L-2018-136, L-2018-136-Attachment 53 Enclosure 1 - Slides and Presentations
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Variable Density Ground Water Flow and Salinity Transport Model Analysis Attribution Analysis Results Pete Andersen, P.E.
James Ross, Ph.D., P.E.
Tetra Tech June 19, 2018 Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 1 of 34
Executive Summary FPL used existing Groundwater Model with additional modifications to conduct the attribution analysis 8 regional and environmental factors were considered and individually modeled to assess their independent effects Each model result was compared to the base case The analysis indicated that the most influential factors were:
- CCS salinity > seawater
- Climate,
- WMD canal operations The least influential factors were:
- Local canals
- Seasonal canals
- Sea level rise*
- Sea level rise over the past 9 years of most significant change may not have reached an equilibrium at the current comparison time. Its effect may therefore be underestimated.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 2 of 34
Outline
Background
Attribution analysis
- Factors considered
- Analysis and reporting methodology Results
- Scenario development
- Visual Conclusion Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 3 of 34
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Background===
DEP Consent Order #16-0241 (CO) was entered into between DEP and Florida Power & Light Company (FPL) on June 20, 2016 Third Objective of CO:
FPL to provide mitigation for impacts related to the historic operation of the Cooling Canal System (CCS), including but not limited to the hypersaline plume and its influence on the saltwater interface (SWI)
To achieve this third objective (in part), paragraph 23(a) of the CO requires FPL to:
Complete an analysis, within 2 years from the effective date of this Order, with input from the Department and other agencies as selected by the Department, using the variable density three-dimensional groundwater model developed under the Miami-Dade County Consent Agreement, that seeks to allocate relative contributions of other entities or factors to the movement of the SWI.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 4 of 34
Factors Considered in Attribution Analysis (8) 1.
Operation of the FPL Cooling Canal System (CCS);
2.
Sea level rise; 3.
Changes in land use:
4.
Decadal-scale changes in precipitation recharge; 5.
Construction of drainage structures and changes to drainage practices; 6.
Construction and operation of controlled freshwater canals; 7.
Changes to groundwater use (changes to the operation and capacity of nearby wellfields); and 8.
Management and operation of mining practices west of the CCS.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 5 of 34
Analysis and Reporting Methodology Description of specific factor to be assessed Base case (calibrated model) condition Scenario modifications Metric: Average change in area (from base case) of salinity > 0.05 (1000 mg/L Cl) west of the CCS over thickness of aquifer Visual: Areal view of saltwater interface line
- Model layer 8, lower high flow zone
- Simulated interface should not be compared to Prinos (2016) because of differing monitoring elevations and intervals Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 6 of 34
Scenario 1: CCS operated at seawater salinity for its period of use
- Replace CCS cells of greater than 35 PSU with 35 PSU
- Run model, process results
- Assesses position and orientation of saltwater interface if CCS salinity remained at 35 PSU Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 7 of 34
Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 1
Limit CCS salinity to 35 PSU 21.45 2.65 11.01%
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 8 of 34
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 9 of 34
- 2. Sea Level Rise Sea-level rise is included in base model:
- Biscayne Bay boundary
- Canal and inland boundary adjustments
- 2.74 inches 1973-2010
- 2.79 inches 2010-2018 Scenario 2: No sea-level rise
- Detrend Biscayne Bay boundary heads to account for no rise, but apply same seasonal and monthly variability
- Adjust CCS stages by same amount to maintain same head differences with Biscayne Bay as base model
- Run model, process results
- Assess influence of sea-level rise Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 10 of 34
- 2. Sea Level Rise Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 2
No Sea Level Rise 23.99 0.11 0.45%
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- 2. Sea Level Rise Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 12 of 34
- 3. Changes in Land Use Land use change is included in base model:
- Recharge (precipitation, agricultural irrigation)
- Runoff (urbanization)
- Drainage canals Scenario 3: No change in land use
- Recharge distribution as in 1960s
- Runoff distribution as in 1960s
- Drainage canals as in 1960s Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 13 of 34
- 3. Changes in Land Use Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 3
No Land Use Changes 23.97 0.13 0.55%
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- 3. Changes in Land Use Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 15 of 34
