ML12157A176

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GNRO-2012/00039 - Entergy Nuclear Grand Gulf Nuclear Station License Renewal Environmental Audit - Hydrology Patton, - Attachment B Labeled Enercon Study Assessing Groundwater Drawdown and Related Impacts.
ML12157A176
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Issue date: 05/23/2012
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GNRO-2012/00039
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Attachment 3 to GNRO-2012/00039 Attachment 3 to GNRO-2012/00039 Entergy Nuclear Grand Gulf Nuclear Station License Renewal Environmental Audit -Hydrology Patton, -Attachment B labeled "Enercon Study Assessing Groundwater Drawdown and Related Impacts" Attachment B Enercon Study Assessing Groundwater Drawdown and Related Impacts ENERCON Exce~ence.-EIverv proje. Every dcoy.May 1.9, 2010 Via Email Mr. Rick Buckley, CHMM Entergy Nuclear Post Office Box 31995 Jackson, MS 31995-1995 RE: Radial Well Withdrawal Impacts Calculation ENTGGG071-CALC-001 Grand Gulf Nuclear Station, Unit. I

Dear Rick,

Per your request, please find attached the calculation package ENTGGG07 I-CALC-00 1 Evaluation of Potential Impacts of Collector Well GrOundwater WithdrawalS, Grand Gulf Nuclear Station, Unit 1. This analysis of the estimated drawdown resulting from operation of the Grand Gulf Nuclear Station (GGNS) radial collector wells was developed .to support the Environmental Assessment (EA) of impacts resulting from Extended Power Uprate. The EA. is anticipated to be used to support a request to the Nuclear Regulatory' Commission for an Extended Power Uprate amendment of GGNS'Operating License. It was also anticipated that this calculation would be used to support the analysis of impacts of the radial collector well system in the Environmental Report for.License Renewal for GGNS..If you have any questions or require additional information, please feel free to call me at (918) 665-7693.Thankyo"s/K nes A. Thomas Manager, Electric Utility Environmental Services Attachment

-ENERCON Calculation ENTGGG071 -CALC-001 Colpof'ne H~onr~ i 100 hisr Shelly fDr,? .Suire 1SO rut.5, (.K 74135 ph)o~ 91$.468-16903 fax 918665.M2~

enefonorn01 CALC NO. ENTGGG071-CALC-001 El E N E R C O N CALCULATION COVER SHEET REV. 0 PAGE NO. 1 of 25 TITLE Evaluation of Potential Impacts of Radial (Ranney) Client: Entergy Nuclear, Inc.Well Groundwater Withdrawals, Grand Gulf Nuclear Station, Unit 1 Project: ENTGGG071 ITEM COVER SHEET ITEMS YES NO Does this calculation contain any open assumptions that require confirmation? (If 1 YES, Identify the assumptions)

X Does this calculation serve as an "Alternate Calculation"? (If YES, Identify the design 2 verified calculation.)

X Design Verified Calculation No.Does this calculation Supersede an existing Calculation? (If YES, Identify the 3 superseded calculation.)

X SSuperseded Calculation No.Scope of Revision.Initial issue.Revision Impact on Results: N/A Study Calculation

[3 Final Calculation 99 Safety Related 0 Non-Safety Related I](Print Name And Sign)Originator:

Randall N. Lantz, P.G. Date: 5/11/2010 Reviewer:

Halfeng -I LDate: 5/13/2010 Stacey Fredenberg

/ -_Approver:

James A. Thomas Date: f CALC. NO. ENTGGG071-CALC-001 SE NE RCON CALCULATION REV. 0 REVISION STATUS SHEET PAGE NO. 2 of 25 CALCULATION REVISION STATUS REVISION DATE DESCRIPTION 0 Initial Issue PAGE REVISION STATUS PAGE NO. REVISION PAGE NO. REVISION 1-25 0 ATTACHMENT REVISION STATUS ATTACHMENT NO. PAGE NO. REVISION NO.1 1-2 0 2 1-5 0 3 1-3 0 4 1-2 0 ENE O CALC. NO. ENTGGG071-CALC-001 E CALCULATION DESIGN VERIFICATION PLAN ...AND

SUMMARY

SHEET PAGE NO. 3 of 25 Calculation Design Verification Plan: Calculation inputs of hydrological characteristics for transmissivity, hydraulic conductivity, and line recharge; pumping rates; and distances to property boundaries shall be verified by checking the documented input with the source references, and if applicable further supported by more recent hydrogeological investigations, if any. Equations used are applicable based on references cited. Check thevalidity of the references for their intended use. All assumptions shall be evaluated and verified to determine if they are based on sound hydrological principles and practices.

Calculation results shall be verified by random checks of at least three (3) equations roteach radial well at each flow rate. Verify the methodology, results and conclusions.(Print Name and Sign for Appro vat -mark "NI/A" If not required)Approver:

James A. Thomas / .7-$- " Date: Calculation Design Veriflcatlon/

Summary: Design inputs, assumptions, methodology, results, and conclusions of Revision 0 are evaluated/verified and were found to be acceptable.

All comments have been incorporated.

Based on the above summary, the calculation Is determined to be acceptable.(Print Name and Sign)Design Verifier:

Haifeng LI Date: 0,r/WobD Others: Stacey Fredenberg Date: wml CALC. NO. ENTGGG071 -CALC-001 CALCULATION REV. 0 REVIEW CHECKLIST OPENERCON PAGENO. 4 of 25 Item Cover Sheet Items Yes No N/A 1 Design Inputs -Were the design inputs correctly selected, referenced latest revision, [ 1j -consistent with the design basis and incorporated in the calculation?

2 Assumptions

-Were the assumptions reasonable and adequately described, 0 El El justified and/or verified, and documented?

3 Quality Assurance

-Were the appropriate QA classification and requirements 0 o o assigned to the calculation?

4 Codes, Standard and Regulatory Requirements

-Were the applicable codes, standards, and regulatory requirements, including issue and addenda, properly El El 0 identified and their requirements satisfied?

5 Construction and Operating Experience

-Has applicable construction and operating

] El 0 experience been considered?

6 Interfaces

-Have the design interface requirements been satisfied, including El 1l 0 interactions with other calculations?

7 Methods -Was the calculation methodology appropriate and properly applied to 0 El satisfy the calculation objective?

8 Design Outputs -Was the conclusion of the calculation clearly stated, did it correspond directly with the objectives and are the results reasonable compared to 0 El El the inputs?9 Radiation Exposure -Has the calculation properly considered radiation exposure to El El 0 the public and plant personnel?

