Final Report Hydrogeological Characterization of the Eastern Turlock Subbasin
March 2016
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PROFESSIONAL CERTIFICATION
Phyllis Stanin, PG 5311, CEG 1899, CHG 482 Vice President and Principal Geologist
Liz Elliott, PG 8446, CHG 973 Senior Hydrogeologist
Maureen Reilly, PE 67841 Senior Engineer
Dan Craig, PG 5048, CHG 66 Senior Hydrogeologist
Table of Contents
1. Executive Summary ...... ES‐1 2. Introduction ...... 1 3. Data Collection ...... 2 3.1. Physical, Geologic, and Hydrologic Data Collection ...... 2 3.2. Hydrogeologic/Groundwater Data Collection ...... 2 3.3. Land Use Data Collection ...... 3 4. Land Use Analysis ...... 5 4.1. Irrigated agricultural area ...... 5 4.1.1. DWRe Land Us Maps ...... 5 4.1.2. County Crop Maps ...... 5 4.1.3. DWR Tabular Irrigated Acreage ...... 5 4.1.4. Irrigated Acreage in the Study Area ...... 6 4.2. Applied Water ...... 7 4.2.1. Crop Coefficients, ET, and Precipitation ...... 7 4.2.2. Irrigation Efficiency ...... 8 4.2.3. Total Water Demand ...... 8 4.3. Groundwater Use Database ...... 8 5. Hydrogeologic Conceptual Model ...... 10 5.1. Physical Setting ...... 10 5.1.1. Topography ...... 11 5.1.2. Climate ...... 11 5.1.3. Surface Water ...... 12 5.1.4. Soils and Restrictive Layers ...... 13 5.1.5. Geologic Setting ...... 13 5.1.6. Groundwater Basin ...... 14 5.2. Aquifer Evaluation ...... 14 5.2.1. Mehrten Formation Information from Technical Reports ...... 15 5.2.2. Evaluation in Study Area Wells ...... 15 5.2.3. Aquifer Textures ...... 18 5.2.4. Groundwater Levels ...... 20
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5.3. Water Balance ...... 21 5.3.1. Groundwater Inflows ...... 22 5.3.1.1. Infiltration from Precipitation ...... 22 5.3.1.2. Turlock Lake Leakage ...... 23 5.3.1.3. Streamflow Leakage ...... 23 5.3.1.4. Irrigation Return Flows ...... 24 5.3.1.5. Domestic Return Flows ...... 24 5.3.1.6. Eastern Boundary Subsurface Inflow and Base Upflow ...... 24 5.3.2. Groundwater Outflows ...... 25 5.3.2.1. Irrigation Pumping ...... 25 5.3.2.2. Domestic Pumping ...... 25 5.3.2.3. Western Boundary Subsurface Outflow ...... 26 5.3.3. Change in Storage ...... 26 6. Numerical Model Simulations ...... 27 6.1. Model Updates and Simulation Scenarios ...... 28 6.2. Updated Baseline Simulation Calibration Results ...... 31 6.3. Future Scenario Simulation Results ...... 32 6.4. Model Summary and Conclusions...... 35 6.5. Model Limitations ...... 36 7. Conclusions ...... 38 8. Data Gaps and Limitations ...... 40 9. References ...... 41
List of Tables
Table 1. Data Collection Summary Table 2. Irrigated Crop Areas, Turlock Lake DAU Table 3. 1995 Land Use Comparison Table 4. 2002 Land Use Comparison Table 5. 2014 Land Use Comparison Table 6. Percentage of DAU Irrigated Lands in the Study Area Table 7. Total Irrigated Acreage in Study Area by Crop Table 8a. Calculated Crop Water Demand
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Table 8b. Calculated Applied Water Table 9. Agricultural Water Use Table 10. Summary of Wells Constructed in the Study Area Table 11. Groundwater Balance Table 12. Simulated Pumping Wells, Updated Baseline Model Table 13. Simulated Groundwater Budget, Updated Baseline Model Table 14. Simulated Groundwater Budget, Constant Future Pumping Model (Scenario 1) Table 15. Simulated Groundwater Budget, Increased Future Pumping Model (Scenario 2) Table 16. Simulated Groundwater Budget, Decreased Future Pumping Model (Scenario 3)
List of Figures
Figure 1. Study Area Figure 2. Township, Range, and Sections within Study Area Figure 3. Well Locations in Water Level Database Figure 4. 1995/1996 DWR Land Use Map Figure 5. 2002/2004 DWR Land Use Map Figure 6. 2014 County Crop Map Figure 7. Estimates of Irrigation Pumping by Crop Figure 8. New Wells Constructed from 1995 ‐ 2013 Figure 9. 2014 Land Use, Study Area Figure 10. Oblique View of Study Area Figure 11. Topographic Profiles Figure 12. Average Annual Isohyetal Map, 1981‐2010 Figure 13. Annual Precipitation, 1999 ‐ 2014 Figure 14. Streamflow Hydrographs, Study Area Figure 15. Soil Restrictive Layers Figure 16. Soil Permeability and Restrictive Layers Figure 17. Study Area Geology Figure 18. Wells Constructed in Study Area, 1951 to 2013 Figure 19. Average Well Depths Figure 20. Specific Capacity vs. Well Depth Figure 21. Geologic Cross Section A‐A’ Figure 22. Texture Data MERSTAN Model Figure 23. Texture Data CVHM Model, Depth of 0 to 50 Feet Figure 24. Texture Data CVHM Model, Depth of 300 to 350 Feet Figure 25. Study Area Groundwater Elevations Figure 26. Groundwater Elevations, March 1971 Figure 27. Groundwater Elevations, 2010 ‐ 2013
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Figure 28. Soil Moisture Balance Zones Figure 29. Conceptual Profile, Leakage from Turlock Lake Figure 30. Model Area and Boundaries Figure 31. Model Layers and Study Area Figure 32. Pumping Comparison, TID and Updated Baseline Models Figure 33. Simulated Pumping Wells in 2012, Updated Baseline Model Figure 34. Simulated Pumping Wells, Increased Future Pumping Model (Scenario 2) Figure 35. Simulated Pumping Wells, Decreased Future Pumping Model (Scenario 3) Figure 36. Total Pumping for Future Scenarios Figure 37. Calibration Well Locations Figure 38. Observed and Simulated Groundwater Hydrographs, Updated Baseline Model 1991 ‐ 2012 Figure 39. Simulated Groundwater Elevation Map December 2012, Updated Baseline Model Figure 40. Simulated Water Budget, Updated Baseline Model 1991 – 2012 Figure 41. Simulated Groundwater Hydrographs for Future Scenarios Figure 42. Simulated Groundwater Elevation Maps 2014‐2042, Constant Future Pumping Model (Scenario 1) Figure 43. Simulated Water Level Changes 2014 to 2042, Constant Future Pumping Model (Scenario 1) Figure. 44 Simulated Water Budget, Constant Future Pumping Model (Scenario 1) Figure 45. Simulated Groundwater Elevation Maps 2014‐2042, Increased Future Pumping Model (Scenario 2) Figure 46. Simulated Water Level Changes 2014 to 2042, Increased Future Pumping Model (Scenario 2) Figure 47. Simulated Water Budget, Increased Future Pumping Model (Scenario 2) .Figure 48 Simulated Groundwater Elevation Maps 2014‐2042, Decreased Future Pumping Model (Scenario 3) Figure 49. Simulated Water Level Changes 2014 to 2042, Decreased Future Pumping Model (Scenario 3) Figure 50. Simulated Water Budget, Decreased Future Pumping Model (Scenario 3)
Appendices
APPENDIX A: Study Area Groundwater Level Measurements, Eastern Turlock Subbasin APPENDIX B: Project Costs and Deliverable Schedule
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1. EXECUTIVE SUMMARY
A hydrogeologic characterization of the eastern portion of the Turlock Subbasin was conducted to evaluate changes in land use and impacts to groundwater over time. The Study Area covers approximately 114 square miles, representing the eastern 20 percent of the subbasin, and is defined by the Tuolumne River on the north, Merced River on the south, and by the groundwater subbasin boundary on the east. The western boundary is coincident with boundaries of the Eastside Water District and the Merced Irrigation District. The Study Area lies east and outside of water and irrigation district boundaries and is also referred to as the eastern non‐district lands.
As noted in the TGBA 2008 Groundwater Management Plan, a significant amount of non‐ irrigated land was converted to irrigated land in the Study Area from the 1990s to 2006. The goal of this study, which was funded by a grant under the Local Groundwater Assistance program, is to improve the hydrogeologic understanding of the eastern Turlock Subbasin and to estimate the impacts of changing groundwater use in the Study Area over time.
Physical, geologic, and hydrogeologic data were collected from various sources, including Stanislaus County, Merced County, Turlock Irrigation District, California Department of Water Resources, U.S. Geological Survey, U.S. Department of Agriculture, California Department of Conservation, California Irrigation Management Irrigation Systems, California Department of Public Health, and Timothy J. Durbin, Inc. Consulting Hydrogeologists. The data were used to conduct a land use analysis, develop a hydrogeologic conceptual model, and simulate groundwater with a numerical model.
A land use analysis was conducted to estimate changes in irrigated acreage and associated groundwater use in the Study Area. This analysis was based on DWR land use maps for both Merced County (1995 and 2002) and Stanislaus County (1996 and 2004) as well as 2014 crops maps for both counties. In addition, tabular crop acreage data were obtained from DWR, and Davids Engineering provided monthly crop coefficients based on remote sensing analysis. The land use analysis shows that there was a significant conversion of non‐ irrigated lands to irrigated lands within the Study Area from 1995 to 2014. During this time, irrigated acreage in the Study Area increased almost 300 percent, from approximately 11,900 acres in 1995 to 34,300 acres in 2014. As a result, agricultural water use (i.e., groundwater use) increased from approximately 44,000 AFY in 1995 to approximately 120,000 AFY in 2014. The increase in water use was primarily driven by the increase in almonds and irrigated pasture. Almond orchards represented 32 percent of the crop acreage in 1995 and increased to 50 percent in 2014.
Using the hydrogeologic data gathered during the initial phase of this project, a hydrogeologic conceptual model of the Study Area was developed including an evaluation of local aquifers, groundwater levels, and an assessment of the groundwater balance. The Mehrten Formation is the principal aquifer in the Study Area and its black sands, composed of andesitic fluvial deposits eroded from the Sierras, are its most unique and visible feature. The Mehrten Formation dips to the west and crops out across much of the Study Area. Well
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Completion Reports for 408 wells constructed in the Study Area from 1951 to 2013 show that, in general, wells target the black sands. Based on pumping data provided in the Well Completion Reports, specific capacity increases with depth and the higher values are associated with the Mehrten black sands.
Groundwater level measurements were available at 38 Study Area well locations from 1971 to 2011. Todd provided TGBA with a list of candidate wells for exploration and potential inclusion into the CASGEM program. These wells are irrigation wells constructed between 2009 and 2013, have accurate location information, and in some cases, are close to wells with water level data. The only well with a continuous record of water level measurements showed a groundwater elevation decline of approximately 61 feet during this 40 year period. Groundwater contour maps developed for 1971 and 2010‐2013 indicate a groundwater elevation decline of approximately 60 to 175 feet. Contour maps illustrate the growth of a cone of depression in the central region of the Study Area.
A groundwater balance, based on the hydrogeologic conceptual model and numerical model simulation results (discussed below), indicate that groundwater storage was depleted by approximately 58,000 acre feet (AF) from 1999 to e2013. Th largest components of the groundwater balance are irrigation pumping and associated return flows, Turlock Lake leakage, Merced River leakage, and western boundary subsurface outflow.
A numerical groundwater flow model developed for Turlock Irrigation District by Timothy J. Durbin and Associates was used to evaluate groundwater resources in the Studye Area. Th model is a three‐dimensional, transient, finite element groundwater flow model based on the model code FEMFLOW3D and simulates groundwater from 1991 to 2012 in the Turlock Subbasin. Todd Groundwater modified the model within the Study Area to incorporate the results of the land use analysis and hydrogeologic conceptual model. The updated and refined model is a suitable tool for simulation and analysis of groundwater level changes in response to land use changes and management actions in the eastern Turlock Subbasin.
The model indicates that groundwater storage decreased approximately 57,500 AF in the Study Area from 1991 to 2012. It was used to simulate three potential future pumping scenarios over a 30‐year time period, from 2013 to 2042: 1) continued current pumping; 2) increased future pumping; and 3) decreased future pumping. Model results show that if current pumping continues with no new irrigated lands being developed, and if future hydrology is similar to 1998‐2012, water levels will decline approximately 10 to 30 feet over the planning period. Future storage loss (i.e., 2014 to 2042) will be approximately 100,000 AF, which is greater than 1.5 times the storage loss that occurred from 1991 to 2014. If pumping increases in the future, assuming that irrigated lands continue to increase at the current rate of development until most of the available area is developed, water levels will decline over 200 feet in parts of the Study Area. Future storage loss will be approximately 170,000 AF, which is almost triple the storage loss from 1991 to 2014 and approximately 70,000 AF more than if pumping remains constant. If pumping decreases in the future, assuming that crops with a limited lifespan are not replaced, there will be a net water level rise of up to 20 feet throughout most of the Study Area. Future storage loss will be approximately 50,000 AF, which is less storage loss than occurred from 1991 to 2014.
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2. INTRODUCTION
The City of Turlock, on behalf of the Turlock Groundwater Basin Association (TGBA), lead a hydrogeologic characterization of the eastern portion of the Turlock Subbasin (Figure 1). The Study Area covers approximately 73,200 acres (114 square miles) and represents about 20 percent of the Turlock Subbasin as shown on Figure 1.s It overlie a portion of southeastern Stanislaus County and northeastern Merced County and is located outside of major population centers in the basin. The Study Area is bounded on the west by Eastside Water District and Merced Irrigation District (ID), and extends to the subbasin boundaries on the north, south, and east. The Study Area is referred to as the Non‐District portions of the eastern Turlock Subbasin, indicating that local irrigation or water districts have not been formed within its boundaries1 (Figure 1). Local agricultural irrigation is presumed to be based solely on groundwater.
Hydrogeologic conditions in the Study Area are not well known and significant data and knowledge gaps exist. These gaps occur in a Study Area associated with increasing groundwater demand at a time when basin‐wide water supplies are stressed due to ongoing drought conditions and declines in groundwater levels. The goals of this study are to improve the hydrogeologic understanding of the eastern Turlock Subbasin and to estimate impacts of changing groundwater use in the Study Area over time. To achieve these goals, the following objectives have been identified:
develop a comprehensive, updated hydrogeologic conceptual model of the local groundwater system; evaluate changing land and groundwater use in the Study Area over time; revise and apply a numerical model as a tool to assist with land use planning and groundwater management decisions throughout the subbasin; and support ongoing groundwater programs such as the California Statewide Groundwater Elevation Monitoring (CASGEM) program.
As noted in the TGBA 2008 Groundwater Management Plan (GWMP), significant conversions from non‐irrigated to irrigated lands had occurred within the Study Area from the 1990s to 2006. A study period from 1995 to 2014 was selected for the land use analysis in order to examine these observations in more detail and to update the previous assessment. The numerical model simulates groundwater from 1991 to 2012. However, available hydrogeologic data were not restricted to specific time periods in order to provide as much data as possible to support the updated hydrogeologic conceptual model.
The study was funded by a grant under the Local Groundwater Assistance (LGA) program and administered by the California Department of Water Resources (DWR). As required by the grant, project data are in Appendix A; project schedule and costs are in Appendix B.
1The Study Area does include approximately 7,264 acres that were annexed into the Sphere of Influence of Eastside Water District in 2012.
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3. DATA COLLECTION
Data collected for this study can be characterized by three categories: 1) data pertaining to the physical, geologic, and hydrologic setting, 2) hydrogeologic/groundwater data, and 3) land use data. Because the Study Area includes two counties, data from both Stanislaus and Merced County were compiled. Selected hydrologic and hydrogeologic data were tabulated into a Data Management System for the project involving relational databases in Microsoft Excel™ and Microsoft Access™, and linked to the Project Geographical Information System (GIS).
Table 1 is a summary of the data collection process, and includes the data type, county, description, source(s), and relevant time period. A summary of the data collection effort is provided below.
3.1. PHYSICAL, GEOLOGIC, AND HYDROLOGIC DATA COLLECTION
Several types of data were collected to help understand the physical, geologic, and hydrologic setting of Turlock Subbasin. Most of these data provide a foundation for the Project GIS. Aerial photographs were obtained from both the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) and Google™ Earth for 1998, 2004, 2005, 2006, 2009, 2010, 2011, and 2012. Landsat aerial imagery was obtained from the United States Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center for the month of July from 2003 through 2013. Normalized difference vegetation index (NDVI) maps were obtained from Mr. Tim Durbin from 1985 through 2014. Precipitation and evapotranspiration data were obtained from three California Irrigation Management Irrigation System (CIMIS) stations in Merced and Stanislaus Counties from 1999 to present. Technical publications pertaining to the geology of Turlock Subbasin and vicinity were obtained from USGS, California Department of Water Resources (DWR), USDA, and the University of California. In addition, several sources of data were compiled in the Project GIS, including: topographic maps from Esri and USGS; California watersheds, including streams and lakes from DWR, USGS National Water Information System (NWIS), and Turlock Irrigation District (TID); State and local geologic maps from the California Geologic Survey; and Soils maps from USDA.
3.2. HYDROGEOLOGIC/GROUNDWATER DATA COLLECTION
Hydrogeologic data were collected to better understand groundwater levels, groundwater occurrence and flow, aquifers, and groundwater wells and use.
Well Completion Reports were acquired from DWR for approximately 820 wells installed from February 1950 to June 2013 within townships and ranges that overlap the Study area
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(Figure 2). At the time of data gathering, Well Completion Reports were not available for wells completed after June 2013. Approximately 299 of the 820 logs were determined to be in sections that are outside of the Study area. Additionally, 113 logs could not be located within the appropriate section due to inadequate location information. Therefore, approximately 408 wells are known to have been drilled within the Study Area between April 1951 and June 2013. Table 1 describes the Well Completion Reports and Figure 2 shows the townships and ranges within the Study Area. Pertinent data from the Well Completion Reports were compiled into a database that was linked with the Project GIS.
Based on several discussions with Merced and Stanislaus County agencies, groundwater use is not estimated by the Counties and well permits are not compiled electronically. Further, not all permits represent a completed well; some permitted wells were not drilled. Staff at both Counties indicated that the DWR Well Completion Reports are the better data source for tracking wells drilled and obtaining reliable well information.
Small community water system information was investigated as a potential data source for wells and groundwater use in the Study Area. Information regarding small community water systems in the Study Area was obtained from the California Department of Public Health (CDPH) Drinking Water Program, District 10 (Stanislaus County) and District 11 (Merced County), as well as County agencies. Only one community water system is located within the Study Area, La Grange Park OHV, which is regulated by Stanislaus County. According to the Merced County Environmental Health Department and CDPH, there are no small systems within the Study Area in Merced County. The source of water supply for the La Grange Park OHV is groundwater and water use is estimated at 2,500 gallons per month (see Table 1).
A database was provided by TID with groundwater levels from 1916 to 2011 for approximately 700 wells within Turlock Subbasin. Recent data, from 2012 to 2014, were downloaded from DWR’s Water Data Library. Water level data are available for 38 wells within the Study Area. Figure 3 presents the locations of these wells.
Information on the number and location of septic systems was requested from both Counties in order to develop reasonable estimates for groundwater return flows and consumptive use by rural residential groundwater users. However, the number of septic systems in the Study Area was not readily available from either Stanislaus or Merced County. Therefore, as described in Section 5.3.2.2, recent aerial photographs were used to estimate the number of residences (and septic systems) within the Study Area.
3.3. LAND USE DATA COLLECTION
Land use data were compiled to document changes in land use, and subsequent groundwater use, over time. Data were reviewed with an emphasis on agricultural irrigation.
Land use maps developed by DWR were acquired for both Merced County (1995 and 2002) and Stanislaus County (1996 and 2004). These maps provide detailed information on
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irrigated lands, including crop type, and represent the most comprehensive data set to support the key analyses of the study (i.e., changes in groundwater use over time). More recent maps have been surveyed by DWR (2010 for Stanislaus and 2012 for Merced), but are currently unavailable to the public due to internal DWR review.
Because these recent 2010 and 2012 maps would support a more comprehensive analysis, DWR personnel were contacted directly to see if their internal review could be expedited. Specifically, Todd Groundwater contacted Jean Woods with DWR (Table 1) and also Laura Peters, who is managing the LGA program for DWR. Both Ms. Woods and Ms. Peters indicated that the review could not be expedited. As of January 2016, neither of these maps are available.
Maps of “Important Farmland” were acquired from the California Farmland Mapping and Monitoring Program (FMMP) for both Counties for every even numbered year from 1984 to 2012. The maps from both DWR and FMMP were incorporated into the Project GIS. The FMMP maps are more frequent than the DWR maps but do not contain specific crop data. However, they do indicate if farmed parcels are irrigated. The specific data from the DWR maps and the more frequent FMMP maps will be calibrated for overlapping time periods so that the FMMP maps can be used to estimate more frequent (biennial) changes in land/groundwater use.
In addition, recent land use data (via 2012 crop reports) were acquired from the Department of Agriculture for both Merced and Stanislaus County. A database of pesticide permit data was also obtained from the Merced County Department of Agriculture. This database contains crop type, acreage, and location for active pesticide permits from 2004 through 2013. Data will be checked for consistency with the land use maps to support the analysis. A 2014 crop map was obtained for both Stanislaus and Merced Counties which shows the specific crops planted in the Study Area.
Crop water use coefficients were obtained from DWR for 64 crop types, 31 of which are grown within the subbasin. These coefficients are used to estimate detailed (daily to monthly) crop consumptive use and provide the most accurate method for determining irrigation needs. Applied water volumes for various crop types were acquired from DWR for 1998 through 2010 to support the crop consumptive use analysis and provide information on irrigation efficiencies for various crops.
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4. LAND USE ANALYSIS
In order to better understand groundwater use in the Study Area, a land use analysis was conducted to estimate annual irrigated acreage in the Study Area. Agricultural water use is a function of irrigated agricultural area and the rates of applied water and consumptive use for each crop.
4.1. IRRIGATED AGRICULTURAL AREA
Estimates of irrigated areas are based on DWR land use maps, County crop maps, and tabular irrigated acreage data from DWR. The following summarizes how these maps and data were applied to the analysis.
4.1.1. DWR Land Use Maps
DWR land use maps were acquired for both Merced County (1995 and) 2002 and Stanislaus County (1996 and 2004). These maps provide detailed information about irrigated lands, including crop type, and were prepared by DWR using aerial photographs, satellite imagery, and field visits by department staff (DWR 2014a).
The maps from 1995 and 1996 and from 2002 and 2004 were combined to create land use maps over the entire Study Area. These 1995/1996 and 2002/2004 composite land use maps are shown for the entire subbasin on Figures 4 and 5, respectively, and were used to determine agricultural land use and crop changes over time.2 DWR land use categories change slightly over time. However, crop water use and pattern were the determining factors for our analysis.
4.1.2. County Crop Maps
More recent crop maps of Stanislaus and Merced County were provided by Mr. Walt Ward of Stanislaus County. These maps were provided in GIS format and show the crops that were planted on each parcel in 2014. As illustrated on Figure 6, the county crop maps were combined to create a composite crop map of the Study Area.
4.1.3. DWR Tabular Irrigated Acreage
In addition to land use maps, DWR also publishes tabular data summarizing the major crops in California for geographic areas called Detailed Analysis Units (DAUs). As part of Task 1, data were provided by Mr. Gholam Shakouri, the DWR point of contact for Agricultural Water Use (2014), from 1998 to 2010 (the available period of record) for the Turlock Lake
2 The field/corn in the western region of the Turlock Subbasin on the 1995/1996 DWR land use map (Figure 4) appears to change to grain/dry bean on the 2002/2004 DWR land use map (Figure 5). However, this is a result of DWR’s categorization of corn as a grain in 2002/2004, and does not reflect an actual switch in crop type.
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DAU. The Turlock Lake DAU, herein referred to as “the DAU,” includes the Study Area and Eastside Water District. The irrigated acreage of each major crop within the DAU is shown on Table 2.
4.1.4. Irrigated Acreage in the Study Area
The land use maps and the tabular irrigated acreage dataU for the DA were used to estimate annual irrigated crop acreage in the Study Area. The tabular data include annual crop acreage from 1998 to 2010 (Table 2), but do not provide information about the spatial distribution of the crops. The land use maps provide spatial detail, but for only a couple of years (1995/1996 and 2002/2004). The crop acreages from the land use maps were compared to the tabular data within the DAU and the larger Turlock Subbasin; acreages were found to be in agreement between the two data sources for overlapping time periods. Therefore, the tabular data for the DAU are judged sufficient to estimate the acreage of the major crops in the Study Area for the intervening years not covered by land use maps or crop maps.
To accomplish this task, the acreage of each major crop within the Study Area was first compared with the acreage of the same crop within the DAU on both the 1995/1996 and 2002/2004 land use maps. These comparisons are illustrated on Tables 3 and 4. The portion of each crop grown in the Study Area was expressed as a percentage of the total acreage of that crop in the DAU. For example, in 1995, 7 percent of the DAU almond acreage occurs within the Study Area (Table 3). Of the total irrigated lands for major crops in the DAU (64,580 acres), about 18 percent (11,879 acres) occurs in the Study Area in 1995. In 2002, this increases slightly to 20 percent.
A similar comparison was made between crop acreages in the DAU and the Study Area using the 2014 County crop map, as shown on Table 5. Table 5 indicates that the total irrigated lands in the Study Area (34,294 acres) represent about 39 percent of the total irrigated lands in the DAU (88,564 acres) in 2014, a significant increase from 1995 and 2002. The percentages of each crop in the Study Area also varied between 1995, 2002 and 2014. For example, the acreage of almonds within the Study Area increased from 7 percent of the total almond acreage in the DAU in 1995, to 13 percent in 2002, and to 37 percent in 2014 (compare Tables 3, 4, and 5). In order to estimate annual crop acreages, a linear interpolation was used to develop ratios between 1996 and 2002, and between 2002 and 2014 (Table 6).
The annual total irrigated acreage of each crop in the Study Area was estimated from 1995 to 2014, as shown on Table 7, by multiplying the Study Area crop ratios (Table 6) by the irrigated acreage of each crop in the DAU (Table 2). For years when DWR land use maps (Figures 4 and 5) or county emaps (Figur 6) are available, those maps were used; otherwise, the DWR tabular data were used (Table 2). Due to lack of available land use data in 1997, the 1995/1996 data were used. Since DAU tabular data are not available after 2010, acreage estimates in 2011, 2012, and 2013 were based on a linear interpolation from 2010 to 2014.
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As shown on Table 7, the total irrigated acreage in the Study Area increased from approximately 11,900 acres in 1995 to approximately 34,300 acres in 2014, almost a 300 percent increase. This increase in irrigated acreage was generally consistent with other data sets compiled for the project including maps from the Farm Monitoring and Mapping Program (FMMP) and from monthly NDVI maps provided by Mr. Tim Durbin.
4.2. APPLIED WATER
The applied water required by each major crop in the Study Area was estimated based on crop‐specific coefficients developed by Davids Engineering, the reference evapotranspiration (ET), precipitation, and the irrigation efficiency. The water demand of the crop and applied water (taking into account irrigation efficiency) are summarized by major crop type on an annual basis from 1999 to 2014 on Tables 8a and Table 8b, respectively. The daily reference ET and precipitation data were downloaded from the California Irrigation Management Information System (CIMIS) for the local Merced, Denair, and Denair II stations. According to long‐term rainfall maps (California Department of Conservation, 1997), precipitation at Denair is sufficiently similar for all but the eastern‐ most portion of the Study Area (where very little irrigated lands occur). CIMIS data at these stations were not available before 1999. The applied water rates are similar to other published applied water rates, including the DWR annual rates presented in the tabular data provided by DWR.
