuclear Generating Station RSPW Rancho Seco Park Well K:\\Vprocess\\25612\\Rancho Seco'Jlydro Assessmcnt\\Text.doc iii Narch 2006

SECTIONONE Hydrogeological Characterization This document presents Phase 1 of the hydrogeological characterization of the Rancho Seco Nuclear Generating Station (RSNGS). The property is owned and operated by the Sacramento Municipal Utility District (District).

1.1 Purpose The purpose of the hydrogeological characterization is to determine the site-specific geological, hydrological, and hydrogeological physical parameters required to develop a mathematical site model to calculate soil derived concentration guideline levels for potential radiological contaminants. If the parameters have not been quantified adequately for use in modeling, the characterization identifies uncertainties in the parameter data that should be addressed. The hydrogeological characterization of RSNGS and the mathematical model will support the development of the License Termination Plan for RSNGS. A key component in the development of the model is the conceptual site model.

1.2 Site Description 1.2.1 Location The RSNGS property, herein called the "site," is in the southeastern part of Sacramento County, California. The site is approximately 25 miles southeast of Sacramento and 26 miles northeast of Stockton, in the central valley of California, between the foothills of the Sierra Nevada Mountains to the east and the Pacific Coast range bordering the Pacific Ocean to the west (Figure 1-1).

1.2.2 Site Description The nuclear facility consists of an approximately 87-acre fence-enclosed industrial area contained within 2,480 acres of the District-owned and District-controlled property (Figure 1-2).

RSNGS had a pressurized water reactor designed and constructed by Bechtel Power Corporation; its nuclear steam supply system, rated at 2,770-megawatt-thermal and 913-megawatt-electric, was provided by Babcock and Wilcox. On the eastern portion of the District-owned property is the Rancho Seco Reservoir created by the damming of an unnamed drainage during construction of RSNGS. The reservoir holds 2,850 acre-feet of water that can be tapped if other water supplies are interrupted. Four groundwater supply wells that produce water as needed were constructed on the site. However, condenser cooling and makeup water for the plant and the reservoir was provided via the Folsom-South Canal, constructed by the Bureau of Reclamation.

1.2.3 Operating History RSNGS was issued its Title 10 Code of Federal Regulations Part 50 operating license (DPR-54) on August 16, 1974, and attained initial criticality 1 month later, on September 16, 1974. The facility became commercial on April 18, 1975. After approximately 15 years of operation, RSNGS was permanently shut down on June 7, 1989, after passage of a nonbinding referendum by the voters of Sacramento County recommending the District discontinue operation of RSNGS. The reactor was completely defueled on December 8, 1989 (Ref 5.1).

KA\\Wprocess\\25612\\Rancho Seco\\Ilydro Assessment\\Text.doc 1-1 March 2006

SECTIONONE Hydrogeological Characterization Figure 1-1.

Location of Rancho Seco Nuclear Generating Station 1-2 March 2006

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SECTIONONE IHydrogeological Characterization 1.2.4 Post-Operation Activities The District formally notified the U.S. Nuclear Regulatory Commission of its intent to permanently shut down the facility, requesting a possession-only license on April 26, 1990. In January 1997, the District's Board approved the Incremental Decommissioning Action Plan.

Spent reactor fuel was transferred to the Interim Spent Fuel Storage Installation on the site (Figure 1-2). As of January 2006, the decommissioning project had removed virtually all of the secondary plant systems (with the exception of imbedded or buried piping), including:

• Main Steam

• Auxiliary Steam

• Main Feed Water

• Main Condensate and Makeup

• Main Circulating Water Pumps

• Main Turbine and Condenser

• Most Support Systems in the Turbine Building Within the Auxiliary Building, virtually all systems have been removed. The original Spent Fuel Building dismantling began in October 2002 (Ref 5.1), and the liner plate has been removed.

Within the Reactor Containment Building, significant progress has been made, including the removal of both once-through steam generators, all four reactor coolant pumps and motors, a substantial portion of the reactor coolant system, the reactor building ventilation system, and the support/electrical/mechanical systems. Significant progress has been made on Reactor Vessel Internals segmentation.

Dismantling activities outside of the facility power block are directed at the removal of temporary buildings and structures and are being carried out in accordance with standard site procedures for the release of potentially contaminated materials and equipment. Final status surveys will be conducted of the "footprint" left from the dismantling of these structures to verify that no residual contamination above the established derived concentration guideline level will remain following license termination (Ref 5.1).

1.2.5 Potential Radiological Contaminant Sources Most regulated waste from the decommissioning of RSNGS will result from the radiological contamination of plant structures and equipment. The primary source of this contamination was the operation of the facility nuclear reactor and its associated support systems. The radiological inventory of the facility and areas impacted by the release of radiouclides is described in the following paragraphs (Ref 5.1).

K:\\Wproccss\\2561 2\\Rancho Scco'J-Iydro Assessment\\Text.doc 1-4 March 2006 KA1Wproccss\\25612\\Rancho Seco\\Elydro Assessmeriffeatdoc l1-4 March 2006

SECTIONONE Ilydrogeological Characterization Plant systems that were internally contaminated by the operation of RSNGS have been characterized (Ref 5.1).

Evidence indicated that water had leaked from the spent fuel pool within the Spent Fuel Building during reactor operation. Spent fuel pool water was also known to have leaked onto the spent fuel pool cooler pad outside of the Spent Fuel Building. Results of the investigation of soil outside of the Spent Fuel Building in the vicinity of the spent fuel pool cooler pad showed penetration of the soil by liquids from the pool. However, cesium 137 and cobalt 60 concentrations decreased with depth, and 14 feet of soil were scraped and removed, resulting in removal of most of the soil activity. In Fall 2004, an investigation was conducted in the soil beneath the spent fuel pool; samples collected below the floor of the pool (down to.

approximately 25 feet below grade level) had no concentrations indicating penetration of spent fuel pool liquid. Therefore, it is unlikely that contaminated spent fuel pool liquid penetrated to groundwater, which is about 120 feet deeper than the depth sampled.

Outside of the facilities or components mentioned above that had been impacted, several additional areas within the industrial area have been identified as having been impacted radiologically by the operation of the facility (Ref 5.1). These areas have relatively low concentrations of radionuclides; however, several pose a potential threat of migration of radionuclides into soils, surface water, or groundwater dissolved in or carried by liquids.

Following are the impacted areas within the industrial area:

• Retention Basins

• Tank Farm

• Barrel Farm

• Regenerant Hold Up Tank areas

• Storm Drains;

• Oily Water Separator

• Turbine Building Drains and Sumps 1.2.6 New Site Construction The District has constructed a 30-acre natural-gas-fired power plant on the RSNGS site, approximately 0.5 mile south of the industrial area boundary. Also within the 2,480-acre site are the 560-acre Rancho Seco Reservoir and Recreation Area, a 50-acre solar power (photovoltaic) electrical generating station, and the 0.9-acre, Title 10 Code of Federal Regulations Part 72 licensed Interim Spent Fuel Storage Installation.

KXWprocess\\2561 2\\Rancho Seco'Jlydro Assessment\\Text.doc 1-5 March 2006 KA\\Wprocess\\2561 2\\Rancho Seco~llydro AssessmenA\\Text.doc l -5 March 2006

SECTIONONE HIydrogeological Characterization 1.3 Demography Land surrounding the site is used in agriculture for grape production, row and silage crops, and cattle grazing. Less than 10 miles west of the site is the City of Galt, which is a rapidly growing community (Figure 1-1). From 1999 to 2025, the population of Galt is expected to grow from 19,000 to 35,500 persons (Ref 5.3). The growth of Galt is important in this characterization because the City of Galt provides water through the operation of six wells distributed throughout the city. As the population increases, more water will be needed, potentially causing more groundwater removal. Groundwater beneath the site flows west-southwesterly, toward the city of Galt.

1.4 Topography The elevation of the RSNGS acreage varies from 147 to 195 feet above mean sea level, and drainage along natural gullies varies from 2 to 6 percent. The plant site's rolling terrain is not directly intersected by any streams; however, drainage from higher levels is well defined and intersects with drainage at lower levels. The plant's grade level of approximately 165 feet above mean sea level allows excellent drainage without danger of flooding.

1.5 Meteorology The climate at the RSNGS site is typical of the Central Valley of California, with hot, dry summers and cool, wet winters. The average annual precipitation estimated for RSNGS is approximately 18 to 19 inches; more than 75 percent occurs between December and March (Ref 5.4). Snow is very rare in Sacramento County; therefore, all of the precipitation is from rain. The average evapotranspiration rate in the Sacramento area is approximately 50 inches per year (Ref 5.5).

In summer, the temperature range may be 35 to 40 degrees Fahrenheit because of cooler marine air that flows through a gap in the Coast Range and across the Sacramento-San Joaquin river delta, lowering the typical 90 to 100+ degrees Fahrenheit daytime highs.

The maximum recorded wind speed in Sacramento County through 1998 was 74 miles per hour.

The average wind speed is 6 miles per hour. Tornados are rare in California, averaging five per year; damage from tornados in the state is rarer.

K:\\Wprocess\\25612\\Rancho Seco'Jlydro Assessment\\Text.doc l1-6 March 2006

SECTIONTWO HIydrogeological Conceptual Model The hydrogeological conceptual model has been developed from all of the surface and subsurface information that has been accumulated for RSNGS. This information consists of surface and subsurface geology, soil parameters, surface and subsurface hydrology, and groundwater-use records.

2.1 Previous Geologic Investigations 2.1.1 Initial Siting Investigation A soil and foundation investigation program was conducted to establish the suitability of the site and to provide the basic criteria for design of RSNGS. The drilling and sampling program began on June 28, 1967, and was concluded on August 25, 1967. Preceding the drilling and sampling program, a geologic reconnaissance and mapping program was performed by Bechtel geologists in consultation with Roger Rhoades, consultant geologist to Bechtel Corporation. Borings drilled on the RSNGS site included 71 exploratory holes and 1 domestic water supply well (Figure 2-1).

The results of the initial siting evaluations are summarized in Section 2.4.7, Wells and Borings, with additional details contained in Appendix 2C, Geology and Seismology, and Appendix 2E, Soils and Foundation Investigation Program, of the District's Unit No. 1 Final Safety Analysis Report (Ref 5.6).

Geophysical logging techniques were employed in DH-23, the deepest geologic boring drilled at the site. These techniques provided a continuous geophysical log of materials with depth between sampling intervals and indicated changes of materials, density, and firmness with depth.

Refraction seismograph traverses also were run in the general area of the proposed site using a portable seismic device. The seismic velocities obtained were used to interpret the densities or changes in the properties of subsurface materials with depth.

The entire investigation program was supervised by Bechtel Corporation; the drilling was carried out under a subcontract with Boyles Bros. from Auburn, California, and Myren Drilling of Sacramento, California. Selected soil samples were tested by the Soil Mechanics and Foundation Engineers, Inc., soils laboratory in Palo Alto, California, and supplemented by classification and other testing performed by the District's soils laboratory facility near Placerville, California.

2.1.2 Geotechnical Investigation for Proposed Evaporation Ponds A geotechnical investigation of a proposed evaporation pond site at RSNGS was performed in Summer and fall 1985. The site is located about 0.25 mile southwest of the industrial area, in an area of gently rolling topography underlain by unconsolidated alluvium and poorly consolidated sedimentary rocks. The purpose of the geotechnical investigation was to collect subsurface geologic and soils data for use in evaluating the suitability of the site for the proposed evaporation ponds and to establish a baseline groundwater and soil pore water monitoring system. The ponds were not constructed.

K:\\Wprocess\\2561 2\\Rancho Seco\\Jlydro Assessmen\\Text.doc 2-I March 2006 KAEWprocess\\2561 2\\Rancho Seco~llydro Assessment\\Tentdoc 2-l March 2006

-R-b n M s mxd CA-S LEGEND AH 1 Auger Hole Location (1967)

DH100 Drill Hole Location (1967)

SW 1 Supply Well Location OW 1 Observation Well Location for Evaporation Pond (1985)

B 5 Boring Location for Evaporation Pond (1985)

MW1A-C Monitoring Well Nest Location (2005)

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Figure 2-1. Locations of Borings Drilled and Sampled at Rancho Seco NGS COC?

SECTIONTWO Hydrogeological Conceptual Model The fieldwork included soil sampling, permeability testing, installation of observation wells and lysimeters, water sampling, and measurement of groundwater levels. Four permeameter holes were drilled for testing permeability of near-surface soils. Four observation wells and two lysimeters were installed. Four test pits were dug for bulk soil samples and 10 soil borings were drilled to collect soils samples for laboratory testing. The water table at this location is at a depth of approximately 150 feet.

Using data from the field program, the effect of a hypothetical pond liner failure on downgradient groundwater quality was analyzed. Based on conservative distribution coefficient assumptions, and considering the effects of adsorption, a travel time of over 20,000 years was calculated for a radiological contaminant to reach the nearest downgradient well 2,200 feet southwest of the evaporation pond site.

A complete description of the geotechnical investigation and its results is contained in Geotechnical Investigation for Proposed Evaporation Ponds (Ref. 5.7).

2.1.3 2005 Update Investigation To reduce uncertainties in the hydrogeological conceptual model, an investigation was undertaken in 2005. The investigation plan was presented to a group of Nuclear Regulatory Commission personnel at their Headquarters in November 2004 to gain preliminary approval of the investigatory approach. At the time that the plan was presented, seven nests of wells were thought to be necessary to fully evaluate hydrogeology and obtain parameters for modeling.