10 Acceptance Criteria -Are the acceptance criteria incorporated in the calculation sufficient to allow verification that the design requirements have been satisfactorily El El 0 accomplished?

11 Computer Software -Is a computer program or software used, and if so, are the E l 1 El 0 requirements of CSP 3.02 met?COMMENTS: Print Name and Sign Reviewer.

Haifeng LI Date: Others: Stacey Fredenberg Date: N Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 5 of 25 TABLE OF CONTENTS 1.0 PU R PO SE .......................................................................................................

6 2.0

SUMMARY

OF RESULTS AND CONCLUSIONS

..........................................

7

3.0 REFERENCES

.................................................................................................

8 4.0 ASSUMPTIONS/DESIGN INPUTS .................................................................

8 5.0 M ETHO DO LOGY ..........................................................................................

12 6.0 CALCULATIO NS ..........................................................................................

13 7.0 CO NCLUSIO NS ............................................................................................

20 FIGURES Page Figure 1 -GGNS Radial Well Locations 21 Figure 2 -GGNS Geologic Cross-Section 22 Figure 3 -Distance to Property Line Observation Points 23 Figure 4 -Radial Well Schematic 24 Figure 5 -December 9, 1983 Potentiometric Surface 25 TABLES Table 1 -Groundwater Drawdown at the Property Line Observation Points (Nominal Pumping Rates Qave) 7 Table 2 -Groundwater Drawdown at the Property Line Observation Points (Maximum Pumping Rates Qmax=10,000 gpm) 7 Table 3 -Aquifer and PSW Well Parameters 9 Table 4 -Distance (r) between PSW Wells and Nearest Property Boundaries 11 ATTACHMENTS Number of Pages Attachment 1 -Groundwater Associates Report, 1994, excerpt pages 2 Attachment 2 -Bechtel Calculation B-861-1, 1986, excerpt pages 5 Attachment 3 -Ranney, Multiple Collector Test and Lateral Evaluation, 1983, excerpt pages 3 Attachment 4 -Hydro Group, Annual Report, Collector Well Performance, PSW Wells 1, 3,4, and 5,1989, excerpt pages 2 Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001

.E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 6 of 25 1.0 PURPOSE The Plant Service Water system (PSW) for Grand Gulf Nuclear Station (GGNS) is supplied by radial (Ranney) collector wells installed along the bank of the Mississippi River. There are four (4) existing radial wells -PSW-1, PSW-3, PSW-4, and PSW-5.These radial wells are located in the floodplain that parallels the Mississippi River and are designed to derive water from the Mississippi River via induced infiltration.

The wells withdraw groundwater from Mississippi River alluvial deposits east of the river.Additional cooling tower make-up water is anticipated to be needed (-3,200 gpm) due to the increase in heat load generated as a result of Extended Power Uprate (EPU), along with the associated increase in water loss through evaporation, blowdown and drift. A new radial well is being installed to ensure that plant service water availability is maintained during EPU conditions since GGNS' existing radial wells degrade over time and thus cannot perform at their design capacity.

Radial well PSW-6 is scheduled to be installed north of the barge slip and operational in March 2012. Figure 1 shows the approximate locations of the existing radial wells and PSW-6.The purpose of the following analysis was to provide an evaluation of the radius of influence effects on the Mississippi River Alluvial Aquifer due to pumping from all five radial wells -PSW-1, PSW-3, PSW-4 and PSW-5, including anticipated pumping from PSW-6, scheduled for installation in 2012. This includes the following: " Determination of the aquifer drawdown effects due to pumping of the five (5)radial wells at rates sufficient to supply PSW needs at EPU conditions; assuming all five (5) radial wells are pumping at maximum Mississippi Department of Environmental Quality (MDEQ) permitted capacity.* Water withdrawal impacts related to operation of the PSW system on potential offsite groundwater users.This calculation is based on historic information and site conditions related to aquifer characteristics developed for GGNS by other vendors. For example, aquifer geology data mentioned in this calculation is based on data supplied by studies completed during the licensing of GGNS Unit 1, and supplemented by recent site characterization studies developed for the Combined Operating License (COL) Application developed for Unit 3.This data is accepted without additional verification.

Aquifer characteristics parameters such as hydraulic conductivity (K), Transmissivity (T), aquifer thickness (m), line recharge, and other are taken from previous GGNS calculations which were completed by other vendors. The aquifer parameter values are representative of tests performed at specific point locations representative of conditions at the time of the tests. These values are accepted without additional verification.

The verification of these parameters is limited to confirmation that the values used are accurately drawn from the referenced documents.

Utilization of these aquifer characteristics in this calculation is based on best professional judgment as being appropriate for the current calculation.

Assumptions cited in Section 4.0 and reflected as input values in the calculations in Section 6.0 contain no open assumptions that require future confirmation.

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 7 of 25 2.0

SUMMARY

OF RESULTS AND CONCLUSIONS Drawdown at any specific point of a well field will be the cumulative drawdown at that location from each well pumping within the area. The individual drawdowns from each PSW well at the five (5) property line observation points (P1 and P3 through P6) are summarized and totaled in Table 3 (nominal pumping rate Qave) and Table 4 (maximum pumping rate Qmax) to give an estimated cumulative drawdown amount at the specified observation point: Table I Groundwater Drawdown at the Property Line Observation Points (ft.)at Nominal Pumping Rates Qave PSW Well P1 P3 P4 P5 P6 PSW-1 3.75 2.52 1.68 0.11 0.09 PSW-3 0.74 0.81 0.78 0.17 0.13 PSW-4 0.40 0.44 0.45 0.31 0.25 PSW-5 0.26 0.28 0.29 0.39 0.32 PSW-6 0.17 0.18 0.19 0.74 0.90 Total 5.32 4.23 3.39 :1.72: 1.69 Table 2 Groundwater Drawdown at the Property Line Observation Points (ft.)at Maximum Pumping Rates Qmax = 10,000 gpm PSW Well P1 P3 P4 P5 P6 PSW-1 8.71 5.85 3.92 0.26 0.22 PSW-3 1.80 1.97 1.91 0.40 0.32 PSW-4 0.76 0.82 0.86 0.58 0.48 PSW-5 0.50 0.53 0.55 0.75 0.62 PSW-6 0.32 0.34 0.36 1.40 1.69 Total 12.09: 9.51 7.60 3.39 3.33 The greatest groundwater drawdown is estimated to be at the southern property boundary, approximately 12.09 feet with all five (5) wells pumping at the 10,000 gpm, in the vicinity of observation point P1. Assuming an average aquifer thickness of 81.20 feet (Table 2, PSW-1), this results in a net reduction of the available aquifer thickness on the southern property line at P1 of 14.89% [(12.09 ft./81.20 ft.)