4.2.1. Crop Coefficients, ET, and Precipitation
The water demand for each crop type was derived from the ET needs of the specific crop, taking into account irrigation efficiency and effective precipitation in order to estimate applied water per acre. The ET needs of a crop can be estimated as ETc = Kc * ETo, where ETc is the ET demand of the crop, Kc is the crop coefficient, and ETo is the reference ET of the geographic area, either measured or observed. Both the crop coefficient (Kc) and the reference ET) (ETo vary and thus the water demand of the crop also varies.
Monthly crop coefficients (Kc) for the ten major crop types in the area were developed by Davids Engineering using remote sensing techniques. Remote sensing uses satellite imagery, climate data, land use maps, and other tools to calculate the evapotranspiration of crops based on spectral channels.
Davids Engineering used data from 1997, 1998, 2000, 2001, 2002, 2008, 2009, 2010, and 2013 to develop monthly crop specific coefficients (that include Ks, the stress coefficient of the crop) for a wet year, typical year, and a dry year. These Kc profiles were nthe applied to all years in the study period based on the year type (wet, typical, or dry). Davids Engineering assumed no irrigation was applied during January and February, so ETc values for these months were not included in the annual water demand by crop type, Table 8a.
Crop coefficients for walnuts and vineyards were lower than expected and may be due to the small acreage of these crops in the remote sensing area. Total acreage for all deciduous trees (excluding almonds and pistachios) and vineyards combined represent less than 20
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percent of the LGA irrigated agriculture area. Small changes in the crop coefficients for these categories would be unlikely to have a significant impact on applied water totals.
4.2.2. Irrigation Efficiency
Because irrigation is not 100 percent efficient, water is applied in excess of the ET demand. Irrigation efficiency, the percent of applied water needed beyond the ET demand of the crop, can vary significantly depending on factors including geographic setting, irrigation method, and crop type. Information from water district managers indicates that efficiency varies greatly from parcel to parcel and over time for similar crops and even similar irrigation methods. However, limited data are available to justify varying irrigation efficiency across the Study Area. Further, irrigation in excess of crop demand is assumed to be returned to the groundwater system as irrigation return flows. Therefore, varying the irrigation efficiency would not affect the estimate on groundwater use over time. A typical efficiency of 80 percent has been assumed by several investigators in the area and is used for this analysis. The applied water rates by crop and year including irrigation efficiency are shown in Table 8b.
4.2.3. Total Water Demand
Table 9 shows the annual estimated agricultural water use in the Study Area from 1995 to 2014. These values represent the total irrigated acreage in the Study Area (Table 7) multiplied by the applied water rate (Table 8b). Figure 7 shows the estimates of irrigation pumping by crop over time.
The total irrigated acreage in the Study Area increased from approximately 13,600 acres in 1995 to 35,100 acres in 2014 (Table 7) and corresponded with an almost 300 percent increase in agricultural water use (Table 9). Agricultural water use increased from approximately 44,000 AFY in 1995 to approximately 120,300 AFY in 2014. The most significant increase appears to occur from 2005 to 2014, when agricultural water use increased from approximately 56,500 AFY to approximately 120,300 AFY.
The increase in water use appears to be driven primarily by the increase in almonds and irrigated pasture in the Study Area. The acreage of almonds increased from 4,354 acres in 1995 to 17,348 acres in 2014e (Tabl 7) and required approximately 35 percent of the total water use in 1995 and approximately 53 percent in 2014 (Table 9). This increase in almonds was confirmed qualitatively by aerial photographs and County crop reports. Groundwater use also increased appreciably (more than double) for irrigated pasture and vines during the Study Period, especially over the last few years.
4.3. GROUNDWATER USE DATABASE
Well completion reports compiled from DWR included records of wells constructed from April 1951 to June 2013. The well completion report database was used to identify wells constructed within the Study Area. A summary of the wells constructed between 1995 and 2013 is provided on Table 10 and illustrated on Figure 8.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 8 TODD GROUNDWATER
Between 1995 and 2013, 164 wells were constructed within the Study Area. As shown on Table 10, most of the wells constructed during this time were domestic (61) or irrigation (80), but there were also test wells (17), monitoring wells (6), one dairy well, and one unspecified well. Two wells, oned constructe in 2003 and the other in 2009, were identified as being for both domestic and irrigation purposes.
Between 1995 and 2013, the increase in well construction, particularly irrigation wells, corresponds with the increase in irrigation pumping. The steadiest increase in well construction within the Study Area occurs between 2005 and 2008, primarily driven by the construction of irrigation wells. Over half of the irrigation wells constructed between 1995 and 2013 were constructed after 2005, and corresponds with the increase in irrigation pumping during this time.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 9 TODD GROUNDWATER
5. HYDROGEOLOGIC CONCEPTUAL MODEL
As stated previously, a study period from 1995 to 2014 was selected for the land use analysis. However, available hydrogeologic data were not restricted to specific time periods in order to provide as much data as possible to support the updated hydrogeologic conceptual model.
5.1. PHYSICAL SETTING
A 2014 aerial photograph is shown on Figure 9 to illustrate the physical setting of the Study Area. As shown on the figure, the Study Area encompasses the more remote portions of the Turlock Subbasin, with more than 50 percent of the area remaining largely undeveloped. Three small unincorporated communities occure in th Study Area: La Grange, Snelling, and Merced Falls. State Highway 59 runs through the eastern Study Area (Figure 9).
The Study Area is defined by the Tuolumne River on the north, by the Merced River on the south, and by the groundwater subbasin boundary as defined by DWR on the east. The western boundary is coincident with boundaries of the Eastside Water District and the Merced Irrigation District (ID), consistent with the goal of studying non‐district lands (Figures 1 and 9).
The northern portion of the Study Area contains Turlock Lake (Figure 9). Constructed in 1913, the lake covers approximately 3,300 acres with depths of about 10 to 30 feet. Turlock Lake is operated by TID. Diversions from the Tuolumne River are conveyed to Turlock Lake via the Turlock Upper Main Canal, and from Turlock Lake through the Turlock Main Canal to irrigated agricultural areas in the TID service area to the west. The lake also supports local recreation; the Turlock Lake State Recreation Area covers the northern shore of the lake and lands between the lake and the Tuolumne River.
Areas of irrigated agriculture are readily identified on Figure 9, typically coincident with APN parcel boundaries. Irrigated parcels are generally located in the western portions of the Study Area and along the Merced River. However, agricultural production has been increasing from west to east across the Study Area and much of the irrigated areas east of Turlock Lake were developed within the last decade. Irrigated agriculture has also increased along the Merced River, especially between the river and Dry Creek in the southwestern arm of the Study Area.
Some vegetated areas along the Merced River, especially between Snelling and Merced Falls, are actually dredge tailings from historical gold mining activities along the river (labeled as Dredge Tailings on Figure 9). These tailings are the result of dredge mining operations that occurred on both the Merced and Tuolumne rivers from the early 1900s through about 1952. Dredging by the La Grange Dredging Company is reported to have covered at least eight miles along the Tuolumne River (California State Parks, 2005). These dredge tailing piles leave a unique signature on the landscape and appear as linear rows of mounds with intervening gullies that collect local runoff and support vegetation. Some areas
Hydrogeologic Characterization of the Eastern Turlock Subbasin 10 TODD GROUNDWATER
of former dredge tailings have been converted to irrigated agriculture over the years. Figure 10 shows an oblique view of the aerial photograph (looking east) and offers a more detailed view of these bands of dredge tailings and agricultural areas along the Merced River.
5.1.1. Topography
The Study Area represents the transition from the relatively flat‐lying San Joaquin Valley sediments into the foothills of the Sierra Nevada. Accordingly, the Study Area is characterized by hummocky topography consisting of irregular hills and intervening depressions. The Study Area topography and foothills to the east can be seen on the oblique aerial photograph provided on Figure 10.
Ground surface elevations in the Study Area range from below 200 feet mean sea level (msl) along the Tuolumne and Merced rivers to above 400 feet msl in the east. Study Area hills are dissected by numerous small drainages. The south‐central portion is drained by Dry Creek, which joins the Merced River just west of the Study Area.
To illustrate the Study Area topography, a series of profiles were generated from the National Elevation Dataset (NED, 10m) developed by the U.S. Geological Survey (USGS). Three of these profiles, along with a profile location map, are shown on Figure 11. A profile across the entire basin (Basin Profile 1 on Figure 11) illustrates the steady increase in surface elevation from west to east and the irregular topography associated with the Study Area. Ground surface elevations rise steeply beyond the Study Area outside of the groundwater basin. Study Area Profile 2 shows ground surface elevations from west to east within the Study Area, from about 200 feet, msl to more than 350 feet, msl. Study Area Profile 3 is a northwest‐southeast transect across the Study Area and shows ground surface elevations rising from the Tuolumne River, across the ycentral Dr Creek drainage and increasing to elevations above 400 feet msl between Dry Creek and the Merced River plain (Figure 11).
5.1.2. Climate
The Turlock Subbasin is characterized as a Mediterranean‐type climate with hot, dry summers and cool, wet winters, with most of the precipitation falling between November ande March. Th long‐term average rainfall in the Turlock area is about 12 inches per year based on data from 1952 – 2006. The average annual precipitation varies across the subbasin, increasing with topography from west to east.
Daily precipitation data in the subbasin were available from various stations in the California Irrigation Management Information System (CIMIS) program including one station in Merced (Station 148) and one in Denair (former Station 168, which was moved to Station 206), the three stations with sufficient data closest in elevation to the Study Area. These stations provide the detailed data necessary to evaluate the daily and seasonal variability of local precipitation patterns for the study period, and were used to support the groundwater budget analysis, discussed in Section 5.3.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 11 TODD GROUNDWATER
In order to evaluate spatial variability of precipitation across the Study Area, data from the PRISM Climate Group were compiled. These data are based on application of an interpolation model, Parameter‐elevation Relationships on Independent Slopes Model (PRISM), to detailed datasets from 1895 to present as developed by Oregon State University and the U.S. Department of Agriculture. A PRISM isohyetal map showing average annual precipitation contours from 1981 – 2010 across the Study Area is presented on Figure 12. This period is slightly wetter than the long‐term average, but provides the most complete data set for evaluation across the Study Area. As shown on Figure 12, isohyets range from 13.25 inches per year in the southwestern tip of the Study Area to about 15 inches per year on the eastern boundary. For most of the Study Area, the average annual precipitation is about 14.25 inches per year for the 20‐year PRISM period (Figure 12).
Annual precipitation amounts available from the CIMIS stations are shown on Figure 13 from 1999 through 2014. The average of this 16‐year period is about 11 inches and represents a drier than normal time period. During this period, precipitation met or exceeded the long‐term annual average in only six of the 16 years (based on the Turlock long‐term average of 12 inches). Relatively wet years included 2000, 2001, 2005, 2006, 2010, and 2011 (Figure 13).
5.1.3. Surface Water
The Study Area is bound by the Tuolumne and Merced rivers and internally drained by numerous smaller drainageways, the largest of which is Dry Creek (Figure 9). Surface water discharge data for the Tuolumne and Merced rivers in the Study Area are available from three gaging stations operated by USGS and DWR. Streamflow hydrographs for these stations are shown on Figure 14; the locations of the gaging stations are included on Figure 9. As seen on Figure 9, both rivers are gaged near the eastern Study Area boundary. These upstream stations are also located immediately downstream of diversions from the river by TID (Tuolumne River) and Merced ID (Merced River) (Durbin, 2008). For the Merced River, them upstrea and downstream gage data indicate decreasing discharge downstream, which could indicate leakage to the groundwater system. However, data from the upstream gage indicates repeated flows of similar magnitude, occurring in spring and summer months, which are likely indicative of controlled releases into the channel that are diverted downstream. As esuch, gag data cannot be used directly to estimate river leakage and groundwater recharge without additional information on these diversions. As discussed in Section 6.0, TID has recently completed an update of its subbasin groundwater flow model, which provides more insight into estimates of groundwater recharge along the Study Area reach of the Merced River.
Data are even more limited along the Study Area reach of the Tuolumne River; however, conditions in this area may provide less opportunity for groundwater recharge to occur. TID measurements of inflows and outflows at Turlock Lake indicate that leakage beneath the lake is recharging groundwater. Groundwater mounding from this leakage is assumed to raise water levels in this area along the Tuolumne River and may restrict groundwater recharge from the river (Durbin, 2008).
Hydrogeologic Characterization of the Eastern Turlock Subbasin 12 TODD GROUNDWATER
5.1.4. Soils and Restrictive Layers
Study Area soil surveys were analyzed from data obtained through the U.S. Department of Agriculture, National Resources Conservation Service (USDA, NRCS). These data indicate that the Study Area is widely covered by low permeability surficial zones, generally referred to as “hardpan.” This generic term refers to a variety of conditions and includes more specific materials identified by the USDA such as duripan (highly cemented soil, typically silica cement) and paralithic and lithic bedrock (in this usage, indicating cemented sediments dominated by matrix material, typically clay), or bedrock (low permeability or crystalline rock). All of these materials are considered restrictive layers in that they restrict or prevent surface water infiltration and serve to reduce groundwater recharge from precipitation or streamflow. The surficial occurrence of these materials is illustrated by the map on Figure 15. With the exception of the low‐lying areas along the Merced River, most of the Study Area is underlain by paralithic bedrock and duripan.
Surface water infiltration is also controlled by the saturated vertical hydraulic conductivity (Kvsat) of the soils. For this analysis, soil depths up to six feet were reviewed to identify the lowest Kvsat, which would control deep percolation. Zones of this Kvsat (in inches per hour) were categorized across the Study Area and presented on Figure 16. In general, low permeability zones on Figure 16 are shown in green, moderate zones in yellow, and higher zones in orange and red. Areas of restrictive layers (shown on Figure 15) are repeated on Figure 16 with cross hatching as shown in the map legend. As readily seen on Figure 16, the higher permeability soil zones occur along the Tuolumne and Merced rivers, with some narrow, high to moderate permeability zones defining the drainageway of Dry Creek.
5.1.5. Geologic Setting
The Study Area is located onn the easter edge of the San Joaquin Valley where thin, valley‐ fill sediments overlie consolidated, westward‐dipping sedimentary units and basement rock of the Sierra Nevada. As shown on the geologic map on Figure 17, most of the northern and central portions of the Study Area are covered by the Pleistocene‐age Turlock Lake Formation (labeled Qtl on the map). Locally, the Turlock Lake Formation consists of a relatively thin veneer of continental sediments overlying older consolidated units of the Tertiary‐age Mehrten Formation (Tm on Figure 17).
The Mehrten Formation crops out as remnant hills throughout the Study Area, especially in the northern Study Area beneath and south of Turlock Lake. The formation includes fluvial deposits (conglomerates) consisting of eroded andesite and other rocks associated with volcanic eruptions in the adjacent Sierra Nevada. The re‐working of andesite has produced distinctive black sands, which are locally well‐sorted with relatively high permeability. These zones represent the primary aquifer system beneath the Study Area, discussed in more detail in Section 5.2.
Additional geologic units shown on Figure 17 include recent sediments associated with the Tuolumne and Merced rivers (shown in light yellow and labeled Q) and other alluvial/riverbank/terrace deposits of the Laguna Formation (Pl), Riverbank Formation (Qr)
Hydrogeologic Characterization of the Eastern Turlock Subbasin 13 TODD GROUNDWATER
and Modesto Formation (Qm). Dredge tailings from historical gold mining operations are also visible on the geologic map (labeled t), especially along the eastern segment of the Merced River (southeastern Study Area).
Geologic units along the eastern Study Area boundary represent the oldest units in the Study Area and include the Tertiary‐age sediments of the Valley Springs Formation and the Ione Formation. These consolidated units are mostly non‐marine sediments that form the bottom of the sedimentary basin. Underlying these formations are Jurassic‐age metamorphic and volcanic rocks of the Sierra Nevada. In general, the Study Area boundary is coincident with the base of the Ione Formation, which crops out along the boundary (Figure 17).
5.1.6. Groundwater Basin
As mentioned previously, the Study Area covers the eastern portion of the Turlock Subbasin of the San Joaquin Valley Groundwater Basin as defined by DWR (basin designation 5‐22.03) (DWR, 2006). The northern, southern, and eastern boundaries of the Study Area are coincident with Turlock Subbasin boundaries. According to DWR, the eastern basin boundary is defined by crystalline basement rock of the Sierra Nevada foothills. As discussed above, this description is consistent with the geologic map on Figure 17.
DWR has categorized the Turlock Subbasin as high priority in the 2014 prioritization ranking of groundwater basins. The ranking was conducted under the California Statewide Groundwater Elevation Monitoring (CASGEM) Program and finalized in 2015 as required by the Sustainable Groundwater Management Act (SGMA). The high priority designation was based primarily on the amount of irrigated land in the subbasin and estimated groundwater use. As documented on the DWR website, groundwater levels are being monitored in the Turlock Subbasin in compliance with the CASGEM monitoring program.
5.2. AQUIFER EVALUATION
The Mehrten Formation is the principal aquifer in the Study Area and consists of fluvial deposits that were eroded from the slopes of the Sierra Nevada during andesitic eruptions during the Miocene to late Pliocene (Piper et al., 1939). The Mehrten Formation is a westerly‐dipping consolidated unit up to 800 feet thick (Page and Balding, 1973, Phillips et al., 2007) and extends beneath the entire Study Area except for a narrow band along the eastern boundary. Based on measurements in Sacramento County, the Mehrten Formation dips at an angle of one to two degrees to the west (DWR, 1974).
Subsurface conditions and aquifer textures beneath the Study Area were evaluated using various datasets including well completion reports and texture models developed by the USGS. These data were supplemented with information available in published technical reports with a focus on the Mehrten Formation as summarized below.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 14 TODD GROUNDWATER
5.2.1. Mehrten Formation Information from Technical Reports
The Mehrten Formation has been described as consisting of two distinct units. The more permeable unit includes gray to black andesitic sands, typically referred to as “black sands” in driller’s logs, and interbedded blue to brown clay, and hard gray tuff‐breccia, typically reported as “lava” by well drillers (DWR, 1974). The black sands, composed of fluvial deposits eroded from the Sierras, represent the most unique and visible component of this formation and yield large quantities of good to excellent quality water (DWR, 1974). The black sands are laminated and range in observed thickness from 5 to 20 feet (DWR, 1974). An additional unit of the Mehrten Formation consists of tuff‐breccia formed by ash flows from andesitic eruptions. This unit is typically dense and hard and yields little water (DWR, 1974). The layers of breccia are minor, but they resist erosion and form mesas, or “haystack” hills that are commonly found in the eastern part of Sacramento County, as well as in the Study Area (Piper, 1939; DWR, 1974).
The Mehrten is overlain by the Turlock Lake Formation and underlain by the Valley Springs Formation. The Turlock Lake Formation is composed of arkosic alluvium (mostly fine sand, silt, and clay) with an estimated thickness of approximately 300 to 850 feet in eastern Stanislaus County (Marchand and Allwardt, 1981). The Mehrten overlies the rhyolitic tuff of the Valley Springs Formation, the contact of which is not easily identified. The Mehrten / Valley Springs contact is typically mapped at the base of the andesitic sands (Piper, 1939).
Although the Mehrten black sands are typically characterized as having favorable hydraulic properties, including relatively high hydraulic conductivity (K), these properties vary with location (DWR, 1974; Page, 1986). Based on testing conducted by DWR and the U.S. Army Corps of Engineers, the K values of the Mehrten Formation range from 0.01 feet per day (ft/day) to about 67 ft/day (Page and Balding, 1973). DWR (DWR, 1967 in Page and Balding, 1973) reports average well yields of approximately 1,000 gallons per minute (gpm) with a horizontal transmissivity (T) of approximately 68,000 gallons per day per foot (gpd/ft).
5.2.2. Evaluation in Study Area Wells
As described previously, key information from DWR Well Completion Reports for Study Area wells was recorded and analyzed in a project database. Based on the available Well Completion Reports, 408 wells were constructed in the Study Area between 1951 and 2013. Most of these wells are difficult to impossible to locate accurately within the Study Area. Although many older Well Completion Reports are known to contain incomplete or inaccurate location information, these Study Area wells are particularly problematic. Most of the older reports do not contain a 40‐acre subsection notation consistent with the California state well numbering system. Some well owner addresses were outside of the Study Area, or even outside of the subbasin. Some of the more recent reports contain an APN parcel number or, rarely, a latitude/longitude, but those reports are the exceptions. In order to consider all wells (including older wells) within at least one mile of the actual location, all Study Area wells were approximated to the centroid of their respective sections. These well locations are presented on Figure 18. In most cases, more than one well was constructed in each section. Although numerous wells may be represented by a single
Hydrogeologic Characterization of the Eastern Turlock Subbasin 15 TODD GROUNDWATER
symbol on Figure 18, the database allows for more detailed assessment of each well report within each section.
Figure 18 indicates that numerous older wells (pre‐1995, represented by a box symbol) have been drilled across the Study Area. Since 1995, most new wells (orange and blue dots) were drilled in the northern Study Area. In particular, many of the most recent wells (blue dots on Figure 18) have been drilled east of Turlock Lake in township‐range T4S/R13E with some wells extending into T4S/R14E. These wells are generally consistent with areas of increasing agriculture.
In general, the Well Completion Reports tindicate tha wells have been drilled deeper with time over the last 60 years. Well depths have increased for various reasons, including well locations at higher elevations, greater depth to water, and other factors. In general, construction depths have increased steadily in the Study Area since 1950 as illustrated on Figure. 19 Over that time period, the average well depth increased from 119 feet (between 1950 and 1954) to 467 feet (between 2010 and 2013) and likely represents the eastward migration of new well construction. Although a few deep wells were drilled in the 1955 to 1964 time frame (Figure 19), more of the deep wells have been drilled in recent years. Although one well was drilled to a depth of 1,680 feet, most of the deeper wells are between 600 and 800 feet deep.
Approximately 20 percent (86 of 408) of the Well Completion Reports also presented some information from pumpinge tests. Ther are significant limitations for the use of these pumping test data. In many cases, the length of the test was unavailable, and test durations varied considerably, a factor that can affect specific capacity. Further, only the basic information is provided and actual water levels recorded during the test are unavailable. Nonetheless, these data represent the best opportunity for evaluating the hydraulic properties of Study Area aquifers. For wells with pumping test information, values for specific capacity and transmissivity have been estimated.
Based on the reported pumping rate (Q in gpm) and drawdown (s in ft), specific capacities (Q/s in gpm/ft) ranged from 0.1 gpm/ft to 94.8 gpm/ft of drawdown (dd) and averaged 22.8 gpm/ft dd. Transmissivity (T) values were estimated from specific capacity using coefficients provided by Driscoll (1986):
T = 2,000 * specific capacity (confined aquifer)
T = 1,500 * specific capacity (unconfined aquifer)
Based on these relationships, average T values are estimated at about 19,366 gallons per day per foot (gpd/ft) (unconfined conditions) and 25,781 gpd/ft (confined conditions). Both unconfined and confined groundwater conditions may be present in the Mehrten Formation beneath the Study Area. Unconfined conditions occur in the eastern Study Area, where the aquifer is closer to or at the surface. Confined conditions are more likely in the western Study Area, where the aquifer is overlain by lower‐permeability beds. Although the unit
Hydrogeologic Characterization of the Eastern Turlock Subbasin 16 TODD GROUNDWATER
crops out across the area, the more permeable black sands appear to occur at significant depths, especially beneath the western Study Area as discussed in more detail below.
The characteristic black sands of the Mehrten Formation were screened in more than half of the wells with pumping test data (48 wells of 86 wells). The estimated specific capacity and transmissivity were higher for these wells than for wells screened in other portions of the Mehrten Formation or in other aquifers. Wells screened in the black sands had an average specific capacity of 30.7 gpm/ft, whereas other wells had an average specific capacity of 12.9 gpm/ft. The high specific capacity of the black sands corresponds to an average T for of 61,409 gpd/ft (assuming confined conditions). This T value derived from Study Area wells is consistent with the estimated T value for the Mehrten Formation published by Page and Balding (1973) of 68,000 gpd/ft.
Figure 20 illustrates the relationship between the specific capacity data and well depth, and differentiates wells that are screened in the Mehrten black sands versus other screened intervals. The figure illustrates that, in general, specific capacity increases with well depth, likely indicating the high production capacity associated with wells that are deep enough to screen the complete interval of black sands. Although specific capacity data are highly variable, the higher values are associated with the Mehrten black sands.
A geologic cross section based on information in the Well Completion Reports is presented as Figure 21. The location of the cross section, shown on the geologic map on Figure 17, traverses the Study Area southeast of Turlock Lake. The ground surface elevations are based on USGS NED and the wells are located in the centroid of their respective sections. In most cases, there is more than one Well Completion Report for each section. Therefore, well depths are based on the average depths of the wells within each section and the screened interval(s) are a composite of the screened interval depths of the wells within that section. Similarly, the formation contacts are based on data from multiple Well Completion Reports in each section.e Th section also contains an estimated water level for the 1970s and 2010 – 2013. A more detailed discussion of groundwater levels in the Study Area is included in Section 5.2.4.
The cross section illustrates the subsurface geometry of the Mehrten Formation and surrounding geologic units. As shown on Figure 21, the upper Mehrten Formation crops out in the southwest and is overlain by a relatively thin veneer of the Turlock Lake and Laguna formations throughout the remainder of the section. Dredge tailings cover the formation on the northeastern end of the section. The younger Turlock Lake Formation is more easily eroded and results in topographic variability on the top of the remnant hills of the older, underlying Mehrten Formation. The Laguna Formation is evident within two erosional surface depressions in the northeastern portion of the section. The cross section also include the westerly dipping Valley Springs Formation underlying the Mehrten Formation within the Study Area.
Depths of the Mehrten black sands were estimated based on descriptions in the Well Completion Reports. The cross section illustrates that the black sands were not identified within the upper portion of the Mehrten Formation throughout much of the Study Area and
Hydrogeologic Characterization of the Eastern Turlock Subbasin 17 TODD GROUNDWATER
occur at depths of about 400 feet in the southwestern portion of the section. The Mehrten Formation with black sands illustrated on the cross section represents laminated layers of black sands, not continuous black sands. The black sands are close to the surface in the east. In general, wells appear tot targe the black sands, although many wells are also screened in other units including upper portions of the Mehrten Formation and in the underlying Valley Springs Formation.
5.2.3. Aquifer Textures
Given the consolidated nature of the geologic units beneath the Study Area, the black sands likely represent the primary unit controlling the storage and movement of groundwater. However, to provide a more comprehensive evaluation of the entire sedimentary package, geologic texture data were incorporated into the study. Textures refer to the proportions of sand, silt, and clay within a geologic unit and can indicate areas of higher permeability. In general, higher percentages of coarse‐grained material (i.e., sand) allow groundwater to be more easily transmitted through the unit. This general relationship can be less certain for consolidated units, depending on the amount and type of cementation.
The USGS has conducted a texture analysis of the entire Central Valley based on geologic logs from Well Completion Reports. This analysis was used to assign hydraulic parameters for a regional groundwater flow model, referred to as the Central Valley Hydrologic Model (CVHM) (Faunt et al., 2010). The CVHM covers more than 20,000 square miles, including the 114 square mile Study Area. Textures in Stanislaus andd Merce counties were examined in more detail by USGS to support the recently completed MERSTAN groundwater flow model (Phillips, et al., 2007 and 2015), which covers the western portions of the Study Area (generally areas west and southwest of Turlock Lake).