However, four nests may be adequate to complete the assessment.

In the investigation, nests of monitoring wells were constructed at four locations between potential sources of contamination (Turbine Building, Spent Fuel Pool, Retention Basin) and the RSNGS property boundary (Figure 2-1). Each nest was intended to have three monitoring wells constructed within one boring. The monitoring wells were constructed such that the well screens were emplaced at three different depths within the boring. Table 2-1 lists the drilling and construction details of each of the well locations. Drilling and construction of wells were permitted by the Environmental Management Department of the County of Sacramento.

The 12-inch-diameter borings were drilled with mud rotary drilling equipment. The subsurface materials being penetrated by the drill were described by the on-site geologist using the drill cuttings brought to the surface by the drilling mud. Drilling logs and construction details are presented in Appendix A. Samples of soil and rock above the water table were collected with split-spoon equipment at three different depths in the borings for MW1 and MW2.

The first boring was drilled into dense sandstone or siltstone at 400 feet below ground surface (bgs). The nature of the rocks penetrated below 320 feet bgs in that boring indicated that vertical migration of any contaminants would be slowed, if not stopped, by the condition of the rock.

Subsequent borings were drilled to 300 to 340 feet bgs after penetrating the top of the same dense rock that would impede contaminant migration. After drilling of each boring, the construction of the three monitoring wells in the boring was decided by the on-site geologist in consultation with a California Certified Hydrogeologist. Between the screen intervals in adjacent K:~Wrocss\\56I2\\Rncho5ec\\Hyro ssesmet\\Tet~dc 23 Mrch200 KAWprocess\\25612\\Rancho SecoUlydro Assessmenffextdoc 2-3 March 2006

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r- ' E- - r7 SEGTIONTWO Hydrogeological Conceptual Model Table 2-1. Construction and Water Elevation Data Groundwater Vertical Gradient Elevation, Between this Well Screen Interval December 6, 2005 and Shallower Well ID Northing Easting (feet bgs)

Water Use (feet msl)

Well (ftlft)

MW1A 1888419.45 6813523.57 160 - 170 Monitoring NA MW1 B 1888419.16 6813522.97 210 - 220 Monitorin

-18.82 NA MWIC 1888419.56 6813522.92 290 - 300 Monitoring

-19.33 0.0064 MW11D NA NA 200 - 220 Monitoring NA NA MW2A 1887946.55 6812353.12 200 - 210 Monitoring

-22.54 MW2B 1887945.27 6812352.87 265 - 275 Monitoring

-22.91 0.0057 MW2C 1887946.21 6812353.24 320 - 340 Monitoring

-22.92 0.0002 MW3A 1888224.36 6810988.02 200 - 210 Monitoring

-24.56 MW3B 1888224.00 6810987.93 265 - 275 Monitoring_

-24.62 0.0009 MW3C 1888224.13 6810988.28 310 - 320 Monitoring

-24.71 0.0020 MW4A 1887086.40 6810770.31 195 - 205 Monitoring

-29.02 MW4B 1887086.44 6810770.72 251 - 261 Monitoring

-29.06 0.0007 MW4C 1887086.10 6810770.56 310 - 320 Monitoring

-28.99

-0.0012 OW-2 1886349.74 6910826.33 168 - 177 Monitoring

-28.7 NA OW-3 1887127.52 6811602.60 177 - 187 Monitoring

-26.54 NA SW-1 NA NA 156 - 400 Water supply NM NA SW-2 NA NA 254 - 295 Water supply NM NA NA = not available NM = not measured K:\\Wprocess\\256 I 2\\Rancho Seco\\Hydro Assessment\\Text.doc 2-4 March 2006 K:\\Wprocess\\25612\\Rancho Seco\\Hydro Assessment\\Text.doc 24 March 2006

SECTIONTWO Hydrogeological Conceptual Model wells are at least 35 feet of less permeable material than that in the screen interval. After the screen decision was made, the wells were constructed with clean, low-carbon steel casing and screen. Following construction of each well nest, each well in the nest was developed to assure groundwater would flow into the screen. All of the wells were developed and water flowed into the screen, with the exception of MW1A, the well with the shallowest well screen at location MW1. The shallowest well in each nest is labeled "A;" the "B" and "C" wells are successively deeper in the boring.

Nine months after construction, Well MW1A had not provided any water level information or groundwater samples. The well screen at 160 to 170 feet bgs has been above the groundwater level since the well was completed. During drilling, it was not possible to confirm that groundwater was present at 160 feet bgs because, when drilling with the mud rotary technique, water containing drilling mud is added to the boring during drilling. Little loss of drilling mud occurred while the drill penetrated through the 140 to 170 feet bgs because the material was a plastic clay; therefore, the penetrated material seemed to be water saturated. Previous work at the site and water-level measurements in existing wells indicated that the groundwater surface would be approximately 140 to 150 feet bgs. Groundwater depths in Wells MW1B and MW1C were greater than 182 feet bgs in December 2005. MW1B has sampling equipment stuck in the casing and cannot be sampled. A new well (MWID) was constructed near the MWIA location in February 2006. The well will be sampled after it is developed.

2.2 Geology and Physical Parameters Geology. The RSNGS site is located within the Great Valley Geomorphic Province, which is a wide structural trough bounded by the Sierra Nevada on the east and the Coast Range on the west. The surface geology of RSNGS and the city of Galt, California, is shown on Figure 2-2 (Ref 5.8). The youngest alluvial deposits occur farthest west, near the City of Galt and Interstate

5. The deposits exposed at the surface are older as one moves east toward RSNGS.

The stratigraphy of the RSNGS site consists of the following deposits:

Recent alluvium consisting of stream-deposited gravel, sand, and silt. This material is confined to present drainage courses and ranges in depth from 0 to 5 feet bgs.

• Older alluvium consists of old stream and terrace deposits of gravel, sand, and silt. This material covers the floodplains in the southwestern portion of the site and deposits of well-rounded cobbles, pebbles, and sand derived chiefly from pre-Cretaceous sediments on pediment surfaces. This category includes the equivalents of the Modesto and Riverbank formations. The thickness on site is 0 to 20 feet.

• The Laguna Formation consists of sand, silt, and some gravel; it may or may not contain clay. It is made up of poorly bedded materials of silicic volcanic origin. This formation occurs at the surface across much of the site; its bottom boundary has been encountered at depths of approximately 130 feet bgs.

K:\\Wprocess\\2561 2\\Rancho Seco'Jlydro Assessment\\Text.doc 2-s March 2006

SECTIONTWO Hydrogeological Conceptual Model A

N LEGEND Qr Recent Alluvium Qmr Modesto-Riverbank Formation TI Laguna Formation Tm Mehrten Formation Tvs Valley Springs Formation Highways/Roads 0

3.2 SCALE IN MILES Rancho Seco\\02-06-Rancho-Srogeoloqy cd - LCT 03.06.06 SAC Figure 2-2.

Geologic Map of Area from Rancho Seco to Gait, California

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SECTIONTWO Hydrogeological Conceptual Model The Mehrten Formation consists of fluviatile sandstone, siltstone, and conglomerate composed primarily of andesitic detritus. Locally, it contains horizons of coarse andesitic agglomerate of mudflow origin. This formation is encountered at the surface west of the industrial area and has an approximate thickness of 225 feet beneath the site.

• The Valley Springs Formation consists of pumice and fine siliceous ash, with much greenish-gray clay and some vitreous tuff, glassy quartz sand, and conglomerate. It is commonly well bedded. It derived largely from rhyolithic material thrown out from the high Sierra Nevada.

This formation has no surface exposures on the site, and an estimated thickness of 250 feet beneath the site.

• The lone Formation is composed of clay, sand, sandstone, and conglomerate. It may have a thickness of 200 to 400 feet beneath the site, and it is not exposed anywhere on the District property. Lying beneath the Valley Springs Formation, the lone Formation is likely to be the deepest sedimentary deposit above the metamorphic basement rocks; however, its depth and thickness are not known because none of the site borings penetrated through the Valley Springs Formation. The approximate depth of the metamorphic basement rocks beneath the site is 2,000 feet bgs.

Borings MW2, MW3, MW4, OW2, and OW3 drilled at RSNGS have penetrated the Older Alluvium, Laguna Formation, and part of the Mehrten Formation. Two borings, DH-23 drilled in 1967 and MW1 drilled in 2005, have penetrated the Older Alluvium, Laguna Formation, Mehrten Formation, and probably hard green siltstone and claystone of the upper part of the Valley Springs Formation.

No faults have been identified within 10 miles of the RSNGS, and the only structure in the sedimentary rocks is identified by gentle westerly dips of I to 3 degrees caused by the gradual uplift of the Sierra Nevada relative to the basin receiving the sediments.

Physical Parameters. Several investigations have measured the physical parameters in samples collected from the subsurface of RSNGS. The parameter values will be used in a mathematical model that predicts the subsurface behavior of groundwater and/or contaminants carried by groundwater. The mathematical model translates the hydrogeological conceptual site model into a series of equations that, at a minimum, describe the geometry and dimensionality of the hydrogeological system, the initial and boundary conditions, the time dependence, and the nature of the relevant physical and chemical processes. The model requires that the site geology and hydrology can be described in terms of physical parameters. Subsurface zones used in the model require site-specific values for the parameters as described in the Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil [Ref 5.13].

Before the 2005 drilling, sampling and analyses values for 12 parameters or data were considered inadequate. After the 2005-2006 investigation and continuing evaluation, the quantity of parameter and other data was manually increased. In Table 2-2, the RSNGS-specific data for each data need are summarized and compared to the pre-investigation status. The laboratory sheets for the physical parameter measurements are included in Appendix B K:\\Wprocess\\2561 2Rancho Seco'Jlydro Assessment\\Text.doc 2-7 March 2006 KAWprocess\\25612\\Rancho SecoUlydro Assessmenffext.doc 2-7 Mtarch 2006

SECTIONTWO Hydrogeological Conceptual Model Table 2-2. Physical Property Data Status for RSNGS Pre-Investigation Parameter or RSNGS Data Adequacy Range After 2005-Post-Investigation Data Need Availability Rating 2006 Investigation Adequacy Rating Soil dry bulk 39 Inadequate; 0.8 to 1.78 grams/cm Adequate; wider density measurements samples from (To be updated with horizontal and vertical limited area February 2006 sample distribution results)

Soil total porosity 15 Inadequate; 0.35 to 0.55 cm /cm Adequate; wider measurements samples from one (To be updated with horizontal and vertical boring February 2006 sample distribution results Effective porosity No data; Inadequate 0.2 to 0.3 cmr/cmJ Adequate; wider calculated (To be updated with horizontal and vertical from other February 2006 sample distribution parameters results)

Hydraulic 8 in Inadequate; no Unsaturated: 2.8 x 10 Adequate; wider conductivity unsaturated data below 200 to 2 x 104 cm/second horizontal and vertical zone; 23 in feet Saturated: 4 x 10-7 to 2 distribution saturated zone x 10'4 cm/second (To be updated with February 2006 sample results)

Volumetric water 71 Adequate 0.12 to 0.358 cm /cm Adequate; wider content measurements horizontal and vertical distribution Soil exponential b No data In table of Dependent on soil type Adequate; values from parameter accepted model table determined from values site soils Hydraulic gradient No data Inadequate 0.0022 to 0.0033 Adequate; determined

- horizontal feet/foot (12/05) from field measurements in new wells Hydraulic gradient No data Inadequate

-0.00119 to 0.0057 Adequate; determined

- vertical feet/foot (12/05) from field measurements in new

____w ells Water table drop Data from Adequate 1 0-foot Adequate rate existing decline/recovery in a subbasin wells year; stable year to year Thickness of No data for Potentially 182 feet at MW1 and Adequate uncontaminated, contamination; adequate 164 to 169 feet at unsaturated zone entire zone is MW2 to MW4 in 12/05.

150 feet Potentiometric No data on site Inadequate See Figure 2-5.

Adequate surface maps K:\\Vproccss\\256 I 2\\Rancho Scco'Jiydro Asscssment\\Text.doc 2-8 March 2006 K:AWprocess\\25612\\Rancho Seco~llydro Assessment\\Text.doc 2-8 hlarcb 2006

SECTIONTWO Hydrogeological Conceptual Model Table 2-2. Continued Pre-investigation Parameter or RSNGS Data Adequacy Range After 2005-Post-investigation Data Need Availability Rating 2006 Investigation Adequacy Rating Groundwater flow No data Can be estimated Horizontal and Adequate paths with hydraulic southwesterly gradients Climatic, land Data available Adequate See Section 1.0 Adequate use, and recharge for subbasin impacts Surface-water No data; Potentially See Section 3.0 Adequate impacts on groundwater adequate groundwater 150 feet below surface Rate of Limited data to Inadequate for Unsaturated: 2.7 x 1 O' Adequate; wider groundwater do calculation entire aquifer; cm/second to 2 x 10-6 horizontal and vertical movement obtained from cm/second distribution.

hydraulic Saturated: 3.9 x 109 to conductivity and 2 x 1 O-6 cm/second gradient Rate of No data Inadequate; Less than groundwater Adequate; wider contaminant calculated from movement; retardation horizontal and vertical transport rate of depends on distribution of rate data groundwater contaminant.

above.

movement Radionuclide No data for soil Inadequate Results reported Assessed elsewhere presence and or groundwater elsewhere extent Kd Partitioning No data To be derived No data obtained To be derived with coefficient with probabilistic probabilistic calculations in the calculations in the model model cm

=

centimeter(s) cm3

=

cubic centimeter(s 2.3 Hydrology Runoff from the site drains into a seasonal unnamed creek, which is tributary to Clay Creek, which empties into Hadselville Creek. Hadselville Creek is a tributary of Laguna Creek South, which flows into the Cosumnes River, which joins the Mokelumne River upstream from its confluence with the San Joaquin River. A portion of the flow in the unnamed creek originates below the dam constructed to create the Rancho Seco Reservoir, approximately 1 mile southeast of the industrial area (Figure 2-3). The remainder of the flow in the creek originates from runoff in the area of its catchment west of the dam and from releases of water from Rancho Seco.