  • 100=14.89%].

If an assumed aquifer thickness of 81.26 ft. exists similar to PSW-5 at Observation Point P5 (See Figure 3) on the GGNS northern property boundary, the reduction of available capacity is 3.39 feet, or 4% [(3.39 ft./81.26 ft.)

  • 100 = 4.17%)].Due to the recharge provided by the Mississippi River, groundwater withdrawals from the GGNS PSW well field would not be expected to have an impact on offsite groundwater.users west of the river.

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 8 of 25

3.0 REFERENCES

Bechtel 1986. Bechtel, Radial Wells 1, 3, 5 -Reduction of Multiple Well Test Data (Geotech Calc G-035). Approved 7/31/86.Driscoll 1986. Groundwater and Wells, Fletcher G. Driscoll, Editor, Johnson Filtration Systems, Inc. 1986.GGNS (Grand Gulf Nuclear Station) 2008. Grand Gulf Nuclear Station Unit 3 Combined License Application, Part 2: Final Safety Analysis Report, Revision 0. February 2008.GGNS (Grand Gulf Nuclear Station) 2009. Updated Safety Analysis Report. 2009.GWA 1994, Ground Water Associates, Evaluation of Means for Supplying Plant Service Water Requirements, Grand Gulf Nuclear Station, June 1994.Hydro 1989. Hydro Group, Inc., Annual Report, Collector Well Performance, PSW Wells 1, 3,4, and 5, Grand Gulf Nuclear Station, February 1989.MDEQ 2010. Mississippi Department of Environmental Quality, Permit to Divert or Withdraw for Beneficial Use the Public Waters, Permit Number MS-GW-16714, System Energy Resources, Inc., March 2010.Ranney 1975. Ranney Company, Report to Mississippi Power And Light Company, Jackson, MS, Hydrogeological Investigation for Ranney Collector Wells at Grand Gulf Nuclear Station, Grand Gulf, MS. 1975.Ranney 1983. Ranney Company, Multiple Collector Test and Lateral Evaluation Program, Ranney Wells 1,3 & 5, for Mississippi Power and Light, Grand Gulf Nuclear Station, December 1983.4.0 ASSUMPTIONS/DESIGN INPUTS 4.1 RADIAL WELL FLOW ESTIMATES Based on input from Entergy, additional cooling tower make-up water is anticipated to be needed (-3,200 gpm) due to the increase in heat load generated as a result of Extended Power Uprate (EPU), along with the associated increase in water loss through evaporation, blowdown and drift.A maximum flow rate of 10,000 gpm was established from the MDEQ permitted well capacities for all five (5) radial wells [MDEQ 2010]. The use of the maximum permitted flow rates is not intended to indicate that actual well yields of 10,000 gpm could be sustained.

The use of Qmax = 10,000 gpm is considered to provide additional conservatism in the estimate of drawdown effects at the GGNS property boundaries.

Therefore, 10,000 gpm is established as the assumed maximum flow rate from each radial well for this calculation.

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E N E R C(0 N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 9 of 25 4.2 AQUIFER PROPERTIES Historic pump testing data was reviewed for the existing PSW wells. This historic pump test data was used to estimate relevant aquifer properties

[Ranney 1975, Ranney 1983].Aquifer properties (transmissivity, hydraulic conductivity, line recharge, thickness) and observed drawdowns during pump tests are used below as input for the determination of groundwater drawdown at the closest property boundary.

Based on information from Entergy, there have been no new pump tests performed in the area radial wells of the GGNS site since 1983. However, the aquifer properties reported from those pump tests remain valid estimates of aquifer conditions since the subsurface geology has not changed since that time, and hydraulic conditions of the site have not been altered. That is, the hydraulic settings (river location, river flows, and areas of recharge) have not changed.Groundwater drawdown due to pumping in the unconfined Mississippi River Alluvial Aquifer at the location of the PSW radial wells (PSW-1, PSW-3, PSW-4, PSW-5, and the proposed PSW-6) adjacent to the Mississippi River is dependent on two hydrologic regimes within the aquifer surrounding the PSW wells. The groundwater aquifer on the western side of the well field is dominated by recharge from the Mississippi River.Although heavily influenced by the Mississippi River, the aquifer on the eastern side of the river also receives recharge from local precipitation, local flooding events, and discharge at the bluffs/floodplain interface from the Pleistocene age undifferentiated terrace deposits (locally identified as the Upland Complex) (Figure 2). These are described in the original Unit 1 licensing documents, as well as more recent evaluations

[Ranney 1975, Ranney 1983, GGNS 2008, GGNS 2009].The calculations below use radial well information developed from collector wells PSW-1, PSW-3, and PSW-5 pumping tests at conditions observed on October 9, 1983 at 12:30 hours [Bechtel 1986]. Mississippi River level was reported at 41.52 ft. msl and is assumed to be consistent throughout the duration of the pumping test for all three wells[Bechtel 1986].Table 3 provides inputs for the calculations below based on the reference cited: Table 3 Aquifer and PSW Well Parameters (Bechtel 1986]Parameter PSW-1 PSW-3 PSW-5 Q Total Flow rate (gpm) 4300 4100 5200 Hydraulic Conductivity K (gpd/ft.2) 2085 2350 2500 m Average Aquifer 81.20 75.41 81.26 Thickness (ft.)T Transmissivity (gpd/ft.)

169,302 177,214 203,150 Distance to line recharge 850 850 850 (ft.)

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 10 of 25 The flow rates from PSW-1, PSW-3, and PSW-5 are used in the calculations to reflect flow rates for comparison against the maximum assumed flow rates of 10,000 gpm per well.Hydraulic conductivity (K) for PSW-4 is listed as 1850 gpd/ft.2 with a nominal pumping rate of 5300 gpm, based on operations in 1988 [Hydro 1989]. As PSW-4 lies approximately midway between PSW-3 and PSW-5, Transmissivity (T) used for drawdown calculation is the average of the PSW-3 and PSW-5 (See values in Table 3), or (190,182 gpd/ft.).PSW-6 has not yet been installed at GGNS. Hydraulic conductivity (K) for PSW-6 is assumed to be the average of the PSW-1, PSW-3 and PSW-5 values (in Table 2) and calculated as 2312 gpd/ft.2.A nominal pumping rate of 5300 gpm is also assumed to be consistent with the PSW-4 estimation.