Both of the texture data sets are associated with a high level of uncertainty, given the incomplete, inconsistent, and often non‐technical geologic descriptions contained on Well Completion Reports on which they are based. Nonetheless, the analysis represents the only comprehensive data set on which to evaluate relative textures in the Study Area subsurface. Texture data from these two models were obtained from USGS and described in more detail below.
A cross section of the texture data within the Study Area from the MERSTAN model is presented as Figure 22. As shown on the inset of the figure, the MERSTAN model domain overlaps only the western portion of the Study eArea. Th cross section shows model texture data in Model Column 131, immediately west of Turlock Lake, from Rows 96 to 153, from the northwestern corner to the southwestern arm of the Study Area. The cross section illustrates textures in each of the sixteen model layers, which range in thickness from 2 to 162 feet, and from an elevation of approximately 300 to ‐700 feet above mean sea level. Each row is approximately 1,300 feet long (400 meters), and the cross section extends approximately 14 miles.
The textures illustrated on the MERSTAN model cross section are mostly fine‐grained, with less than 50 percent coarse‐grained sediment. There is a localized area containing between
Hydrogeologic Characterization of the Eastern Turlock Subbasin 18 TODD GROUNDWATER
50 and 60 percent coarse‐grained sediment in the shallow model layers near the Tuolumne River and the northwest corner of Turlock Lake. In general, shallow sediments range from 25 to 50 percent coarse‐grained and overlay regional finer‐grained units at elevations around mean sea level (msl). The deeper finer ‐grained units, with textures less than 25 percent coarse‐grained sediment, are approximately 400 feet thick throughout most of the transect, except in the southern arm of the Study Area where the fine‐grained unit extends to the base of the model. The textures do not appear to be consistent at the intersection with the geologic cross section on Figure 21, where the more permeable Mehrten black sands extend to elevations around 200 feet to 400 feet below msl.
The CVHM data extend to the eastern edge of the Turlock Subbasin and include textures over the entire Study Area. Texture data within the Study Area are available in 46 layers, from ground surface to a depth of 2,300 feet with uniform layer thicknesses of 50 feet. The lateral grid cell size is one mile by one mile. Plan view maps of the texture data at depths of 0 to 50 and 300 to 350 from the CVHM are presented as Figures 23 and 24. In order to highlight the relative changes across the Study Area, the CVHM data are displayed in more detail than the texture data on Figure 22. As shown by the legend on Figures 23 and 24, the percentages of coarse‐grained textures are shown in 10 percent increments from 20 percent to 50 percent.
Figure 23 shows relative textures across the Study Area at an average depth of 25 feet (combined data from surface to 50 feet). These depths are generally above the water table and represent the shallow vadose zone. As shown on the figure, most of the Study Area contains sediments with 30 to 50 percent coarse‐grained textures. In general, finer‐grained sediments are in the southern Study Area. Figure 24 shows relative textures at an average depth of 325 feet with a higher occurrence of coarse‐grained sediments in the northern Study Area around Turlock Lake. As indicated on Figure 23, this area may be consistent with the occurrence of the Mehrten black sands.
Both texture models illustrate that the Study Area is dominated by fine‐grained sediments (less than 50 percent coarse‐grained sediment). At shallow depths, coarser sediments are in close proximity to the Tuolumne River and Turlock Lake, and between Dry Creek and the Merced River. Both models show that textures, in general, become finer below the surface within the upper 300 to 500 feet, and then become coarser below this depth. Between a depth of 600 and 1,000 feet, the CVHM model has relatively uniform texture percentages (between 30 and 50 percent coarse‐grained sediment), which is consistent with the MERSTAN model. At a depth of 1,000 feet, textures in the CVHM model between Dry Creek and Tuolumne River become finer, which is also consistent with the texture fining with depth in this region of the MERSTAN model. Notwithstanding these observations, it is unlikely that these deeper data sets represent reliable textures. These deeper zones are based on only a few data points and are extrapolated great distances. Due to a lack ofp dee data, the CVHM uses the deepest data available and repeats that texture signature to the base of the model.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 19 TODD GROUNDWATER
5.2.4. Groundwater Levels
An evaluation of Study Area groundwater levels was conducted using water level data provided by DWR and TID, and static depth‐to‐water measurements on Well Completion Reports. The project water level database contains groundwater levels measured between 1916 and 2014 for approximately 700 wells in the Turlock Subbasin, 38 of which are located in the Study Area. Groundwater levels in the Study Area were measured primarily between March 1971 and November 2011, with three measurements taken in the 1960s. The Study Area groundwater level measurements are illustrated on Figure 25 and summarized in Appendix A.
As illustrated on Figure 25, there is only one well (State Well Number (SWN) 04S12E03C001M) with a continuous record of groundwater levels from 1971 to 2011. This well is on the northwestern edge of the Study Area and may be more indicative of declining water levels in the adjacent Eastside Water District than changes in the Study Area. Nonetheless, the depth to water in this well has increased from approximately 64 feet in 1971 to approximately 125 feet in 2011 (elevations 132 feet msl to 71 feet msl, respectively), corresponding to a water level decline of approximately 61 feet. With the exception of this well, there is a large data gap in Study Area water level measurements between November 1983 and April 1999. Despite this data gap, Figure 25 illustrates that a declining water level trend is evident throughout the Study Area.
Groundwater levels measured at 25 wells in March 1971 represent the oldest water level data set available in the Study Area. The depth to groundwater in March 1971 ranged from 31.5 feet along the southern boundary of the Study Area near Dry Creek to 188 feet approximately 2.5 miles east of Turlock Lake. A contour map of the May 1971 groundwater levels (Figure 26) illustrates that groundwater generally flows from east to west, ranging in elevation from approximately 282 feet msl in the eastern Study Area to about 132 feet msl along the western boundary of the Study Area. There is evidence of two localized pumping cones of depression east of Turlock Lake.e Th first is located approximately 2.5 miles east of the lake (evident by the water level measurement of 197.5 feet msl) and exhibits approximately 25 to 30 feet of drawdown. A second cone of depression, located approximately 4.5 miles southeast of Turlock Lake (evident by the closed contour of 210 feet msl), has approximately 10 to 15 feet of drawdown compared to regional levels.
A groundwater elevation contour map based on more recent data (combined measurements from 2010 to 2013) is presented as Figure 27. This contour map is primarily based on static depth to water measurements recorded in Well Completion Reports for twelve wells constructed between May 2010 and June 2013. In addition, groundwater levels from the project database measured in March 2011 at four wells, located along the western edge of the Study Area, were included on the contour map. Ground surface elevations were not included in the Well Completion Reports, but were estimated either based on the elevation at the center of the section in which the well was located, or based on the rough location information provided in the Well Completion Report and with the aid of a USGS topographic map or, in some cases, Google Earth. Becausee th ground surface
Hydrogeologic Characterization of the Eastern Turlock Subbasin 20 TODD GROUNDWATER
elevations at these wells are estimated, the groundwater elevations are less certain than the data from the project water level database.
Given the uncertainty of the data and the significant data gaps, it is difficult to compare the two maps on Figures 26 and 27. Although contours are reasonable for eache of th data sets, data from wells interpreted east of Turlock Lake on Figure 26 are not available on Figure 27. However, in general, data indicate that water levels have declined across the Study Area. As illustrated on Figure 27, there is a large cone of depression in the central/southeastern area of the Study Area, similar to the vicinity of the cone of depression on Figure 26 but with significantly lower levels. In 2010‐2013 (Figure 27), groundwater elevations range from approximately 44 to 70 feet msl in this area, and reflect a local drawdown of approximately 80 to 85 feet based on the regional contours interpreted on the figure. However, comparing these levels to levels in this vicinity on Figure 26, water levels could have fallen from around 200 feet msl to 40 feet msl, a decline of about 160 feet over the 40‐year period (approximately four feet per year).
In 2010 to 2013, groundwater elevations ranged from approximately 320 feet msl along the eastern boundary of the Study Area to approximately 30 feet msl in the western boundary of the Study Area. Groundwater elevations in the eastern Study Area appear to be relatively similar to those in March 1971; the cone of depression does not appear to extend into this area. Figure 27 also indicates that the cone of depression within the Eastside Water District extends into the western region of the Study Area. Groundwater elevations at SWN 4S12E03C001M, located in the northwest corner of the Study Area, declined approximately 70 feet between March 1971 and March 2011 (131.6 to 60 feet msl). In the center of the Study Area, east of Turlock Lake, groundwater elevations appear to have declined between approximately 60 and 175 feet over the 40 year period (1.5 feet per year to more than 4 feet). per year
5.3. WATER BALANCE
In order to evaluate changes to groundwater storage over time, a groundwater balance was developed for the Study Area from 1999 to 2013. This balance consists of primary inflows (recharge) and outflows (discharge) associated with the groundwater system. A simple subtraction of outflows from inflows represents the change in groundwater storage. These components are summarized on Table 11.
Several of the components, including surface water‐groundwater interaction along the Merced and Tuolumne rivers, as well as western boundary subsurface outflow, are too uncertain to be quantified. As discussed in Section 6.0, a calibrated numerical model was used to simulate groundwater in the Study Area. This tool was used to estimate certain components of the groundwater balance summarized on Table 11. The following is a summary of each groundwater inflow and outflow component affecting the Study Area.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 21 TODD GROUNDWATER
5.3.1. Groundwater Inflows
Groundwater inflows into the Study Area include infiltration from precipitation, leakage from Turlock Lake, surface water leakage, irrigation return flows, domestic return flows, and subsurface inflow across the eastern Study Area boundary. The data and methodology for components of groundwater inflow are discussed below.
5.3.1.1. Infiltration from Precipitation Precipitation contributes to groundwater recharge from infiltration into shallow soils and deep percolation beyond the root zone to the water table. The amount of water subject to deep percolation was estimated from 1999 to 2013 using a monthly soil moisture balance for the non‐agricultural areas of the Study Area according to a modified Thornthwaite and Mather method (Dunne and Leopold, 1978). Irrigated agricultural areas were excluded from the soil moisture balance because precipitation in agricultural areas was incorporated into the irrigation analysis summarized in Section 4.0. The non‐agricultural areas of the Study Area are based on the 2014 lands use map and divided into two soil moisture balance zones: 1) soils without restrictive layers (approximately 25 percent of the Study Area), and 2) soils with restrictive layers (approximately 30 percent of the Study Area). These two zones, along with the agricultural areas, are shown on Figure 28.
Each soil moisture balance zone tracks monthly potential evapotranspiration (PET), actual ET (AET), change in soil moisture, and excess water that is available for groundwater recharge or surface runoff. For each month of the water balance, AET is dependent on PET and the amount of available water, which comprises precipitation and available soil water in the root zone at the start of the month. When available water exceeds PET, AET is equal to PET, and additional available water carries over to the next month as soil water in the root zone. When available water exceeds AET and the soil water storage capacity of the root zone, excess water is available for either runoff or groundwater recharge. When available water is less than PET, AET is limited to available water, and no water is available for groundwater recharge or surface runoff.
Soil water storage is the capacity of the soil in the root zone to store water, which is then available for crop uptake and ET. Shallow, coarse‐grained soils have lower soil water storage capacities than deeper, fine‐grained soils. Soil water storage across the Study Area was estimated using soil hydraulic property information contained in soil surveys of Stanislaus County and Merced County from the USDA. Using the USDA Soil Data Viewer® for ArcGIS, a continuous GIS coverage was developed for the Study Area watershed representing the weighted‐average soil water storage (in inches) for the upper 5 feet of soil, the maximum root depth. Water storage capacities within the upper 5 feet of soil beneath irrigated crop areas ranged from 0 to 10 inches. The average soil moisture holding capacity for the non‐ agricultural non‐restrictive soils is 5.73 inches, and 3.14 inches for the non‐agricultural restrictive soils. Figure 28 illustrates the soil water holding capacities for the non‐ agricultural and non‐restrictive soils.
For the non‐agricultural non‐restrictive soils, it was assumed that half of the available water occurs as surface water runoff and the other half recharges groundwater. This analysis
Hydrogeologic Characterization of the Eastern Turlock Subbasin 22 TODD GROUNDWATER
results in groundwater recharge amounts that are approximately five percent of the total precipitation, a reasonable assumption for the Study Area. For non‐agricultural restrictive soils, the opportunity for infiltration is reduced by the low permeability at the surface and runoff is likely much greater than on more permeable soils. For these areas, it was assumed that 80 percent of the available water contributes to surface water runoff and the remaining 20 percent recharges groundwater.
Conceptually, the increased runoff on restrictive soils likely funnels the water into local drainages. As indicated on Figure 28, some of these local drainages contain the soils with relatively high soil water holding capacities. Therefore, a portion of the available runoff (23 percent) is re‐routed in the soil moisture balance and contributes to the available water in the zone of non‐restrictive soils. There a portion of the re‐routed water is recharged, using the same methodology for estimating groundwater recharge from direct precipitation.
5.3.1.2. Turlock Lake Leakage Potential leakage from Turlock Lake has been evaluated by TID as a source of groundwater recharge for portions of the Study Area beneath and in the vicinity of the lake. Turlock Lake’s surface area and corresponding depth varies depending on time of year and water supply availability. For the purposes of this study, it was assumed that Turlock Lake has an approximate surface area of 3,300 acres with maximum water depths of approximately 30 feet, based on the normal pool elevation of 240 feet shown on the USGS 7.5 minute topographic map for the Turlock Lake Quadrangle.
As shown on the geologic map (Figure 17), the Mehrten Formation underlies Turlock Lake, as evidenced by outcrops on islands in the lake and adjacent to its eastern and southern shores. Figure 29 illustrates a conceptual diagram of Turlock Lake based on surface elevations from the USGS NED, estimated lake depths based on the USGS topographic map, and 2010 – 2013 groundwater elevations (Figure 27). The conceptual diagram shows that water in Turlock Lake leaks to the underlying water table in the Mehrten Formation. The water table appears to occur approximately 30 to 40 feet beneath the base of the center of the Lake and groundwater elevations indicate mounding beneath the Lake.
A monthly Turlock Lake water balance was developed from 2002 to 2006 by TID that provides an estimate of annual Turlock Lake leakage. The spreadsheet was shared with Todd Groundwater in support of this study. TID’s model results reflects these leakage numbers, and therefore annual estimates of Turlock Lake leakage from the model, from 1999 through 2014, are incorporated into the groundwater budget provided in Table 11.
5.3.1.3. Streamflow Leakage As mentioned previously, stream gage data are insufficient alone to analyze surface water‐ groundwater interaction along the rivers that bound the Study Area. A comparison of surface elevations to groundwater elevations in the Study Area suggest that flows in both the Tuolumne and Merced rivers have the opportunity to recharge groundwater, especially in the eastern reaches of the Study Area. Model simulations provide a time‐varying approach to estimate streamflow leakage from both rivers, therefore model results are incorporated into the groundwater balance.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 23 TODD GROUNDWATER
Model simulation results indicate that as water levels decline, leakage from both Tuolumne and Merced rivers increase. In 1999, Tuolumne River leakage was approximately 2,700 AFY and increased to 14,203 AFY in 2014. Merced River leakage was significantly greater than Tuolumne River leakage. Model simulation results indicate that Merced River leakage increased from approximately 44,700 AFY in 1999 to 54,175 AFY in 2014, and reached a maximum of 65,600 AFY in 2011. These values are included as inflows in Table 11.
5.3.1.4. Irrigation Return Flows Water is applied to crops in excess of ET demand because irrigation is not 100 percent efficient. The irrigation pumping estimates described in Section 4.2 assumed an irrigation efficiency of 80 percent. Based on this assumption, 20 percent of the groundwater pumped for irrigation is not used by the crops and is assumed to provide groundwater recharge through return flows.
The recharge simulated by the model includes these irrigation return flows, but also includes domestic return flows and infiltration from precipitation on both non‐agricultural land and agricultural land. Because our analysis of infiltration from precipitation was for non‐agricultural land, the irrigation return flow summarized on Table 1 incorporates both the 20 percent irrigation return flow and infiltration from precipitation on agricultural land. The recharge calculated by the model is equivalent to three of the recharge components summarized on Table 11: infiltration from precipitation on non‐agricultural land, irrigation return flows, and domestic return flows.
5.3.1.5. Domestic Return Flows Except for small diversions along the Merced River (Durbin, 2008), the Study Area does not have an available source of surface water. As such, Study Area residents are reliant on groundwater wells for their domestic supply. Although domestic pumping and associated return flows are a relatively small component of the groundwater balance, estimated amounts have been developed for completeness and are included in Table 11. The methodology and analysis for domestic pumping and associated return flows are discussed together in Section 5.3.2.2.
5.3.1.6. Eastern Boundary Subsurface Inflow and Base Upflow Conceptually, small amounts of precipitation and runoff in areas east of the Study Area contribute to a local water table and result in subsurface inflow into the Study Area. This inflow would originate from adjacent crystalline bedrock and would likely be limited by low subsurface groundwater storage. Further, inflow would likely occur into the Valley Springs and Ione formations and limited by the low permeability of these consolidated sediments. Notwithstanding these limitations, subsurface inflow likely occurs, involving more than 8,000 linear feet along the Study Area boundary. Given the uncertainty associated with this inflow, typical methodologies, such as a Darcy equation flow analysis (Q=KiA), produce results that vary over several orders of magnitude. Estimates developed by Durbin (2008 and 2014) in conjunction with a three‐dimensional calibrated flow model indicate approximately 1,000 AFY for subsurface inflow. This estimate is judged reasonable and is reproduced in Table 11 for the Study Area water balance.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 24 TODD GROUNDWATER
The model simulates base upflow from the crystalline bedrock below the base of the model into the Ione Formation, the bottom layer of the model. Base upflow is simulated as 2,000 AFY distributed uniformly throughout the subbasin (i.e., model area). Since the Study Area is approximately 20 percent of the subbasin, Study Area base upflow is estimated to be 400 AFY.
5.3.2. Groundwater Outflows
Groundwater outflows from the Study Area include irrigation pumping, domestic pumping, and western boundary subsurface outflow.
5.3.2.1. Irrigation Pumping As described in Section 4.0, irrigation pumping estimates from 1995 to 2014 were developed based on changing land use, monthly crop coefficients, and the applied water rate (Table 9). These annual irrigation pumping volumes are included in the water budget.
5.3.2.2. Domestic Pumping Most of the rural population of the Study Area relies on groundwater for domestic water supply. According to the well completion reports, about 196 domestic wells have been drilled in the area, a number that is consistent with estimates of the Study Area population. To estimate groundwater pumping associated with this water use, the number of private residences was estimated using recent aerial photographs. The review indicated that there are approximately 198 households in the Study Area, about one‐half (94 households) of which are associated with the unincorporated community of Snelling in the southern Study Area along the Merced River (Figure 9). Snelling likely uses groundwater and its proximity to the river may result in groundwater withdrawal that originated as river leakage. In general, the remaining households are scattered throughout the Study Area. Although there is also an increased density of households in the community of La Grange (northeastern Study Area), most of the developed parcels receive surface water from TID for domestic use. In addition, most of the development is outside of the Study Area. For the purposes of the water balance, most parcels along the river and all of the ones outside of the Study Area were not included in the analysis. However, approximately 45 parcels appear sufficiently south of the river and scattered throughout the northern Study Area to be excluded from the La Grange surface water supply and are included in the estimate for domestic pumping.
Domestic water use is typically estimated in terms of inside and outside use. For outside use, there appears to be very little landscape irrigation separate from the surrounding irrigated agriculture. Therefore, any outside water use is assumed to be included in the estimates of agricultural pumping (Table 9). Indoor use is estimated at 100 gallons per capita per day, consistent with previous water budget methodology (Durbin, 2008). Using the 2010 population data from Snelling of 231 persons associated with 94 households, 2.4 persons per household is assumed for the analysis. For the 168 households in the Study Area, this method indicates that groundwater pumping for domestic water use is about 40,320 gallons per day (about 14.7 million gallons per year), equivalent to 45 AFY. However, very little of this amount is actually consumed and most (about 95 percent) would return to the groundwater system through septic return flows. For the purposes of the groundwater
Hydrogeologic Characterization of the Eastern Turlock Subbasin 25 TODD GROUNDWATER
budget, 45 AFY is assumed for domestic groundwater pumping and 42 AFY is assigned to domestic return flows (Table 11).
In addition, there is a small community water system within the Study Area called La Grange Park OHV. According to Tom Diaz, the manager of this system, this is a recreational park with a bathroom and water fountain that rely on a groundwater well. Groundwater use averages 2,500 gallons per month, or less than 0.1 AFY. Given the small amount of groundwater use, this was not included in the water balance.
5.3.2.3. Western Boundary Subsurface Outflow Groundwater leaves the Study Area as subsurface outflow across the western boundary. The model simulation results, discussed in Section 6.0, were used to quantify the groundwater outflow summarized in Table 11. Western boundary outflow fluctuates between 1999 and 2014, ranging from approximately 32,800 AFY in 2014 to 63,700 AFY in 2005. Subsurface outflow across the western Study Area boundary decreases slightly in certain years because the continued pumping within the Study Area is reducing aquifer saturated thickness, westward hydraulic gradients, and associated outflow.
5.3.3. Change in Storage
The Study Area has experienced a significant loss of groundwater in storage since 1999. The groundwater balance shows a cumulative storage loss from 1999 to 2013 of approximately 58,000 AF. Annual storage change ranged from approximately ‐13,300 AF in 2012 (storage loss) to approximately 5,700 AF in 2013 (storage gain). The largest components of the groundwater balance are irrigation pumping and associated return flows, Turlock Lake leakage, Merced River leakage, and western boundary subsurface outflow; these components control the resulting change in storage.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 26 TODD GROUNDWATER
6. NUMERICAL MODEL SIMULATIONS
A basin‐wide three‐dimensional numerical groundwater flow model was updated and applied to assess potential impacts of changing land use on groundwater in the Study Area. This approach allows for prediction of potential future groundwater trends and for prioritization of key data and knowledge gaps to be addressed by future management.
The model used for this evaluation was developed for the Turlock Irrigation District (TID) by Timothy J. Durbin and Associates. The model, referred to herein as the TID model, is a three‐ dimensional, transient, finite element groundwater flow model based on the model code FEMFLOW3D. FEMFLOW3D was published by Timothy J. Durbin (Durbin) with the United States Geologic Survey (USGS) in 1997, and simulates river‐aquifer interactions, crop demand and consumptive use, and evapotranspiration (USGS, 1997). TID first began working with Durbin on a FEMFLOW3D model of the Turlock Subbasin in the 1990s. The model was recently updated to simulate a 22‐year period from 1991 to 2012 (Durbin, 2014).
For this project, a new subroutine was added to the FEMFLOW3D program code to calculate simulated changes in groundwater storage in the Study Area. Previous versions of the model did not include the provision to calculate storage changes in sub‐areas of the model. Working with Todd Groundwater, Mr. Durbin developed the new subroutine and recompiled the model code for this purpose.
Figure 30 shows the TID model area and its finite element mesh, which covers approximately 542 square miles (mi2) and is defined by the Tuolumne River on the north, the San Joaquin River on the west, the Merced River on the south, and an eastern boundary along the Sierra Nevada foothills.
The finite element mesh has six layers, each representing a separate geologic formation or hydrostratigraphic unit. Figure 31 illustrates the geometry of these six layers with a cross‐ section of the model (Durbin, 2014). As shown by the legend on Figure 31, the lowest unit of the groundwater system is the Ione Formation, overlain by the Valley Springs and Mehrten formations. The Mehrten Formation is overlain by three tunits tha represent separate alluvial‐fan episodes, including the Turlock Lake, Riverbank, and Modesto formations. Both the Modesto and Turlock Lake formations contain lacustrine and flood‐ plain deposits. Where those fine‐grained deposits occur within the Turlock Lake Formation, they are referred to as the Corcoran Clay (Durbin, 2014). As discussed previously, the Mehrten Formation is the primary aquifer system in the Study Area.
The FEMFLOW3D groundwater flow model is coupled with a Water module that estimates natural recharge and irrigation return flow based on land use input parameters, such as crop demand, irrigation efficiency, hydrologic information such as precipitation and evapotranspiration, and pumping. Data for surface‐water deliveries, groundwater pumping, crop type and acreages, urbanized acreages, consumptive use, precipitation, streamflow, and canal spills are used to develop input parameters to the Water module.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 27 TODD GROUNDWATER
The model uses a Fortran computer program and complex input file structure, requiring numerous input data files that are managed in spreadsheets and pre‐ and post‐processing programs in order to modify and run the model. Todd Groundwater worked with Mr. Durbin, the original TID model developer, to ensure proper use of the model.
The model was reviewed for numerical stability and simulation accuracy in the Study Area. Model components such as aquifer geometry and parameters, surface water‐groundwater interaction (including leakage from Turlock Lake), subsurface inflow, and pumping were compared to the hydrogeologic conceptual model. Hydrographs of Study Area wells were plotted and compared to model‐simulated water levels. In general, the TID model was determined to be suitable for analysis in the Study Area with some modifications.
6.1. MODEL UPDATES AND SIMULATION SCENARIOS
In order to analyze the impact of land use changes in the eastern Turlock Subbasin, the original TID model was updated within the Study Area and three future groundwater use scenarios were simulated. The updated model, referred to as the “updated baseline model”, is a revised version of the TID model which includes pumping and land use information developed by Todd Groundwater for this project. The updated baseline model simulates the same 22‐year period as the original TID model from 1991 to 2012.
Three predictive future scenarios were also simulated to evaluate changes to water levels and groundwater storage under potential future land use conditions in the Study Area. These future conditions were defined to test a range of possible groundwater responses to various changes in groundwater use. A planning horizon of 30 years (2013 – 2042) was simulated for each of the future scenarios. Future scenarios incorporate pumping and land use estimates for 2013 and 2014 as discussed in Section 4.0.
Updated Baseline Simulation
Todd Groundwater modified the TID model within the Study Area to incorporate results of the land use analysis and hydrogeologic conceptual model described in Sections 4.0 and 5.0. Model revisions were made to total monthly pumping, irrigation well locations and timing, crop acreages and percentages, and consumptive use.
Monthly pumping rates were revised in the model from 1995 to 2012 based on estimates of agricultural water use (see Table 9). Figure 32 compares the annual agricultural pumping in the TID model to the estimates developed by Todd Groundwater. Annual pumping estimates developed by Todd Groundwater are similar to or slightly lower than the pumping in the TID model from 1995 to 2007 (Figure 32). After 2007, the new estimates of pumping are higher than pumping in the TID model. By 2012, the final year of the TID model, estimated pumping exceeds the TID model pumping by approximately 15,000 AFY. The TID model was updated with the Todd Groundwater pumping estimates.
Pumping well locations were revised in the model to represent changing land use and the estimated pattern and proportion of pumping associated with each crop type. Updated well
Hydrogeologic Characterization of the Eastern Turlock Subbasin 28 TODD GROUNDWATER
locations in the TID model were revised based on the 1995/1996 and 2002/2004 DWR land use maps and the 2014 county crop map (Figures 4, 5, and 6). Wells were placed on irrigated parcels such that the number of wells and percentage of pumping on each parcel were consistent with the crop‐specific pumping estimates (see Table 9). For example, in 1995/1996, 35 percent of the estimated agricultural water use was for almonds; therefore, 35 percent of the pumping in the model is from wells located in almond orchards.
The TID model is designed to distribute total pumping evenly among Study Area wells, so wells were placed according to the amount of pumping associated with each crop type. Well construction (i.e., depth and perforated interval) for the updated wells was consistent with the original TID model wells. Pumping schedules were based on cropping patterns from the land use maps. Since land use maps were not available for every year, wells were turned on and off in the model between the three periods in which land use maps were available (1995/1996, 2002/2004, and 2014). Wells based on the 1995/1996 land use map begin pumping in 1991 (i.e., the beginning of the model simulation period); wells placed according to the 2002/2004 land use map begin pumping in 1999 (i.e., between 1996 and 2002); and wells placed according to the 2014 county crop map begin pumping in 2009 (i.e., between 2004 and 2014). Table 12 summarizes the revised model pumping wells and Figure 33 illustrates the pumping well locations for the updated baseline model that were pumping in 2012.