Water, most of which is conveyed to the site from the Folsom South Canal, is consistently released to the creek from the RSNGS industrial area at an average rate of 6,000 gallons per minute.

K:\\Wprocess256I 2\\Rancho Seco'Jlydro Assessment\\Text.doc 2-9 March 2006 KAVprocess\\256 12\\Rancho Seco\\l lydro Assessment\\Text.doc 2-9 March 2006

SECTIONTWO Hydrogeological Conceptual Model Recharge to the groundwater occurs primarily by the infiltration of surface water along the active channels of streams, such as the Cosumnes River, Dry Creek, and Mokelumne River, and by deep percolation of applied irrigation water (Ref 5.9). Some recharge also occurs from the direct infiltration of precipitation; however, direct infiltration is limited by the relatively low (18-inch) annual rainfall, relatively high (50-inch or more) evapotransporation rate, the moderate to low permeability (0.07 to 0.08 inch per hour) of surface soil, and the deep (greater than 140 feet bgs) water table.

Widening of the unnamed creek occurs at the District's western property boundary in an area where the gradient decreases. Most of the flow into unnamed creek originates from the Folsom South Canal and is discharged from the site in the liquid effluent pathway downstream of the site retention basins. Since the investigation of the RSNGS began in the 1960s, no flooding or inundation from storm runoff has occurred within the site boundaries. The industrial portion of the site would not be flooded during a 100-year storm event (Ref 5.16). The topography of the site and the soil types promote runoff away from site buildings. However, seasonal marshes and vernal pools develop west of the industrial area in shallow surface depressions during and after the December through March rainy season.

2.4 Hydrogeology The RSNGS site is located within the Cosumnes Subbasin of the San Joaquin Valley Groundwater Basin (Ref 5.10). The subbasin consists of the unconsolidated and semi-consolidated sedimentary deposits that may hold groundwater between the Cosumnes River on the north and the Mokelumne River on the south. All of the sedimentary deposits in the Cosumnes Subbasin, and possibly the basement rocks if they are fractured, may contain groundwater. Figure 2-4 is a cross section illustrating the extent of hydrogeologic information with a three-dimensional perspective. Thirteen borings on the site have penetrated the groundwater; four of those borings were completed as water supply wells, and geologic information was not saved for two of them. Three observation borings, each to a depth of 200 feet bgs, one boring drilled to 602 feet bgs, four 2005 borings, and one 2006 boring for monitoring well nests provide the geologic information about the aquifer.

Subsurface deposits beneath RSNGS are dominated by fine-grained deposits of clay and silt with interbedded thin sands and gravels to a depth of approximately 120 to 130 feet bgs; above that depth interval, deposits become more indurated with depth, such that some intervals can be considered claystone and siltstone. Beneath 130 feet, the deposits are siltstone and claystone with thin (10 feet or less) interbedded sandstone and conglomerate; this interval is mostly within the Mehrten Formation. At approximately 290 to 330 feet bgs in all of the deeper borings, drilling became very difficult as the drill penetrated gray to green well-indurated siltstones with thin sandstones and claystones. This change in drilling and lithology of deposits is interpreted as the top of the Valley Springs Formation.

K:\\Wprocess\\2561 2\\Rancho Seco\\Hydro Assessment\\Text.doc 2-11 March 2006 KAWprocess\\25612\\Rancho Scco\\Hydro Assessment\\Text-doe 2-1 March 2006

SECTIONTWO Hydrogeological Conceptual Model The upper groundwater surface beneath the site now occurs at depths greater than 165 feet bgs (December 2005) in the sediments of the Mehrten Formation. Therefore, groundwater may be present from approximately 165 feet bgs in the Mehrten Formation to perhaps 2,000 feet bgs, where the lone Formation is in contact with much denser rocks. The sand and gravel zones of these formations yield water readily to wells predominantly west of the facility in the Central Valley. The Mehrten Formation is known for yielding large volumes of water to wells (Ref 5.11)

Beneath the site, however, the Mehrten Formation consists predominantly of siltstones and claystones that are likely to have lower hydraulic conductivity values (1 x 10-7 to 1 x 104 centimeters per second [cm/sec]

from permeability tests [Ref 5.7]) than the typical Mehrten Formation, which is sand/sandstone dominated. The sediments of the Laguna Formation are above the water table and, therefore, do not produce groundwater to wells. However, the hydraulic conductivity range of samples collected in the unsaturated Laguna Formation is 2.8 x l0-7 to 5.8 x 10-4 cm/sec. The Valley Springs and lone formations are considered small-yield aquifers because of low hydraulic conductivity values caused by claystone and siltstone layers (Ref 5.11).

In the Cosumnes Subbasin, groundwater flows to the west from the foothills and the RSNGS area. For at least 40 years (since the initial investigation of the site), a groundwater depression has been caused by the pumping of municipal and agricultural wells in the Galt area. Figure 2-5 shows contours of groundwater elevations in southern Sacramento County (Ref 5.12); the top part of the figure shows contours for Spring 2003, and the bottom part shows contours for Fall 2003; the 2003 maps are the most recent contour maps available from the county. On both figures, a groundwater depression is roughly centered on the town of Herald, which lies between the site and Galt. The depression had an elevation approximately 10 feet lower in Fall 2003 than in Spring 2003. The shape and values of the groundwater elevation contours on the figures indicate that groundwater beneath the site will flow southwesterly toward the depression.

Groundwater levels in the four new well nests suggest that there is one aquifer between the water table and 300 feet bgs, that the horizontal gradient is southwesterly, and the vertical hydraulic gradient is upward. A potentiometric surface map, constructed with data collected in the monitoring wells on December 6, 2005, is shown in Figure 2-6. The contours support the hypothesis of southwesterly gradient beneath RSNGS. The average hydraulic gradient calculated from potentiometric data for the wells is 0.0028 feet per foot. Only one potentiometric surface map was prepared because the data suggest that the horizontal gradients are similar in all depth intervals from 170 to 300 feet bgs (Table 2-1). Vertical gradients were upward from the deepest screen interval (approximately 300 feet bgs) toward the shallower screen depths, except between MW4C and MW4B. However, the gradient is upward from MW4B to MW4A. Therefore, an upward gradient averages 0.0028 foot per foot among six pairs of wells. This vertical gradient value is essentially identical to the average horizontal gradient among the wells.

No pumping tests have been conducted at the site. Hydraulic conductivity values have only been estimated from laboratory hydraulic conductivity tests and in situ packer permeability tests (Ref.

5.7).

K:\\Wproccss\\2561 2\\Rancho Seco\\Hydro Assessment\\Text.doc 2-13 March2006 KAVprocess\\2561 2\\Rancho Seco~llydro Assessment\\Text.doc 2-13 March 2006

SECTIONTWO Hydrogeological Conceptual Model Groundwater Levels Southern Sacramento County Spring 2003 Groundwater Levels Southern Sacramento County Fall 2003 Figure 2-5. Groundwater Elevation Contours Measured in 2003, Southern Sacramento County cO(U K:\\Wprocess\\256 1 2\\Rancho Seco\\liydro Assessrnent\\Text.doc 2-14 March 2006

V I-E V1r7 7

C

-7 C-C7 V-jE7 U

r-r r-

[77-nir-VA me

=4 0

z m

ozn tca.~

C C'

Figure 2-6. Potentiometric Surface Map for Groundwater Beneath RSNGS, December 2005

SEOTIONTWO Hydrogeological Conceptual Model With site-specific data obtained in the 2005-2006 investigation and previous investigations, an estimate of the migration speed of a water particle can be made. Assuming the highest hydraulic conductivity measured (2 x 10-4 cm/sec) and a travel distance of 165 feet from a near-surface source to groundwater, a particle would require approximately 80 years to reach groundwater.

Once the particle reached groundwater, and again assuming the highest hydraulic conductivity of 2 x 104 cm/sec and a distance of 3,100 feet, the travel time to the RSNGS property boundary is estimated at approximately 1,500 years. However, the hydraulic conductivities of some clayey deposits above the groundwater and below the groundwater surface may be only l/1000h of the value used in the preceding calculations. Therefore, it is likely that migration to groundwater will require more than 80 years and migration to the property boundary will require more than 1,500 years.

Long-term hydrographs for 23 wells in the Cosumnes Subbasin indicate that water levels declined from the mid-1960s until approximately 1980, unless the wells were in the recharge area of the Cosumnes River, which is several miles north of the site. From 1980 until 1986, water levels in most wells recovered as much as 10 feet from pre-1980 levels. Water elevations again decreased approximately 10 to 15 feet during the drought years of 1987 to 1992 and recovered 15 to 20 feet from 1993 to 2003 (Ref 5.10).

Water from the Laguna and Mehrten formations is considered generally good quality in the vicinity of RSNGS. Potable water used on the site comes from one of four site wells. Since 1969, Supply Well 1 has been producing at a rate of 300 gallons per minute, on demand, from the Mehrten Formation from the depth interval of 200 to350 feet bgs (Ref 5.7).

K:\\Vprocess\\256I 2\\Rancho Seco\\Hydro Assessment\\Text.doc 2-16 March 2006 K:\\Wprocess\\2561 2\\Rancho Seco\\Hydro Assessmenff~eatdoc 2-16 March 2006

SECTIONTHREE Groundwater Evaluation The 2005 investigation of RSNGS was conducted to evaluate hydrology and hydrochemistry that would affect migration of any contaminants migrating in groundwater. Water samples were collected in 10 new wells and 3 water supply wells to evaluate groundwater chemistry and water quality.

3.1 Sampling for General Minerals in Groundwater Groundwater samples were collected from 10 of the 12 monitoring wells constructed in 2005 and analyzed for a suite of analytes that characterize the natural constituents in groundwater that originate from the atmosphere and from the soluble anions and cations from soil and aquifer material. Well MWIA did not produce sufficient water for a sample and Well MW1B became obstructed with sampling equipment. Sometimes referred to as "general minerals," the analytes in the suite are used to determine differences between groundwater bodies that may be vertically separated. Near-surface groundwater may have a different geochemical composition than deeper groundwater because of constituents dissolved from soil and anthropological sources. In addition to the general mineral constituents, analyses were performed for the total boron because boric acid was added to the water heated by nuclear reactions and would be an indicator that leakage of water from the reactor area reached groundwater.

In addition to the 10 samples from monitoring wells, a sample from one groundwater supply well in the RSNGS industrial area, SW-2; a sample from the supply well, SW-1, just east of the industrial area; and one sample from a well at Rancho Seco Park (RSPW), approximately a mile southeast of the industrial area, were also sampled for the suite of analytes. Results from the two wells located east of the industrial area are representative of "background conditions" because the groundwater moving through those wells has not been affected by any discharges from RSNGS activities. Groundwater at SW-i and RSPW can be considered unaffected by any contaminants from the RSNGS industrial area because groundwater has been flowing from northeast to southwest for at least 38 years.

Table 3-1 lists the results of the general minerals results for groundwater samples. It is readily evident that borate is not a contaminant in the samples analyzed because it was detected in only one sample, from Well MW2A, at a concentration equal to the reporting limit of 0.05 milligrams per liter (mg/L). Furthermore, the results are notable for the similarity of values among the wells sampled. The only readily identifiable differences in the table are the variations in total iron concentration, higher level of total dissolved solids, presence of detectable concentrations of nitrate nitrogen, and pH 1.5 to 2.1 units lower in Wells SW-1, SW-2, and RSPW than in most of the monitoring well samples. Laboratory sheets for the groundwater analyses are included in Appendix C.

The similarity of most parameters among all monitoring well locations and all depths indicate that groundwater is not stratified with large differences in constituent concentrations vertically.

Graphical techniques that show the similarity or difference in general mineral concentrations between waters were used to confirm that groundwater up hydraulic gradient from the industrial area, beneath the industrial area, and down hydraulic gradient from the industrial area are the same. Piper and Stiff diagrams were prepared with concentrations of the major cations and anions occurring in groundwater: calcium, magnesium, potassium, sodium, bicarbonate, carbonate, chloride, and sulfate concentrations (Figures 3-1 and 3-2).