Transmissivity (T) used for drawdown calculation is the average of the PSW-1, PSW-3 and PSW-5 values in Table 3 (183,222 gpd/ft.).4.3 MISSISSIPPI RIVER RECHARGE EFFECTS Plant service water is supplied from radial collector wells located in the floodplain that parallels the Mississippi River (Figure 4). The collector wells are designed to derive water from the Mississippi River via induced infiltration.

Multiple assessments and yield calculations have been performed for radial wells installed at GGNS. The distance to the "line source of recharge" has been assumed to be approximately 850 ft. to the west of the wells [Bechtel 1986]. The "line source of recharge" is a theoretical line where the infiltration rate from the recharge source (Mississippi River) is balanced with the groundwater withdrawal rate; therefore producing a line of zero drawdown in the underlying aquifer. The line recharge distance is measured from the pumping well. The Bechtel 1986 calculations derive line recharge distances specific to PSW-1, PSW-3, and PSW-5 at the cited flows (Q) and river stage.Bechtel did not calculate a line recharge distance for PSW-4 or PSW-6. ENERCON uses an assumed line recharge distance of 850 feet in this current calculation package, as a reasonable distance.

Use of this line recharge distance is consistent with other calculations performed by Bechtel [Bechtel 1986]. The Mississippi River is approximately 3300 feet wide at the location of GGNS. Pumping from the GGNS PSW wells on the eastern side of the Mississippi will not affect groundwater users on the western side of the Mississippi River.Previous aquifer testing at the locations of PSW-1, PSW-3, and PSW-5 (Figure 5)showed a sharp groundwater gradient from the Mississippi River bank to the pumping well, and a more gradual, but limited, cone of depression on the landward side of the well [Ranney 1983].

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 AE N E R CO N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 11 of 25 4.4 MISSISSIPPI RIVER ALLUVIAL AQUIFER EFFECTS East of the Mississippi River, the radial wells will draw groundwater not only from induced infiltration from the Mississippi River, but also from the alluvial aquifer itself.Groundwater pumping tests were conducted between 1975 and 1983 for aquifer parameter and yield determinations; however, none of the tests were conducted at pumping rates of 10,000 gpm [Bechtel 1986].4.5 DRAWDOWN OBSERVATION POINT DISTANCES Distances from each radial well (PSW-1, PSW-3, PSW-4, PSW-5, and PSW-6) were developed by ENERCON to a point approximately corresponding to the nearest property boundary.

These distances were developed approximations using measurement capabilities of publically available aerial photography software (Google Earth). These distances are not surveyed distances, and therefore any drawdowns derived from the calculations below are representative of the estimated effects at the specified distance from the cited well. Figure 3 provides locations of observation points on the GGNS property boundary and well locations.

Using Equation 2, the distances in Table 4 were used to calculate the drawdown at the GGNS property boundary for a location nearest to each of the collector wells. Observation points P1, P3, and P4 are located on the southern property boundary.

Observation points P5 and P6 are located on the northern property boundary (Figure 3).Table 4 Distance (r) between PSW Wells and Nearest Property Boundaries (ft.)I IObservation Point PSW Well P1 P3 P4 P5 P6 PSW-1 1050 1450 1920 8650 9450 PSW-3 3000 2850 2900 6700 7550 PSW-4 4650 4450 4350 5350 5900 PSW-5 5600 5400 5300 4500 5000 PSW-6 7400 7150 7000 3400 3050 4.6 RIVER STAGE The calculations below use radial well information developed from collector wells PSW-1, PSW-3, and PSW-5 pumping tests at conditions observed on October 9, 1983 at 12:30 hours [Bechtel 1986]. Mississippi River level was reported at 41.52 ft. msl and is assumed to be constant.

Actually, the river level at 41.52 ft. msl is a relatively low stage of the river, and adds additional conservatism to the consideration groundwater drawdown.

Maximum well drawdown in each PSW is fixed, based on the established pump intake elevation.

The GGNS minimum water levels for each well are established above the actual pump intake. The river level affects the available saturated thickness of the aquifer, and in effect the available well yield is reduced when the river level Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit 1 PAGE NO. 12 of 25 declines because of a corresponding reduction of the aquifer saturated thickness.

The relationship between aquifer thickness and available yield is illustrated by Darcy's equilibrium well equation: Q = (K(H 2-h 2))/(1055 log R/r) (Driscoll 1986, pg. 213)Where: Q = well yield or pumping rate (gpm)K = Hydraulic conductivity of the formation (gpd/ft.2)H = static head measured from the bottom of the aquifer (ft.)h = depth of water in the well while pumping (ft.)R = radius of the cone of depression (ft.)r = radius of the well (ft.)As shown in Darcy's equation, if the radius (R) of the cone of depression is assumed to remain constant, the flow (Q) is reduced as the static head (H) decreases.

If the flow is held constant, the radius of the cone of depression is decreased, if the static head decreases.

The aquifer parameters (transmissivity, hydraulic conductivity) cited in Table 3 are based on the point in time where the river level was 41.52 ft. above mean sea level. All calculations below are based on assumption of a constant river stage and aquifer potentiometric surface elevation of 41.52 ft. above mean sea level.5.0 METHODOLOGY ENERCON reviewed readily available hydrogeological reference literature for methodologies to best estimate drawdown effects that would include the maximum number of site conditions, such as recharge from the Mississippi River, other local recharges, horizontal collector well design and operating conditions, and multiple well interferences.

Most hydrogeologic references discuss recharge conditions such as rivers, lakes, and local precipitation, but cite the need to use pump test data to predict drawdown at distance.

This is because site specific aquifer properties control observable drawdown.

Ultimately, ENERCON chose to use the equations previously used for estimating radial well yield as most applicable, because the equations consider the recharge from the river. Use of the same equations also provides for consistency of evaluation methodologies.

Equation 1 (Section 5.1) includes recharge from the river, as a line recharge boundary, although it does not include other recharge sources (e.g.,ýprecipitation events). Therefore, it must be noted that the calculations performed below are conservative, and will overestimate the probable drawdown.

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 FJ E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 13 of 25 5.1 EQUATIONS AND INPUT PARAMETERS The method used for this calculation is based on the equations utilized by Bechtel in 1983 to determine drawdown interference effects between adjacent PSW well pumping[Bechtel 1986]. Use of these equations is consistent with previous evaluations at the site; and the equations take the recharge of the Mississippi River into account in the evaluation.