Total irrigated acreage and crop percentages were revised in the model from 1995 to 2012 based on Todd Groundwater’s analysis (Table 7). Monthly crop coefficients developed by Davids Engineering were updated in the Study Area portion of the model from 1995 to 2012. It is our understanding that crop coefficients have also been revised for other portions of the model outside of the Study Area, but are not incorporated into this baseline update, as this analysis was focused on changes within the Study Area only.
Future Scenario 1 ‐ Continued Current Pumping
In order to test the long‐term impacts to water levels and storage from the current rate of pumping, Future Scenario 1 simulates the continuation of current pumping into the future. Future Scenario 1 assumes that new land will not be converted to irrigated agriculture, and that current irrigated parcels will remain in production with similar crop types. Assuming a 30‐year planning horizon, the model was run for a 30‐year simulation period (2013 – 2042) using 2014 pumping rates and well locations. Hydrologic conditions from the most recent 15‐year period of the model, 1998 – 2012, were repeated twice for the 30‐year simulation. This period did not include a major drought cycle. This 15‐year period represents average hydrologic conditions, and contains both wet and drought conditions, but does not include the entire duration of the current (major) drought. Precipitation for this time period is within one percent of the long‐term average.
Future Scenario 2 ‐ Increased Future Pumping
Future Scenario 2 assumes that irrigated land will continue to increase in the Study Area at the current rate of development until most of the available area is being irrigated. As of
Hydrogeologic Characterization of the Eastern Turlock Subbasin 29 TODD GROUNDWATER
2014, almost one‐half of the Study Area had been developed for agriculture. This represents an increase of about 15 percent over the preceding five years, when irrigated agriculture covered less than 35 percent of the area. Recognizing the impracticality of irrigated agriculture covering the entire Study Area, Scenario 2 assumes that agricultural development will expand at the current rate until approximately 75 percent of the available land is irrigated (about 55,000 acres). This is estimated to occur in 2022. After 2022, it is assumed that new land will not be converted to crops, crop types will remain the same, and that 2022 pumping amounts will remain constant throughout the remaining 20 years of the simulation period.
Although the exact parcels for future development are unknown, additional pumping and pumping wells were reasonably placed throughout the Study Area from 2015 to 2022 to test the overall impacts on basin‐wide groundwater levels. Pumping was only increased on newly‐developed lands in the Study Area; all other basin‐wide pumping remained constant in order to isolate the impacts of this increased development. Figure 34 illustrates the pumping wells that were added to the model between 2015 and 2022. The well symbols are color‐coded to show the phasing of additional simulated wells. The pumping well locations in the updated baseline model (Figure 33) remained constant in 2013 and 2014.
As with Future Scenario 1, the model hydrologic conditions from 1998 ‐ 2012 are repeated twice for the future simulation to represent overall average hydrologic conditions.
Future Scenario 3 – Decreased Future Pumping
Future Scenario 3 recognizes the potential for a future decrease in pumping to occur in the Study Area. This scenario acknowledges that some orchards may have a limited productive life span, assumed at approximately 20 years. This observation and other factors could potentially result in a decrease in irrigated lands over time. The scenario provides the opportunity to evaluate the rate of recovery of the groundwater system.
For this scenario, current (2014) pumping amounts and locations remain constant until 2023, and at that time, groundwater use was assumed to decline as some irrigated crops are converted to un‐irrigated lands. The land use conversion and pumping decline occurs at the same rate of crop increase between 2003 and 2013. This pumping decline was simulated for 9 years, until 2032, when most of the land use conversions were assumed to have been completed. To simulate this change, irrigation wells are incrementally removed from portions of the model that contained orchards (mostly almonds in the Study Area). Figure 35 illustrates the locations of the pumping wells removed from the model from 2024 and 2032. As with Future Simulations 1 and 2, the model hydrologic conditions from 1998 ‐ 2012 are repeated twice for the future simulation to represent overall average hydrologic conditions.
For this scenario, the model was used to examine water level rise over time in response to decreased pumping.
Figure 36 illustrates the pumping volumes and timing in each model scenario.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 30 TODD GROUNDWATER
6.2. UPDATED BASELINE SIMULATION CALIBRATION RESULTS
Available groundwater elevation data for the baseline period were compared with the updated model to assess model calibration quality. Water level calibration hydrographs and a simulated water level contour map at the end of the simulation period (2012) were developed. Figure 37 illustrates the locations of four calibration hydrographs which are shown on Figure 38. Simulated groundwater elevation contours from December 2012 are presented on Figure 39.
As shown on Figure 38, the updated baseline model results provide a reasonable match to observed data between 1991 and 2012. Hydrographs at locations A (State Well Number (SWN) 04S11E08A001M) and B (SWN 05S11E13J001M), west of the Study Area, show that simulated groundwater elevations are both slightly lower (up to approximately 10 feet) than observed data (location A, north central portion of the subbasin) and slightly higher (up to approximately 10 feet) than observed data (location B, south central portion of the subbasin). Hydrographs at locations C (SWN 4S12E21B001M) and D (SWN 04S13E28B001M) show that simulated groundwater elevations within or next to the Study Area are slightly higher than observed data in the last 5 to 9 years by up to 20 feet. The overall declines in water levels observed between 2002 and 2012 are reasonably well simulated by the updated baseline model.
As shown on Figure 39, simulated groundwater elevations in December 2012 range from about 400 feet above mean sea level (msl) at the eastern boundary of the Study Area to approximately 40 feet msl at the western edge of the Study Area. The high elevations along the eastern edge of the Study Area are a result of groundwater mounding from subsurface inflow entering thin model elements at the edge of the model domain. There is a simulated cone of depression east of Turlock Lake, with groundwater elevations approximately 100 feet msl, which corresponds with a cluster of pumping wells (Figure 33). There is also a relatively steep groundwater gradient between the eastern boundary of the model and this cone of depression. The gradient is less steep in the western region of the Study Area where additional wells are also pumping.
Because of the shallow depths, and limited saturated thickness of the Mehrten Formation in portions of the Study Area, portions of the Mehrten aquifer are simulated as dewatered. In the FEMFLOW3D model, as water levels drop, the top nodes of the finite element mesh “deform” and are automatically lowered until the model layer reaches a minimum thickness of 1 foot; at that point the mesh remains at that minimum thickness (and associated low transmissivity) as a “confined” aquifer layer. The model still allows calculation of water levels, even though they are below the model layer bottom. This is a limitation of the FEMFLOW3D code,t bu may indicate that the Mehrten Formation alone cannot sustain future pumping. Therefore, future pumping in the eastern Study Area will need to increasingly rely on wells completed in the underlying Valley Springs Formation rather than the more productive Mehrten Formation. For the purposes of these simulations, fewer wells were added to the eastern Study Area where the Mehrten Formation is either not present or associated with more limited groundwater resources (see Figure 34).
Hydrogeologic Characterization of the Eastern Turlock Subbasin 31 TODD GROUNDWATER
The simulated water budget from 1991 to 2012 is summarized on Table 13 and illustrated on Figure 40. Groundwater inflows listed in Table 13 are shown above the zero line on the graph on Figure 40; groundwater outflows are shown below the line. The red line represents a subtraction of the outflows from the inflows and provides a cumulative change in storage over the entire model simulation period.
As shown on Figure 40, rates of recharge from Merced River and Tuolumne River leakage increase slightly over time, due to decreasing water table elevations and associated increased river‐groundwater gradients. Other components of inflow remain relatively consistent over time. As discussed previously, annual irrigation pumping rates are relatively stable between 1992 and 2003, then increase through 2012. Subsurface outflow from the Study Area to downgradient portions of the subbasin, calculated as the difference in all other water budget and change in storage rates, remains relatively constant between 1991 and 2012.
Groundwater storage decreases 57,505 AF in the Study Area from 1991 to 2012. Storage decreases during 1991 and 1992, increases between 1993 and 1998, and then decreases relatively steadily after 1998. Although groundwater storage increases somewhat during the relatively wet periods of 2010 and 2011, the net depletion of groundwater storage continues throughout the entire second half of the simulation period.
6.3. FUTURE SCENARIO SIMULATION RESULTS
Results of future scenario simulations are depicted on simulated hydrographs and contour maps in 2014, 2022, 2032, and 2042 for each scenario. Figure 37 illustrates the locations of eight simulated hydrograph wells. Figure 41 shows the simulated water levels for these eight wells for each of the three Future Scenarios. Simulated groundwater elevation contours for Future Scenarios 1, 2, and 3 are presented on Figures 42, 45, and 48, respectively. Simulated changes in groundwater elevation, from 2014 to 2042 for each Future Scenario are illustrated on Figures 43, 46, and 49, respectively. Positive values on the contour maps indicate that groundwater elevations have risen from 2014 to 2042, while negative values indicate that groundwater elevations have declined during this time. The simulated water budgets for each future scenario are summarized on Tables 14, 15, and 16 and illustrated on Figures 44, 47, and 50. These results are discussed in more detail below.
Results of Future Scenario 1 ‐ Continued Current Pumping
The contour maps shown on Figure 42 illustrate a similar pattern of groundwater flow direction and gradient from 2014 to 2042 as a result of the constant pumping volumes and well locations. Regional groundwater flow directions from east to west are maintained away from the pumping centers. In the eastern Study Area, groundwater flow converges toward the cone of depression east of Turlock Lake; in the western Study Area, groundwater generally flows to the southwest toward pumping centers outside of the Study Area. The cone of depression east of Turlock Lake expandse over tim as pumping continues.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 32 TODD GROUNDWATER
Groundwater elevations decline relatively steadily between 2014 and 2042. As shown on the contour maps (Figure 43) and the hydrographs (Figure 41), groundwater elevation declines are greatest east of Turlock Lake and at the western edge of the Study Area (hydrograph locations G, H and C – see Figure 37 for locations). Groundwater elevations do not decline as much in the southern Study Area, which is influenced by recharge from the Merced River (Figure 41, hydrograph locations I and J). As shown on Figure 43, groundwater elevations between 2014 and 2042 decline between approximately 10 to 30 feet throughout the Study eArea. In th eastern portion of the Study Area, water levels are simulated as below the base of the Mehrten Formation.
The simulated water budget from 1991 to 2042 for Future Scenario 1 is summarized on Table 14 and illustrated on Figure 44. As shown on Figure 44, recharge from natural and irrigation return flow increases during this period. Between 2014 and 2042, rates of net recharge from Merced River and Tuolumne River leakage increase slightly, due to decreasing water table elevations and associated increased river‐groundwater gradients. Pumping increases from 1991 through 2014 then remains constant. Subsurface outflow across the western Study Area boundary decreases slightly in certain years from 2014 to 2042 because the continued pumping within the Study Area is reducing aquifer saturated thickness, westward hydraulic gradients, and associated outflow. From 1991 to 2042, total storage decreases by 159,841 AF. The predicted storage loss associated with future pumping (2014 to 2042) is approximately 100,000 AF.
Results of Future Scenario 2 ‐ Increased Future Pumping
As shown on Figure 45, the cone of depression east of Turlock Lake expands significantly and shifts slightly eastward from 2014 to 2042 as a result of the increased pumping and addition of pumping wells in the eastern Study Area (Figure 34). The center of the cone of depression declines from an elevation of approximately 90 feet msl in 2014 to approximately ‐90 feet msl in 2042, a change of 180 feet. As a result of the eastward shift of the cone of depression, the maximum decline in groundwater elevations from 2014 to 2042 is approximately 220 feet (Figure 46). Significant groundwater elevation declines, in excess of 200 feet, also occur to the southeast of the cone of depression as a result of additional pumping wells. In the eastern portion of the Study Area, water levels are simulated as below the base of the Mehrten Formation.
Hydrographs presented on Figure 41 at locations G, H, and I illustrate the steep groundwater elevation declines in the eastern Study Area. The groundwater gradient increases through time along the eastern edge of the Study Area due to the expanding cone of depression and constant subsurface inflow at the eastern edge of the model.
Groundwater elevation declines are much less in the western portion of the Study Area because the additional pumping wells are primarily in the east. Groundwater elevation declines west of Turlock Lake between 2014 and 2042 are approximately 20 to 30 feet (Figure 46). Hydrographs at locations west of Turlock Lake (Figure 41, locations C, E, and F) illustrate this muted response to the increase in pumping. The muted response is also likely due to the increase in Turlock Lake recharge through time as a result of the continued
Hydrogeologic Characterization of the Eastern Turlock Subbasin 33 TODD GROUNDWATER
decline in groundwater elevations. Similarly, the declines in groundwater elevations are less in the southern arm of the Study Area (Figure 41, hydrograph location J); likely due to the increasing leakage from the Merced River (Table 15).
The simulated water budget from 1991 to 2042 for Future Scenario 2 is summarized on Table 15 and illustrated on Figure 47. As shown on Figure 47, rates of pumping increase from 1991 through 2022 then remain constant. Natural recharge and irrigation return flows also increase during this period, as do net recharge amounts from Merced River and Tuolumne River leakage. Subsurface outflow through the western boundary decreases throughout this future scenario due to significant water level declines in the Study Area. From 1991 to 2042, total storage decreases by 229,790 AF. Loss of groundwater storage from 2014 to 2042 is approximately 170,000 AF. Approximately 40 percent of this storage loss occurs from 2014 to 2022, during the period of increased pumping.
Results of Future Scenario 3 – Decreased Future Pumping
As shown on Figure 48, groundwater elevations decrease between 2014 and 2022 in response to continued and constant pumping, but then increase after 2023 as a result of declining pumping. Figure 49 illustrates that groundwater elevations throughout most of the Study Area either remain the same or increase slightly between 2014 and 2042. The effect of pumping is most apparent within the cone of depression east of Turlock Lake. The center of the cone of depression decreases in elevation from approximately 88 feet msl in 2014 to approximately 71 feet msl in 2022 in response to the constant pumping, but then rebounds to approximately 78 feet in 2032 and 95 feet msl in 2042 as a result of decreased pumping (Figure 48).
The pattern of incremental well removal has a significant effect on groundwater elevations. Groundwater elevations in the western Study Area rebound as wells are removed from the model annually from 2023 to 2032. This is illustrated most clearly in the hydrographs for locations D, E and F on Figure 41. Hydrograph G also shows significant water level recovery in the vicinity of the cone of depression east of Turlock Lake. Along the eastern edge of the Study Area model boundary, groundwater elevations decrease over time because of the remaining pumping wells in this area. Groundwater elevations also decrease slightly in the southern portion of the Study Area due to the pumping wells that remain in this region. In most areas of the Study Area, water levels recover to near‐current levels (2014‐2015) by the end of the simulation period.
Wells in the southern Study Area, Hydrographs I and J on Figure 41, do not recover at the rate of other wells because not many wells are removed from the model in this area. Groundwater elevation declines in the southern portion of the Study Area are likely muted by the leakage from the Merced River.
The simulated water budget from 1991 to 2042 for Future Scenario 3 is summarized on Table 16 and illustrated on Figure 50. As shown on Figure 50, pumping increases from 1991 through 2014 then remain constant until 2023, when they begin to decline. Rates of recharge from natural and irrigation return flow are generally higher between 2014 and
Hydrogeologic Characterization of the Eastern Turlock Subbasin 34 TODD GROUNDWATER
2023, then decline slightly as a result of less irrigation. Between 2014 and 2023, rates of net recharge from Merced River and Tuolumne River Leakage increase slightly, then remain relatively stable. Subsurface outflow through the western boundary increases as water levels recover in the Study Area. From 1991 to 2042, total groundwater in storage decreases by 111,405 AF. Future loss of storage, as simulated from 2014 to 2042, is approximately 50,000 AF. However, during the period of decreased pumping from 2023 to 2042, groundwater storage increases by approximately 12,000 AF.
6.4. MODEL SUMMARY AND CONCLUSIONS
The TID model was updated with land use and pumping information developed as part of the LGA project to simulate the effect of changing land use on groundwater. The revised TID model, referred to as the updated baseline model, simulated groundwater elevations from 1991 to 2012, the same time period as original TID model. Calibration results show that the updated baseline model provides a reasonable match to observed data from 1991 to 2012.
Three model scenarios were designed to simulate future land use and pumping conditions for a 30‐year simulation period, 2013 through 2042: continued current pumping, increased pumping, and decreased pumping.
The continued current pumping scenario (Future Scenario 1) shows that if current levels of pumping continue for 30 years, groundwater elevations will decline steadily by about 10 to 30 feet. The cone of depression east of Turlock Lake is expected to expand. The largest water elevation declines of approximately 30 feet will likely occur in the vicinity of this cone of depression and also in the western region of the Study Area, which is also influenced by pumping occurring west of the Study Area. Water elevation declines are slightly less, on the order of 10 to 20 feet, in the southern Study Area as a result of the increasing leakage from the Merced River. Future groundwater flow directions and patterns remain similar to current conditions because pumping well locations remain constant. The water budget shows that future (i.e., 2014 to 2042) storage loss is relatively steady and is estimated at approximately 100,000 AF. This is more than 1.5 times the storage loss that occurred from 1991 to 2014.
The increased future pumping scenario (Future Scenario 2) shows that groundwater elevations will decline significantly if recent increasing agricultural development and related pumping rates continue until most (approximately 75 percent) of the Study Area is developed with irrigated agriculture. The effect of increased agricultural development and pumping is most significant in the central and eastern Study Area where future crops and pumping wells will likely be located. Under these pumping conditions, groundwater elevation declines from 2014 to 2042 in the eastern Study Area are predicted to exceed 200 feet. Groundwater elevation declines west of Turlock Lake are less, approximately 20 to 30 feet, because most of the land in this area is already developed with agriculture and therefore, pumping is not likely to increase significantly in the future. Additionally, leakage from Turlock Lake recharges groundwater in the western Study Area. Groundwater elevation declines are also less in the southern arm because of significant leakage from the
Hydrogeologic Characterization of the Eastern Turlock Subbasin 35 TODD GROUNDWATER
Merced River. However, the water level declines associated with the cone of depression propagate throughout the Study Area. The water budget shows that future storage loss, from 2014 to 2042 is approximately 170,000 AF, which is almost triple the amount of storage loss that occurred from 1991 to 2014. Approximately 40 percent of the storage loss that occurs between 2014 and 2042 occurs during the period of increasing pumping (2014 to 2022). In the future, approximately 70,000 AF more storage loss will occur if pumping increases (Future Scenario 2) than if pumping remains constant (Future Scenario 1).
The decreased future pumping scenario (Future Scenario 3) shows that the net effect of decreasing irrigation pumping is that groundwater elevations continue to decline in the near‐term, then recover and increase up to 20 feet from 2014 to 2042 throughout most of the Study Area. Groundwater elevations throughout most of the Study Area decline approximately 10 to 20 feet until 2023 while current pumping levels continue, and then begin to recover after 2023 once almond orchards are converted to un‐irrigated land and pumping declines. The center of the cone of depression decreases in elevation by about 17 feet from 2014 to 2022 in response to constant pumping, but then recovers almost 25 feet after pumping is reduced. Well removal is simulated incrementally on an annual basis, roughly from the west to east, from older to younger almond orchards. Groundwater elevations along the western boundary of the Study Area decline approximately 10 to 20 feet over time. Groundwater elevations decline up to 90 feet along the eastern edge of the Study Area because of the remaining pumping wells in this area. The water budget shows that future storage loss, from 2014 to 2042, is approximately 50,000 AF, which is slightly less than the storage loss that occurred from 1991 to 2014. During the period of decreased pumping, from 2023 to 2042, storage increases by approximately 12,000 AF.
6.5. MODEL LIMITATIONS
There is some uncertainty about the sustainability of future groundwater in the eastern Study Area. Our hydrogeological conceptual model indicates that the Mehrten Formation is the primary aquifer in the Study Area. But, because of the shallow depths of the Mehrten Formation in the east, model results indicate that the aquifer is being dewatered. It appears that the Mehrten Formation alone cannot sustain increased future pumping. Therefore, future pumping in the eastern Study Area will need to increasingly rely on the underlying Valley Springs Formation.
The future model simulations assumed that the hydrologic conditions for the most recent 15‐year period, 1998‐2012, were repeated twice. Although precipitation for this time period is within one percent of the long‐term average, it did not include a major drought cycle. Additional model simulations could be run in the future to evaluate drought cycles, climate change, and other conditions that could influence the results.
TID recently developed updated crop coefficients throughout the subbasin. These updated crop coefficients were incorporated into the model within the Study Area, but not in other portions of the subbasin. The updated model meets the objectives of this study, which involves an evaluation of the impact of changing land use on groundwater in the Study Area.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 36 TODD GROUNDWATER
No conclusions about specific groundwater impacts to the west of our Study Area should be made prior to additional model updates.
Although, as noted above, the model is not used to quantify changes outside of the Study Area, it is clear that increased pumping in the Study Area reduces subsurface outflow to the west. This condition will exacerbate water level declines in other parts of the subbasin.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 37 TODD GROUNDWATER
7. CONCLUSIONS
A better understanding of the hydrogeology of the eastern Turlock Subbasin was developed during this study. The impacts of changing groundwater use over time was estimated based on an evaluation of changing land use, the development of a hydrogeologic conceptual model, and the application of a numerical model to simulate groundwater.
The land use analysis shows that there was a significant transformation of non‐irrigated lands to irrigated lands within the Study Area from 1995 to 2014. During this time, irrigated acreage in the Study Area increased almost 300 percent, from approximately 11,900 acres in 1995 to 34,300 acres in 2014. As a result, agricultural water use (i.e., groundwater use) increased from approximately 44,000 AFY in 1995 to approximately 120,000 AFY in 2014. The increase in water use was primarily driven by the increase in almonds and pasture crops.
The systematic compilation of available data was used to develop a hydrogeologic conceptual model. Well completion reports for 408 wells constructed within the Study Area from April 1951 to June 2013 were used to evaluate the geology and primary aquifer, the Mehrten Formation, within the Study Area. The Mehrten Formation crops out in the southwest region of the Study Area and is overlain by the Turlock Lake and Laguna formations throughout the remainder of the Study Area. The saturated thickness is lower in the eastern Study Area where the Mehrten thins and becomes closer to the surface. In general, most of the wells appear to target the black sands of the Mehrten Formation. An analysis of available pumping data from the Well Completion Reports showed that specific capacity increases with well depth and is higher for wells that are screened in Mehrten black sands.
Groundwater level measurements available at 38 wells within the Study Area from 1971 to 2011 illustrate steadily declining groundwater elevations. mData fro the only well with continuous measurements, located along the northwest edge of the Study Area, showed a groundwater elevation decline of approximately 60 feet from 1971 to 2011. Groundwater contour maps developed in 1971 and 2010‐2013 show that groundwater elevations appear to have declined between approximately 60 and 175 feet over this 40 year period. Contour maps also illustrate the growth of a cone of depression in the central/southeastern region of the Study Area.
A water balance, based on the hydrogeologic conceptual model and results of the numerical model, shows that groundwater storage was depleted in the Study Area by approximately 58,000 AF from 1999 to 2013. The largest components of the groundwater balance are irrigation pumping and associated return flows, Turlock Lake leakage, Merced River leakage, and western boundary subsurface outflow.
TID’s groundwater flow model was revised to incorporate results of the land use analysis and hydrogeologic conceptual model. The updated and refined model is a suitable tool for simulation and analysis of groundwater level changes in response to land use changes and
Hydrogeologic Characterization of the Eastern Turlock Subbasin 38 TODD GROUNDWATER
management actions in the eastern Turlock Subbasin. The model, which was developed to simulate groundwater from 1991 to 2012, was then used to simulate three potential future pumping scenarios from 2013 to 2042: 1) continued current pumping; 2) increased future pumping; and 3) decreased future pumping. Model results show that if current pumping continues with no new irrigated lands being developed, and future hydrology is similar to 1998‐2012, water levels will decline approximately 10 to 30 feet. Future storage loss (i.e., 2014 to 2042) will be approximately 100,000 AF, which is greater than 1.5 times the storage loss that occurred from 1991 to 2014. If pumping increases in the future, assuming that irrigated lands will continue to increase at the current rate of development until most of the available area is developed, water levels will decline over 200 feet in parts of the Study Area. Future storage loss is approximately 170,000 AF, which is almost triple the storage loss from 1991 to 2014 and approximately 70,000 AF more than if pumping remains constant. If pumping decreases in the future, assuming that crops with a limited lifespan are not replaced, there will be a net water level increase of up to 20 feet throughout most of the Study Area. Future storage loss will be approximately 50,000 AF, which is less storage loss than occurred from 1991 to 2014.
TID recently developed updated crop coefficients throughout the subbasin. These updated crop coefficients were incorporated into the model within the Study Area, but not in other portions of the subbasin. The updated model meets the objectives of this study, which involves an evaluation of the impact of changing land use on groundwater in the Study Area. No conclusions about specific groundwater impacts to the west of our Study Area should be made prior to additional model updates. However, it is clear that increased pumping in the Study Area reduces subsurface outflow to the west. This condition will exacerbate water level declines in other parts of the subbasin.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 39 TODD GROUNDWATER
8. DATA GAPS AND LIMITATIONS
Several data gaps and limitations were identified during the course of this study:
Water level measurements were available at 38 wells in the Study Area between 1951 and 2011. Water level monitoring in these wells should continue in the future. Todd provided TGBA with a list of candidate wells for exploration and potential inclusion into the CASGEM program. These wells are irrigation wells constructed between 2009 and 2013, have accurate location information, and in some cases, are close to wells with water level data. Pumping test data relied upon for this study were from Well Completion Reports. It would be helpful to conduct pumping tests throughout the Study Area, with a focus on the wells that are screened in the Mehrten black sands, in order to develop more accurate aquifer properties. The land use analysis was based on DWR land use maps from 2002/2004 and 1995/1996 and from a 2014 County crop map. Because pumping records will continue to be confidential in the future, it is important that DWR update their land use maps more frequently to allow for groundwater use analyses such as this. TID recently updated crop coefficients throughout the subbasin. These values were updated in the model within the Study Area, but not the rest of the subbasin. Model results show that future pumping in the eastern Study Area will need to increasingly rely on the underlying Valley Springs Formation because it appears that the Mehrten Formation alone cannot sustain increased future pumping. The groundwater flow model was used to simulate water levels within the Study Area and should not be used to make conclusions about specific groundwater impacts to the west of the Study Area. However, it is clear that increased pumping in the Study Area reduces subsurface outflow to the west which will exacerbate water level declines in other parts of the subbasin.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 40 TODD GROUNDWATER
9. REFERENCES
California Department of Conservation, 1997, California Spatial Information Library, precipitation.
California Department of Water Resources (DWR), Land Use Survey Overview, http://www.water.ca.gov/landwateruse/lusrvymain.cfm, Last Accessed June 2014a.
California Department of Water Resources (DWR), Annual Land and Water Use Estimates, http://www.water.ca.gov/landwateruse/models.cfm, Last Accessed June 2014b.
California Department of Water Resources (DWR), Agricultural Water Use Models, http://www.water.ca.gov/landwateruse/models.cfm, Last Accessed June 2014c.
California Department of Water Resources (DWR), 2006, San Joaquin Valley Groundwater Basin, Turlock Subbasin, California’s Groundwater Bulletin 118, groundwater basin descriptions, updated January 20, 2006.
California Department of Water Resources (DWR), 1974, Evaluation of Ground Water Resources: Sacramento County, Bulletin 118‐3, July.
California State Parks, Turlock Lake State Recreation Area, 2005.