K:AlVprocess\\2561 2\\Rancho Seco\\}lydro Assessment\\Text.doc 3-1 March 2006

SECTIONTHREE Groundwater Evaluation MW1 C O MW2A

+ MW2B O MW2C

+ MW3A MW3B MW3C MW4A MW4B MW4C SW-1

+ SW-2 O RSPWI 0

8 8

9 89 2

Ca 60,-

40 20 Na+K HCO3 +C0 3 20 40 v 60 Calcium (Ca)

Chloride (Cl)

CATIONS

%meq/7 A N I O N S Cl Figure 3-1. Piper Diagram for Groundwater Concentrations Beneath RSNGS Co2 3-3 March 2006

SECTIONTHREE Groundwater Evaluation MWIC Sw-I Cabons I Anions eL qL Na+K Cl Cations I Anions meqfL meqL Na+K CI

n. HCO3 4 C03

> HCO3

+ C03 Mg S04 MWV2A SW-2 Cations I Anions mel Na+K ca Cations I Anions ma+L CL Na+K Cl K

HCO3 b +COS Ca 504 Mg S04

+ HC03

+C03 MW3B RSPW CationsI Anions qOL eqL Na +K CI 23/4 HCO3 C

t+C03 Mg S04 Cations I Anions meqIL Na+K CI

>. HCO3

+ C03 MW4C CaIons Anions L

mqL Na+K CI.~

X !

HC Figure 3-2. Stiff Diagrams of Cation and Anion Concentrations in Groundwater Beneath and Upgradient from RSNGS

(,Oj2 K:\\Wprocess\\256 12\\Rancho Seco\\Hydro As sessmrent\\Text.doc 3-4 March 2006

SECTIONTHREE Groundwater Evaluation In the Piper diagram, each of the 13 well samples is represented by one dot on each of the three diagrams. For this diagram, concentrations of the major cations and anions are converted to meq and totaled. The location of dots representing wells is determined by the percentages of the total that each cation or anion (or a combination such as sodium and potassium) contributes. The close clustering of all the dots representing monitoring well samples as well as the three supply wells indicates that no great difference occurs in the groundwater from 1 mile upgradient to 3,500 feet downgradient of the industrial area. Furthermore, groundwater from 300 feet bgs from the "C" depth monitoring wells is not distinguishable from the groundwater in the "A" and "B" depth wells.

Stiff diagrams use the same meq/L data. However, they are arrayed in a different plot. Stiff diagrams are made for rapid pattern recognition to classify a groundwater and determine similarities from location to location and shallow to greater depths. Figure 3-2 illustrates a series of Stiff diagram plots that further support the similarity of groundwater among all of the wells sampled. These diagrams also indicate that the groundwater beneath District property, including RSNGS, is a sodium-bicarbonate type.

3.2 Data Interpretation Two wells up hydraulic gradient from the industrial area (SW-1 and RSPW) tap groundwater that has the same composition and similar concentrations of general mineral constituents as groundwater beneath and down hydraulic gradient from the industrial area. Therefore, the two wells can be used as indicators of background quality to compare with any wells that are suspected of being contaminated.

The general mineral constituents at 190 feet bgs in the groundwater beneath RSNGS are essentially the same as at 320 feet bgs. This condition and the upward hydraulic gradient from greater depth to shallower suggests that sampling of most of the "C" depth wells for contaminants will not be necessary because contamination, if any is suspected in the "A" depth wells, is unlikely to migrate downward against the gradient.

K:\\Wprocess\\2561 2\\Rancho Seco'JIydro Asscssmcnt\\Text.doc 3-5 March 2006 K:\\Wprocess\\2561 2\\Rancho Seco\\Hydro Assessment\\Textdoc 3-5 March 2006

SECTIONFOUIR Conclusions and Recommendations On the basis of the data obtained in previous geologic investigations and in the recent hydrogeological investigation, the hydrogeological conceptual model was updated and conclusions have been developed. From those conclusions, recommendations for additional investigation and sampling are presented.

4.1 Conclusions The following conclusions have been developed from updating of the conceptual model with data obtained in 2005:

• Because groundwater between the depths of 180 and 320 feet bgs has an average upward gradient of 0.0028 foot per foot, any dissolved contaminants from RSNGS releases are more likely to remain in the shallower zones rather than being drawn to the deepest levels of the aquifer.

• Groundwater in all depth intervals has a southwesterly horizontal gradient.

Physical parameters measured from subsurface samples indicate diversity in hydrologic conductivity and other parameters needed for mathematical modeling.

• Groundwater from 180 to 320 feet bgs can be classified as sodium bicarbonate type that varies minimally in composition whether samples are collected upgradient, beneath, or downgradient of the RSNGS industrial area.

• A well with a screen at approximately 180 to 190 feet bgs is needed for sampling near the MW1 nest of wells. A new well replacing MW1B was installed at the nest in February 2006.

No additional monitoring well locations or soil samples are needed for hydrogeologic characterization unless contamination is discovered in newly constructed monitoring wells.

4.2 Recommendations The following recommendations are made to further enhance the hydrogeological conceptual model and determine whether contamination from RSNGS activities has reached groundwater:

Sample the newly constructed monitoring well near the MWI nest of wells.

• Evaluate the sample results to confirm similarity with general minerals and boron at other Rancho Seco wells.

K:\\Wprocess\\256 I 2\\Rancho Seco'Jlydro Assessment\\Text.doc 4-1 March 2006 KA\\Wprocecss\\2561 2\\Rancho Seco~llydro Assessmeriffeaduoc 4-1 March 2006

SECTIONFIVE References 5.1 Sacramento Municipal Utility District, 2004. Rancho Seco Nuclear Generating Station, Historical Site Assessnment. 100 p.

5.2 United States (U.S.) Government, 1999. Federal Register. Vol. 64, No 234, FR Doc. 99-31508.

5.3 Sacramento Area Council of Governments, 2001. Population Projection by Regional Analysis Districts.

5.4 Masters-Bevan, L., 2000. Clinate of Sacramento, California. National Weather Service Office, Sacramento.

5.5 Bertoldi, G., R. Johnston, and K. Evenson, 1991. Groundwater in the Central Valley, California-A Summary Report. U.S. Geological Survey Professional Paper 1401-A, 44p.

5.6 Sacramento Municipal Utility District, 1971. Rancho Seco Nuclear Generating Station, Unit No. 1, Final Safety Analysis Report.

5.7 Sacramento Municipal Utility District, 1989. Geotechnical Investigation for Proposed Evaporation Ponds. ERPT-C0104, Rev.1. April 5.

5.8 Wagner, D., C. Jennings, T. Bedrossian, and E. Bortungno, 1981. Geologic Map of the Sacramento Quadrangle, Map No. IA, California Division of Mines and Geology, 4 sheets.

5.9 California Department of Water Resources, 1978. Evaluation of Ground Wlater Resources, Sacramento County. Bulletin 118-3.

5.10 California Department of Water Resources, 2004. San Joaquin Valley Groundwater Basin, Cosumnes Subbasin. Bulletin 118, 5 p.

5.11 Page, R., 1986. Geology of the Fresh Ground-Water Basin of the Central Valley, California with Texture Maps and Sections. U.S.G.S. Professional Paper 1401-C, 54 p.

5.12 Sacramento County Department of Water Resources, 2003. Water Level Elevation Maps for Sacramento County.

5.13 Yu, C., et al., 1993. Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil. Environmental Assessment and Information Sciences Division, Argonne National Laboratoiy, Argonne, Illinois. April. Accessed from:

http://web.ead.anl.gov/ resrad/ documents/data collection.pdf.

5.14 Sacramento County, 1996. County Drainage Manual, Volume 2: Hydrology Standards.

5.15 Federal Emergency Management Agency (FEMA). 1980. Flood Insurance Rate Maps 500 and 525, Sacramento County.

K:\\Wprocess\\2561 2\\Rancho Seco'Jlydro Assessment\\Text.doc 5-1 March 2006

APPENDIX A 2005 Drilling Logs and Well Construction Details

Project: Rancho Seco Nuclear Generation Station l Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project:.17325612 MW1A, MWIB, MW1C Drilling Contractor:

Water Development Borehole Diameter-12-inch Borehole Name: MWI Loggeqd By: P. Phillips, S. Plunkett Drilling Method: Mud Rotary Dates Drilled: 5/2-5/2005 Well Construction:

5/5/2005 Checked B13Sm 3

Drilled by: Randy Criner Casing Diameter: 2.5-inch CasingType:

LowCarbon Steel Slot Size: A- 0.010-inch; B, -0.020-inch Total Depth Drilled:

400-feet Screen Intervals (ft bgs):

A-160-170'; B-210-220'; C-290-300' Well Development Dates:

6/6/2005 Sampling Method: Grab Top of Casing Elevations:

A-163.77; B; 163.61; C-163.43 Ground Surface Elevation:

164.20 A: Norlhing:

1888419.45 Easting: 6813523.57 B: Northing:

1888419.16 Easting:

6813522.97 C: Northing:

1888419.56 Easting: 6813522.92 Comments: Flat graded pad on AB base.

I)

E

'.5 Cn S

4)0 Sample ID P

LITHOLOGY DESCRIPTION WELL CONSTRUCTION 0b I I

I sssnlv vail Iaju 5

10 15-20-25 30-35-40-45-50-55-60-65-6i 61 &Y D 20 6; D 6 iY 20.0~Q2 Varigated, sandy, medirm pebble to coarse pebble gravel, abundant rock fragments (GP).

Schist, chert, milky and clcar quartz, biotite, basalt. moderately abundant.

light brown (7 5YR 614), well indurated schist, possible matrix to gravel.

z I

I MWIA MWlB Varigated mafic very coarse grained sand with abundant pebble gravel, abundant rock fragments (SP).

Clayey Sandy Silt. Brownish yellow (IOYR 6/6), abundant very coarse grained sand and rock fragments (ML).

Minor increase in pebble gravel.

Moderately abundant N arigated rock fragments.

Abundant very fine to very coarse grained sand.

Significant increase it very coarse grained sand.

>1

>1

>1

>1

>1

>1 Y

>1 Y

>1 Y

>1 Y

>1 Y

Y Y

Y

>1

>1 Y

Y I

Flush mount vault box Wells secured with locking pressure caps MWIA 2.5-inch inner-diameter (ID) Low Carbon Steel (LCS) blank casing to 160' MWI B 2.5-inch ID LCS blank casing to 210 MWIC 2.5-inch ID LCS blank casing to 290' Neat Cement from near ground surface to 152'.

a O 0

-5 20

-10

-15

-20 25

-30

-3s

-40

-45

-50

-55

-60

-65 2870 Gatiray Oaks Dr., Ste 300 Sacramento, CA 95833 is i,,

916-679-2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Ilearld, California 95638 Project: 17325612 l MWIA, MW1B, MW1C Il

.CL E-E to

.2t E!

Sample ID I

LITIIOLOGY DESCRIPTION WVELL CONSTRUCTION 70-75-80-85-90 95 100 105 110 -

115 7 1207 125 -

130-135 -

140 -

145 -

150-

'
N Granular to fine pebble gravel with abundant rock fragments in light brown (7.5YR 6/4) mud. volcanics, siltstone, abundant very fine to very coarse grained sand, angular to rounded, clear and milky quartz, red chert. ultra mafics, plagioclase, grecnstone (GW).

z MWIC SC /

QClayey Gravel. Reddish brown (5YR 4/4), abundant silt to very coarse grained sand to medium pebble gravel in silty/sandyclay.

/o

.o Gravelly, Sandy, Clay. Reddish brown (5YR 4/3), with moderately abundant rock fragments (CL).

.A0

.0.

>, CX g.X CSilty Gravel with abundant light pinkish gray (5YR 6/2) silty clay and i* cl *J abundant rock fragments. Gravel subrounded to rounded (GM).

?

'X ftl'

-70

-75

-80

-85

-90

-95

-100 105

-110 115 120 125

~ 130 135 140 145 150 L

1'

!r Sandy Clayey Silt/Silty Clay. Reddish gray (5YR 5/2), abundant gravel and rock fragments (CL).

Silt/Clay grading to reddish brown (5YR 5/4).

Continuing change in silt/clay color.

Silty Clay. Brown (7.5YR 5/4), plastic, very minor poorly indurated siltstone (CL).

14.4 liL L

I I L

t t

2870 Gateway Oaks Dr., Ste 300 Sacraento.CA 95833

_~~1 __

-s e

w

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, learld, California 95638 Project: 17325612 MW1A, MWIB, MW1C e

(a E

Lvi_

Sample ID F

0 LITIIOLOGY DESCRIPTION WVELL CONSTRUCTION 155-160 165-170-175-180-185-190-195-200-205-210-215-220 -

225 230-Ht

A A

A A

I Increase in siltstone and minor to moderate amounts of well cemented, medium grained sandstone.

Significant increase in sandstone and very coarse grained to granular gravel.

Continued presence of gramel and decrease in sandstone.

Decrease in both gravel an, sandstone fragments.

Interbeds of increasing sard to granular gravel layers.

Marked increase in indurated siltstone.

Indurated siltstone increa:(es to 20%.

Silty fine grained sandstone/sandy siltstone increases in abundance.

XXX

/_<X

/_4r,<

XA4

/_<X

/_<X X_<X XXX

/VX

/"(X

/VX

/_<X X/V

/-.<X

/V_<

XXX Bentonite Seal 152-155'

1. 30 Transition Sand 155-157' MWIA 2.5-inch ID LCS, 0.010-inch Continuous Slot Screen 160-170'

1. 3 Filter Pack Sand 157-171.5' Neat Cement 1715-203' Bentonitc Seal 203-205'

1. 30 Transition Sand 205-207' MWIB 2.5-inch ID LCS, 0.020-inch Continuous Slot Screen 210-220'

1. 3 Filter Pack Sand 207-221.5' 155 160 165 170

- 175 E-180

-1385

-190

- 195

- 200 205 210 215 220 225 230 Ve

... VXXIM X..le 1%,

Sandstone. Strong brown (7.5YR 5/6), fragmented, moderately cemented, rounded to subrounded (SS).