The equation for drawdown is derived from the following equation (Equation 1) for calculation of aquifer transmissivity:

527.7Q log(' ?a2 +r2.T = r (Equation

1) [Bechtel 1986, sheet 2 of 35, Attachment 2]s Where: T = Transmissivity (gpd/ft.)Q = Pumping rate, gpm a = Distance from pumping well to the line source of recharge* (ft.)r = Distance from pumping well to a selected observation point (ft.)s = Groundwater drawdown at the selected observation point r (ft.)* The "line source of recharge" is a theoretical line where the infiltration rate from the recharge source (Mississippi River) is balanced with the groundwater withdrawal rate; therefore producing a line of zero drawdown in the underlying aquifer.Rearranging Equation 1 to solve for the groundwater drawdown (s) at an observation point (r) yields the following:

5 2 7.7 QIog(-4 a2+r)S =T r (Equation 2)6.0 CALCULATIONS The following is an assessment of the drawdown, both individually and cumulatively, at each of the five observation points specified in Table 1. The assessment will evaluate the observation point drawdown for a nominal flow rate (Qave), used in the Bechtel assessment

[Bechtel 1986]. A maximum flow rate of 10,000 gpm was established from the MDEQ permitted well capacities for all five (5) radial wells, as requested by Entergy.The use of the maximum permitted flow rates is not intended to indicate that actual well yields of 10,000 gpm could be sustained.

The use of Qmax = 10,000 gpm is considered to provide additional conservatism in the estimate of drawdown effects at the GGNS property boundaries.

The calculations below use radial well information developed from collector wells PSW-1, PSW-3, and PSW-5 pumping tests at conditions observed on October 9, 1983 at 12:30 hours [Bechtel 1986]. Mississippi River level was reported at 41.52 ft. msl and is assumed to be consistent.

Actually, the river level at 41.52 ft. msl is a relatively low Evaluation of Potential Impacts of CAM NO. ENTGGG071-CALC-001 EJ E N E R C 0 N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 14 of 25 stage of the river, and adds additional conservatism to the consideration groundwater drawdown.6.1 ESTIMATED DRAWDOWN AT GGNS PROPERTY BOUNDARIES 6.1.1 PSW-1 Estimated Drawdown Using Equation 2, and parameter values from Tables 1 and 2, the drawdown at each observation point for a nominal flow rate (Qave) of 4,300 gpm, and for a maximum flow rate (Qmax) of 10,000 gpm is as follows: Qave = 4300 gpm Qmax = 10,000 gpm PSW-1: Observation Point P1 2 05 0008054050+10502)05 48 2 '0.5..... .... ._______+_o

_ +1050/27.7*43U00*IOg( 1050 ) 527.7*10000*"og 1050 )S =-- 1050 5 1050 169302 169302 s = 3.75 ft. s = 8.71 ft.PSW-1: Observation Point P3 (4-850 2 500 2 0.52 1 g 4 BS0+1 4 02 527.7*4300*log( '145 027.7"10000*o 4 S --- 145 10 S ---t- 1450 169302 169302 s = 2.52 ft. s =5.85 ft.PSW-I: Observation Point P4 527.7*4300*log( " 4 8 5 0+1202 _27.710000.Iog4850+190°° S -- 1920 N- 1920 169302 169302 s = 1.68 ft. s= 3.92 ft.PSW-I: Observation Point P5 ('4*8502 +8650.)05 48502+86520

'27.7*4300*Iog( 86 527"7" lO000*log

_" 5°2+85°2°so" S=50 k. 8650 169302 169302 s = 0.11 ft. s 0.26 ft.PSW-1: Observation Point P6 2 -05450040.50

.(4*850 +o4530)0.5 24-8502+94002 0 5 S27.7*4300*logt 50 "27.7*0000*og " 9450 )169302 169302 s = 0.09 ft. s = 0.22 ft.

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 15 of 25 The nearest property boundary to PSW-1 is near Observation Point P1 in Table 2 (southern property boundary) and is calculated to have a drawdown of 3.75 ft. at 4,300 gpm, and 8.71 ft. at 10,000 gpm. PSW-1 is approximately 8,650 ft. from the nearest point on the northern property boundary (Observation Point P5), and is calculated to cause approximately 0.11 ft. of drawdown at a pumping rate of 4,300 gpm, and approximately 0.26 ft. of drawdown at a pumping rate of 10,000 gpm.6.1.2 PSW-3 Estimated Drawdown Using Equation 2, and parameter values from Tables 1 and 2, the drawdown at each observation point for a nominal flow rate (Qave) of 4,100 gpm, and for a maximum flow rate (Qmax) of 10,000 gpm is as follows: Qave = 4100 gpm Qmax = 10,000 gpm PSW-3: Observation Point P1 (4850o2 +30002).5

((4*8502+300(2)0,5 S -3000 527.7*S*log 3000 177214 177214 s = 0.74 ft. s = 1.80 ft.PSW-3: Observation Point P3 ('4ý,50 2 +2S50 2 0.5 (ý4ký850 2+2850 2 0.5 527.7*4100.*og( 2350 )°" = 527.7*10000*log(" 2850 )S -250 ___ ___ __ ___ _0 177214 177214 s = 0.81 ft. s = 1.97 ft.PSW-3: Observation Point P4 2 0 5, 2 0.5 S27.7.4100*log( (4m8s0 2 +2900 527.7* 10000*log(4R50°+20002Q

°S = 2900 S = 29000 177214 177214 s = 0.78 ft. s = 1.91 ft.PSW-3: Observation Point P5 (4u850 2+67002 0.5 2(4*850 2+670020o.5 S 27.74100og( 6700 S 527.7* *og 6700 177214 177214 s = 0.17 ft. s = 0.40 ft.PSW-3: Observation Point P6.....4 *ý 8 5 0 2 + 7 5 5 0 2 ) ". 5 527.7* 1UUUU*log t" 7 :; n 177214 s = 0.13ft.s = 0.32 ft.