Driscoll, 1986, Groundwater and Wells, second edition, Copyright © 1986 by Johnson Screens, St. Paul, Minnesota.
Dunne, T., and Leopold, L.B., 1978, Water in Environmental Planning, W.H. Freeman and Company, New York.
Faunt, C.C., Belitz, K., and Hanson, R.T., 2010, Development of a Three‐Dimensional Model of Sedimentary Texture in Valley‐Fill Deposits of Central Valley, California, Hydrogeology Journal 18: 625‐649.
Marchand, D.E., and Allwardt, A., 1981, Late Cenozoic stratigraphic units, northeastern San Joaquin Valley, California, U.S. Geological Survey Bulletin 1470.
Page, R.W., 1986, Geology of the fresh ground‐water basin of the Central Valley, California (Regional aquifer‐system analysis), U.S. Geological Survey professional paper; 1401‐C.
Page, R.W., and Balding, G.O., 1973, Geology and quality of water in the Modesto‐Merced Area, San Joaquin Valley, California, with a brief section on hydrology, U.S. Geological Survey Water‐Resources Investigations 6‐73, Prepared in Cooperation with the California Department of Water Resources.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 41 TODD GROUNDWATER
Phillips, S.P., Rewis, D.L., and Traum, J.A., 2015. Hydrologic Model of the Modesto Region, California, 1960‐2004. U.S. Geological Survey Scientific Investigations Report (SIR), 2015‐ 5045.
Phillips, S.P., Green, C.T., Burow, K.R., Shelton, J.L., and Rewis, D.L., 2007, Simulation of multiscale ground‐water flow in part of the northeastern San Joaquin Valley, California: U.S. Geological Survey Scientific Investigations Report 2007‐5009, 43 p.
Piper, A.M., Gale, H.S., Thomas, H.E., and Robinson, T.W., 1939, Geology and Ground‐Water Hydrology of the Mokelumne Area, California, U.S. Geological Survey Water‐Supply Paper 780.
Shakouri, Gholam, Department of Water Resources, Personal Communication (e‐mail), February 2014.
Timothy J. Durbin, Inc. Consulting Hydrologists (Durbin), 2008, Groundwater Model Documentation, Prepared for Turlock Irrigation District, December.
Timothy J. Durbin, Inc. Consulting Hydrologists (Durbin), 2014, (Updated) Draft Groundwater Model Documentation, Prepared for Turlock Irrigation District, September 2.
Turlock Groundwater Basin Association, Turlock Groundwater Basin, Groundwater Management Plan, prepared for Turlock Irrigation District, March 18, 2008.
USGS, 1997, FEMFLOW3D: A Finite‐Element Program for the Simulation of Three‐ Dimensional Aquifers. By T.J Durbin and L.D. Bond. Open‐File Report 97‐810.
Wagner, D.L., Bortugno, E.J., and McJunking, R.D., 1991, Geologic Map of the San Francisco‐ San Jose Quadrangle, California, 1:250,000.
Hydrogeologic Characterization of the Eastern Turlock Subbasin 42 TODD GROUNDWATER
Table 1 ‐ Data Collection Summary Turlock Eastern Subbasin LGA
Data Type County Description Source(s) Time Period
Obtained approximately 820 Well Completion Reports from the California Department of Water Resources in Townships and Ranges that are within, or overlap, the LGA study area. Some of these Merced and Well Logs Well Completion Reports are in Sections that are outside of the study area. Data efrom th Well Chris Guevara, DWR South Central Region through June 2013 Stanislaus Completion Reports, including location, completion date, well construction, depth to water, and pumping rate have been compiled into a database.
The Merced County Environmental Health Department and Stanislaus County Environmental Health Vicky Jones, Merced County Environmental Merced Department require permits for the construction of all new wells. During the permitting process, the ‐‐ Health Department County ensures that the proposed well construction is in accordance with State and County Well Permits and Groundwater Use regulations. Well permits are not kept in an electronic format and may contain information for wells that were not drilled. Both Counties indicated ethat th DWR Well Completion Reports are the best Nicole Damin and Rachel Riess, Stanislaus Stanislaus source of well data including location, construction, lithology, well tests, and completion dates. The County Environmental Resources ‐‐ Counties do not track groundwater use. Department
In general, Small Community Water Systems that have less than 200 connections are regulated by the County, and systems with more than 200 connections are regulated by the California Department of Brent Cronk, Merced County Public Health (CDPH). In January 2014, Merced County handed regulatory oversight authority for the Environmental Health Department and Merced current systems with less than 200 connections back to CDPH. According to Merced County and CDPH, there Kassy Chauhan, CDPH Drinking Water are no small community water systems within the LGA study area (<200 connections or >200 Program District 11 connections).
Small Community Water Systems CDPH does not regulate any small community water systems in the LGA Study Area. Stanislaus County regulates one small community water system within the Study Area: La Grange Park OHV. Well Janis Mein, Stanislaus County construction details and pumping rates are confidential under a non‐disclosure agreement with the Environmental Resources Department and State. The County indicated that publically‐available information on this water system can be found at Bhupinder Sahota; CDPH Drinking Water Stanislaus current the DRINC Portal, operated by CDPH and the U.C. Davis Information Center for the Environment. Program District 10; CDPH DRINC Portal; Based on data from the DRINC Portal, and from Tom Diaz, the manager of the La Grange Park OHV, the and Tom Diaz, Manager of the La Grange source of water at the La Grange Park OHV is groundwater and water use averages 2,500 gallons per Park OHV month.
Obtained and reviewed water level database provided by Turlock Irrigation District (TID). The database contains groundwater elevation data for almost 700 wells within Turlock Subbasin, 38 of 1916 to March 2011 Merced and Debbie Liebersbach, Turlock Irrigation Water Levels which are within the LGA study area. The database includes data from the water level database (database); January 2011 to Stanislaus District; DWR's Water Data Library maintained by DWR and key monitoring data compiled by TID from 1916 to March 2011. In addition, present (Water Data Library) water level data from 2011 to present were downloaded from DWR's Water Data Library.
Page 1 of 3 Table 1 ‐ Data Collection Summary Turlock Eastern Subbasin LGA
Data Type County Description Source(s) Time Period
Requested septic system information from the Merced County Department of Environmental Health, Merced County Environmental Health Merced but no information was received. Department Septic Systems ‐‐ Stanislaus County indicated that there are septic systems within the LGA study area. However, an in‐ Janis Mein, Stanislaus County Stanislaus person file review is required to obtain this information because the records aret no available Environmental Resources Department electronically.
1998, 2004, 2005, 2006, 2009, Google Earth Downloaded aerial photographs of the LGA study area from two sources: Google Earth and USDA. The 2010, 2011 Merced and Aerial Photographs aerial photographs from the USDA have been incorporated into the Project Geographical Information Stanislaus System (GIS). United States Department of Agriculture, 2004, 2005, 2006, 2009, 2010, Natural Resources Conservation Service 2012
U.S. Geological Survey Earth Resources Merced and Obtained landsat aerial imagery from USGS. The images help identify the presence of vegetative cover Landsat Aerial Imagery Observation and Science 2003 through 2013 (in July) Stanislaus and will be used to cross‐check other land use data. (EROS) Center
Downloaded land use survey data developed by California Department of Water Resources (DWR) Merced through its Division of Planning and Local Assistance. Maps provide crop types for agricultural land DWR 1995 and 2002 Land Use Maps use. These maps have been incorporated into the Project GIS. More recent maps have been completed (information on recent maps from Jean by DWRr (2010 fo Stanislaus and 2012 for Merced), but are unavailable to the public, pending internal Woods) Stanislaus 1996 and 2004 quality control review.
California Department of Conservation, Downloaded available maps of "Important Farmland" for each County. These maps are being used to California Farmland Mapping and Merced and Division of Land Resource Protection, 1984 to 2012, even numbered estimate the amount of irrigated and non‐irrigated agriculture in the LGA over time. These maps have Monitoring Program Maps Stanislaus Farmland Mapping and Monitoring years been incorporated into the Project GIS. Program
Merced and Walt Ward, Stanislaus County Water Crop Maps Obtained crop maps showing specific crops planted in the Study Area. 2014 Stanislaus Resources Program Manager
Downloaded the most recently available County reports of agriculture. The reports summarize the Merced and Department of Agriculture in both Merced Crop Reports acreage, production, and gross value of agricultural commodities. The locations of specific crops are 2012 Stanislaus and Stanislaus County not available.
Page 2 of 3 Table 1 ‐ Data Collection Summary Turlock Eastern Subbasin LGA
Data Type County Description Source(s) Time Period
Obtained pesticide permit database. Growers are required to submit a permit to the County when David Robinson and Sean Runyon, Merced Merced they purchase or use pesticides for agriculture. The database contains the permit date, grower's ‐‐ County Department of Agriculture commodity type, acreage, and location. Received 2014 County Crop map. Crop Data
Stanislaus Requested cropa dat from Merced County. Stanislaus County 2004 through 2013
Merced and Obtained normalized difference vegetation index (NDVI) maps which show irrigated versus non‐ Timothy J. Durbin, Inc. Consulting NDVI Maps 1985 to 2014 Stanislaus irrigated lands. Hydrogeologists
Merced and Applied Water Obtained applied water volumes for various crop types. Gholam Shakouri, DWR 1998 through 2010 Stanislaus
Merced and Crop Coefficients Obtained crop coefficients for 64 crop types, 31 of which are grown within the LGA study area. DWR Consumptive Use Program ‐‐ Stanislaus
Downloaded daily precipitation and evapotranspiration data from three CIMIS stations in Merced and California Irrigation Management Irrigation Merced and Stanislaus Counties: 1) Station 148 (Merced ‐ south of Turlock subbasin), 1/4/99‐8/27/02; 2) Station Precipitation and Evapotranspiration Systems (CIMIS), Department of Water January 1999 to present Stanislaus 168 (Denair ‐ within Turlock subbasin), 8/28/02‐4/8/09; and 3) Station 206 (Denair II ‐ within Turlock Resources, Office of Water Use Efficiency subbasin), 4/9/09‐12/31/14
Obtained various technical publications from USGS, DWR, USDA, and University of California with a Technical Publications ‐‐ ‐‐ ‐‐ focus on the Study Area geology and Mehrten Formation (aquifer).
Page 3 of 3 Table 2 ‐ Irrigated Crop Areas, Turlock Lake DAU Eastern Turlock Subbasin units in acres Total Year Almonds Corn Dry Bean Grain Deciduous1 Field Truck2 Pasture Citrus3 Vine Acreage 1998 34,600 5,700 1,900 7,900 4,100 200 1,100 8,500 ‐ 9,300 73,300
1999 35,400 5,400 1,300 5,900 4,000 1,000 1,800 7,500 ‐ 9,200 71,500
2000 35,600 5,600 1,300 8,600 4,100 ‐ 2,200 8,500 ‐ 9,100 75,000
2001 36,300 5,800 1,200 7,700 3,800 ‐ 2,500 7,300 ‐ 9,600 74,200
2002 40,700 4,400 500 4,100 2,900 ‐ 8,700 6,800 ‐ 7,300 75,400
2003 41,000 4,500 300 5,300 2,900 ‐ 8,000 6,500 ‐ 7,000 75,500
2004 41,100 5,300 1,000 1,800 2,600 800 6,200 7,300 ‐ 6,100 72,200
2005 41,900 5,600 800 1,600 2,500 800 7,000 7,700 ‐ 6,100 74,000
2006 44,900 6,400 1,000 1,200 2,700 3,700 5,300 6,200 ‐ 6,400 77,800
2007 45,800 6,300 1,400 800 2,900 3,800 5,000 5,400 ‐ 6,200 77,600
2008 48,100 6,800 700 1,000 2,700 3,800 5,500 5,200 ‐ 6,100 79,900
2009 48,100 6,900 1,100 1,300 2,600 4,000 7,200 5,000 ‐ 5,900 82,100
2010 53,100 7,000 400 1,200 2,400 4,000 5,300 5,000 ‐ 5,900 84,300
Notes: 1. The deciduous crop category includes many tree crop varieties including fruits and nuts. DWR subdivides the general category into 14 subclasses for specific crops including apples, peaches, and walnuts. 2. The truck crop category includes truck, nursery, and berry crops. DWR subdivides the general category into 25 subclasses including lettuce, strawberries, tomatoes, potatoes, and cole crops. 3. The citrus category includes a variety of subtropical fruits including olives. DAU = Detailed Analysis Unit Table 3 ‐ 1995 Land Use Comparison Irrigated Acreage in the Study Area and DAU by Crop Eastern Turlock Subbasin units in acres
Estimated Portion of Crop Crop Type Study Area Land Use1 DAU Land Use1 Area in the Study Area
Almonds 2,479 33,203 7% Corn 2,390 4,702 51% Dry Bean 134 2,248 6% Grain 216 3,477 6% Deciduous 2,070 4,435 47% Field 637 1,557 41% Truck 150 498 30% Pasture 2,752 8,336 33% Citrus 3 49 0% Vine 1,048 6,074 17% Total 11,879 64,580 18%
Notes: 1. Based on 1995/1996 DWR land use map.
DAU = Detailed Analysis Unit Table 4 ‐ 2002 Land Use Comparison Irrigated Acreage in the Study Area and DAU by Crop Eastern Turlock Subbasin units in acres
Estimated Portion of Crop Crop Type Study Area Land Use1 DAU Land Use1 Area in the Study Area
Almonds 5,552 41,622 13% Corn 1,771 5,256 34% Dry Bean ‐‐ 1,423 0% Grain 2,212 7,700 29% Deciduous 409 2,438 17% Field 711 2,523 28% Truck 234 2,082 11% Pasture 2,719 6,913 39% Citrus ‐‐ 83 0% Vine 1,782 6,768 26% Total 15,389 76,809 20%
Notes: 1. Based on 2002/2004 DWR land use map.
DAU = Detailed Analysis Unit Table 5 ‐ 2014 Land Use Comparison Irrigated Acreage in the Study Area and DAU by Crop Eastern Turlock Subbasin units in acres
Estimated Portion of Crop Crop Type Study Area Land Use1 DAU Land Use1 Area in the Study Area
Almonds 17,348 65,028 27% Corn 2,283 10,660 21% Dry Bean ‐‐ 138 0% Grain 2,220 5,391 41% Deciduous 2,282 6,338 36% Field 90 444 0% Truck 794 2,276 35% Pasture 6,862 12,432 55% Citrus ‐‐ 24 0% Vine 3,196 10,790 30% TOTAL 35,075 113,521 31%
Notes: 1. Based on 2014 County crop maps. Table 6 ‐ Percentage of DAU Irrigated Lands in the Study Area Eastern Turlock Subbasin
Year Almonds Corn Dry Bean Grain Deciduous Field Truck Pasture Citrus Vine
1995 1 7% 51% 6% 6% 47% 41% 30% 33% 0% 17% 1996 1 7% 51% 6% 6% 47% 41% 30% 33% 0% 17% 1997 8% 48% 5% 10% 42% 39% 27% 34% 0% 19% 1998 9% 45% 4% 14% 37% 37% 24% 35% 0% 20% 1999 10% 42% 3% 17% 32% 35% 21% 36% 0% 22% 2000 11% 39% 2% 21% 27% 32% 18% 37% 0% 23% 2001 12% 37% 1% 25% 22% 30% 14% 38% 0% 25% 2002 1 13% 34% 0% 29% 17% 28% 11% 39% 0% 26% 2003 14% 33% 0% 30% 18% 26% 13% 41% 0% 27% 2004 16% 32% 0% 31% 20% 23% 15% 42% 0% 27% 2005 17% 31% 0% 32% 22% 21% 17% 43% 0% 27% 2006 18% 30% 0% 33% 23% 19% 19% 45% 0% 27% 2007 19% 29% 0% 34% 25% 16% 21% 46% 0% 28% 2008 20% 28% 0% 35% 26% 14% 23% 47% 0% 28% 2009 21% 27% 0% 36% 28% 12% 25% 49% 0% 28% 2010 22% 26% 0% 37% 30% 9% 27% 50% 0% 29% 2011 23% 24% 0% 38% 31% 7% 29% 51% 0% 29% 2012 24% 23% 0% 39% 33% 5% 31% 53% 0% 29% 2013 26% 22% 0% 40% 34% 2% 33% 54% 0% 29% 2014 2 27% 21% 0% 41% 36% 0% 35% 55% 0% 30%
Notes: 1. Based on DWR land use maps. See Tables 2 and 3. 2. Based on County crop maps. See Table 4. Table 7 ‐ Total Irrigated Acreage in Study Area by Crop Eastern Turlock Subbasin units in acres
Year Almonds Corn Dry Bean Grain Deciduous Field Truck Pasture Citrus Vine Total
1995 1 4,354 2,390 134 157 2,108 ‐ 152 3,030 8 1,253 13,586 1996 1 4,354 2,390 134 157 2,108 ‐ 152 3,030 8 1,253 13,586 1997 1 4,354 2,390 134 157 2,108 ‐ 152 3,030 8 1,253 13,586 1998 3,261 2,572 76 1,083 1,505 73 262 2,985 ‐ 1,886 13,702 1999 3,682 2,282 39 1,030 1,269 345 372 2,713 ‐ 2,004 13,738 2000 4,052 2,207 26 1,825 1,096 ‐ 386 3,164 ‐ 2,120 14,875 2001 4,487 2,120 12 1,923 826 ‐ 360 2,794 ‐ 2,382 14,904 2002 1 7,271 425 ‐ 2,309 504 907 472 2,902 38 2,144 16,973 2003 6,280 1,509 ‐ 1,609 520 ‐ 973 2,757 ‐ 1,924 15,571 2004 7,109 1,769 ‐ 576 496 188 810 3,322 ‐ 1,747 16,016 2005 8,076 1,860 ‐ 538 506 169 978 3,742 ‐ 1,818 17,686 2006 9,543 2,115 ‐ 423 578 695 789 3,204 ‐ 1,981 19,328 2007 10,640 2,072 ‐ 295 655 624 790 2,957 ‐ 1,991 20,024 2008 12,126 2,225 ‐ 385 641 535 918 3,008 ‐ 2,029 21,869 2009 13,078 2,247 ‐ 521 648 469 1,268 3,047 ‐ 2,031 23,309 2010 15,488 2,268 ‐ 501 626 376 981 3,201 ‐ 2,099 25,540 2011 2 15,953 2,272 ‐ 931 1,040 304 934 4,116 ‐ 2,373 27,924 2012 2 16,418 2,275 ‐ 1,360 1,454 233 887 5,032 ‐ 2,648 30,308 2013 2 16,883 2,279 ‐ 1,790 1,868 161 841 5,947 ‐ 2,922 32,691 2014 3 17,348 2,283 ‐ 2,220 2,282 90 794 6,862 ‐ 3,196 35,075
Notes: 1. Based on DWR land use maps. 2. Based on linear interpolation from 2010 to 2014. 3. Based on 2014 County crop maps. Table 8a ‐ Calculated Crop Water Demand Eastern Turlock Subbasin units in acre feet per year per acre (AFY/ac)
Year Almonds Corn Dry Bean Grain Deciduous Field Truck Pasture Citrus Vine
1999 3.1 2.8 2.3 2.1 2.7 2.6 2.2 3.3 3.3 1.3 2000 3.0 2.7 2.2 2.1 2.6 2.6 2.2 3.3 3.2 1.3 2001 3.1 2.8 2.3 2.2 2.7 2.6 2.2 3.3 3.3 1.3 2002 3.0 2.7 2.2 2.1 2.6 2.5 2.1 3.2 3.2 1.3 2003 2.9 2.6 2.2 2.0 2.6 2.5 2.1 3.2 3.1 1.2 2004 3.0 2.7 2.2 2.2 2.6 2.6 2.2 3.3 3.2 1.3 2005 2.9 2.6 2.2 2.0 2.6 2.5 2.1 3.1 3.1 1.2 2006 2.8 2.5 2.0 1.9 2.5 2.4 2.0 3.0 2.9 1.2 2007 2.9 2.6 2.1 2.1 2.6 2.5 2.1 3.1 3.1 1.2 2008 2.8 2.6 2.1 2.1 2.5 2.4 2.1 3.1 3.1 1.2 2009 2.9 2.6 2.2 2.1 2.6 2.5 2.1 3.2 3.1 1.2 2010 2.8 2.6 2.1 2.0 2.5 2.5 2.0 3.1 3.0 1.2 2011 2.8 2.5 2.1 2.0 2.5 2.4 2.0 3.0 3.0 1.2 2012 2.8 2.5 2.1 1.9 2.5 2.4 2.0 3.1 3.0 1.2 2013 3.0 2.7 2.3 2.2 2.7 2.6 2.2 3.3 3.3 1.3 2014 1 3.1 2.7 2.3 2.2 2.7 2.6 2.2 3.4 3.3 1.3 Average 2.9 2.6 2.2 2.1 2.6 2.5 2.1 3.2 3.1 1.2
Notes: 1. 2014 applied water assumed to be the same as 2013. Table 8b‐ Calculated Applied Water (80 percent Irrigation Efficiency) Eastern Turlock Subbasin units in acre feet per year per acre (AFY/ac)
Year Almonds Corn Dry Bean Grain Deciduous Field Truck Pasture Citrus Vine
1999 3.7 3.3 2.7 2.6 3.3 3.2 2.6 4.0 3.9 1.6 2000 3.6 3.3 2.7 2.5 3.2 3.1 2.6 3.9 3.8 1.5 2001 3.7 3.3 2.7 2.6 3.3 3.1 2.6 4.0 3.9 1.6 2002 3.5 3.2 2.6 2.5 3.1 3.1 2.5 3.9 3.8 1.5 2003 3.5 3.1 2.6 2.5 3.1 3.0 2.5 3.8 3.8 1.5 2004 3.6 3.3 2.7 2.6 3.2 3.1 2.6 4.0 3.9 1.5 2005 3.5 3.1 2.6 2.4 3.1 3.0 2.5 3.8 3.7 1.5 2006 3.3 3.0 2.5 2.3 3.0 2.9 2.4 3.6 3.5 1.4 2007 3.5 3.1 2.6 2.5 3.1 2.9 2.5 3.8 3.8 1.5 2008 3.4 3.1 2.5 2.5 3.0 2.9 2.5 3.8 3.7 1.5 2009 3.5 3.2 2.6 2.5 3.1 3.0 2.5 3.8 3.8 1.5 2010 3.4 3.1 2.5 2.4 3.0 3.0 2.4 3.7 3.6 1.5 2011 3.3 3.0 2.5 2.3 3.0 2.9 2.4 3.6 3.6 1.4 2012 3.4 3.1 2.5 2.3 3.0 2.9 2.4 3.7 3.6 1.4 2013 3.7 3.3 2.7 2.7 3.3 3.1 2.6 4.0 4.0 1.6 2014 1 3.7 3.3 2.7 2.7 3.3 3.2 2.7 4.0 4.0 1.6 Average 3.5 3.2 2.6 2.5 3.1 3.0 2.5 3.8 3.8 1.5
Notes: 1. 2014 applied water assumed to be the same as 2013. Table 9 ‐ Agricultural Water Use Eastern Turlock Subbasin units in acre feet per year (AFY) Year Almonds Corn Dry Bean Grain Deciduous Field Truck Pasture Citrus Vine Total 1995 1 15,250 7,550 349 391 6,566 ‐ 382 11,566 32 1,868 43,954 1996 1 15,250 7,550 349 391 6,566 ‐ 382 11,566 32 1,868 43,954 1997 1 15,250 7,550 349 391 6,566 ‐ 382 11,566 32 1,868 43,954 1998 1 11,422 8,123 196 2,691 4,688 221 657 11,397 ‐ 2,811 42,206 1999 13,488 7,558 106 2,648 4,147 1,089 973 10,772 ‐ 3,142 43,924 2000 14,485 7,244 70 4,625 3,468 ‐ 995 12,378 ‐ 3,227 46,492 2001 16,612 6,998 32 5,040 2,703 ‐ 947 11,227 ‐ 3,815 47,374 2002 25,774 1,357 ‐ 5,814 1,584 2,775 1,201 11,231 143 3,219 53,098 2003 21,917 4,753 ‐ 3,946 1,625 ‐ 2,424 10,498 ‐ 2,827 47,989 2004 25,552 5,765 ‐ 1,514 1,568 582 2,112 13,133 ‐ 2,675 52,901 2005 28,041 5,849 ‐ 1,311 1,564 507 2,431 14,130 ‐ 2,693 56,525 2006 31,753 6,274 ‐ 965 1,721 1,989 1,858 11,514 ‐ 2,783 58,858 2007 36,803 6,392 ‐ 742 2,019 1,839 1,969 11,173 ‐ 2,933 63,870 2008 41,410 6,855 ‐ 974 1,920 1,572 2,289 11,327 ‐ 2,959 69,306 2009 45,821 7,127 ‐ 1,283 2,038 1,411 3,155 11,615 ‐ 3,015 75,465 2010 52,907 6,976 ‐ 1,203 1,882 1,110 2,400 11,878 ‐ 3,105 81,460 2011 53,429 6,850 ‐ 2,179 3,137 869 2,211 14,978 ‐ 3,363 87,017 2012 55,433 6,959 ‐ 3,107 4,424 682 2,110 18,423 ‐ 3,742 94,881 2013 61,730 7,473 ‐ 4,803 6,077 504 2,226 23,785 ‐ 4,562 111,159 2014 64,191 7,508 ‐ 5,927 7,509 284 2,109 27,777 ‐ 4,983 120,290