Interbeds of moderately indurated siltastone.

Continue presence of interbeds (less than 1-inch thick).

l l..... E.-.

I ::::.: E ::

I :-:-: -:- =

l.-.-:-:- = :-

..:.E.

I :::::: E ::

. E.-

I :: :.: E ::

I ::::::::::: :-: :

wtW 2870 Gateaay Oaks Dr.. Ste 300 1rSacramenio, CA 95833

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, llcarld, California 95638 Project: 17325612 MW1A, MWIB, MW1C L*

t E

En 0

01 r

C)

E F

^

1

-.y i ?

t7 235 s_

LITIIJOLOGY DESCRIITION WELL CONSTRUCTION Abundant rock fragments.

Abundant siltstone interbeds.

Decrease in siltstone and continued presence of rock fragments in moderately abundant amounts.

L L

Very well cemented sandstone clasts and varigated conglomerate granitic gravel interbeds, dark brown (7.5YR 3/2).

Cemented sandstone with minor clasts. dark yellowish brown (IOYR 314).

minor clasts > 0.5-inch. angular to subrounded.

I '!

L L

Sand. Minor gravel, dark grayish brown (IOYR 412), fine to coarse grained sand, moderately to well graded, subangular to subrounded, chert and quartz material, rock fragments (SWV).

Increasing very fine to medium grained sand, gravels decrease.

oL.

L L

Color change to Dark olive (SY 412). mafic, subrounded to angular, very fine to coarse grained sandstone (probably siltstone or claystone) (SLTST).

L L

2870 Gir'ray Oaks Dr., Stc 300 Sacrmrnto, CA 95833

_,ig916-679.2000

-I-L Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, Ilearld, California 95638 Project: 17325612 CI E

4 T

c;

'b Samiale ID E-C Lii'!JOl.OCY DESCI Log of Monitoring Wells:

MW1A, MWIB, MWIC 0

-V0 Siltstonc/Claystone. Mafic, very fine to fine grained sand, reddish brown (5YR 4/3), massive, slighty fractured, brittle, indurated (silica rich?).

(serpentinite?) (SLTST).

Sandstone. Dark olive (5Y 3/2), very fine to medium grained, subangular to subrounded, competent, silty, larger fragments are brittle (SS).

Sandstone. Dark Olive (5Y 3/2). very fine to medium grained, brittle, angular, elastic material, rock fragments (serpentinite?), competent, minor fractures (SS).

Siltstone. Dark olive (5Y 3/2). content of fines increase, silts and clays, angular to subrounded rock fragments, brittle, clayey siltstone <20% very fine to medium grained sand (SLTST).

Boring back-filled with Neat Cement I from TD to 301 ft bgs Clayey Siltstone. Silt and clay content increases, very little sand, soft.

No Recovery.

2870 Gateway Oaks Dr.. Ste 300 Sacramento. CA 95833 A,/SSAMAq

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Well:

Location: 14440 Twin Cities Road, Ilearld, California 95638 Project: 17325612 MW1D DrillingContractor:

WaterDevelopment Borehole Diameter:

12-inch BoreholeName: MWID Logged By: S. Lookingbill Drilling Method: ARCH; Mud Rotary Dates Drilled: 2/15-16/2006 Well Construction: 2/16/2006 Checked B&

fl091 Drilled by: Ryan Casing Diameter: 4-inch Casing Type: SC!! 40 PVC; LC Slot Size: 0.020-inch Total Depth Drilled:

220 feet Screen Interval (ft bgs):

200-220' Well Development:

Ground Surface Elevation:

Sampling Method: Grab Top of Casing Elevation:

Northing:

Easting:

Comments: 0-20 ft bgs drilled using Air Rotary Casing lammer (ARCH);20-220 ft bgs drilled using Mud Rotary.

L L

L 0_

2r_

V)

Sample ID F

1 LITIIOLOGY DESCRIPTION atZ,,.

WELL CONSTRUCTION Sandy Gravel. Brown, very fine grained sand, gravel to I-inch dianeter, subrounded. trace silt, dry (GP).

III L

.K V

,L I

II Silt. Light reddish brown, firm, non-plastic, trace sand (ML).

Li L

2870 GaIeWay Oaks Dr.. Ste 300

_Sxraniento, CA 95833 bttW916-679-2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Well:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 MW1D1 r-E E

L Sample ID F

LITIIOLOGY DESCRIPTION WFLI, CONSTRUCTION 70-75-80-85-90-95-100-105-l10 -

115-120-125 -

Sandy Siltstone. Brown, trace subrounded to subangular gravel (SLTST).

Silty Sand with gravel. Grayish brown, 80% coarse grained sand and gravel, gravel is subrounded to angular with quartz, feldspar, and volcanics (SM).

Sandy Siltstone. Light brown, very fine to fine grained sand. cemented (SLTST).

Gravel. Poorly graded, medium grained. subrounded to angular, trace coarse 522T252.

grained sand (GP).

Sandy Siltstone. Light reddish brown, fine grained sand, cemented (SLTST).

Silty Sandstone. Grayish brown, fine to coarse grained sand, trace gravel.

cemnted (SS).

Sand. Gray, very fine to fine grained, poorly graded, dense, cohesive (SP).

Consistent grain size throughtout.

Sandy Silt. Brown, hard, very fine grained sand (ML).

Silty Sand. Light brovn, coarse grained, subrounded to subangular. loose (SM).

-70

-75

-80

-85

-90

-95

-100 105

- 110

-115

-120 125 130 135 140 145 150 MWNIE 130-135-140-145-150 -

Silt. Reddish brown. tard, partly indurated, trace fine grained sand (ML).

Becomes brown.

2870 Gateway -.Aks Dr., Ste 300 Sawrainerio, CA 95833 TH IS ll 4,.A.V7V5

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Well:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 MW1D 2

-C

.0.

E T1 Ens i I I

00co

.2 E

P

.P 0

&IL Sample ID LITHIOLOGY DESCRIPTION W1E.LL CONSTRUCTION 155 160 165 170 175 180 185 190-195-200 -

205 -

210-215-220-Minor clay.

Clayey Silt. Brown, hard, trace very fine grained sand (ML).

I-155

-160 165 170 175 M

-185

-190

- 195 200 205 210 215 9\\A L

L U

r::.-:

Silty Sand. Grayish brown, medium to coarse grained, subrounded to subangular, non-cobesive, mostly mafic minerals, trace gravel (SM).

Bentonite Seal 193-196'

1. 60 Transition Sand 196-198' MWID 4-inch Low Carbon Steel, 0.020-inch Continuous Slot Screen 200-220'

1. 3 Filter Pack Sand 198-220' Total Depth Drilled 220 feet bgs MWIF I IL L

Silty Sandstone. Brown, very fine grained, bard, cemented (SS).

-7220

• l L

L 2870 Gate.ay Oaks Dr., Stc 300

_Sacrarnio, CA 95833 U_",

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hearld, California 95638 Project: 17325612 MW2A, MW2B, MW2C Drilling Contractor:

Water Development Borehole Diameter:

12-inch Borehole Name:

MW2 Logged By: R. Nommenson Drilling Method: Mud Rotary Dates Drillcd: 5/16-17/2005 Well Construction:

5/18/2005 Checked BFIff&

7°/4T'473 Drilled by: Randy Criner Casing Diameter:

2.5-inch Casing Type:

Low Carbon Steel Slot Size: 0.020-inch Total Depth Drilled:

333-feet Screen Intervals (ft bgs):

A-190-200'; B-255-265'; C-310-320' Well Development Dates:

6n/2005 Sampling Method: Grab Top of Casing Elevations:

A-145.48; B-145.28; C-145.10 Ground Surface Elevation:

146.10 A: Northing:

1887946.55 Easting: 6812353.12 B: Northing:

1887945.27 Easting:

6812352.87 C: Northing:

1887946.21 Easling: 6812353.24 Comments: Asphalt surface approximately 75 feet west of surface water holding ponds.

0 E

o5-10 15 20 25 30 35 40 45 50 55 60 65

.2 EP o

Sample ID LITHIIOLOGY DESCRIPTION WVELL CONSTRUCTION Sandy Gravel. Light brown (7.5YR 6/4). well graded (GW).

own (7.5YR 6/4), coarse grained, gravel, angular fragments, Gravel. Poorly graded, minor sand and clay (GP).

NlW2A MW2B Clay with trace gravel (CL).

I Flush mount vault box Wells secured with locking pressure caps MW2A 2.5-inch inner-diameter (ID) Low Carbon Steel (LCS) blank casing to 190' MW2B 2.5-inch ID LCS blank casing to 255' M1W2C 2.5-inch ID LCS blank casing to 310' Neat Cement from near ground surface to 183'.

u

-5 r-10 Is 20

-25

-30

-35

-40

-45

-50

-55 60 65 Gravels increase.

2870 Gateway Oaks Dr.. SI 300 C R E

s!

Sacranrnto, CA 95833 M

J

'1.4.^..-

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 MW2A, MW2B, MW2C L

r-

'.30 En V) co 0

0~

E ID

• EZ LITIIOLOGY DESCRIFTION WELL CONSTRUCTION 70 Light brown (7.5YR 6/4), trace gravel.

Sand and gravel.

L L

NIW2C Sand. Pinkish gray (5YR 6/), medium to coarse grained, well graded, cemented, minor clay (SW).

L L

L L

lt-i IL U

9.

Sandstone. Minor silt and clay, fine grained, brown (7.5YR 514). strongly cemented (SS).

Medium to coarse grained.

Fne to medium grained, brown (7.5YR 5/4). clayey cemented sand (SS).

L L

2870 Gateway Oaks Dr.. Ste 300 Sacranrnto, CA 95833 o.*1:70.7nr

L I Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, llearld, Calitornia 95638 Project: 17325612 Log of Monitoring Wells:

MW2A, MW2B, MW2C i-ID

'i2 L I co 22 E

S D

Sample ID I-t v

-S -1 U,

0 -e ITIIOLOGY DESCRIPTION WVELL CONSTRUCTION 155 160 165 170 175 180 185 190 195 200 205 210 215 220 -

225-230-Sand. Brown (7.5YR 514), coarse grained, minor silt (SP).

Sandy Clay. Brown (7.5YR 5/4). fine grained sand (CL).

NA Claystone. Brown (7.5YR 516), hard (CS).

Trace (<5%) sand.

'.E.X.x

'.X.E.Z t:. j./j Clayey Sand. fine to medium grained, poorly graded (SC).

/7 7

.X..:

Sandy Clay. 15-20% fine to medium grained sand, well indurated (CL).

Sand decreases.

Fractured, secondary Fermeability.

Sand. Mledium to coasse grained. minor clay (SW).

x<

Bcntonite Seal 183-185'

1. 60 Transition Sand 185-187' MW2A 2.5-inch ID LCS.

0.020-inch Continuous Slot Screen 190-200'

1. 3 Filter Pack Sand 187-201.5' Neat Cement 201.5-248' 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 X lt tt 2870 Gateway Oaks Dr.. Ste 300 MJBP "14bb, Swranrrto. CA 95833 916-679-2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 MW2A, MW2B, MW2C L

r r0 E

Ln to 0

4, 0

E E

Sample ID t0 CU V1)

(10.-

LITIIOLOGY DESCRIPTION WELL CONSTRUCTION

~.

................. v.

235 240-245 250 255 260 7 265-270-275 -

280 -

285-290-295 -

300 -

305 -

310-315-

-.-.;-.4..--

..f.Z.R

.f.i...

I.Z M. / /

eeeee V ////.

Clay. Medium grained sand, angluar (CL).

Possibly sandstone (SS).

Clayey Sand. Dark brown (7.5YR 3/2), poorly graded, fine to medium grained (SC).

Sand. Dark grayish brown (IOYR 412), fine to medium grained, poorly graded, angular, minor clay (SP).

Less cemented Medium grained, angular. dark sand.

e f

Minor clay, fine grained sand.

.,...-.'.. 3.'.

.3 I.:.::::..::.

• o.

.Z.X.X./i

.Z.X.:X.:Z.:;

.ZZ.:Z.:Z.:i

.ZZ.:Z.:Z.:;

.ZZ.:Z.:Z..i

./././.Xi

.S.X./.Z.i

'.A.A.X.Z.i i

Clayey Sand. Medium to coarse grained sand, very angular, 25-40% clay (S tn.

Claystone. Increasing clay content (CS).

Bentonite Seal 248-250'

1. 60 Transition Sand 250-252' MW2B 2.5-inch ID LCS, 0.020-inch Continuous Slot Screen 255-265'

1. 3 Filter Pack Sand 252-266.5' Neat Cement 266.5-303' Bentonite Seal 303-305'

1. 60 Transition Sand 305-307' MNV2C 2.5-inch ID LCS, 0.020-inch Continuous Slot Screen 310-320'

1. 3 Fher Pack Sand 307-321.5'

-235

-240

-245

-250

-255

-260

-265

-270

-275

-280

-285

-290

-295

-300

-305

-310

-315 IL L

L I.