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 16 of 25 The nearest property boundary to PSW-3 is near Observation Point P3 in Table 2 (southern property boundary) and is calculated to have a drawdown of 0.81 ft. at 4,100 gpm, and 1.97 ft. at 10,000 gpm. PSW-3 is approximately 6,700 ft. from the nearest point on the northern property boundary (Observation Point P5), and is calculated to cause approximately 0.17 ft. of drawdown at a pumping rate of 4,100 gpm, and approximately 0.40 ft. of drawdown at a pumping rate of 10,000 gpm.6.1.3 PSW-4 Estimated Drawdown Hydraulic conductivity (K) for PSW-4 is listed as 1850 gpd/ft.2 with a nominal pumping rate of 5300 gpm, based on operations in 1988 [Ranney 1983, Hydro 1989]. As PSW-4 lies approximately midway between PSW-3 and PSW-5, Transmissivity (T) used for drawdown calculation is the average of the PSW-3 and PSW-5 (See values in Table 2), or (190,182 gpd/ft.).Qave = 5300 gpm Qma, = 10,000 gpm PSW-4: Observation Point P1 527.7*5300*-og( (4,,502 +4650 2) 527.7*10000*logý-

4A5°2+4650° 06-0 S 60S = k 4650 190182 190182 s = 0.40 ft. s= 0.76 ft.PSW-4: Observation Point P3 (4S502 +44502), 05 527.7*5300-1og( 4450 527"7"10000"1°g

°4450 190182 190182 s = 0.44 ft. s =0.82 ft.PSW-4: Observation Point P4.(4-8502 +4350°2) 0.5 (4*8502 +43502)°0.5 S 527.7*5300*og( 4350 4350 190182 190182 s = 0.45 ft. s =0.86 ft.PSW-4: Observation Point P5 S27.7.5300.1og( (4*8502+53502)0'5

$27.7*10000*log((4 ,so2+5350 2)0'5 S -- 5350 S = %. 5350 190182 190182 s = 0.31 ft. s =0.58 ft.PSW-4: Observation Point P6 527,7*S300*Iog( (4802+902)

.;27 ,7 .10000 .1og (ý 8'5c)°2 +5900 0 .5)11 Aqn 5900 190182 190182 s = 0.25 ft.s = 0.48 ft.

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 F E N E R Co N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 17 of 25 The nearest property boundary to PSW-4 is near Observation Point P4 in Table 2 (southern property boundary) and is calculated to have a drawdown of 0.45 ft. at 5,300 gpm, and 0.86 ft. at 10,000 gpm. PSW-4 is approximately 5,350 ft. from the nearest point on the northern property boundary (Observation Point P5), and is calculated to cause approximately 0.31 ft. of drawdown at a pumping rate of 5,300 gpm, and approximately 0.58 ft. of drawdown at a pumping rate of 10,000 gpm.6.1.4 PSW-5 Estimated Drawdown Using Equation 2, and parameter values from Tables 1 and 2, the drawdown at each observation point for a nominal flow rate (Qave) and for a maximum flow rate (Qmax) of 10,000 gpm is as follows: Qave = 5200 gpm Q max = 10,000 gpm PSW-5: Observation Point P1 527.7,5200,1og (4*8502 +56002)°05 527.7,10000,og (4ýS502+56002)°o5 S -- 5600 S = 5600 203150 203150 s = 0.26 ft. s = 0.50 ft.PSW-5: Observation Point P3 527.7*5200*,Iog (4552 +54002 0's 527.7,10000,]og (4-8502+54002) 0'5 S = 5400 k__-- 5400 203150 203150 s = 0.28 ft. s = 0.53 ft.PSW-5: Observation Point P4 (4..8502 +5312105 527075 527,7S200o( 5300 27.7*1 0 0 00*l o g(4*55°2+5300-)0'5 S = 7 2 5300 s k 5300 203150 203150 s = 0.29 ft. s = 0.55 ft.PSW-5: Observation Point P5 00*1og.(4,S502

+450020°5 S27.7..10000,Iog 6 4 8 5 02+4 5 002)°05 S = 4500 S = 4500 203150 203150 s = 0.39 ft. s = 0.75 ft.PSW-5: Observation Point P6.... ' 8502+50002 0.5 527.7*0uuuu logv 203150 s = 0.32 ft.s = 0.62 ft.

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 E E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit 1 PAGE NO. 18 of 25 The nearest property boundary to PSW-5 is near Observation Point P5 in Table 2 (northern property boundary) and is calculated to have a drawdown of 0.39 ft. at 5,200 gpm, and 0.75 ft. at 10,000 gpm. PSW-5 is approximately 5,300 ft. from the nearest point on the southern property boundary (Observation Point P4), and is calculated to cause approximately 0.29 ft. of drawdown at a pumping rate of 5,200 gpm, and approximately 0.55 ft. of drawdown at a pumping rate of 10,000 gpm.6.1.5 PSW-6 Estimated Drawdown PSW-6 has not yet been installed at GGNS. Hydraulic conductivity (K) for PSW-6 is assumed to be the calculated average of the PSW-1, PSW-3 and PSW-5 values (in Table 2) and calculated as 2312 gpd/ft.2.A nominal pumping rate of 5300 gpm is also assumed to be consistent with the PSW-4 estimation.

Transmissivity (T) used for drawdown calculation is the average of the PSW-1, PSW-3 and PSW-5 values in Table 2 (183,222 gpd/ft.).Qavc = 5300 gpm Qmax = 10,000 gpm PSW-6: Observation Point P1 ,(4*350 +7400 527"7*1000*Ig5 4"SS02+7 4 00205 5327.7*5300*Iog( 7400 )00*lg 5 = s=700% 7400 183222 183222 s =0.17 ft. s 0.32 ft.PSW-6: Observation Point P3 245 +752)0 5 2___________

527.7,53 00,1og(("4s5o

+715o0)°')

527.7,10000*1og(6 4 So 5 0 2+7 1 5 0 S = 5 3 7150 S --_ 7150 183222 183222 s = 0.18 ft. s =0.34 ft.PSW-6: Observation Point P4 527.7.5300.1og(.(4ýS5o 2 +70002)0 5 527.7*10000*!ogý 4s,85°2+7°°°2)015)

S = 7000 S =-- 7000_183222 183222 s = 0.19 ft. s = 0.36 ft.PSW-6: Observation Point P5 5-27.7*5300*1og(.

2+3402)05 527.7*10000*1o(4-850+3400° 0)5 S = 00 S ="- k 3400 183222 183222 s = 0.74 ft. s = 1.40 ft.PSW-6: Observation Point P6 527.7*100O0*1og(4 85°2+3°5°2)°'5 5 7 3050 183222 S=O0.90Oft.

s= 1.69ft.