Notes: 1. Used average applied water use (from Table 7b). 2. Assumes irrigation efficiency of 80%. Table 10 ‐ Summary of Wells Constructed in the Study Area Eastern Turlock Subbasin
Number of Well Type Well Depth (ft) Static DTW Year New Wells domestic irrigation test monitoring dairy not specified Min Max Min Max 1995 5 3 2 180 375 47 122 1996 6 4 2 120 635 56 110 1997 21 7 5 2 6 1 30 720 72 185 1998 10 4 4 2 235 740 20 236 1999 1 1 650 not available 2000 5 3 2 300 560 86 192 2001 3 1 2 450 614 144 192 2002 4 2 1 1 150 620 90 160 2003 10 1 7 4 160 700 96 170 2004 11 7 4 162 660 58 175 2005 6 5 1 190 600 90 151 2006 11 1 5 5 175 620 116 206 2007 16 5 11 170 510 62 208 2008 19 4 14 1 160 520 20 216 2009 10 1 4 6 1 140 820 78 230 2010 4 2 2 265 530 25 177 2011 5 2 3 440 1680 128 2012 13 2 9 2 240 610 20 224 2013 4 4 360 617 204 235 Total 164 61 80 17 6 1 1
Notes: 1. One well specified as both domestic and irrigation. 2. DTW = depth to water Table 11 ‐ Groundwater Balance Eastern Turlock Subbasin units are in acre feet per year (AFY) 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Groundwater Inflows Infiltration from Precipitation (non‐ag) 0 7,374 9,131 6,354 3,957 6,976 8,658 7,560 1,388 7,095 2,833 12,284 5,416 3,536 0 **
Turlock Lake Leakage 1 27,307 27,433 27,605 27,852 28,021 28,183 28,109 28,021 28,484 28,970 29,716 30,359 30,519 31,354 31,616 32,205 Merced River Leakage 1 44,673 48,707 45,836 48,055 39,881 39,295 59,027 57,915 57,869 54,584 57,955 61,273 65,565 50,753 63,716 54,175 Tuolumne River Leakage 1 2,743 2,920 1,563 3,084 3,566 3,963 7,205 6,311 3,446 5,501 6,303 10,840 12,490 8,329 16,307 14,203 Irrigation Return Flows 1, 2 14,251 13,581 13,552 12,315 12,354 12,936 16,918 19,740 15,488 9,287 25,309 29,037 32,125 33,199 62,517 ** Domestic Return Flows 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42
Base Upflow 1 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 Eastern Boundary Subsurface Inflow 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 Total Groundwater Inflows 90,417 101,457 99,128 99,101 89,222 92,794 121,359 120,990 108,117 106,879 123,558 145,236 147,557 128,614 175,599 102,024 Groundwater Outflows Irrigation Pumping 43,924 46,492 47,374 53,098 47,989 52,901 56,525 58,858 63,870 69,306 75,465 81,460 87,017 94,881 111,159 120,290 Domestic Pumping 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45
Western Boundary Subsurface Outflow 1 50,410 54,002 52,697 55,347 49,319 48,063 63,639 61,734 54,135 46,623 55,320 61,953 58,340 46,953 58,742 32,783 Total Groundwater Outflows 94,380 100,538 100,116 108,490 97,353 101,009 120,210 120,637 118,050 115,974 130,830 143,458 145,402 141,878 169,946 153,118 Change in Storage Annual ‐3,962 919 ‐988 ‐9,388 ‐8,131 ‐8,215 1,149 353 ‐9,933 ‐9,095 ‐7,272 1,778 2,155 ‐13,264 5,653 ** Cumulative ‐3,962 ‐3,044 ‐4,032 ‐13,420 ‐21,551 ‐29,766 ‐28,617 ‐28,264 ‐38,197 ‐47,292 ‐54,564 ‐52,787 ‐50,632 ‐63,896 ‐58,243 **
Notes: 1. Based on model results: 1999 to 2012 based on Updated Baseline Model results; 2013 and 2014 based on Constant Future Pumping Model results. 2. Irrigation Return Flow is based on the model recharge minus the infiltration from precipitation (non‐ag) and domestic return flows. ** Incomplete Data Set Table 12 ‐ Simulated Pumping Wells, Updated Baseline Model Eastern Turlock Subbasin
Ground Depth of Screened Interval Surface Well Depth (ft) Begin Well Name X Y End Pumping Elevation (ft (ft) Pumping msl) Top Bottom PRVF‐001 6524368 2049073 220 388 256 388 1991 PRVF‐002 6526396 2047656 222 320 235 320 1991 PRVF‐003 6522799 2045989 197 388 256 388 1991 PRVF‐004 6525854 2045017 208 320 235 320 1991 PRVF‐005 6550024 2029492 320 660 340 660 1991 1999 PRVF‐006 6552703 2028350 278 590 270 590 1991 PRVF‐007 6534633 2023598 297 425 176 425 1991 PRVF‐008 6535831 2025664 277 389 148 389 1991 PRVF‐009 6515471 2031932 271 596 305 596 1991 1999 PRVF‐010 6521221 2036349 210 650 335 650 1991 1999 PRVF‐011 6559440 2025194 232 366 270 366 1991 PRVF‐012 6564042 2023040 248 320 235 320 1991 PRVF‐013 6570063 2006047 225 510 208 510 1991 PRVF‐014 6573542 2012790 299 398 189 398 1991 PRVF‐015 6546376 2000182 169 463 199 463 1991 PRVF‐016 6549042 1996265 171 463 199 463 1991 PRVF‐017 6567963 2022231 307 320 235 320 1991 PRVF‐018 6562136 2025626 215 320 235 320 1991 PRVF‐019 6570952 2020926 271 320 235 320 1991 2009 PRVF‐020 6538859 1994973 158 320 235 320 1991 PRVF‐021 6563084 2042105 329 333 120 333 1991 PRVF‐022 6549006 1999057 175 463 199 463 1991 PRVF‐023 6545675 1996172 167 463 199 463 1991 1999 PRVF‐024 6518308 2036279 236 650 335 650 1991 PRVF‐025 6523655 2035064 231 650 335 650 1991 PRVF‐026 6523169 2037668 201 650 335 650 1991 PRVF‐027 6517892 2032425 243 596 305 596 1991 PRVF‐028 6513100 2031140 274 740 365 740 1991 PRVF‐029 6552256 1997588 182 449 257 449 1991 PRVF‐030 6557002 2048068 247 401 221 401 1991 PRVF‐031 6549927 2037409 324 495 240 495 1991 PRVF‐032 6520804 2048488 198 388 256 388 1991 PRVF‐033 6526960 2052902 127 508 243 508 1991 PRVF‐034 6526431 2050800 149 508 243 508 1991 1999 PRVF‐035 6529531 2052500 137 508 243 508 1991 1999 PRVF‐036 6531597 2052567 176 320 235 320 1991 PRVF‐037 6559518 2050752 259 240 113 240 1991 1999 PRVF‐038 6546848 2049523 240 290 173 290 1991 PRVF‐039 6559001 2005482 202 375 225 375 1991 PRVF‐040 6545391 2002546 169 381 138 381 1991 PRVF‐041 6554113 1996299 184 449 257 449 1991 PRVF‐042 6564937 1997922 209 40 15 40 1991 PRVF‐043 6563394 1999909 209 40 15 40 1991 PRVF‐044 6554620 2003753 189 375 225 375 1991 PRVF‐045 6535563 2051768 223 620 310 620 1991 PRVF‐046 6544483 2049668 232 600 330 600 1991 PRVF‐047 6545471 2050448 241 600 330 600 1991 PRVF‐048 6547735 2049837 252 290 173 290 1991 PRVF‐049 6556310 2051018 167 240 113 240 1991 PRVF‐050 6557456 2049685 253 240 113 240 1991 PRVF‐051 6560894 2048206 274 401 221 401 1991 PRVF‐052 6551914 2041643 320 288 128 288 1991 PRVF‐053 6559876 2000599 198 40 15 40 1991 PRVF‐054 6600948 2009304 314 530 256 530 1991 2009 PRVF‐055 6604713 2013528 363 100 50 100 1991 1999 PRVF‐056 6606538 2018584 442 20 10 20 1991 1999 PRVF‐057 6600699 2016946 404 438 210 438 1991 PRVF‐058 6568207 2060197 312 75 50 75 1991 2009 PRVF‐059 6544563 2035452 285 170 120 170 1991 PRVF‐060 6578680 2037494 312 320 96 320 1991 1999 PRVF‐061 6549922 2005641 178 381 138 381 1991 PRVF‐062 6549227 2002168 176 381 138 381 1991 PRVF‐063 6553422 2006224 185 436 83 436 1991 2009 PRVF‐064 6556283 2000252 193 449 257 449 1991 PRVF‐065 6557172 2008668 199 436 83 436 1991 PRVF‐066 6562310 2002891 207 155 55 155 1991 2009 PRVF‐067 6564769 2002974 213 155 55 155 1991 2009 PRVF‐068 6579319 2013336 254 620 200 620 1991
Page 1 of 3 Table 12 ‐ Simulated Pumping Wells, Updated Baseline Model Eastern Turlock Subbasin
Ground Depth of Screened Interval Surface Well Depth (ft) Begin Well Name X Y End Pumping Elevation (ft (ft) Pumping msl) Top Bottom PRVF‐069 6581819 2012470 261 620 200 620 1991 2009 PRVF‐070 6575852 2012886 248 398 189 398 1991 PRVF‐071 6600082 2013139 336 438 210 438 1991 2009 PRVF‐072 6605082 2015436 379 100 50 100 1991 PRVF‐073 6605499 2018236 443 50 25 50 1991 1999 PRVF‐074 6599233 2024966 370 35 15 35 1991 PRVF‐075 6580897 2028935 274 327 152 327 1991 PRVF‐076 6577470 2039994 339 320 96 320 1991 2009 PRVF‐077 6565336 2056249 262 100 50 100 1991 2009 PRVF‐078 6568102 2063239 205 30 10 30 1991 PRVF‐079 6529280 2053492 134 508 243 508 1991 PRVF‐080 6557166 1995342 190 320 150 320 1991 PRVF‐081 6540994 2029452 279 334 154 334 1991 2009 PRVF‐082 6564172 2001279 210 40 15 40 1991 1999 PRVF‐083 6565585 2041513 325 333 120 333 1991 PRVF‐084 6564895 2012685 298 518 264 518 1991 PRVF‐085 6572159 2005503 230 60 35 60 1991 PRVF‐086 6564145 2015967 288 518 264 518 1991 PRVF‐087 6516784 2030647 267 596 305 596 1999 PRVF‐088 6519436 2035107 216 650 335 650 1999 PRVF‐089 6520576 2038189 209 650 335 650 1999 PRVF‐090 6523993 2045064 198 388 256 388 1999 PRVF‐091 6528193 2047513 233 320 235 320 1999 PRVF‐092 6529673 2047325 211 320 235 320 1999 PRVF‐093 6531517 2026488 271 425 176 425 1999 PRVF‐094 6532847 2024778 306 425 176 425 1999 PRVF‐095 6533798 2026773 272 425 176 425 1999 PRVF‐096 6537884 2022687 271 240 145 240 1999 PRVF‐097 6538248 2030180 250 334 154 334 1999 2009 PRVF‐098 6539025 2019930 249 240 145 240 1999 PRVF‐100 6541306 2022211 260 510 208 510 1999 PRVF‐101 6542827 2020025 262 510 208 510 1999 PRVF‐102 6543817 1998824 162 400 182 400 1999 PRVF‐103 6543862 2025980 270 667 345 667 1999 PRVF‐104 6544347 2022306 222 510 208 510 1999 PRVF‐105 6548868 2029189 314 660 340 660 1999 PRVF‐106 6551452 2003421 180 436 83 436 1999 PRVF‐107 6552684 2030022 280 590 270 590 1999 PRVF‐108 6556741 1996572 190 320 150 320 1999 2009 PRVF‐109 6558995 2000046 191 320 150 320 1999 PRVF‐110 6559520 2002825 200 375 225 375 1999 PRVF‐111 6561979 1997055 198 40 15 40 1999 PRVF‐112 6562950 2040245 354 333 120 333 1999 PRVF‐113 6563181 2044182 315 333 120 333 1999 PRVF‐114 6564211 2005436 212 155 55 155 1999 2009 PRVF‐115 6565728 2022972 258 320 235 320 1999 PRVF‐116 6570474 2005359 222 60 35 60 1999 PRVF‐117 6571420 2011638 282 512 322 512 1999 PRVF‐118 6571978 2019700 289 320 235 320 1999 PRVF‐119 6573129 2019780 282 398 189 398 1999 2009 PRVF‐120 6574011 2019059 313 398 189 398 1999 2009 PRVF‐121 6580118 2013156 256 620 200 620 1999 PRVF‐123 6520370 2045634 186 388 256 388 2009 PRVF‐124 6527937 2041561 223 603 242 603 2009 PRVF‐125 6530076 2039856 245 603 242 603 2009 PRVF‐126 6531060 2044264 282 603 242 603 2009 PRVF‐127 6531322 2030971 247 603 242 603 2009 PRVF‐128 6532248 2037115 262 603 242 603 2009 PRVF‐129 6533839 2029929 254 603 242 603 2009 PRVF‐130 6534303 2043427 303 603 242 603 2009 PRVF‐131 6534481 2040551 274 603 242 603 2009 PRVF‐132 6538342 2039662 313 603 242 603 2009 PRVF‐133 6539453 2040662 269 603 242 603 2009 PRVF‐134 6541116 2025443 255 667 345 667 1999 PRVF‐135 6541231 2037523 263 170 120 170 2009 PRVF‐136 6543203 2036912 264 170 120 170 2009 PRVF‐137 6544944 2029364 289 334 154 334 2009 PRVF‐138 6545009 2048356 278 600 330 600 2009
Page 2 of 3 Table 12 ‐ Simulated Pumping Wells, Updated Baseline Model Eastern Turlock Subbasin
Ground Depth of Screened Interval Surface Well Depth (ft) Begin Well Name X Y End Pumping Elevation (ft (ft) Pumping msl) Top Bottom PRVF‐139 6547528 2032070 283 660 340 660 2009 PRVF‐140 6549898 2032074 273 660 340 660 2009 PRVF‐141 6553631 2024895 256 565 250 565 2009 PRVF‐142 6556595 2041122 262 288 128 288 2009 PRVF‐143 6557891 2037521 318 420 135 420 2009 PRVF‐144 6559187 2031926 310 476 190 476 2009 PRVF‐145 6559273 2034964 325 420 135 420 2009 PRVF‐146 6560081 2040640 336 333 120 333 2009 PRVF‐147 6560894 2048206 273 401 221 401 2009 PRVF‐148 6563180 2032360 273 383 156 383 2009 PRVF‐149 6563407 2036522 309 333 120 333 2009 PRVF‐150 6568713 2024414 235 320 235 320 2009
Page 3 of 3 Table 13 ‐ Simulated Groundwater Budget, Updated Baseline Model Eastern Turlock Subbasin
Groundwater Inflows Groundwater Outflows Change in Storage Eastern Western Year Turlock Merced Tuolumne Total Total Boundary Base Irrigation Boundary Recharge Lake River River Groundwater Groundwater Annual Cumulative Subsurface Upflow Pumping Subsurface Leakage Leakage Leakage Inflows Outflows Inflow Outflow 1991 7,805 27,938 35,620 662 1,000 400 73,425 40,632 45,802 86,434 ‐13,009 ‐13,009 1992 18,588 28,179 42,385 2,509 1,000 400 93,061 40,459 57,064 97,523 ‐4,462 ‐17,472 1993 21,407 28,156 52,425 4,697 1,000 400 108,084 41,210 64,088 105,298 2,786 ‐14,685 1994 19,111 28,177 48,338 2,944 1,000 400 99,970 44,812 57,106 101,919 ‐1,948 ‐16,634 1995 22,511 27,822 58,398 8,551 1,000 400 118,683 43,954 65,699 109,654 9,029 ‐7,605 1996 24,129 27,653 51,525 5,546 1,000 400 110,253 43,954 61,103 105,057 5,195 ‐2,409 1997 15,786 27,556 51,769 5,654 1,000 400 102,165 43,954 60,703 104,658 ‐2,493 ‐4,902 1998 23,819 27,357 51,940 5,322 1,000 400 109,839 42,229 56,947 99,176 10,663 5,761 1999 14,293 27,307 44,673 2,743 1,000 400 90,417 43,924 50,410 94,335 ‐3,917 1,844 2000 20,998 27,433 48,707 2,920 1,000 400 101,457 46,492 54,002 100,494 964 2,807 2001 22,725 27,605 45,836 1,563 1,000 400 99,128 47,374 52,697 100,071 ‐943 1,864 2002 18,712 27,852 48,055 3,084 1,000 400 99,101 53,098 55,347 108,445 ‐9,343 ‐7,479 2003 16,353 28,021 39,881 3,566 1,000 400 89,222 47,989 49,319 97,308 ‐8,086 ‐15,565 2004 19,954 28,183 39,295 3,963 1,000 400 92,794 52,901 48,063 100,964 ‐8,170 ‐23,735 2005 25,618 28,109 59,027 7,205 1,000 400 121,359 56,525 63,639 120,165 1,194 ‐22,541 2006 27,342 28,021 57,915 6,311 1,000 400 120,990 58,858 61,734 120,591 398 ‐22,143 2007 16,918 28,484 57,869 3,446 1,000 400 108,117 63,870 54,135 118,005 ‐9,888 ‐32,031 2008 16,424 28,970 54,584 5,501 1,000 400 106,879 69,306 46,623 115,929 ‐9,050 ‐41,081 2009 28,184 29,716 57,955 6,303 1,000 400 123,558 75,465 55,320 130,785 ‐7,227 ‐48,309 2010 41,363 30,359 61,273 10,840 1,000 400 145,236 81,460 61,953 143,413 1,823 ‐46,486 2011 37,583 30,519 65,565 12,490 1,000 400 147,557 87,017 58,340 145,357 2,200 ‐44,286 2012 36,778 31,354 50,753 8,329 1,000 400 128,614 94,881 46,953 141,833 ‐13,219 ‐57,505 Total 2,389,909 2,447,414 ‐57,505 ‐‐
Notes: Base Upflow: 2,000 AFY uniformly distributed over the base of the model. Study Area is 20% of subbasin/model. Western Boundary Subsurface Outflow: not calculated by the model, based on the storage and other inflows and outflows. Change in Storage: calculated by the model. Table 14 ‐ Simulated Groundwater Budget, Constant Future Pumping Model (Scenario 1) Eastern Turlock Subbasin
Groundwater Inflows Groundwater Outflows Change in Storage Eastern Western Year Turlock Merced Tuolumne Total Total Boundary Base Irrigation Boundary Recharge Lake River River Groundwater Groundwater Annual Cumulative Subsurface Upflow Pumping Subsurface Leakage Leakage Leakage Inflows Outflows Inflow Outflow 1991 7,622 27,938 35,626 664 1,000 400 73,250 40,632 45,670 86,302 ‐13,051 ‐13,051 1992 18,377 28,183 42,411 2,517 1,000 400 92,888 40,459 56,932 97,392 ‐4,504 ‐17,555 1993 21,235 28,160 52,474 4,707 1,000 400 107,976 41,210 64,000 105,211 2,765 ‐14,790 1994 18,924 28,183 48,383 2,956 1,000 400 99,845 44,812 57,002 101,814 ‐1,969 ‐16,759 1995 22,411 27,827 58,448 8,576 1,000 400 118,662 43,954 65,679 109,633 9,029 ‐7,730 1996 24,142 27,659 51,554 5,558 1,000 400 110,314 43,954 61,164 105,118 5,195 ‐2,535 1997 15,800 27,563 51,787 5,661 1,000 400 102,210 43,954 60,728 104,682 ‐2,472 ‐5,007 1998 23,590 27,362 51,978 5,339 1,000 400 109,667 42,229 56,796 99,025 10,642 5,635 1999 14,211 27,311 44,702 2,758 1,000 400 90,382 43,924 50,375 94,299 ‐3,917 1,718 2000 21,108 27,435 48,727 2,932 1,000 400 101,602 46,492 54,084 100,575 1,027 2,744 2001 22,774 27,609 45,836 1,570 1,000 400 99,188 47,374 52,757 100,131 ‐943 1,802 2002 18,628 27,860 48,063 3,089 1,000 400 99,041 53,098 55,286 108,384 ‐9,343 ‐7,542 2003 16,508 28,021 39,883 3,571 1,000 400 89,384 47,989 49,481 97,470 ‐8,086 ‐15,628 2004 20,142 28,183 39,284 3,961 1,000 400 92,970 52,901 48,197 101,098 ‐8,128 ‐23,756 2005 25,439 28,109 59,014 7,209 1,000 400 121,171 56,525 63,493 120,019 1,152 ‐22,604 2006 27,550 28,026 57,897 6,311 1,000 400 121,183 58,858 61,865 120,722 461 ‐22,143 2007 17,004 28,484 57,847 3,443 1,000 400 108,178 63,870 54,196 118,066 ‐9,888 ‐32,031 2008 16,717 28,968 54,555 5,495 1,000 400 107,135 69,306 46,816 116,122 ‐8,987 ‐41,018 2009 28,262 29,710 57,914 6,296 1,000 400 123,581 75,465 55,344 130,809 ‐7,227 ‐48,246 2010 41,087 30,357 61,262 10,834 1,000 400 144,940 81,460 61,720 143,181 1,760 ‐46,486 2011 37,689 30,519 65,546 12,490 1,000 400 147,644 87,017 58,406 145,423 2,221 ‐44,265 2012 36,931 31,354 50,735 8,325 1,000 400 128,745 94,881 47,042 141,922 ‐13,177 ‐57,442 2013 62,559 31,616 63,716 16,307 1,000 400 175,599 111,159 58,742 169,901 5,698 ‐51,744 2014 41,684 32,205 54,175 14,203 1,000 400 143,667 120,290 32,783 153,073 ‐9,406 ‐61,150 2015 53,001 32,823 59,653 16,099 1,000 400 162,975 120,290 46,435 166,725 ‐3,750 ‐64,900 2016 55,224 33,422 55,443 12,891 1,000 400 158,380 120,290 42,615 162,905 ‐4,525 ‐69,425 2017 44,969 34,101 57,012 13,907 1,000 400 151,390 120,290 41,930 162,220 ‐10,831 ‐80,256 2018 44,655 34,528 44,614 16,651 1,000 400 141,848 120,290 33,898 154,187 ‐12,339 ‐92,595 2019 47,109 34,817 42,107 16,263 1,000 400 141,696 120,290 33,389 153,679 ‐11,983 ‐104,578 2020 58,558 34,560 69,212 24,525 1,000 400 188,255 120,290 66,142 186,432 1,823 ‐102,755 2021 62,538 34,201 69,390 20,958 1,000 400 188,487 120,290 65,830 186,120 2,367 ‐100,388 2022 37,349 34,807 66,612 13,191 1,000 400 153,358 120,290 43,312 163,602 ‐10,244 ‐110,632 2023 35,275 35,559 61,054 15,013 1,000 400 148,300 120,290 40,475 160,765 ‐12,465 ‐123,097 2024 48,882 36,049 65,190 16,369 1,000 400 167,890 120,290 55,331 175,621 ‐7,730 ‐130,827 2025 66,345 35,877 72,078 24,525 1,000 400 200,226 120,290 77,171 197,461 2,765 ‐128,062 2026 58,684 35,148 80,795 23,847 1,000 400 199,875 120,290 74,913 195,203 4,672 ‐123,390 2027 53,361 35,567 59,225 13,963 1,000 400 163,517 120,290 50,433 170,723 ‐7,206 ‐130,597 2028 68,676 35,163 78,206 25,307 1,000 400 208,753 120,290 75,182 195,471 13,282 ‐117,315 2029 41,246 35,056 64,115 19,278 1,000 400 161,095 120,290 44,932 165,222 ‐4,127 ‐121,442 2030 52,942 35,226 69,732 20,515 1,000 400 179,815 120,290 58,435 178,725 1,089 ‐120,352 2031 55,224 35,542 62,868 15,179 1,000 400 170,213 120,290 50,991 171,281 ‐1,068 ‐121,421 2032 44,969 36,081 62,896 15,362 1,000 400 160,708 120,290 48,525 168,815 ‐8,107 ‐129,528 2033 44,655 36,363 46,290 18,300 1,000 400 147,008 120,290 37,444 157,734 ‐10,726 ‐140,254 2034 47,109 36,495 42,862 17,877 1,000 400 145,743 120,290 36,054 156,344 ‐10,600 ‐150,854 2035 58,558 36,032 74,897 28,284 1,000 400 199,172 120,290 73,812 194,102 5,070 ‐145,785 2036 62,538 35,481 77,339 23,765 1,000 400 200,523 120,290 74,744 195,034 5,489 ‐140,296 2037 37,349 36,024 71,480 14,130 1,000 400 160,383 120,290 48,368 168,658 ‐8,275 ‐148,571 2038 35,275 36,761 63,921 15,739 1,000 400 153,097 120,290 43,931 164,221 ‐11,124 ‐159,695 2039 48,882 37,229 68,133 16,990 1,000 400 172,634 120,290 58,775 179,065 ‐6,431 ‐166,126 2040 66,345 36,956 76,709 26,804 1,000 400 208,214 120,290 83,064 203,354 4,860 ‐161,266 2041 58,684 36,078 88,188 25,846 1,000 400 210,197 120,290 82,491 202,781 7,416 ‐153,850 2042 53,361 36,449 62,162 14,631 1,000 400 168,004 120,290 53,706 173,996 ‐5,991 ‐159,841 Total 7,520,977 7,680,818 ‐159,841 ‐‐
Notes: Base Upflow: 2,000 AFY uniformly distributed over the base of the model. Study Area is 20% of subbasin/model. Western Boundary Subsurface Outflow: not calculated by the model, based on the storage and other inflows and outflows. Change in Storage: calculated by the model. Table 15 ‐ Simulated Groundwater Budget, Increased Future Pumping Model (Scenario 2) Eastern Turlock Subbasin