Li L

L 2870 Gateway Oaks Dr., Ste 300 Sacranwnto, CA 95833

Project: Rancho Seco Nuclear Generation Station Log of Monitoring WVells:

Location: 14440 Twin Cities Road, i1earld, Calirornia 95638 Project: 17325612 MW2A, MW2B, MIW2C 4) ra a-2 rm LI) 4)

R.

421 a.

4) 1 E

F)

LITHIOLOGY DESCRIPTION WELL CONSTRUCTION No Recovery.

2870 Gameway Oaks Dr.. Ste 300 Sacranwmno. CA 95833 I

A d

d 916.679 2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 TWin Cities Road, Hearld, California 95638 Project: 17325612 MW3A, MW3B, MW3C Drilling Contractor:

Water Development Borehole Diameter:

12-inch Borehole Name:

MW3 Logged By: S. Plunkett Drilling Method: Mud Rotary Dates Drilled: 6/1/2005 Well Construction:

6/5/2005 Checked By7A 7

43 Drilled by: Randy Criner Casing Diameter. 2.5-inch Casing Type:

Low Carbon Steel Slot Size: 0.020-inch Total Depth Drilled:

320-feet Screen Intervals (ft bgs):

A-200-210; B-265-275'; C-310-320' Well Development Dates:

6n/2005 Sampling Method: Grab Top of Casing Elevations:

A-142.93; B-142.77; C-142.56 Ground Surface Elevation:

143.60 L

L L

A: Northing:

1888224.36 Easting: 6810988.02 B: Northing:

1888224.00 Easting: 6810987.93 C: Northing:

1888224.13 Easting: 6810988.28 Comments:

2 0-.2 E

LI) 0~

CsI

-5 a U

F.

Sample ID LITHOLOGY DESCRIPTION WVELL CONSTRUCTION u

5 10 15 20 25 30-35-40-45-50-55-60-65-I Boring not logged from ground surface to 60 feet bgs.

YY

>1

>1

>1

>1

>1

>1 lHush mount vault box Wells secured with locking pressure caps 1 W3A 2.5-inch inner-diameter (ED) Low Carbon Steel (LCS) blank casing to 200' MW313 2.5-inch ID LCS blank casing to 265' hlW3C 2.5-inch ID LCS blank casing to 310' Neat Cement from near ground surface to 187.

U

-5

-10 20 25 30 35 40 45 50 55 60 65 L

I.

L L

U L

L 4/Y/

Silty Clay. Brown (7.5YR 4/4), soft, non-plastic, dry (CL).

L u

2870 Gateway Oaks Dr.. Ste 300 Sarralenio, CA 95833 AIR

_ r m

Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, llearld, California 95638 Project: 17325612 Log of Monitoring Wells:

MW3A, MW3B, MW3C 2

.E 2Pa

._.C P.-

4s 4 Um,,,

n.

U ID LITIIOLOGY DESCRITIlON WFLL CONSTRUCTION Silty Clay. Brown (7.5YR 4/2), soft claystone. low plasticity. <15% sand and gravel (CL).

Silty Claystone. Medium plasticity, minor very fine grained sand.

claystone (CS).

Sandstone. Reddish brown (SYR 413), competent. indurated, angular to subrounded, quartz rich, silicious, massive (SS).

Content of fines increases to 30% silt.

Silty Sandstone. Strong brown (75YR 4/6), very fine to medium grained sand, minor gravel to 10%, poorly graded, angular to subrounded, massive (SS).

Siltstone. Dark reddish gray (5YR 4/2), very fine sandy silt with minor clay and gravel, soft, non-plastic (SLTST).

Silty Sandstone. Coarse content increasing, medium grained sand (SS).

Siltstone. Dark reddish gray (5YR 412), fine content increasing, very fine grained sand siltstone, weak, minor clay 25% (SLTST).

Sandstone. Dark reddish brown (5YR 3/3), silty, very fine to coarse grained sand, poorly graded, massive, quartz rich, angular to subrounded (SS).

2870 Gaiew.y Oaks Dr., SIC 300 Sxrwirnto. CA 95833 g

d, V

9t6-679-2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hearld, California 95638 Project: 17325612 l MW3A, MW3B, MW3C 1;

2

.E

.2 9n U) ba

-I 0.

'~

L a

I)E Sample ID 17 LITIIOLOGY DESCRIPTION WELL CONSTRUCTION 155 160 165 170 175 180 185 19 0 j 195-200 -

205-210-215-220-225 -

230-We....

vem-ee Sandy Siltstone. Brown (7.5YR 4/4). low plasticity, soft, very fine grained sand, clay (SLTST).

Sandy Silistone. Brown (7.5YR 4/3), 30% very fine to medium grained sand, 60% silt, 10% clay, soft (SLTST).

Clayey Siltstone. Brown (7.5YR 4/4). clay content increases, moderate plasticity, 20% sand (SLTST).

Sandy Siltstone. Brown (7.5YR 4/3), sand content increases to 25-30%,

quartz rich, subangular to subrounded, clayey silt matrix, soft, non-plastic (SLTST).

Bentonite Seal 187-195'

1. 60 Transition Sand 195-197' NfW3A 2.5-inch ID LCS, 0.020-inch Continuous Slot Screen 200-210'

1. 3 Filter Pack Sand 197-210.5' Bentonite Seal 210.5-260'

-155

-160

-165

-170

-175

-18

- 185

-190

-195

-200

-205

-210

-215

-220

-225

-230 L

I I L.4 L

IL eXXXXXI

... NV.

,:.XXX.e."

Silty Sandstone. 50-60% very fine to coarse grained sand with minor clay and silt (30%) (SS).

Coarse content increases to 60-70% sand and gravel, 20% silt. 10% clay.

Content of silt and clay decreases to trace, massive indurated poorly graded gravel sandstone. subrounded to angular rock fragmetns. quartz rich (SS).

L Sacramento, CA 95833 nag San Adv1

Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, Hlearld, Calirornia 95638 Project: 17325612 tU U

M E

EL)

Sample ID LITHIOLOGY DESCRI L

ram,,,-

-,I Log of Monitoring Wells:

MW3A, MW3B, MW3C

-5.-

PTION WELL CONSTRUCTION Silty Claystone. Minor sand and gravel, moderately plastic, sticky (CS).

Silty Sandstone. Brown (7.5YR 4/3), very fine lo medium grained sand, indurated, massive, tough, angular to subrounded, quartz rich (SS).

Sandy Siltstone. 40% si It, 20% clay, 30-40% very fine to coarse grained sand, soft, non-plastic (SLTST).

Sandstone. (7YR 413), massive, tough, competent, quartz rich, 20% silt and clay (SS).

Color change to greenish gray sandstone 295 2S70 GairWy Oaks Dr.. Stc 300 Sacranrnio. CA 95833 R

ato9t6.679-2000

Project: Rancho Seco Nuclear Generation Station l Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearild, California 95638 Project: 17325612 MW3A, MW3B, MW3C 1 'I P

r-

.2r-EM W

0 0.c

_ - CV.

E Sample ID LITHIOLOGY DESCRIPTION W'ELL CONSTRUCTION 1

I I

I 14-4-1 r

35 I

I 320

v-1 iIL L

L L

U L

I U

I,

LU 2870 Gateway Oaks Dr.. Ste 300 la X

^5rwrar to, CA 95833 TRq...._....

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 MW4A, MW41B, MW4C DrillingContractor:

WaterDevelopment Borehole Diameter:

12-inch Borehole Name: MW4 Logged By: S Plunkett Drilling Method: Mud Rotary Dates Drilled: 5/23-2412005 Well Construction:

6/212005 Checked B

/4473 Drilled by: Randy Criner Casing Diameter: 2.5-inch Casing Type:

Low Carbon Steel Slot Size: 0.020-inch Total Depth Drilled:

320-feet Screen Intervals (ft bgs):

A-195-2'5; B-251-261'; C-310-320' Well Development Dates:

6/912005 Sampling Method: Grab Top of Casing Elevations:

A-140.41; B-140.21; C-140.07 Ground Surface Elevation:

140.8 A: Northing:

1887086.40 Easting: 6810770.31 B: Northing:

1887086.44 Easting:

6810770.72 C: Northing:

1887086.10 Easting: 6810770.56 Comments:

0.2 E

00 Sampe I

II.'.L I

LITnIOLOGY DESCRIPTION NVELL CONSTRUCTION ut 10 IO-15-20-25-30-35-40-45-50-55-60-65-L/.,LA L i2 6 6 Gravel. Brown (7.5YR 4/4), angular rock fragments from large boulder, very tough, quartz ric, silicious with minor mafic component, minor clay (GP).

/77

.~

Sandy Clay. Brown (7.5YR 5/4), non-plastic, fine to medium grained sand, minor rock fragments, dry (CL).

Gravelly. Sandy, Silty Clay. Light bluish grey (GLEY2 7/5PB) low plasticity, dry (CL).

Silty Sandy Gravel. Olive (5Y4/3), subangular to subrounded, quartz rich

?F '9J q 0.

with feldspar (GNM).

• O*O Gravelly Silty Clay. Reddish brown (SYR 5/3), low plasticity, 30% gravel, slightly moist (CL).

Silty Sandy Gravel. Subangular to subrounded, quartz rich, minor rock n.Q fragments, dry (GM).

Gravelly Silt. Reddish brown (SYR 5/4), coarse component decreasing (NIL).

<20% gravel.

Silty Clay. Soft. low Flasticity (CL).

Flush mount vault box Wells secured with locking pressure caps MW4A 2.5-inch inner-diameter (1)) Low Carbon Steel (LCS) blank casing to 195' MW4B 2.5-inch ID LCS blank casing to 251 MW4C 2.5-inch I) LCS blank casing to 3I0' Neat Cement from near ground surface to 185'.

0 e 0o t5 20 25 30 35 40 45 50 55 60 65

./b -16 le Sandy Gravelly Clay. Reddish brown (SYR 5/4), 25-30% sand and gravel (CL).

y Silty Claystone. Soft, low plasticity. <% sand and gravel, slightly moist (CS).

I s t~t 2870 Gate ay Oaks Dtr., Ste 300 e

l l Lott S.ranslsno, CA 95833 t 9 I 96-679-2000

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 l MW4A, MW4B, MW4C i

i.5 E

to 0

0~

0.

C I L Z;I.

LITMIOLOGY DESCRIPTION Silty Claystone. Reddish brown (5YR 5/4). soft, low plasticity, <10% sand.

minor gravel (CS).

L L

Clayey Siltstone. Soft, low plasticity. trace sand, slightly damp (SLTST).

Sandy Siltstone. Weak red (2.5YR 512), sand content increasing to 25%.

subangular to angular elasts, poorly graded (SLTST).

Sandy Siltstone. Yellowish red (5YR 4/6). clay and silt content increasing, very fine grained sand 10-15% with minor gravel (SLTST).

Sand and gravel content 25-30%. angular to subrounded. coarse.

L L

Siltstone. Dark gray (7.5YR 411). very fine grained sand 10-15%. trace coarse material (SLTST).

L L

Clayey Siltstone. Brown (7.5YR 4/4), soft, non-plastic (SLTST).

L 2t70 Gateway Oaks Dr.. Ste 300 Sacrazrrnto. CA 95833 U

R S,

916-679-2Doo

Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, Hlearld, California 95638 Project: 17325612 Ano ri i1; U

Q Log of Monitoring Wells:

MW4A, MW4B, MW4C I

C.)0 r-vs C.)

.2 0.

i e

>E D

Samplc ID I-LITIIOLOGY DESCRIPTION WELL CONSTRUCTION 0

LITHOLOCY DESCRIPTiON 155-160-165 170-175-180 -

185 -

190-195-200-205-210-215 -

220 -

225-230-Sandstone. Very fine to coarse grained sand, quartz rich, massive, poorly graded, angular to subrounded, <10% fines, cemented (SS).

Clayey Siltstone. Brown (7.5YR 4/4). content of fines increased, <5% sand and gravel (SLTST).

Clayey Siltstone. Non-plastic. <5% sand and gravel (SLTST).

Sandy Clayey Siltstone. Brown (7.5YR 414), soft. tow plasticity, sand content increasing 10-159b, very fine to medium grained (SLTST).

Clayey Siltstonc. Reddish brown (5YR 4/3), low plasticity, sand content decreasing <5%, very fine to medium grained, dry (SLTST).

Sandy Siltstone. Minor clay, sand and coarse sand content increased to 20%, poorly graded, subangular to subrounded, quartz (SLTST).

Sandy Clayey Siltatone. NMedium stiff, tight, medium plasticity, sand content decreasing, <10% sand (SLTSI).

Bentonite Seal 185-191'

1. 60 Transition Sand 191-193' MW4A 2.5-inch ID LCS, 0.020-inch Continuous Slot Screen 195-205'

1. 3 Filter Pack Sand 193-205.5 Bentonite Seal 205.5-246'

-155

-160

-165

-170

-175

-180

-185

-190

-195

-200

-205

-210

-215

-220

-225

-230 leU 2870 Gateway Oaks Dr., Ste 300 1 1 M Sacrrntno, CA 95833 am_0ooo.,rn

l XL Project: Rancho Seco Nuclear Generation Station Location: 14440 Twin Cities Road, learld, California 95638 Project: 17325612 Log of Monitoring Wells:

MW4A, MW4B, MW4C L

t_

.E C-E M

C47 10 0

p. -

s vi c

LITIIOLOGY DESCRIPTION WELL CONSTRUCTION I'L U

I'1 L

U Sandy Claystone. Reddish brown (5YR 4/3), 35% very fine to fine grained sand (CS).