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 19 of 25 The nearest property boundary to PSW-6 is near Observation Point P6 in Table 2 (northern property boundary) and is calculated to have a drawdown of 0.90 ft. at 5,300 gpm, and 1.69 ft. at 10,000 gpm. PSW-6 is approximately 7,000 ft. from the nearest point on the southern property boundary (Observation Point P4), and is calculated to cause approximately 0.19 ft. of drawdown at a pumping rate of 5,300 gpm, and approximately 0.36 ft. of drawdown at a pumping rate of 10,000 gpm.6.1.6 Cumulative Estimated Drawdown Drawdown at any specific point of a well field will be the cumulative drawdown at that location from each well pumping within the area. The individual drawdowns from each PSW well at the five (5) property line observation points (P1 and P3 through P6) are summarized and totaled in Table 3 (nominal pumping rate Qave) and Table 4 (maximum pumping rate Qmax) to give an estimated cumulative drawdown amount at the specified observation point: Table 3 Groundwater Drawdown at the Property Line Observation Points (ft.)at Nominal Pumping Rates Qave PSW Well P1 P3 P4 P5 P6 PSW-1 3.75 2.52 1.68 0.11 0.09 PSW-3 0.74 0.81 0.78 0.17 0.13 PSW-4 0.40 0.44 0.45 0.31 0.25 PSW-5 0.26 0.28 0.29 0.39 0.32 PSW-6 0.17 0.18 0.19 0.74 0.90 Total 5.32 4.23 3.39 1.72 1.69 Table 4 Groundwater Drawdown at the Property Line Observation Points (ft.)at Maximum Pumping Rates Qrax = 10,000 gpm PSW Well P1 P3 P4 P5 P6 PSW-1 8.71 5.85 3.92 0.26 0.22 PSW-3 1.80 1.97 1.91 0.40 0.32 PSW-4 0.76 0.82 0.86 0.58 0.48 PSW-5 0.50 0.53 0.55 0.75 0.62 PSW-6 0.32 0.34 0.36 1.40 1.69 Total 12.09 9.51 7.60 3.39 3.33 The greatest groundwater drawdown is estimated to be at the southern property boundary, approximately 12.09 feet with all five (5) wells pumping at the 10,000 gpm, in the vicinity of observation point P1. Assuming an average aquifer thickness of 81.20 feet (Table 2, PSW-1), this results in a net reduction of the available aquifer thickness on the Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 P. E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 20 of 25 southern property line at P1 of 14.89% [(12.09ft./81.20ft.)*100=14.89%].

If an assumed aquifer thickness of 81.26 ft. exists similar to PSW-5 at Observation Point P5 (See Figure 3) on the GGNS northern property boundary, the reduction of available capacity is 3.39 feet, or 4% (3.39/81.26*100=4.17).

7.0 CONCLUSION

S

..... .. .. .... ............

....Due to the recharge provided by the Mississippi River, groundwater withdrawals from the GGNS PSW well field would not be expected to have an impact on offsite groundwater.users west of the river..Calculation of the groundwater drawdown effects at the GGNS property boundaries, due...to pumping all five PSW wells at an assumed maximum. flow rate of 10,000 gpm each,.resulted in a calculated cumulative drawdown at the closest point on the southern: property boundary (observation point P1, Figure 1) of approximately

'12.09 feet, or.'14.89% of the available aquifer thickness, and 3.39 feet or 4%: of. available, aquifer', thickness at northern property boundary..;

Evaluation of Potential Impacts of CAM NO. ENTGGG071-CALC-001 1 E N E R CO N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 21 of 25 Figure 1 GGNS Radial Well Locations Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 A ENERC0N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 22 of 25 I A.i I U*0 N Si.

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit 1 PAGE NO. 23 of 25 Figure 3 Distance to Property Line Observation Points Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 t E N E R C 0 N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 24 of 25 Figure 4 Radial Well Schematic I M~1 )-NK)I~--V ///I///CAISSON t/-7 HORIZOiNTAL LATERAL ABOUT 200 FEET LONG N PLAN hECIRCULAT1ON LINE, G RAVEL ZONE -FINES DURING INSTALLATION LATERAL SECTION NTS.

FQ ENERCON Evaluation of Potential Impacts of Collector Well Groundwater Withdrawals, Grand Gulf Nuclear Station, Unit I CALC. NO. ENTGGG071-CALC-001 REV. 0 PAGE NO. 25 of 25 Figure 5 December 9, 1983 Groundwater Potentiometric Surface (Ranney, 1983)

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 CD E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO.1 of 2 Attachment 1 GROUND WATER ASSOCIATES, INC.Prepared for Entergy Operations, Inc.Port Gibson, Mississippi Operations EVALUATION OF MEANS FOR SUPPLYING PLANT SERVICE WATER REQUIREMENTS GRAND GULF NUCLEAR STATION June, 1994 I A hWmo Group, Inc. Company Li"'

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 A E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 2 of 2 E:xperience has shown thast the design life of laterals is gen erally between 25 and 40 years.Given Ihe site's water quality and production rates, lateral design lilk: of 25 to 30 years should be expected.New laterals would be oriented.

in the 180' sector from parallel lo the river to toward the river and be constructed of 12-inch ID stainless steel (similar to PSW Well No. ,. Installation of new laterals would generally.require 4 to 6 months to complete and nonnally be perfotTned with the. well off line. It is possible that soine production firom the well could be maintained during the process by tnanifolding selected laterals, but this would may he add 10 percent to the overall.cost.h 3.2.4 New Radial Collector Well In the arly and mid 19801s several.investigations were conducted .to evaluate additional sites for new radial collector wellk (Ranney, 1980, 1984). IBased upon those reports and the projected i PSW mupply needs. two.sites appear viable:for.consideration.

These sites referred to as Well 2 and WeIl 6 are shown on Figure 7..i Propsed Well.2 is located midway hetween.PSW Well NO.. I mid Well NO. 3 while proposed i Well 6 is ocated.about 1700 feet north of PSW Well No. 5. Given the better perfornance and water quality of ISW Well Nos. 4 aid S and higher projected yield of Well 6 (8000 -10.000: gpm) aMd less interiercnce with existing wells, it is recomtnended that.Well 6 be the next site lbr an, newvradial collector well. Costs [Lr the development of Well 6 auuld be slightly ligher I3-6 Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 K3 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 1 of 5 Attachment 2-: UALITYASSURANCE PROGRAM 'CALC.NO.C J&CALCULAMMO COVER SHEET .-.mL,'. G1RANDGULFNUCLEARrWS,3,-"" UNITI NOI F 80.i0F JOB NO 9645/I sozC. VISCPUNE IJ L...TITLE MISSISSIPPI POWER & LIGHT COMPANY GRAND GULF NUCLEAR STATION UNIT I SUBJECT.. .. -. .STATEMENT OF PROBLEM* *. C-A.,, .* .. ....4C: I..SAR CHECKED BAR CHANGE REOGD. .AR CHANGE REQUEST INITIATED 0 YES NO, .SOURCES OF DATA SOURCES OF FORMULAE.&

REFERENCES.K:: L-4 .S k -m COMMITrED PRELIMINARY CALC 0 FINALCALC_

SUPERSEDES CALCNO._____

NO. r ' AL -ALC.-C rN-A GEI HIECKED I ATE4/APPRNEDDBY I'AtTE N.DATE DESCRIPTION ORIGINATOR 1*B G~t~UR1~3 Evaluation of Potential Impacts of CAM NO. ENTGGG071-CALC-001