Groundwater Inflows Groundwater Outflows Change in Storage Eastern Western Year Turlock Merced Tuolumne Total Total Boundary Base Irrigation Boundary Recharge Lake River River Groundwater Groundwater Annual Cumulative Subsurface Upflow Pumping Subsurface Leakage Leakage Leakage Inflows Outflows Inflow Outflow 1991 7,622 27,938 35,626 664 1,000 400 73,250 40,632 45,670 86,302 ‐13,051 ‐13,051 1992 18,377 28,183 42,411 2,517 1,000 400 92,888 40,459 56,932 97,392 ‐4,504 ‐17,555 1993 21,235 28,160 52,474 4,707 1,000 400 107,976 41,210 64,000 105,211 2,765 ‐14,790 1994 18,924 28,183 48,383 2,956 1,000 400 99,845 44,812 57,002 101,814 ‐1,969 ‐16,759 1995 22,411 27,827 58,448 8,576 1,000 400 118,662 43,954 65,679 109,633 9,029 ‐7,730 1996 24,142 27,659 51,554 5,558 1,000 400 110,314 43,954 61,164 105,118 5,195 ‐2,535 1997 15,800 27,563 51,787 5,661 1,000 400 102,210 43,954 60,728 104,682 ‐2,472 ‐5,007 1998 23,590 27,362 51,978 5,339 1,000 400 109,667 42,229 56,796 99,025 10,642 5,635 1999 14,211 27,311 44,702 2,758 1,000 400 90,382 43,924 50,375 94,299 ‐3,917 1,718 2000 21,108 27,435 48,727 2,932 1,000 400 101,602 46,492 54,084 100,575 1,027 2,744 2001 22,774 27,609 45,836 1,570 1,000 400 99,188 47,374 52,757 100,131 ‐943 1,802 2002 18,628 27,860 48,063 3,089 1,000 400 99,041 53,098 55,286 108,384 ‐9,343 ‐7,542 2003 16,508 28,021 39,883 3,571 1,000 400 89,384 47,989 49,481 97,470 ‐8,086 ‐15,628 2004 20,142 28,183 39,284 3,961 1,000 400 92,970 52,901 48,197 101,098 ‐8,128 ‐23,756 2005 25,439 28,109 59,014 7,209 1,000 400 121,171 56,525 63,493 120,019 1,152 ‐22,604 2006 27,550 28,026 57,897 6,311 1,000 400 121,183 58,858 61,865 120,722 461 ‐22,143 2007 17,004 28,484 57,847 3,443 1,000 400 108,178 63,870 54,196 118,066 ‐9,888 ‐32,031 2008 16,717 28,968 54,555 5,495 1,000 400 107,135 69,306 46,816 116,122 ‐8,987 ‐41,018 2009 28,262 29,710 57,914 6,296 1,000 400 123,581 75,465 55,344 130,809 ‐7,227 ‐48,246 2010 41,087 30,357 61,262 10,834 1,000 400 144,940 81,460 61,720 143,181 1,760 ‐46,486 2011 37,689 30,519 65,546 12,490 1,000 400 147,644 87,017 58,406 145,423 2,221 ‐44,265 2012 36,931 31,354 50,735 8,325 1,000 400 128,745 94,881 47,042 141,922 ‐13,177 ‐57,442 2013 62,559 31,616 63,716 16,307 1,000 400 175,599 111,159 58,742 169,901 5,698 ‐51,744 2014 41,684 32,205 54,175 14,203 1,000 400 143,667 120,290 32,783 153,073 ‐9,406 ‐61,150 2015 57,449 33,114 59,230 16,101 1,000 400 167,294 129,255 42,690 171,945 ‐4,651 ‐65,801 2016 64,427 34,277 54,433 13,204 1,000 400 167,741 138,220 35,135 173,355 ‐5,614 ‐71,415 2017 56,706 35,469 57,772 14,604 1,000 400 165,952 147,185 31,147 178,332 ‐12,381 ‐83,796 2018 60,219 36,164 45,112 17,749 1,000 400 160,645 156,150 18,699 174,849 ‐14,203 ‐98,000 2019 67,388 36,569 42,842 17,455 1,000 400 165,653 165,115 15,077 180,191 ‐14,539 ‐112,538 2020 87,499 36,254 73,672 26,499 1,000 400 225,325 174,080 51,957 226,037 ‐712 ‐113,251 2021 98,173 35,796 77,621 22,193 1,000 400 235,182 183,045 51,509 234,554 628 ‐112,622 2022 64,555 36,512 72,710 14,178 1,000 400 189,355 192,010 11,801 203,810 ‐14,455 ‐127,077 2023 61,369 37,543 66,015 16,162 1,000 400 182,489 192,010 7,867 199,877 ‐17,388 ‐144,465 2024 82,279 38,320 71,187 17,737 1,000 400 210,922 192,010 30,393 222,402 ‐11,480 ‐155,945 2025 109,114 38,222 80,795 28,278 1,000 400 257,809 192,010 65,003 257,013 796 ‐155,149 2026 97,329 37,394 103,825 27,280 1,000 400 267,228 192,010 71,028 263,038 4,190 ‐150,959 2027 89,174 38,012 66,425 15,614 1,000 400 210,625 192,010 29,279 221,288 ‐10,663 ‐161,622 2028 112,696 37,639 102,051 29,878 1,000 400 283,665 192,010 77,933 269,943 13,722 ‐147,900 2029 69,959 37,595 76,584 22,333 1,000 400 207,871 192,010 23,801 215,810 ‐7,940 ‐155,840 2030 89,089 37,920 83,553 24,468 1,000 400 236,430 192,010 45,719 237,729 ‐1,299 ‐157,139 2031 92,039 38,414 72,799 17,371 1,000 400 222,023 192,010 33,931 225,940 ‐3,917 ‐161,056 2032 76,266 39,328 71,763 16,521 1,000 400 205,278 192,010 25,356 217,365 ‐12,088 ‐173,144 2033 75,783 39,908 48,699 20,105 1,000 400 185,895 192,010 9,556 201,565 ‐15,670 ‐188,814 2034 79,554 40,164 44,287 20,557 1,000 400 185,962 192,010 9,434 201,444 ‐15,481 ‐204,295 2035 97,147 39,506 85,276 35,383 1,000 400 258,711 192,010 63,999 256,009 2,702 ‐201,593 2036 103,264 38,766 97,617 28,701 1,000 400 269,748 192,010 72,543 264,552 5,195 ‐196,398 2037 64,555 39,541 82,590 15,937 1,000 400 204,024 192,010 24,584 216,594 ‐12,569 ‐208,967 2038 61,369 40,775 70,852 16,978 1,000 400 191,374 192,010 15,747 207,756 ‐16,382 ‐225,349 2039 82,279 41,609 76,152 18,376 1,000 400 219,816 192,010 38,050 230,060 ‐10,244 ‐235,593 2040 109,114 41,249 90,055 33,961 1,000 400 275,778 192,010 79,768 271,777 4,001 ‐231,592 2041 97,329 39,914 127,038 32,417 1,000 400 298,098 192,010 95,614 287,623 10,475 ‐221,117 2042 89,174 40,417 72,766 16,914 1,000 400 220,671 192,010 37,334 229,344 ‐8,673 ‐229,790 Total 8,780,784 9,010,574 ‐229,790 ‐‐
Notes: Base Upflow: 2,000 AFY uniformly distributed over the base of the model. Study Area is 20% of subbasin/model. Western Boundary Subsurface Outflow: not calculated by the model, based on the storage and other inflows and outflows. Change in Storage: calculated by the model. Table 16 ‐ Simulated Groundwater Budget, Decreased Future Pumping Model (Scenario 3) Eastern Turlock Subbasin
Groundwater Inflows Groundwater Outflows Change in Storage Eastern Western Year Turlock Merced Tuolumne Total Total Boundary Base Irrigation Boundary Recharge Lake River River Groundwater Groundwater Annual Cumulative Subsurface Upflow Pumping Subsurface Leakage Leakage Leakage Inflows Outflows Inflow Outflow 1991 7,622 27,938 35,626 664 1,000 400 73,250 40,632 45,670 86,301 ‐13,051 ‐13,051 1992 18,377 28,183 42,411 2,517 1,000 400 92,888 40,459 56,932 97,392 ‐4,504 ‐17,555 1993 21,235 28,160 52,474 4,707 1,000 400 107,976 41,210 64,001 105,211 2,765 ‐14,790 1994 18,924 28,183 48,383 2,956 1,000 400 99,845 44,812 57,002 101,814 ‐1,969 ‐16,759 1995 22,411 27,827 58,448 8,576 1,000 400 118,662 43,954 65,679 109,633 9,029 ‐7,730 1996 24,142 27,659 51,554 5,558 1,000 400 110,314 43,954 61,164 105,119 5,195 ‐2,535 1997 15,800 27,563 51,787 5,661 1,000 400 102,210 43,954 60,728 104,682 ‐2,472 ‐5,007 1998 23,590 27,362 51,978 5,339 1,000 400 109,667 42,229 56,796 99,025 10,642 5,635 1999 14,211 27,311 44,702 2,758 1,000 400 90,382 43,924 50,375 94,299 ‐3,917 1,718 2000 21,108 27,435 48,727 2,932 1,000 400 101,602 46,492 54,083 100,575 1,027 2,745 2001 22,774 27,609 45,836 1,570 1,000 400 99,188 47,374 52,758 100,131 ‐943 1,802 2002 18,628 27,860 48,063 3,089 1,000 400 99,041 53,098 55,286 108,384 ‐9,343 ‐7,541 2003 16,508 28,021 39,883 3,571 1,000 400 89,384 47,989 49,480 97,470 ‐8,086 ‐15,627 2004 20,142 28,183 39,284 3,961 1,000 400 92,970 52,901 48,197 101,098 ‐8,128 ‐23,755 2005 25,439 28,109 59,014 7,209 1,000 400 121,171 56,525 63,494 120,019 1,152 ‐22,603 2006 27,550 28,026 57,897 6,311 1,000 400 121,183 58,858 61,864 120,722 461 ‐22,142 2007 17,004 28,484 57,847 3,443 1,000 400 108,178 63,870 54,196 118,066 ‐9,888 ‐32,030 2008 16,717 28,968 54,555 5,495 1,000 400 107,135 69,306 46,816 116,122 ‐8,987 ‐41,017 2009 28,262 29,710 57,914 6,296 1,000 400 123,581 75,465 55,343 130,808 ‐7,227 ‐48,244 2010 41,087 30,357 61,262 10,834 1,000 400 144,940 81,460 61,720 143,180 1,760 ‐46,484 2011 37,689 30,519 65,546 12,490 1,000 400 147,644 87,017 58,406 145,423 2,221 ‐44,263 2012 36,931 31,354 50,735 8,325 1,000 400 128,745 94,881 47,042 141,922 ‐13,177 ‐57,440 2013 62,559 31,616 63,716 16,307 1,000 400 175,599 111,159 58,742 169,901 5,698 ‐51,742 2014 41,684 32,205 54,175 14,203 1,000 400 143,667 120,290 32,783 153,073 ‐9,406 ‐61,148 2015 53,001 32,823 59,653 16,099 1,000 400 162,975 120,290 46,435 166,725 ‐3,750 ‐64,898 2016 55,224 33,422 55,443 12,891 1,000 400 158,380 120,290 42,615 162,905 ‐4,525 ‐69,423 2017 44,969 34,101 57,012 13,907 1,000 400 151,390 120,290 41,931 162,221 ‐10,831 ‐80,254 2018 44,655 34,528 44,614 16,651 1,000 400 141,848 120,290 33,898 154,187 ‐12,339 ‐92,593 2019 47,109 34,817 42,107 16,263 1,000 400 141,696 120,290 33,390 153,679 ‐11,983 ‐104,576 2020 58,558 34,560 69,212 24,525 1,000 400 188,255 120,290 66,142 186,432 1,823 ‐102,753 2021 62,538 34,201 69,390 20,958 1,000 400 188,487 120,290 65,830 186,120 2,367 ‐100,386 2022 37,349 34,807 66,612 13,191 1,000 400 153,358 120,290 43,312 163,602 ‐10,244 ‐110,630 2023 35,275 35,559 61,054 15,013 1,000 400 148,300 120,290 40,475 160,765 ‐12,465 ‐123,095 2024 45,660 36,051 65,358 16,383 1,000 400 164,852 113,973 57,206 171,179 ‐6,327 ‐129,422 2025 58,321 35,720 72,937 23,129 1,000 400 191,506 107,656 80,331 187,987 3,519 ‐125,903 2026 47,745 34,803 83,205 20,959 1,000 400 188,111 101,339 81,074 182,413 5,698 ‐120,205 2027 40,015 34,983 60,624 12,090 1,000 400 149,111 95,022 58,907 153,929 ‐4,818 ‐125,023 2028 47,837 34,413 82,158 20,493 1,000 400 186,302 88,705 82,430 171,135 15,167 ‐109,856 2029 24,674 34,084 67,151 15,366 1,000 400 142,675 82,388 60,434 142,822 ‐147 ‐110,003 2030 29,232 33,837 73,299 15,793 1,000 400 153,561 76,071 73,049 149,120 4,441 ‐105,562 2031 28,266 33,596 65,902 11,829 1,000 400 140,993 69,754 68,306 138,060 2,933 ‐102,629 2032 18,638 33,447 65,716 12,338 1,000 400 131,540 63,437 71,705 135,143 ‐3,603 ‐106,232 2033 18,852 33,112 47,040 13,662 1,000 400 114,066 63,437 57,479 120,916 ‐6,850 ‐113,082 2034 19,624 32,821 43,402 12,630 1,000 400 109,877 63,437 53,667 117,104 ‐7,227 ‐120,309 2035 26,426 32,249 77,719 17,620 1,000 400 155,414 63,437 85,483 148,920 6,494 ‐113,815 2036 28,968 31,723 82,007 14,935 1,000 400 159,033 63,437 88,158 151,596 7,437 ‐106,378 2037 14,874 31,975 73,879 9,066 1,000 400 131,194 63,437 71,778 135,216 ‐4,022 ‐110,400 2038 13,042 32,280 65,150 10,627 1,000 400 122,499 63,437 66,017 129,454 ‐6,955 ‐117,355 2039 21,302 32,427 69,402 11,304 1,000 400 135,835 63,437 75,792 139,229 ‐3,394 ‐120,749 2040 31,354 32,203 78,425 15,261 1,000 400 158,642 63,437 90,093 153,530 5,112 ‐115,637 2041 26,922 31,625 90,132 15,031 1,000 400 165,109 63,437 93,710 157,148 7,961 ‐107,676 2042 24,106 31,847 63,178 8,686 1,000 400 129,217 63,437 69,508 132,946 ‐3,729 ‐111,405 Total 6,973,449 7,084,854 ‐111,405 ‐‐
Notes: Base Upflow: 2,000 AFY uniformly distributed over the base of the model. Study Area is 20% of subbasin/model. Western Boundary Subsurface Outflow: not calculated by the model, based on the storage and other inflows and outflows. Change in Storage: calculated by the model.
Don Pedro Reservoir
mne River Tuolu
132 T uolumne River
Hickman Ceres Study Hughson Modesto Area Turlock Eastside Irrigation District Water District Keyes
Denair
S a n Turlock J o a er q Riv 59 u ed in rc R e iv M e r Stanislaus County Legend Merced County Delhi District Area Hilmar Turlock ID iver 99 Eastside WD d R ce Merced ID er M Ballico-Cortez WD Non-District Area 165 Foothills Merced River "N San Joaquin River ( Tuolumne River 0 4 January 2016 Scale in Miles Figure 1 Study Area 6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1
"N 7 8 9 10 11 12 7 8 9 10 11 12 7 8 9 10 11 12
18 17 16 15 14 13 18 17 16 15 14 13 18 17 16 15 14 13 ( 03S 12E 03S 13E 0 4 03S 14E 19 20 21 22 23 24 19 20 21 22 23 24 19 20 21 22 23 24
Scale in Miles 30 29 28 27 26 25 30 29 28 27 26 25 30 29 28 27 26 25
31 32 33 34 35 36 31 32 33 34 35 36 31 32 33 34 35 36
6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1
7 8 9 10 11 12 7 8 9 10 11 12 7 8 9 10 11 12 7 8 9 10 11 12
18 17 16 15 14 13 18 17 16 15 14 13 18 17 16 15 14 13 18 17 16 15 14 13 04S 12E 04S 13E 04S 14E 04S 15E 19 20 21 22 23 24 19 20 21 22 23 24 19 20 21 22 23 24 19 20 21 22 23 24
30 29 28 27 26 25 30 29 28 27 26 25 30 29 28 27 26 25 30 29 28 27 26 25
31 32 33 34 35 36 31 32 33 34 35 36 31 32 33 34 35 36 31 32 33 34 35 36
6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1
7 8 9 10 11 12 7 8 9 10 11 12 7 8 9 10 11 12
18 17 16 15 14 13 18 17 16 15 14 13 18 17 16 15 14 13 05S 13E 05S 14E 05S 15E 19 20 21 22 23 24 19 20 21 22 23 24 19 20 21 22 23 24
Stanislaus County 30 29 28 27 26 25 30 29 28 27 26 25 30 29 28 27 26 25 Merced County 31 32 33 34 35 36 31 32 33 34 35 36 31 32 33 34 35 36
Legend County Line Study Area Turlock Subbasin January 2016 Figure 2 Township, Range, and Sections within Study Area "(N 0 4
Scale in Miles
Legend
Wells Outside of Study Area Inside of Study Area Study Area Turlock Subbasin
January 2016 Figure 3 Well Locations in Water Level Database Stanislaus County Merced County
Legend Major Crop Type County Citrus Study Area Deciduous/Almonds Turlock Lake DAU Field/Corn Turlock Subbasin Grain/Dry Bean Idle Pasture Rice Service Layer Credits: Truck "N Vine Water ( Urban 0 4
Scale in Miles
January 2016 Figure 4 1995 / 1996 DWR Land Use Map Stanislaus County Legend Merced County County Study Area Turlock Lake DAU Turlock Subbasin Major Crop Type Citrus Deciduous/Almonds Field/Corn Grain/Dry Bean Idle Pasture Truck Vine "N Water ( Urban 0 4
Scale in Miles January 2016 Service Layer Credits: Figure 5 2002 / 2004 DWR Land Use Map Stanislaus County Merced County
Legend
Major Crop Type County Citrus Study Area Deciduous/Almonds Field/Corn Turlock Lake DAU Grain/Dry Bean Turlock Subbasin Pasture Truck Vine "(N Water 0 4
Scale in Miles January 2016 Figure 6 2014 County Crop Map 160,000
Vine 140,000 Citrus Pasture Truck 120,000 Field Deciduous Grain
100,000 Dry Bean Corn Almonds
80,000 Agricultural Demand Agricultural (AFY) 60,000
40,000
20,000
- 0 1995 1 1996 1 1997 1 1998 1 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
January 2016 Figure 7 Notes: - Pumping estimates assume an 80% irrigation e ciency. Estimates of - 1995-1998 uses an average applied water use (from Table 6) Irrigation Pumping by Crop 24
22
20 irrigation domestic test monitoring dairy not specified
18
16
14
12
10 Numberof New Wells
8
6
4
2
0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
January 2016 Figure 8 New Wells Constructed from 1995 - 2013 La Grange *# USGS-11289650 "(N 0 2 132 Scale in Miles Tuolumne River
k Turloc Lake
Stanislaus County
Merced County 59
Irrigated Agriculture
Undeveloped
Snelling USGS-11270900 *# Dry Creek Merced Falls Legend Study Area Dredge County Tailings *# Stream Gage *# DWR-MSN
January 2016 Figure 9 Merced River 2014 Land Use Study Area Legend LGA Study Area (Approximate) January 2016 Figure 10 Oblique View Study Area SW NE SW NE 900 400 Turlock Subbasin Dry Creek Drainageway
600
Study Area 200
300 Elevation (feet MSL) (feet Elevation Elevation (feet MSL) (feet Elevation
0 0 0 100,000 200,000 0 30,000 60,000 Feet Feet Basin Profile 1 Study Area Profile 2 NW SE 600
Tuolumne River Dry Creek 400
Merced River
200 Elevation (feet MSL) (feet Elevation
0 0 30,000 60,000 Feet Study Area Profile 3 January 2016 Profile Location Map Figure 11 Topographic Profiles 19.5 15 15.5 15.25 19.5 19.25
15.5 14.75 "N 14.5 14.25 16
16.25 ( 0 2
Scale in Miles
15 21.25
14 21
15.75
14.5
14.25 16 13.5Legend Precipitation Contour (0.25-inch interval) 15.25 Turlock Subbasin 13.25 16 Turlock Lake 15.5 Study Area
13.75
County Line 14.75 January 2016 15.75 Figure 12 14.75 14.5 13 Average Annual Note: Based on PRISM Climate Data. 12.75 Isohyetal Map 1981 - 2010 14 18
CIMIS Stations: 148 (Merced): 1/4/99 - 8/27/02 16 168 (Denair): 8/28/02 - 4/8/09 206 (Denair II): 4/9/09 - 12/31/14
14
Turlock Long-term Average 12
10 on(inches)
8 Precipita ti
6
4
2
0 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
January 2016 Figure 13 Annual Precipitation 1999 - 2014 USGS 11289560 - Tuolumne River Discharge (cfs)
10,000
8,000
6,000
4,000
2,000
0 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015
Merced River Discharge (cfs)
10,000
11270900 (upstream) MSN (downstream) 8,000
6,000
4,000
2,000
0 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015
January 2016 Figure 14 Streamflow Hydrographs Study Area "(N 0 2
Scale in Miles
Legend Study Area
Restrictive Soil Layer Duripan Paralithic bedrock Lithic bedrock Bedrock January 2016 Figure 15 Soil Restrictive Layers "(N 0 2
Scale in Miles
Legend Study Area
Paralithic bedrock; Lithic bedrock Duripan Area
Soil Permeability (Ksat, in/hr) High to very high (5.95 to 19.98) High (1.98 to 5.95) Moderately high to high (0.57 to 1.98) Moderately high (0.20 to 0.57) Moderately low to moderately high (0.06 to 0.20) Very low to moderately low (0.00 to 0.06) January 2016 Very low (0.00) Figure 16 Water (NA) Soil Permeability Gravel Pit, Outcropping Bedrock/Terrace (NA) and Restrictive Layers "N A' ( 0 2
Scale in Miles
Legend Study Area A
A A'Cross Section
Geologic Units t Dredge Tailings PI Laguna Formation Q Alluvium Qr Riverbank Formation Qtl Turlock Lake Formation Tm Mehrten Formation Tvs Valley Springs Formation Ei Ione Formation Note: Only the geologic units shown on the cross section are listed in legend. February 2016 Source: Wagner, D.L., Bortugno, E.J., and McJunking, R.D., 1991, Figure 17 Geologic Map of the San Francisco-San Jose Quadrangle, Study Area California, 1:250,000. Geology ) 03S 12E 03S 13E ) )!( 03S 14E "N )!( ( 0 2 ) )!( ) )!( ) ) ) )!( Scale in Miles
)!( )!( )! )!( )!(!!!!(! )! ! )!
) )!( ) ) ) )!(!!! )!! !!!! ) !!! !!! ! ) )!( ) !( !( !( )! ) ! !! ! 04S 13E ) ) ! )!!!) ! ) ! !( 04S 15E ! ! !( ) ! !(! ! ! 04S 12E ) !( )!( ) ) ) 04S 14E
)! ! )!( )! )!( )!(!!! )
)!( ) )! )!(! ) ) )!( ) )! Legend ! !(! ! ! Year Constructed ) ) ) ) ) ) ) ) ) ) ) )!( ! 2005 - 2013 !( 1995 - 2004 )! ! ) ) ) ) ) ) 1951 - 1994 05S 13E )! )! ! )!(! !( ) ) 05S 14E 05S 15E January 2016 Figure 18 )! !!! )!(! )!( )!(! Note: Wells located in centroid of Section. Wells Constructed in Study Area 1951 - 2013 1950-1954 1955-1959 1960-1964 1965-1969 1970-1974 1975-1979 1980-1984 1985-1989 1990-1994 1995-1999 2000-2004 2005-2009 2010-2013 0
50
100
150
200
250 Depth (feet)
300
350
400
Average Well Depth 450
500
January 2016 Figure 19 Note: Based on well completion reports. Average Well Depths 100
Wells screened in other units 90 Wells screened in Mehrten black sands
80
70
60
50 c Capacity (gpm/foot) fi 40 Speci
30
20
10
0 0 100 200 300 400 500 600 700 800 900 Well Depth (feet)
January 2016 Note: Based on well completion report pumping test data. Figure 20 Specific Capacity vs. Well Depth A A’ Southwest Northeast 400 Laguna Turlock Lake Dredge Tailings ?
? 200 1971
2010-2013
Mehrten 0 Formation
Mehrten Black Sands
-200
Valley Springs
-400
0 10,000 20,000 30,000 40,000 50,000
January 2016 Figure 21 Geologic Cross Section A - A’ Northwest Model Column 131 Southeast 400
300
200
100
0
-100
-200
-300 Elevation (feet)
-400
-500
-600 % Coarse-grained sediment >50 percent -700 25 to 50 percent <25 percent
-800 96 100 105 110 115 120 125 130 135 140 145 150 Cross Model Row Section Location January 2016 Figure 22 Texture Data MERSTAN Model Legend USGS Texture Wells Percent coarse at 0 to 50 feet 0 - 20% 20 - 30% 30 - 40% 40 - 50% >50% Study Area County Line
"(N 0 2
Scale in Miles January 2016 Figure 23 Texture Data CVHM Model Depth of 0 to 50 Feet Legend USGS Texture Wells Percent coarse at 300 to 350 feet 0 - 20% 20 - 30% 30 - 40% 40 - 50% >50% Study Area County Line
"(N 0 2
Scale in Miles January 2016 Figure 24 Texture Data CVHM Model Depth of 300 to 350 Feet 300
04S12E03C001M 04S12E03J001M 04S12E09Q002M 04S12E16A001M 04S12E16A002M 04S12E21B001M 04S12E21G001M 04S12E21H001M 04S12E21M001M 04S12E25B001M 04S13E01B001M 04S13E01G001M 250 04S13E03D001M 04S13E11D001M 04S13E11G001M 04S13E12M001M 04S13E13D001M 04S13E14J001M 04S13E15D001M 04S13E17D001M 04S13E20M001M 04S13E23C001M 04S13E24G001M 04S13E27C001M 04S13E29P001M 04S13E30P001M 04S13E34H001M 04S14E08J001M 04S14E17J001M 04S14E18H001M 200 04S14E20G001M 04S14E21P001M 04S14E30H001M 04S14E32P001M 04S14E33H001M 05S13E16K001M 05S13E19Q001M 05S13E27D001M on on MSL) (feet
150 Groundwaterti Eleva
100
50
0 Jan-70 Jan-75 Jan-80 Jan-85 Jan-90 Jan-95 Jan-00 Jan-05 Jan-10
January 2016 Figure 25 Study Area Source: TID Water Level Database and DWR Data Library. Groundwater Elevations N
0 2 130 Scale in Miles 150 170 233.1 250 270 180.5 210 190 230 131.6 197.5 134.8 232 210.9 203.4 282.2 207.5 196.4 179.5 215.4 273.2 192.6
210.5 206.3 210 185
230 270 215.2 205.2
190 167.4 250
151.5 210 170 173.5 224.2 ? 230.7
?
150 130 January 2016 Figure 26 Groundwater Elevations Source: DWR/TID Database. March 1971 N
130 150 210 270 110 170 190 250 0 2 90 230 70 Scale in Miles
290 50 60
172
310 30 29 110
37 23 108 85 90 28 96 273
111 70 70 50 44
Source Well Completion Reports DWR/TID Database 152 210 (March 2011) 230 323 250 290
50 70 270 30 90 310 110
190
130 150 170
January 2016 Figure 27 Groundwater Elevations 2010 - 2013 "(N 0 2
Scale in Miles
Legend Study Area Water 2014 Crops Restrictive Layers Soil Water Holding Capacity (inches) 8 - 10 6 - 8 4 - 6 2 - 4 0 - 2 January 2016 Figure 28 Soil Water Holding Capacity 450
400
350
300 Turlock Lake
250
200 Elevation (Feet MSL) (Feet Elevation 150
100 Based on 2010-2013 groundwater elevations 50
0 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 55,000 60,000 Based on 2010-2013 Feet groundwater elevations
TOPOGRAPHIC PROFILE LOCATION
January 2016 Figure 29 Conceptual Profile Leakage from Turlock Lake "N Don Pedro ( Reservoir 0 4
Scale in Miles
mne River AëE Tuolu
Study Area
S a n J o a q u in r R ive iv R e d r ce er M
?yE AÎE Legend Model Area AhE Model Mesh January 2016 Study Area Figure 30 Model Area and Boundaries West East
Study Area San Joaquin San Joaquin River River Highway 99
Model Layers
January 2016 Adapted from Durbin, 2014. Figure 31 Model Layers and Study Area TID Model Updated Baseline Model
January 2016 Figure 32 Pumping Comparison, TID and Updated Baseline Models "(N 0 2
Scale in Miles
Legend Simulated Pumping Wells Turlock Subbasin January 2016 Figure 33 Study Area Simulated Pumping Wells in 2012, Updated Baseline Model "N ! ( 0 2 ! Scale in Miles ! ! ! !