Fine grained sand content increased to 45%.

Sandy Siltstone. Clay content decreased, very fine grained sand, no color change (SLTST).

Clayey Sandy Siltstone (SLTST).

Sandy Siltstone. Reddish brown (2.5YR 4/4), non plastic, very fine to fine grained sand, poorly graded, minor clay 10-15%, trace coarse material, interbedded sandstone and siltstone (SLTST).

L Clay content decreases.

Sandstone. Massive, tough, quartz rich, minor silt and clay (SS).

L L

Sandstone. Massive, indurated, angular elastic material, well graded gravel sand mixture (SS).

i LI 2870 Gateway Ot.A.s Dr.. Ste 300 Sacramento, CA 95833 i

916-679-2n(s

Project: Rancho Seco Nuclear Generation Station Log of Monitoring Wells:

Location: 14440 Twin Cities Road, flearld, California 95638 Project: 17325612 MW4A, MW4B, MW4C E

Sample ID P

° LITIIOLOGY DESCRIPTION WVELL CONSTRUCTION 320:

r 320 2870 Gateway Oaks Dr.. Ste 300 Iff 'NY 9Saranimo, CA 95833 tn s'W~mD9167679-20D0

APPENDIX B 2005 Physical Parameter Laboratory Results

-a J, m

Environmental w

• l

G.

Geotechnology N.3..

'Laboratory, Inc.

July 13, 2005 URS Corporation 2870 Gateway Oaks, Suite 300 Sacramento, CA 95833 Attn:

Mr. Clif Gary RE:

LABORATORY TEST RESULTS/REPORT Project Name: Hydorlogic Characterization of Rancho Seco Project No.17325612.30000 EGL Job No.: 05-008-020

Dear Mr. Francis,

We have completed the testing program conducted on samples from the above project. The tests were performed in accordance with testing procedures as follows:

TEST METHOD Total Porosity Moisture & Density Effective Porosity Sandy Soils (less than 15%)

Other Soils (less than 15%)

Hydraulic Conductivity ASTM D2937 ASTM D5084 Enclosed is the Summary of Laboratory Test Results.

We appreciate the opportunity to provide testing services to URS Corporation. Should you have any questions, please call the undersigned.

Sincerely yours, Environmental Geotechnology Laboratory, Inc.

Hank 'ong, PE, GE Manager Enclosure 11819 Goldring Road, Suite A, Arcadia, CA 91006 i Tel.: (626) 263-3588, Fax: (626) 263-3599 E-MAIL: MAIL@EGLAB.COM

SUMMARY

OF LABORATORY TEST RESULTS Specific Gravity, Total Porosity PROJECT NAME: Hydrologic Characterization of Rancho Seco Job No.: 17325612.30000 EGL JOB NO.: 05-008-020 CLIENT: URS DATE: 06-30-05 SUMMARIZED BY: VW SAMPLE DEPTH DRY SPECIFIC TOTAL ID NO DENSITY GRAVITY POROSITY ASTM ASTM D2937 (ft)

(pco)

D854 (do )

MWI-A 15-18.5 100.2 2.772 42.1 MWI-B 30 90.9 2.684 45.8 MWI-C 90 104.4 2.711 38.3 MW2-A 25.5-26.5 77.3 2.734 54.7 MW2-B 50.5 83.7 2.667 49.7 MW2-C 101 82.2 2.636 50.1 L

L L

L

SUMIARY OF PERMEABILITY TEST RESULTS PROJECT NAME: Hydrologic Characterization of Rancho Seco PROJECT NO.: 17325612.30000 DATE: 06-30-05 EGL JOB NO.: 05-008-020 CLIENT: URS SUMMARIZED BY: VW SAMPLE SAMPLE DEPTH MOISTURE DRY EFFECTIVE SATURATED ID NO CONTENT DENSITY CONFINED HYDRAULIC ASTM ASTM PRESSURE CONDUCTIVITY D2216 D2937 ASTM D5084 (ft)

(%)

(pcf (psi)

(cr/sec)

N/A l

MW1-A l

15-18.5 l

12.20 l

100.2 l

8.7 5.8E-004 N/A MWI-B 30 25.80 90.9 15.9 3.5E-006 N/A MWI-C 90 25.5 104.4 40 7.1E-007 N/A MW2-A 25.5-26.5 34.5 77.3 12.5 1.4E-004 NIA MW2-B 50.5 33.7 83.7 26.2 2.8E-007 N/A MW2-C 101 35.8 82.2 40 3.6E-006

L I

1.20 1.10 1.00 0.90 0.80 0.70 0.60 0.50 0.40__

0.30 0.20 0.10

__===

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 Li L

I I LI PORE VOLUME (CC)

L L

PROJECT NAME: Hydrologic Environmental Characterization of Rancho Seco l

Geotechnology Client: URSS i

k.

Job No.: 17325612.30000 A

Laboratory EGL Project No.: 05-008-020 l

I L

BROMIDE BREAKTHROUGH METHOD (SWRCB)

FIGURE 06/05

1.20 1.10 1.00 0.90 0.80 0.70 0

0Q 0.60

_ X=== =_

===, /I I

I

(...............I.........................................

0.50 0.40 0.30 0.20 0.10 0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 PORE VOLUME (CC).

1.00 1.10 1.20 PROJECT NAME: Hydrologic Environmental Characterization of Rancho Seco Geotechnology Client: URS Job No.: 17325612.30000 aboratory EGL Project No.: 05-008-020 BROMIDE BREAKTHROUGH METHOD (SWRCB)

I 06/05

-,nI MrC F IG u I

L L

L L

1.20 1.10 1.00 0.90 0.80 0.70 0

0 0.60 0.50 0.40 0.30 0.20

_X/_ ___=

0.10 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 jI II PORE VOLUME (CC)

! I I

.::-PROJECT NAME: Hydrologic Environmental Characterization of Rancho Seco Geotechnology Client URS Job No.: 17325612.30000

• J....,

Laboratory EGL Project No.: 05-008-020 BROMIDE BREAKTHROUGH METHOD notnr (SWRCB) cirIIRE L