.E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 2 of 5::Wrsam pomm &LIGHT COW LAMSHE.50CUM CME No. FIEV. INO.IM EN.[ORIGINATR OATE U~l AIT;2~i it -Aa At -j A" -A. _.%-, No Lit!104% , 'Ax_ _Ii~~ t1 1__I I I jo-T 8 1 -4 I .al 20 1 u L h¶ A L .21 lii qIIIl oid 11i 25 277 29 1. I 29 34 _ _31t 1Vh.Vis, C17A IL 32 35 ~ v~iiiiiii 38 _ _ _ _ _- --P --

Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 7 E N E R C 0 N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 3 of 5 A LTM" Co"LICULArimsHEET 4 E S 1 1 JOB.NO NO.ETN OMIGHATOR DATE C~tE DATE.- .___ ........ ..r ., 4 4 ...- -..._B --.7 I.__t A I I.I I IA A~i~ 01[-ii I---------------

i.I ... .....I o ...........

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..I i I I J i ..* ...I lilt I I I-I I -* .I I i 4 t ?I I i I I I I I. I I II I I I., ! , ! i I I I______________

I I II I i I I !I* I i i i ; i I I I.1! I II q i I I 1A I I I ~ I I ii_I I U~-i--~---r1flrII I I 35 Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 Fi E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 4 of 5 ISSrrnPOYM L-M -OP4JCULATION SHEET"20 N O .-C A WC .N O .R E N O .1 0 E4 M N O .OR~OINATOR OA1E CHfi(E DT i.- ýj L tL--ý a[.1210i. f 1! L L V IT I J 4.--s~# -~ ~ ti ~ ...........

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---30 31 3: 33 34 3d 38 Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001 IJ E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 5 of 5 a gisrPT P()7"! A ~ CALCULATION SHEET^0.;P10 -W

  • CALC. NO, MVO. NO. ISHEET W.Ii .G -o. L0 I,...:x OR1IGINATOR DATE DT GAl 1 21 C_~' r- -A 4x-.&t ni*.~ P- ...... t near .4 -............... ..-- ~~~~~ ~~ .......... .c~ c C-2 e h.'rki-iie'....... ...1oJ ... .~~V VH .... ... .r: 1070 I Evaluation of Potential Impacts of CAM NO. ENTGGG71-.CALC-001E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. i of 3 Attachment 3 THE RONNE'C-p, FF~.I ;-Ai AL sv fjV4AftkC.A Zj "" }ANd -44$ I"'<3 7'M".~$1fl~P~W~R i~I~'4~AH?'x, "

Evaluation of Potential Impacts of CALC. NO. ENTGGG071-CALC-001 U E N E R CO N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO.2of3 1 -g.4~4.I~ 1.-I~~~ VA____i.J /7// /7-1~~~ 1: -_______________________

1/'.~/1// -4 U..i/I ~ f[.~)/ li/V_ _ _ _ _ _.... .......

Evaluation of Potential Impacts of CAM NO. ENTGGG071-CALC-001 , E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 3 of 3 Yield of Collector 4 The following values and Equation 5 were utilized Collector 4 yield under mean low conditions:

to determine Grade Elevation Elevation Top of Potential Aquifer Elevation Base of Aquifer Effective Distance *to. Line Source of Recharge, a Hydraulic Conductivity, K Ground Water Temperature, Test Conditions Design Temperature, Mean Low Condition' Average Lateral Length Radius of Laterals, rL Radius of Caisson,-rc Elevation Centerline of Laterals Vertical Position of Laterals, Zi Design Pumping Level.Average Saturated Thickness, m'75 ft.65 ft.-43 ft.(MSL)(MSL)(MSL)850 ft.1,850. gpd/ft 2 62OF 60OF 208 ft.0.5 ft.10. ft.-38 ft. (MSL)78 ft.-22 ft. (MSL)52 ft.ml 52 feet 2 Therefore, Evaluation of Potential Impacts of CAL NO. ENTGGG071-CALC-001E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit 1 PAGE NO. 1 of 2 Attachment 4 I P F) Tg i i RANNEY DIVISION COLLECTOR WELL PERFORMClANCE PSW WELLS 1. 3. 4 AND 5'FOR SYSM4 ENERGY RESOURCES, INC.(GRAND GULF NUCLEAR STATION)OF PORT GIBSON, MISSISSIPPI I Hydra Group, Inc., 2 No.Ih St~e Stre~t.P.O S~r 729 Wes(evII~, Oho430a1.(614) a62-3104 iI Hydro Group, Inc., 2 North StafeStr"tRO.

ft 729.WesteMile, 0hio43M1-(614)882-3104 Evaluation of Potential Impacts of CAM NO. ENTGGG071-CALC-001 E N E R C O N Collector Well Groundwater Withdrawals, REV. 0 Grand Gulf Nuclear Station, Unit I PAGE NO. 2 of 2 W e IPerfbrmannee

-PSW W e 1I 4 Figure 16 -Monthly Production

'l.rends il.lustrates the pumping level in PSW Wcell 4 as it .luctuatos in response to changes in.the Mississippi River level and pumping. rate. Also shownm is the xvater level in nearby observation well P148Ai As shown in Figure i6, during 1988 ISW Wt11 4 was operated at.rates ranging from 535(0 to 9760 gpm,. Pumping levels, ranged from. a high of +20.5 f-cet ,N., in Marcli (which was coincident:

wvith a relatively high. river level of +63.0 fee.t MSL and a lowy pumping rate of 5350 gSin) and a low otf -14.5 feet MSL in August (coinciding with low rive.r level eonditi:ons of +35.6 feet,MSL)Figure 17 -I-,W Well 4 Monthly Operating Trends presents graphs of Water l'cnmpcraturc, Apparent Spcei.t'i.a

cVapacit" and D)iffe.r-ential. As shown, during: 1988 ground water temperature as incas-ured in. I-h Well 4 ranged from a lnw oE 51 degrees Fahicnheiat in March to a high of 01 degrees in Septemrber and with some modera-tion, closel.y mirrored.

river temperature.

The apparent spe.ific capacity of SlV WoII 4 fluctuated consider-ably during 1988 ranging. between 104.9 and 260.6 gpm/ft which nky al.so indicate possible.

problems in data collection.

Differ-ential water level, between P-W Weil 4 and Observation Well PWSA,* with the exception of February, remained at low levels of around 2 to 4 feet/!.000 ppn,-41-

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