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Legend ! ! Simulated Pumping Wells ! ! ! Year Added ! ! ! ! Updated Baseline Well ! ! ! 2015 ! ! ! ! ! ! 2016 ! 2017 ! ! ! 2018 ! ! 2019 ! 2020 ! ! ! 2021 ! January 2016 ! 2022 Figure 34 Turlock Subbasin Simulated Pumping Wells, Study Area Increased Future Pumping Model (Scenario 2) "N
! ( 0 2 ! ! ! ! ! ! ! Scale in Miles ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Legend ! ! ! Simulated Pumping Wells Year Removed Not Removed ! ! 2024 ! ! 2025 ! 2026 ! 2027 ! 2028 ! 2029 ! ! 2030 ! ! 2031 ! 2032 January 2016 Turlock Subbasin Figure 35 Study Area Simulated Pumping Wells, Decreased Future Pumping Model (Scenario 3) 0
January 2016 Figure 36 Total Pumping for Future Scenarios "(N 0 4
Scale in Miles
F
A G
E C H D
I
B J
Legend See Figure 9 January 2016 See Figures 9 and 12 Figure 37 See Figure 12 Calibration Well Locations A B 100 80
90 70
80 60
70 50
60 40
50 30 Groundwater Elevation Groundwater Elevation (ft) Groundwater Elevation Groundwater Elevation (ft) 40 20
30 10
20 0 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 C D 80 160
70 150
60 140
50 130
40 120
30 110 Groundwater Elevation Groundwater Elevation (ft) Groundwater Elevation Groundwater Elevation (ft) 20 100
10 90
0 80 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011
January 2016 Figure 38 Observed Observed and Simulated Updated Baseline Model Groundwater Hydrographs, Updated Baseline Model 1991 - 2012 30 -20 110 0 100 160 "N 110 120 ( 240 0 2 150 200 130 120 Scale in Miles 120 110 100
130 110 210 270 100 250 310 70 100 60 260 430 300
80 90 100 300
110 330 120 130 140 150 160 250 280 170 180 190 200 210 220
400 440 340 240 290
260 280 230 180 200 Legend 260 250 240 Simulated Groundwater Elevation, December 2012 270 280 Turlock Subbasin 290
Study Area 190 160 200
150
140
130
180
170 January 2016 Figure 39 Simulated Groundwater Elevation Map December 2012, Updated Baseline Model 150,000
100,000
50,000
0 Annual Water Budget
-50,000
-100,000
-150,000 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Natural and Irrigation Return Flow Turlock Lake Leakage Merced River Leakage Tuolumne River Leakage Eastern Boundary Subsurface Inflow Base Upflow Irrigation Pumping Western Boundary Subsurface Outflow Cumulative Storage Change January 2016 Figure 40 Simulated Water Budget, Updated Baseline Model 1991 - 2012 D E C 180 180 180
160 160 160
140 140 140
120 120 120
100 100 100
80 80 80
60 60 60 Groundwater Elevation Groundwater Elevation (ft) Groundwater Elevation Groundwater Elevation (ft)
Groundwater Elevation Groundwater Elevation (ft) 40 40 40
20 20 20
0 0 0 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 G H F 180 180 180
160 160 160 140 140 140 120 120 120 100 100 100 80 80 80 60 60 60 40 Groundwater Elevation Groundwater Elevation (ft) Groundwater Elevation Groundwater Elevation (ft)
Groundwater Elevation Groundwater Elevation (ft) 40 20 40
20 0 20
0 -20 0 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045
I J 240 180
220 160
200 Legend 140 180 Updated Baseline Model 120 160 Future Simulation 1
140 100 Future Simulation 2
120 80 Future Simulation 3
100 60 Observed
Groundwater Elevation Groundwater Elevation (ft) 80 Groundwater Elevation (ft) 40 60
20 40 January 2016 Figure 41 20 0 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 Simulated Groundwater Hydrographs for Future Scenarios 90 2014 110 2022
170 110 230 90 80
80 90 70
70 140 220 150 110 120 180 130 150
180 300 200
250 240
190
170 190
120 130
170 2032 90 2042
110 100 140 210 290 70
80 90 70 290 60 90 280 50 180 230
70 120 70 140 150
160 180 330 330 200 230 240 190 200
130
150
"N Legend ( Simulated Groundwater Elevation January 2016 Figure 42 0 2 Turlock Subbasin Simulated Groundwater Elevation Maps 2014-2042, Scale in Miles Study Area Constant Future Pumping Model (Scenario 1) 30 80
"N -10 ( -10 0 2
-30 Scale in Miles -40
-20 -20 0 -10
-30
0
-20 10
-20 -50 -10
Legend Simulated Drawdown, 2014 - 2042 Turlock Subbasin Study Area
-10 January 2016 Figure 43 Simulated Water Level Changes 2014 to 2042, Constant Future Pumping Model (Scenario 1) 250,000
200,000
150,000
100,000
50,000
0
-50,000 Annual Water Budget(AFY)
-100,000
-150,000
-200,000
-250,000 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
Natural and Irrigation Return Flow Turlock Lake Leakage Merced River Leakage Tuolumne River Leakage Eastern Boundary Subsurface Inflow Base Upflow Irrigation Pumping Western Boundary Subsurface Outflow Cumulative Storage Change January 2016 Figure 44 Simulated Water Budget, Constant Future Pumping Model (Scenario 1) 90 2014 90 2022
90 130 80 70 210 260 90
150 50 120
70 60 170
110 220 120 130 150 180 180 200
250
240
170 190 140 160
320 2032 2042
0 100 220 30 -50 -20 -80 250 270 160
40 210 170 -10 30 -30 240 180
140
340
0 230 60 50 100 230 240 150 230 110 90 200
120 130 130 110 120 150 "N Legend ( Simulated Groundwater Elevation January 2016 Figure 45 0 2 Turlock Subbasin Simulated Groundwater Elevation Maps 2014-2042, Scale in Miles Study Area Increased Future Pumping Model (Scenario 2) 270 70
290 "(N 0 2
-50 Scale in Miles -110 -100 -20 -30 -190
-10 -30 -40 -40 -170 -210 -200
-120 -90
-70 -20 -100 -120 -90 -170 -80 -130 -180
-70 -190 40 30 80 70
-150 -120 -140 -40 -110 0 -100 -80 Legend -90 -70 Simulated Drawdown, 2014-2042 -60 -40 Turlock Subbasin -50 Study Area -30
-20
January 2016 Figure 46 Simulated Water Level Changes 2014 to 2042, Increased Future Pumping Model (Scenario 2) 300,000
200,000
100,000
0 Annual Water Budget(AFY) -100,000
-200,000
-300,000 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
Natural and Irrigation Return Flow Turlock Lake Leakage Merced River Leakage Tuolumne River Leakage Eastern Boundary Subsurface Inflow Base Upflow Irrigation Pumping Western Boundary Subsurface Outflow Cumulative Storage Change January 2016 Figure 47 Simulated Water Budget, Increased Future Pumping Model (Scenario 2) 90 2014 110 2022
170 110 230 90 80
80 90 70
70 140 220 150 110 120 180 130 150
180 300 200
250 240
190
170 190
120 130
90 0 2032 60 2042
120 110 120 220 270 100 220 90 80 280 90 70 60 190 60 330 100
120
300 200 130 200 140 150 230
180 230 240 260 210 190 190
130 140 150 110 120 130 140 150 "N Legend ( Simulated Groundwater Elevation January 2016 Figure 48 0 2 Turlock Subbasin Simulated Groundwater Elevation Maps 2014-2042, Scale in Miles Study Area Decreased Future Pumping Model (Scenario 3) -40 -90 -20 -60 "(N 0 2
0 Scale in Miles
20
10 -20 -10 0
0 -10
10
-10 -20 -20
0
-30
-40
-30 -40
-10 -20
-10 -80 -50 Legend Simulated Drawdown, 2014-2042 -10 Turlock Subbasin Study Area
-10 January 2016 Figure 49 Simulated Water Level Changes 2014 to 2042, Decreased Future Pumping Model (Scenario 3) 250,000
200,000
150,000
100,000
50,000
0
-50,000 Annual Water Budget(AFY)
-100,000
-150,000
-200,000
-250,000 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
Natural and Irrigation Return Flow Turlock Lake Leakage Merced River Leakage Tuolumne River Leakage Eastern Boundary Subsurface Inflow Base Upflow Irrigation Pumping Western Boundary Subsurface Outflow Cumulative Storage Change January 2016 Figure 50 Simulated Water Budget, Decreased Future Pumping Model (Scenario 3)
44
APPENDIX A
Study Area Groundwater Level Measurements, Eastern Turlock Subbasin
Hydrogeologic Characterization of the Eastern Turlock Subbasin TODD GROUNDWATER
Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S12E03C001M 3/23/1971 195.5 63.9 131.6 04S12E03C001M 10/18/1971 195.5 67.0 128.5 04S12E03C001M 3/16/1972 195.5 68.0 127.5 04S12E03C001M 10/19/1972 195.5 71.4 124.1 04S12E03C001M 3/28/1973 195.5 68.4 127.1 04S12E03C001M 10/29/1976 195.5 78.5 117.0 04S12E03C001M 2/28/1977 195.5 76.5 119.0 04S12E03C001M 11/2/1977 195.5 79.5 116.0 04S12E03C001M 2/28/1978 195.5 77.0 118.5 04S12E03C001M 10/25/1978 195.5 81.0 114.5 04S12E03C001M 2/6/1979 195.5 78.0 117.5 04S12E03C001M 10/22/1979 195.5 70.0 125.5 04S12E03C001M 3/12/1980 195.5 79.0 116.5 04S12E03C001M 10/7/1980 195.5 83.0 112.5 04S12E03C001M 3/11/1981 195.5 79.0 116.5 04S12E03C001M 3/4/1982 195.5 80.0 115.5 04S12E03C001M 10/13/1982 195.5 90.0 105.5 04S12E03C001M 4/5/1983 195.5 78.0 117.5 04S12E03C001M 11/2/1983 195.5 85.0 110.5 04S12E03C001M 11/20/1984 195.5 84.0 111.5 04S12E03C001M 3/20/1985 195.5 83.0 112.5 04S12E03C001M 11/6/1985 195.5 86.0 109.5 04S12E03C001M 3/21/1986 195.5 81.0 114.5 04S12E03C001M 11/5/1986 195.5 87.0 108.5 04S12E03C001M 3/10/1987 195.5 86.5 109.0 04S12E03C001M 11/12/1987 195.5 88.5 107.0 04S12E03C001M 3/8/1988 195.5 87.5 108.0 04S12E03C001M 10/25/1988 195.5 93.5 102.0 04S12E03C001M 3/7/1989 195.5 89.5 106.0 04S12E03C001M 10/31/1989 195.5 94.5 101.0 04S12E03C001M 2/6/1990 195.5 90.5 105.0 04S12E03C001M 2/7/1991 195.5 90.5 105.0 04S12E03C001M 2/19/1992 195.5 90.5 105.0 04S12E03C001M 10/27/1992 195.5 95.5 100.0 04S12E03C001M 3/3/1993 195.5 90.5 105.0 04S12E03C001M 10/27/1993 195.5 92.5 103.0 04S12E03C001M 2/16/1994 195.5 91.5 104.0
Page 1 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S12E03C001M 11/2/1994 195.5 92.5 103.0 04S12E03C001M 3/7/1995 195.5 91.5 104.0 04S12E03C001M 11/8/1995 195.5 93.5 102.0 04S12E03C001M 11/27/1996 195.5 92.5 103.0 04S12E03C001M 3/11/1997 195.5 92.5 103.0 04S12E03C001M 11/6/1997 195.5 103.5 92.0 04S12E03C001M 4/7/1998 195.5 97.5 98.0 04S12E03C001M 11/3/1998 195.5 98.5 97.0 04S12E03C001M 3/4/1999 195.5 97.5 98.0 04S12E03C001M 11/3/1999 195.5 102.5 93.0 04S12E03C001M 3/21/2000 195.5 100.0 95.5 04S12E03C001M 11/7/2000 195.5 98.0 97.5 04S12E03C001M 3/7/2001 195.5 99.0 96.5 04S12E03C001M 11/7/2001 195.5 101.0 94.5 04S12E03C001M 3/14/2002 195.5 98.0 97.5 04S12E03C001M 3/25/2003 195.5 101.0 94.5 04S12E03C001M 3/30/2004 195.5 108.0 87.5 04S12E03C001M 3/23/2006 195.5 103.0 92.5 04S12E03C001M 11/21/2006 195.5 105.0 90.5 04S12E03C001M 3/22/2007 195.5 135.2 60.3 04S12E03C001M 3/26/2008 195.5 133.1 62.4 04S12E03C001M 12/9/2008 195.5 118.0 77.5 04S12E03C001M 4/27/2009 195.5 158.3 37.2 04S12E03C001M 11/23/2009 195.5 139.8 55.7 04S12E03C001M 5/11/2010 195.5 134.1 61.4 04S12E03C001M 3/15/2011 195.5 135.6 59.9 04S12E03C001M 11/15/2011 195.5 124.8 70.7 04S12E03J001M 3/23/1971 194.0 59.2 134.8 04S12E03J001M 10/18/1971 194.0 64.2 129.8 04S12E03J001M 3/16/1972 194.0 68.1 125.9 04S12E03J001M 10/19/1972 194.0 65.4 128.6 04S12E03J001M 3/28/1973 194.0 73.0 121.0 04S12E03J001M 4/11/1974 194.0 67.0 127.0 04S12E03J001M 3/25/1975 194.0 67.0 127.0 04S12E03J001M 2/25/1976 194.0 70.0 124.0 04S12E03J001M 2/28/1977 194.0 72.0 122.0 04S12E09Q002M 10/8/1975 221.0 105.0 116.0
Page 2 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S12E09Q002M 2/25/1976 221.0 100.0 121.0 04S12E09Q002M 8/6/1976 221.0 109.0 112.0 04S12E09Q002M 10/29/1976 221.0 105.0 116.0 04S12E09Q002M 2/28/1977 221.0 105.0 116.0 04S12E09Q002M 7/13/1977 221.0 109.0 112.0 04S12E09Q002M 8/24/1977 221.0 109.0 112.0 04S12E09Q002M 11/8/1977 221.0 109.0 112.0 04S12E09Q002M 2/28/1978 221.0 104.0 117.0 04S12E09Q002M 10/26/1978 221.0 105.0 116.0 04S12E09Q002M 10/7/1980 221.0 113.0 108.0 04S12E16A001M 4/11/1974 210.0 89.0 121.0 04S12E16A001M 3/26/1975 210.0 98.5 111.5 04S12E16A001M 10/8/1975 210.0 96.0 114.0 04S12E16A001M 2/25/1976 210.0 94.0 116.0 04S12E16A001M 8/6/1976 210.0 97.0 113.0 04S12E16A001M 10/29/1976 210.0 97.0 113.0 04S12E16A001M 2/28/1977 210.0 98.0 112.0 04S12E16A001M 7/13/1977 210.0 99.0 111.0 04S12E16A001M 8/24/1977 210.0 100.0 110.0 04S12E16A002M 2/28/1978 210.0 98.0 112.0 04S12E16A002M 10/26/1978 210.0 100.0 110.0 04S12E16A002M 2/6/1979 210.0 100.0 110.0 04S12E16A002M 10/23/1979 210.0 103.0 107.0 04S12E16A002M 3/13/1980 210.0 102.0 108.0 04S12E16A002M 10/7/1980 210.0 108.0 102.0 04S12E16A002M 3/11/1981 210.0 102.0 108.0 04S12E16A002M 10/8/1981 210.0 109.0 101.0 04S12E16A002M 3/25/1982 210.0 100.0 110.0 04S12E16A002M 10/13/1982 210.0 109.0 101.0 04S12E16A002M 4/5/1983 210.0 101.0 109.0 04S12E16A002M 11/2/1983 210.0 104.0 106.0 04S12E21B001M 4/14/1999 272.3 207.0 65.3 04S12E21B001M 11/3/1999 272.3 215.0 57.3 04S12E21B001M 3/21/2000 272.3 204.0 68.3 04S12E21B001M 3/7/2001 272.3 205.0 67.3 04S12E21B001M 4/21/2005 272.3 213.0 59.3 04S12E21B001M 3/13/2006 272.3 215.0 57.3
Page 3 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S12E21B001M 11/21/2006 272.3 220.0 52.3 04S12E21B001M 3/22/2007 272.3 223.0 49.3 04S12E21B001M 3/26/2008 272.3 224.0 48.3 04S12E21B001M 12/9/2008 272.3 229.0 43.3 04S12E21B001M 3/29/2011 272.3 235.7 36.6 04S12E21B001M 11/15/2011 272.3 236.0 36.3 04S12E21G001M 10/8/1975 253.6 161.0 92.6 04S12E21G001M 2/25/1976 253.6 156.0 97.6 04S12E21G001M 8/6/1976 253.6 166.0 87.6 04S12E21G001M 10/29/1976 253.6 163.0 90.6 04S12E21G001M 2/28/1977 253.6 161.0 92.6 04S12E21G001M 7/13/1977 253.6 170.0 83.6 04S12E21G001M 8/24/1977 253.6 168.0 85.6 04S12E21G001M 11/8/1977 253.6 167.0 86.6 04S12E21G001M 2/28/1978 253.6 160.0 93.6 04S12E21G001M 10/26/1978 253.6 162.0 91.6 04S12E21G001M 10/23/1979 253.6 161.0 92.6 04S12E21G001M 10/7/1980 253.6 172.0 81.6 04S12E21H001M 4/14/1999 247.0 197.0 50.0 04S12E21H001M 11/3/1999 247.0 208.0 39.0 04S12E21H001M 3/21/2000 247.0 202.0 45.0 04S12E21H001M 3/7/2001 247.0 201.0 46.0 04S12E21H001M 4/21/2005 247.0 211.0 36.0 04S12E21H001M 3/13/2006 247.0 215.0 32.0 04S12E21H001M 11/21/2006 247.0 219.0 28.0 04S12E21H001M 3/22/2007 247.0 218.0 29.0 04S12E21H001M 3/26/2008 247.0 220.0 27.0 04S12E21H001M 12/9/2008 247.0 226.0 21.0 04S12E21H001M 3/29/2011 247.0 224.5 22.5 04S12E21H001M 11/15/2011 247.0 233.0 14.0 04S12E21M001M 4/14/1999 249.3 194.0 55.3 04S12E21M001M 11/3/1999 249.3 204.0 45.3 04S12E21M001M 3/21/2000 249.3 193.0 56.3 04S12E21M001M 3/7/2001 249.3 194.0 55.3 04S12E21M001M 4/21/2005 249.3 202.0 47.3 04S12E21M001M 11/21/2006 249.3 210.0 39.3 04S12E21M001M 3/26/2008 249.3 212.0 37.3
Page 4 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S12E21M001M 12/9/2008 249.3 217.0 32.3 04S12E21M001M 3/29/2011 249.3 221.1 28.2 04S12E25B001M 11/8/1977 233.5 101.5 132.0 04S12E25B001M 10/8/1980 233.5 109.0 124.5 04S12E25B001M 10/8/1981 233.5 110.0 123.5 04S13E01B001M 3/23/1971 312.8 79.7 233.1 04S13E01G001M 3/23/1971 277.0 79.5 197.5 04S13E01G001M 10/18/1971 277.0 79.5 197.5 04S13E03D001M 2/11/1964 272.5 74.8 197.7 04S13E03D001M 3/22/1965 272.5 71.9 200.6 04S13E03D001M 3/22/1966 272.5 73.0 199.5 04S13E03D001M 3/12/1971 272.5 92.0 180.5 04S13E03D001M 10/11/1971 272.5 74.2 198.3 04S13E03D001M 3/16/1972 272.5 89.2 183.3 04S13E03D001M 4/15/1973 272.5 77.5 195.0 04S13E03D001M 10/7/1975 272.5 79.0 193.5 04S13E11D001M 3/23/1971 255.0 44.1 210.9 04S13E11D001M 10/18/1971 255.0 45.7 209.3 04S13E11D001M 3/21/1972 255.0 47.9 207.1 04S13E11D001M 10/7/1975 255.0 46.0 209.0 04S13E11G001M 3/18/1971 296.3 64.3 232.0 04S13E11G001M 10/20/1971 296.3 75.8 220.5 04S13E12M001M 3/18/1971 391.5 188.1 203.4 04S13E12M001M 10/20/1971 391.5 197.0 194.5 04S13E13D001M 3/18/1971 368.0 160.5 207.5 04S13E13D001M 10/20/1971 368.0 167.9 200.1 04S13E14J001M 3/18/1971 300.8 121.3 179.5 04S13E14J001M 10/20/1971 300.8 145.4 155.4 04S13E14J001M 10/9/1975 300.8 116.8 184.0 04S13E15D001M 3/18/1971 292.5 96.1 196.4 04S13E15D001M 10/7/1975 292.5 100.5 192.0 04S13E17D001M 10/29/1976 265.8 2.8 263.0 04S13E20M001M 10/7/1975 295.0 137.0 158.0 04S13E20M001M 10/29/1976 295.0 139.0 156.0 04S13E23C001M 3/17/1971 325.0 132.4 192.6 04S13E23C001M 10/9/1975 325.0 132.0 193.0 04S13E24G001M 3/16/1971 328.3 117.8 210.5
Page 5 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S13E24G001M 10/20/1971 328.3 141.4 186.9 04S13E27C001M 3/23/1971 271.0 86.0 185.0 04S13E27C001M 10/18/1971 271.0 89.7 181.3 04S13E27C001M 3/21/1972 271.0 94.8 176.2 04S13E29P001M 3/23/1971 246.0 78.6 167.4 04S13E29P001M 10/18/1971 246.0 91.0 155.0 04S13E29P001M 3/21/1972 246.0 87.4 158.6 04S13E29P001M 10/19/1972 246.0 90.0 156.0 04S13E29P001M 10/9/1975 246.0 89.0 157.0 04S13E30P001M 3/18/1971 325.0 173.5 151.5 04S13E30P001M 10/18/1971 325.0 176.1 148.9 04S13E30P001M 3/21/1972 325.0 186.7 138.3 04S13E30P001M 10/19/1972 325.0 194.8 130.2 04S13E30P001M 10/9/1975 325.0 187.0 138.0 04S13E30P001M 2/25/1976 325.0 184.0 141.0 04S13E30P001M 8/6/1976 325.0 189.0 136.0 04S13E30P001M 10/29/1976 325.0 190.0 135.0 04S13E30P001M 3/2/1977 325.0 196.0 129.0 04S13E30P001M 7/1/1977 325.0 192.0 133.0 04S13E30P001M 8/24/1977 325.0 215.0 110.0 04S13E30P001M 11/7/1977 325.0 207.0 118.0 04S13E30P001M 3/1/1978 325.0 197.0 128.0 04S13E34H001M 3/18/1971 205.0 31.5 173.5 04S13E34H001M 10/20/1971 205.0 17.7 187.3 04S14E08J001M 3/16/1971 361.5 79.3 282.2 04S14E08J001M 10/21/1971 361.5 80.7 280.8 04S14E17J001M 3/16/1971 307.0 33.8 273.2 04S14E17J001M 10/21/1971 307.0 34.9 272.1 04S14E18H001M 3/16/1971 316.0 100.6 215.4 04S14E18H001M 10/20/1971 316.0 87.7 228.3 04S14E20G001M 3/16/1971 304.5 98.2 206.3 04S14E20G001M 10/21/1971 304.5 95.8 208.7 04S14E21P001M 3/16/1971 259.0 53.8 205.2 04S14E21P001M 10/9/1975 259.0 85.0 174.0 04S14E30H001M 3/16/1971 250.0 34.8 215.2 04S14E30H001M 10/21/1971 250.0 37.1 212.9 04S14E30H001M 3/22/1972 250.0 37.7 212.3
Page 6 of 7 Appendix A ‐ Study Area Groundwater Level Measurements Eastern Turlock Subbasin
Source: DWR/TID database
Depth to Reference Point Groundwater Groundwater Below State Well No. Date Elevation Elevation Reference Point (feet msl) (feet msl) (feet) 04S14E30H001M 10/9/1975 250.0 41.0 209.0 04S14E32P001M 3/17/1971 331.0 100.3 230.7 04S14E32P001M 10/21/1971 331.0 103.1 227.9 04S14E32P001M 10/9/1975 331.0 117.0 214.0 04S14E33H001M 3/17/1971 293.0 68.8 224.2 04S14E33H001M 10/21/1971 293.0 71.1 221.9 05S13E16K001M 10/6/1975 172.0 25.0 147.0 05S13E19Q001M 10/6/1975 217.0 78.0 139.0 05S13E19Q001M 11/3/1977 217.0 79.0 138.0 05S13E27D001M 10/6/1975 172.0 20.0 152.0
Page 7 of 7
APPENDIX B
Project Costs and Deliverable Schedule
Hydrogeologic Characterization of the [Grab your Eastern Turlock Subbasin reader’s 44 TODD GROUNDWATER attention with Appendix B Project Costs and Deliverable Schedule
Cost and Disposition of Funds ORIGINAL Invoice Amount Amount of Check Date of Invoice Date Check Received Professional and Received from Submitted to DWR Personnel Services Total from DWR Consultant Services DWR 04/08/14$ 745.00 $ 46,326.56 $ 47,071.56 7/21/2014$ 44,717.98 04/08/14$ 64.14 $ 8,835.75 $ 8,899.89 10/16/2014$ 8,454.90 07/01/14 $ ‐ $ 17,692.00 $ 17,692.00 2/23/2015$ 16,807.40 05/05/15 $ ‐ $ 21,726.25 $ 21,726.25 7/2/2015$ 20,639.94 08/18/15 $ ‐ $ 5,829.00 $ 5,829.00 10/9/2015$ 5,537.55 11/04/15 $ ‐ $ 39,235.75 $ 39,235.75 1/8/2016$ 37,273.96 02/01/16 $ ‐ $ 14,657.75 $ 14,657.75 Not received yet Not received yet 03/23/16 $ 2,310.86 $ 1,026.94 $ 3,337.80 Not received yet Not received yet $ ‐ $ ‐ $ ‐ $ ‐ $ ‐ $ ‐ Total $ 3,120.00 $ 155,330.00 $ 158,450.00 $ 133,431.73 Grant Budget (ORIGINAL) $ 2,850.00 $ 155,600.00 $ 158,450.00 Remaining $ (270.00) $ 270.00 $ ‐
REVISED Invoice Amount Amount of Check Date of Invoice Date Check Received Professional and Received from Submitted to DWR Personnel Services Total from DWR Consultant Services DWR 04/08/14$ 745.00 $ 46,326.56 $ 47,071.56 7/21/2014$ 44,717.98 04/08/14$ 64.14 $ 8,835.75 $ 8,899.89 10/16/2014$ 8,454.90 07/01/14 $ ‐ $ 17,692.00 $ 17,692.00 2/23/2015$ 16,807.40 05/05/15 $ ‐ $ 21,726.25 $ 21,726.25 7/2/2015$ 20,639.94 08/18/15 $ ‐ $ 5,829.00 $ 5,829.00 10/9/2015$ 5,537.55 11/04/15 $ ‐ $ 39,235.75 $ 39,235.75 1/8/2016$ 37,273.96 02/01/16 $ ‐ $ 14,657.75 $ 14,657.75 Not received yet Not received yet 03/23/16 $ 2,310.86 $ 1,026.94 $ 3,337.80 Not received yet Not received yet $ ‐ $ ‐ $ ‐ $ ‐ $ ‐ $ ‐ Total $ 3,120.00 $ 155,330.00 $ 158,450.00 $ 133,431.73 Grant Budget (REVISED) $ 3,120.00 $ 155,330.00 $ 158,450.00 Remaining $ ‐ $ ‐ $ ‐
*To ensure the use of the total funded grant amount, it was requested to transfer $270.00 from “Professional and Consultant Services” to “Personnel Services”.
Additional Project Information Grant Agreement Requirement: Discussion of problems that occurred during the work and how those problems were resolved. Response: The project went very smoothly and there were no major problems. The most challenging issue that was encountered involved the decision to use Turlock Irrigation District’s numerical model instead of the USGS model for Task 4: Evaluate and Apply Numerical Model to Land Use Analysis. The work plan described that the project would rely on the USGS model for this task. However, because the USGS model only covers two‐thirds of the Turlock Subbasin and the eastern‐most boundary is a no‐ flow boundary, it was decided that Turlock Irrigation District’s (TID) numerical model for the entire subbasin would be a more appropriate tool.
Grant Agreement Requirement: Discussion of factors that positively or negatively affected the project cost and any deviation from the original project cost estimate.
Response: The project cost estimate of $158,450 was met. There were no cost deviations.
Reports and/or Products The following is a summary of major deliverables.
Deliverable Name Deliverable Date Date Submitted to DWR Description
Technical Memorandum No. 1, Hydrogeologic April 30, 2014 This technical memorandum describes the data collection Characterization of the Eastern Turlock April 21, 2014 (per agreed upon schedule) efforts. Subbasin, Turlock LGA Project
Technical Memorandum No. 2, Land Use August 29, 2014 This technical memorandum describes the analysis of current Analysis, Hydrogeologic Characterization of the August 28, 2014 (per agreed upon schedule) and historical land use and agricultural water use. Eastern Turlock Subbasin, Turlock LGA Project
Technical Memorandum No. 3, Hydrogeologic This technical memorandum describes the development of Conceptual Model, Hydrogeologic April 3, 2015 April 3, 2015 the hydrogeologic conceptual model. It also contains a Characterization of the Eastern Turlock (per agreed upon schedule) revised Technical Memorandum No. 2 as Appendix A. Subbasin, Turlock LGA Project Technical Memorandum No. 4, Numerical This technical memorandum describes the development and Model Simulations, Hydrogeologic November 18, 2015 February 3, 2016 application of a numerical groundwater flow model to Characterization of the Eastern Turlock evaluate groundwater resources. Subbasin, Turlock LGA Project
Final Report, Hydrogeologic Characterization of This is the final report which synthesizes the information March 2016 March 16, 2016 the Eastern Turlock Subbasin presented in the four Technical Memoranda.