usuiuu Ilux

1.20 1.10 1.00 0.90 0.80 0.70 00 0.60 I I X1 1I Il 1 D= =_

2 A

=

~~~"

__==

0.50 0.40 0.30 0.20 0.10 I

0.00 &

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 PORE VOLUME (CC)

:PROJECT NAME: Hydrologic

Environmental Characterization of Rancho Seco

i Geotechnology Client: URS La bot Job No.: 17325612.30000 oraory EGL Project No.: 05-008-020 BROMIDE BREAKTHROUGH METHOD (SWRCB)

FIGURE 06/05

L 1.20 1.10.

1.00 0.90 0.80 0.70 00 0.60 0.50 0.40 0.30 0.20 0.10 0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 PORE VOLUME (CC)

.i...:.....

.,,6.

Environmental Geotechnology Laboratory PROJECT NAME: Hydrologic Characterization of Rancho Seco l l Client: URS Job No.: 17325612.30000 EGL Project No.: 05-008-020 l

BROMIDE

1.20 1.10 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 b.A.L.

.. A d

... L........

.1.

0.00 0.10 0.20 0.30 0.40 0.50

.0.60 0.70 0.80 0.90 1.00 1.10 1.20 PORE VOLUME (CC)

PROJECT NAME: Hydrologic Environmental Characterization of Rancho Seco Geotechnology Client: URS

.........Io Job No.: 17325612.30000 LabJoratory EGL Project No.: 05-008-020 BROMIDE BREAKTHROUGH METHOD (SWRCB)

FIGURE 06/05

APPENDIX C 2005 Groundwater Sample Laboratory Results

Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 209/223-2800 Fax 209/223-2747 Email sflivolcano.net L

SNUD 09/01/2005 08/02/2005 09/01/2005 Page 3 of 8 am le Descri tion Taken Received Mail rogen, Ammonia-N

<0.50 mg/L 0.50 08/10/2005 KR pH, La

\\

6.9 unit 0.1 08/10/2005 KRS 583406 Effluent 08/11/2005 0745 08/11/2 08/16/2005 G WW pa r

Units EQL zed By Renewal wa onic tox 3rd ed by SFL 08/11/2005 SFL L

Alkalinity, Total 24 g

08/15/2005 RK Chlorine Residual,Total, L

<0.10 mg/L

.10 08/11/2005 L&R gen, Dissolved, Lab*

5

/11/2005 L&R L

Hardne 32 mg/L 5.0 08 5

KR Specific Conduct

5.

hocm 1.00 08/11/2005 Nitrogen, Ammonia-N

<0.50 mg/L 0.50 08/15/2005 KR pH, Lab unit 008/11/2005 RK LA L

583612 I

D CHARGE (PE) 0/5/2005 08/15/2005 08/22/2005 G

81 Pa r

Results Units EQL lyzed By tal Coliform Bacteria, 20 tube 2

J/100ml 2.0 08/1 583883 MW1C 08/17/2005 1010 08/18/2005 08/31/2005 G W Parameter Cation/Anion Balance Alkalinity, Total Alkalinity, Bicarbonate Alkalinity, Carbonate Chloride Magnesium, Calculation Nitrogen, Total Nitrate-N Sulfate Iron, FAA Potassium, FAA Boron-total, ICP Calcium, Titrimetric Hardness Sodium, FAA Solids, Total Dissolved pH, Lab*

Results 2.04 / 1.92 86 57 29 7.1 2

<0.050

<0.50 17 3.86

< 0.05 5.9 24 34

-_-126 9.5 Units meq/meq mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L unit EQL 5.0 5.0 5.0 1.0 2.0 0.050 0.50 0.050 0.050 0.05 3.0 5.0 0.10 10 0.1 Analyzed 08/31/2005 08/22/2005 08/22/2005 08/22/2005 08/1 9/2005 08/25/2005 08/1 8/2005 08/1 8/2005 08/24/2005 08/25/2005 08/23/2005 08/23/2005 08/19/2005 08/25/2005 08/19/2005 08/18/2005 By DEG RK RK RK KR KL KR KR TN TN Jo KR KR TN MG --

K&R F

w 583884 MW2A 583884 MW2A 08/17/2005 1155 08/17/2005 1155 08/18/2005 08/31/2005 G WQ Parameter Cation/Anion Balance Alkalinity, Total Alkalinity, Bicarbonate Alkalinity, Carbonate Chloride Magnesium, Calculation Nitrogen, Total Nitrate-N Sulfate Iron, FAA Potassium, FAA Results 2.36 / 2.20 86 86

<5.0 14 3

<0.050 4.2 23 3.34 Units meq/meq mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L EQL 5.0 5.0 5.0 1.0 2.0 0.050 0.50 0.050 0.050 Analyzed 08/31/2005 08/22/2005 08/22/2005 08/22/2005 08/1 9/2005 08/25/2005 08/18/2005 08/18/2005 08/24/2005 08/25/2005 By DEG RK RK RK KR KL KR KR TN TN

L Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 209/223-2800 Fax 209/223-2747 Email sfl@volcano.net L

SMUD 09/01/2005 08/02/2005

- 09/01/2005 Page 4 of 8 Sample Description Taken Received Mail Boron-total, ICP 0.05 mg/L 0.05 08/23/2005 JQ Calcium, Titrimetric 4.0 mg/L 3.0 08/23/2005 KR Hardness 24 mg/L 5.0 08/19/2005 KR Sodium, FAA 42 mg/L 0.10 08/25/2005 TN Solids, Total Dissolved 151 mg/L 10 08/19/2005 MG pH, Lab*

7.6 unit 0.1 08/18/2005 K&R 583885 MW2B 08/17/2005 1340 08/18/2005 08/31/2005 G W Parameter Results Units EQL Analyzed By Cation/Anion Balance 1.78 / 1.58 meq/meq 08/31/2005 DEG Alkalinity, Total 64 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 64 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate

<5.0 mg/L 5.0 08/22/2005 RK Chloride 9.6 mg/L 1.0 08/19/2005 KR Magnesium, Calculation 4

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N

<0.050 mg/L 0.050 08/18/2005 KR Sulfate 1.4 mg/L 0.50 08/18/2005 KR Iron, FAA 73 mg/L 0.050 08/24/2005 TN Potassium, FAA 3.46 mg/L 0.050 08/25/2005 TN Boron-total, ICP

< 0.05 mg/L 0.05 08/23/2005 JQ Calcium, Titrimetric 4.7 mg/L 3.0 08/23/2005 KR Hardness 28 mg/L 5.0 08/19/2005 KR Sodium, FAA 26 mg/L 0.10 08/25/2005 TN Solids, Total Dissolved 101 mg/L 10 08/19/2005 MG pH, Lab, 8.9 unit 0.1 08/18/2005 K&R 583886 MW2C 08/17/2005 1425 08/18/2005 08/31/2005 G W Parameter Results Units EQL Analyzed By Alkalinity, Total 62 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 36 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate 26 mg/L 5.0 08/22/2005 RK Borcn-total, ICP

< 0.05 mg/L 0.05 08/23/2005 JQ Cation/Anion Balance 1.55 / 1.43 meq/meq 08/31/2005 DEG Calcium, Titrimetric 4.7 mg/L 3.0 08/23/2005 KR Chloride 6.7 mg/L 1.0 08/19/2005 KR Iron, FAA mg/L 0.050 08/24/2005

'TN Hardness 20 mg/L 5.0 08/19/2005 KR Potassium, FAA 4.03 mg/L 0.050 08/25/2005 TN Magnesium, Calculation 2

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N

<0.050 mg/L 0.050 08/18/2005 KR Sodium, FAA 24 mg/L 0.10 08/25/2005 TN Sulfate

<0.50 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 88 mg/L 10 08/19/2005 MG pll, Lab*

9.6 unit 0.1 08/18/2005 K&R 583958 MW3A 08/18/2005 0715 08/18/2005

/

/

L L

LL I -

L UL L

L U

L L

L G W Parameter Cation/Anion Balance Alkalinity, Total Alkalinity, Bicarbonate Results 1.09 / 1.20 53 42 Units meq/meq mg/L mg/L EQL Analyzed 08/31/2005 5.0 08/22/2005 5.0 08/22/2005 By DEG RK RK L

Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 2091223-2800 Fax 209/223-2747 Email sfl@volcano.net SMU1) 09/01/2005 08/02/2005

- 09/01/2005 Page 5 of 8 Sample Description Alkalinity, Carbonate Chloride Magnesium, Calculation Nitrogen, Total Nitrate-N Sulfate Iron, FAA Potassium, FAA Boron-total, ICP Calcium, Titrimetric Hardness Sodium, FAA Solids, Total Dissolved pH, Lab*

11 5.0

<2.0

<0.050

<0.50 38 2.41

< 0.05 3.2 16 20 70 9.3 Taken mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L unit 5.0 1.0 2.0 0.050 0.50 0.050 0.050 0.05 3.0 5.0 0.10 10 0.1 Received 08/22/2005 RK 08/19/2005 KR 08/25/2005 KL 08/18/2005 KR 08/18/2005 KR 08/24/2005 TN 08/25/2005 TN 08/23/2005 JQ 08/23/2005 KR 08/22/2005 KR 08/25/2005 TN 08/19/2005 MG 08/18/2005 K&R Mail 583959 MW3B G W Parameter Cation/Anion Balance Alkalinity, Total Alkalinity, Bicarbonate Alkalinity, Carbonate Chloride Magnesium, Calculation Nitrogen, Total Nitrate-N Sulfate Iron, FAA Potassium, FAA Boron-total, ICP Calcium, Titrimetric Hardness Sodium, FAA Solids, Total Dissolved pH, Lab*

08/18/2005 0750 08/18/2005

/

/

Results 1.01 / 1.11 49 42 7.0 4.6

<2.0

<0.050

<0.50 27 2.50

< 0.05 3.2 16 18 71 9.3 Units meq/meq mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L unit EQL 5.0 5.0 5.0 1.0 2.0 0.050 0.50 0.050 0.050 0.05 3.0 5.0 0.10 10 0.1 Analyzed 08/31/2005 08/22/2005 08/22/2005 08/22/2005 08/19/2005 08/25/2005 08/18/2005 08/18/2005 08/24/2005 08/25/2005 08/23/2005 08/23/2005 08/22/2005 08/25/2005 08/1 9/2005 08/1 8/2005 By DEG RK RK RK KR KL KR KR TN TN JQ KR KR TN MG K&R 583960 MW3C G W Parameter Cation/Anion Balance Alkalinity, Total U

Alkalinity, Bicarbonate Alkalinity, Carbonate Chloride L

Magnesium, Calculation Nitrogen, Total Nitrate-N Sulfate Iron, FAA b

Potassium, FAA Boron-total, ICP Calcium, Titrimetric Hardness Sodium, FAA Solids, Total Dissolved 08/18/2005 0805 08/18/2005

/

/

Results 1.14 / 1.0S 49 38 11 3.7 2

<0.050

<0.50 4.65 3.09

< 0.05 4.0 20 16 71 Units meq/meq mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L EQL 5.0 5.0 5.0 1.0 2.0 0.050 0.50 0.050 0.050 0.05 3.0 5.0 0.10 10 Analyzed 08/31/2005 08/22/2005 08/22/2005 08/22/2005 08/19/2005 08/25/2005 08/1 8/2005 08/18/2005 08/24/2005 08/25/2005 08/23/2005 08/23/2005 08/22/2005 08/25/2005 08/1 9/2005 By DEG RK RK RK KR KL KR KR TN TN JQ KR KR TN MG

L Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 209/223-2800 Fax 209/223-2747 Email sfl@volcano.net L

SMUD 09/01/2005 08/02/2005

- 09/01/2005 Page 6 of 8 Sample Description Taken Received Mail pH, Lab*

9.3 unit 0.1 08/18/2005 K&R 583961 MW4A 08/18/2005 0835 08/18/2005

/

/

G W Parameter Results Units EQL Analyzed By Alkalinity, Total 49 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 45 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate

<5.0 mg/L 5.0 08/22/2005 RK Boron-total, ICP

< 0.05 mg/L 0.05 08/23/2005 JQ Cation/Anion Balance 1.26 / 1.16 meq/meq 08/31/2005 DEG Calcium, Titrimetric 4.0 mg/L 3.0 08/23/2005 KR Chloride 5.6 mg/L 1.0 08/19/2005 KR Iron, FAA 203 mg/L 0.050 08/24/2005 TN Hardness 20 mg/L 5.0 08/22/2005 KR Potassium, FAA 2.69 mg/L 0.050 08/25/2005 TN Magnesium, Calculation 2

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N

<0.050 mg/L 0.050 08/18/2005 KR Sodium, FAA 19 mg/L 0.10 08/25/2005 TN Sulfate 1.1 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 69 mg/L 10 08/19/2005 MG pH, Lab*

9.0 unit 0.1 08/18/2005 K&R 583962 MW4B 08/18/2005 0925 08/18/2005

/

/

G W Parameter Results Units EQL Analyzed By Alkalinity, Total 51 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 40 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate 11 mg/L 5.0 08/22/2005 RK Boron-total, ICP

< 0.05 mg/L 0.05 08/23/2005 JQ Cation/Anion Balance 1.02 / 1.17 meq/meq 08/31/2005 DEG Calcium, Titrimetric 3.2 mg/L 3.0 08/23/2005 KR Chloride 5.2 mg/L 1.0 08/19/2005 KR Iron, FAA 5.3 mg/L 0.050 08/24/2005 TN Hardness 14 mg/L 5.0 08/22/2005 KR Potassium, FAA 2.97 mg/L 0.050 08/25/2005 TN Magnesium, Calculation

<2.0 mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N

<0.050 mg/L 0.050 08/18/2005 KR Sodium, FAA 18 mg/L 0.10 08/25/2005 TN Sulfate

<0.50 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 72 mg/L 10 08/19/2005 MG pi], Lab' 9.4 unit 0.1 08/18/2005 K&R 583963 MW4C 08/18/2005 0945 08/18/2005

/

/

1 12 L

L 1

12 L

1 1

1 L

1 L

L G W Parameter Alkalinity, Total Alkalinity, Bicarbonate Alkalinity, Carbonate Boron-total, ICP Cation/Anion Balance Calcium, Titrimetric Chloride Iron, FAA Results 58 51 7.0

< 0.05 1.44 / 1.32 4.0 5.7 6.4 Units mg/L mg/L mg/L mg/L meq/meq mg/L mg/L mg/L EQL 5.0 5.0 5.0 0.05 3.0 1.0 0.050 Analyzed 08/22/2005 08/22/2005 08/22/2005 08/23/2005 08/31/2005 08/23/2005 08/19/2005 08/24/2005 By RK RK RK JQ DEG KR KR TN L

1

Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 209/223-2800 Fax 209/223-2747 Email sfl@volcano.net SMUD 08/02/2005

- 09/01/2005 09/01/2005 Page 7 of 8 Sample Description Taken Received Mail Hardness 22 mg/L 5.0 08/22/2005 KR Potassium, FAA 3.16 mg/L 0.050 08/25/2005 TN Magnesium, Calculation 3

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N

<0.050 mg/L 0.050 08/18/2005 KR Sodium, FAA 21 mg/L 0.10 08/25/2005 TN Sulfate

<0.50 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 81 mg/L 10 08/19/2005 MG pli, Lab*

9.2 unit 0.1 08/18/2005 K&R 583964 SAS 08/18/2005 1125 08/18/2005 G W Parameter Results Units EQL Analyzed By Alkalinity, Total 55 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 55 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate

<5.0 mg/L 5.0 08/22/2005 RK Boron-total, ICP

< 0.05 mg/L 0.05 08/23/2005 Jo Cation/Anion Balance 1.45 / 1.44 meq/meq 08/31/2005 DEG Calcium, Titrimetric 4.7 mg/L 3.0 08/23/2005 KR Chloride 4.1 mg/L 1.0 08/19/2005 KR Iron, FAA

<0.050 mg/L 0.050 08/24/2005 TN Hardness 24 mg/L 5.0 08/22/2005 KR Potassium, FAA 3.8 mg/L 0.050 08/19/2005 TN Magnesium, Calculation 3

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N 1.8 mg/L 0.050 08/18/2005 KR Sodium, FAA 20 mg/L 0.10 08/19/2005 TN Sulfate 4.8 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 165 mg/L 10 08/24/2005 DS pH, Lab*

7.6 unit 0.1 08/18/2005 K&R 583965 RSP 08/18/2005 1045 08/18/2005

/ /

G W Parameter Results Units EQL Analyzed By Alkalinity, Total 65 mg/L 5.0 08/22/2005 RK Alkalinity, Bicarbonate 65 mg/L 5.0 08/22/2005 RK Alkalinity, Carbonate

<5.0 mg/L 5.0 08/22/2005 RK Boron-total, ICP

< 0.05 mg/L 0.05 08/23/2005 JQ Cation/Anion Balance 1.69 / 1.54 meq/meq 08/31/2005 DEG Calcium, Titrimetric 6.3 mg/L 3.0 08/23/2005 KR Chloride 5.8 mg/L 1.0 08/19/2005 KR Iron, FAA 0.24 mg/L 0.050 08/24/2005 TN Hardness 35 mg/L 5.0 08/22/2005 KR Potassium, FAA 3.7 mg/L 0.050 08/19/2005 TN Magnesium, Calculation 5

mg/L 2.0 08/25/2005 KL Nitrogen, Total Nitrate-N 0.64 mg/L 0.050 08/18/2005 KR Sodium, FAA 20 mg/L 0.10 08/19/2005 TN Sulfate 1.4 mg/L 0.50 08/18/2005 KR Solids, Total Dissolved 180 mg/L 10 08/24/2005 DS pH, Lab*

7.4 unit 0.1 08/18/2005 K&R

L Sierra Foothill Laboratory, Inc.

255 Scottsville Blvd PO Box 1268 Jackson, CA 95642 Phone 209/223-2800 Fax 209/223-2747 Email sfl@volcano.net L

SMUD L

09/01/2005 08/02/2005

- 09/01/2005 Page 8 of 8 Sample Description 583966 SITE Taken 08/18/2005 1105 Received 08/18/2005 Mail

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L G W Parameter Alkalinity, Total Alkalinity, Bicarbonate Alkalinity, Carbonate Boron-total, ICP Cation/Anion Balance Calcium, Titrimetric Chloride Iron, FAA Hardness Potassium, FAA Magnesium, Calculation Nitrogen, Total Nitrate-N Sodium, FAA Sulfate Solids, Total Dissolved pH, Lab' Results 52 52

<5.0

< 0.05 1.46 / 1.35 3.2 4.0

<0.050 20 3.9 3

1.8 22 3.5 168 7.7 Units mg/L mg/L mg/L mg/L meq/meq mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L unit EQL 5.0 5.0 5.0 0.05 3.0 1.0 0.050 5.0 0.050 2.0 0.050 0.10 0.50 10 0.1 Analyzed 08/22/2005 08/22/2005 08/22/2005 08/23/2005 08/31/2005 08/23/2005 08/19/2005 08/24/2005 08/22/2005 08/19/2005 08/25/2005 08/18/2005 08/1 9/2005 08/1 8/2005 08/24/2005 08/18/2005 By RK RK RK JQ DEG KR KR TN KR TN KL KR TN KR DS K&R L

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583967 SITE WELL 08/18/2005 1238 08/18/2005 08/26/2005 G W Parameter Results Units EQL Analyzed By Iron, FAA

<0.050 mg/L 0.050 08/24/2005 TN Manganese, FAA 0.02 mg/L 0.020 08/24/2005 TN 59 2

COMBINED DISCHARGE (PE) 08/23/2005 0725 08/23/2005 08/30/200 Parameter Results Units EQL Analyzed By Nitrogen, Ammoni

<0.50 mg/L 0.50 08/29/20 584263 COMBINED DISC E (PE) 08/23/2005 0725 08/23/2005 08/31/2005 G WW 78125 Parameter Re Units EQL Analyzed By Total Coliform Bacteria, 20 tube 26

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2.0 08/23/2005 DS 584811 COMBINED DISCHARGE (PE) 30/2005 0800 08/30/2005 G WW 78127 Parameter Results Units EQL Analyzed By Total Coliform Bacteria, be

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584830 Inhib 3due 08/30/2005 1240 1/2005 meter Results Units EQL Analyzed By Inhibitory Residue

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