- 4. Decadal-Scale Changes in Climate Actual climatic variability is included in base model
- Precipitation / ET as measured/estimated from 1968-2015 Scenario 4: Alternative decadal-scale change in recharge
- Repeat 1967-1976 precipitation and ET through present
- Determine effects of recent (drier) climate Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 16 of 34
- 4. Decadal-Scale Changes in Climate Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 4
Decadal-Scale Change in Climate 22.81 1.29 5.38%
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- 4. Decadal-Scale Changes in Climate Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 18 of 34
- 5. Construction of Drainage Structures and Changes to Drainage Practices Controlled freshwater canals are included in base model:
- Progressive addition of canals with time Scenario 5a: Localized alternate management of drainage structures
- Higher dry season heads in canals northwest of CCS
- North, Florida City, and C-103 heads assumed equal to L31-E Scenario 5b: Widespread alternate management of drainage structures
- Set observed maximum seasonal heads in all controlled canals Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 19 of 34
- 5. Construction of Drainage Structures and Changes to Drainage Practices Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 5A Local canals to L-31E 24.09 0.01 0.06%
5B High seasonal canal stages 24.05 0.05 0.20%
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5a: Localized alternate management of drainage structures Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 21 of 34
5b: Widespread alternate management of drainage structures Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 22 of 34
- 6. Construction and Operation of Controlled Freshwater Canals Controlled freshwater canals are included in base model:
- Progressive addition of canals with time
- Management practices represented as they occurred Scenario 6: 1960s canal distribution present through 2017
- L31-E and other freshwater canals (built in late 1960s and early 1970s) not included in scenario
- Assesses influence of freshwater canal construction Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 23 of 34
- 6. Construction and Operation of Controlled Freshwater Canals Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 6
No WMD canals 23.34 0.76 3.15%
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 24 of 34
- 6. Construction and Operation of Controlled Freshwater Canals Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 25 of 34
- 7. Changes to Groundwater Use Changes to the operation and capacity of nearby wellfields are included in base model Scenario 7a: Municipal Pumping
- Eliminate municipal pumping from model
- Run model, process results Scenario 7b: Agricultural Pumping
- Eliminate agricultural pumping from model
- Run model, process results Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 26 of 34
- 7. Changes to Groundwater Use Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.10 7A No municipal pumping 23.94 0.16 0.66%
7B No ag pumping 23.93 0.17 0.71%
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7a: Municipal Pumping Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 28 of 34
7b: Agricultural Pumping Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 29 of 34
- 8. Management and Operation of Mining Practices West of the CCS Progressive addition of mining is included in base model:
- 3 mines/quarries
- Water balance based on recharge / evapotranspiration differences (generally an ET draft)
Scenario 8:
- Eliminate mines: assume natural conditions present in mine footprints
- Run model, process results
- Assesses influence of mine presence and water use Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 30 of 34
- 8. Management and Operation of Mining Practices West of the CCS Number Description Average areal extent of saltwater (mi2)
Reduction from Base (mi2)
% Reduction from Base 0
Base 24.1 8
No mining 23.73 0.37 1.54%
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 31 of 34
- 8. Management and Operation of Mining Practices West of the CCS Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 32 of 34
Summary Attribution analysis has been performed in accordance with FDEP requirements Model was updated to be better suited for this type of analysis Changes to areal extent of SWI:
Attribution Scenario Change in Areal Extent (sq mi)
CCS hypersalinity 2.65 Climate 1.30 WMD canals 0.76 Mining 0.37 Agricultural pumping 0.17 Municipal pumping 0.16 Land use 0.13 Sea-level rise 0.11 Seasonal canals 0.05 Local canals 0.01 TOTAL 5.72 Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 33 of 34
Conclusions The analysis indicated that the most influential factors were:
- CCS salinity > seawater
- Climate,
- WMD canal construction and operations The least influential factors were:
- Local canals
- Seasonal canals
- Sea level rise*
Sea level rise over the past 9 years of most significant change may not have reached an equilibrium at the current comparison time. Its effect may therefore be underestimated.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to NRC RAI No. WR-12 L-2018-136 Attachment 53 Enclosure 1 Page 34 of 34