Salt and Nitrate Sources Pilot Implementation Study Report Summary Central Valley Salinity Coalition Salt and Nitrate Sources Pilot Implementation Study Report Summary March 11, 2010 Re-formatted team list. Larry Walker Associates Systech Water Resources, Inc. Luhdorff & Scalmanini Consulting Engineers NewFields Agricultural and Environmental Resources

Overall Study Goals Develop and document procedures and methodologies to quantify, fairly and equitably, the significant salt and nitrate sources in the Central Valley. Pilot procedures in selected areas to evaluate the appropriateness and region-wide applicability of the procedures. Provide guidance on approaches and tools to accomplish better salt and nutrient management

Selected Pilot Areas Yolo - Active CVHM area Modesto Cache-Putah Subbasins - Mix of urban, rural, ag - Mix of SW & GW supplies Modesto - Parts of Modesto, Turlock, & Delta Mendota Subbasins - Urban with food processing, rural, ag - Mix of SW & GW supplies Tule River - Entire Tule Subbasin, also parts of Tulare Lake and Kaweah Subbasins - Mostly ag land, some urban - Mix of SW & GW supplies 3 sections to survey 3

Pilot Area Comparisons Characteristic Yolo Modesto Tule River Central Valley Area (acres) 720,778 548,201 871,083 26,880,000 Population 165,000 523,000 178,000 6,500,000

Specific Study Objectives Define salt and nutrient sources of significance. Provide methods and manner of collection, characterization, and use of the salt and nutrient source data for the pilot areas. Outline data currently available and the quality of the data. ID additional data that should be collected or developed. Indicate how methodology accounts for total salt loading balance and accumulation and ID critical concentration discharges.

Specific Study Objectives Ensure accurate accounting of all sources. ID how historic, current, and future source quantities will be determined or estimated to provide trend information. ID and quantify areas where NO3 impacting beneficial uses of waters. Select analytical tools and methods that work for the pilot areas as well as other parts of the Central Valley.

Potentially Signif. Salt & NO3 Sources/Sinks SW upstream inflow SW outflow Imported SW SW diversions Irrigation Near-surface GW Fertilizer Deeper GW Stormwater discharges Plant uptake Septic tank discharges Reaction decay Land application, incld. dairies Gaseous loss, volatiliz. Point Sources (WWTP & Indus.) Livestock facilities Mineral weathering / rxn prod. Atmospheric deposition GW extraction (dewatering)

Summary of Data Needs Hydrologic Data SW flows (N) Imported water flows (N) Water diversions (N) Point source flows (N/E) Irrigation return flows (E) Meteorology/effective rainfall (N) Land cover classes (N) ET rates (N) Irrigation rates (E) Irrigation efficiency (E) GW pumpage (N/E) GW recharge (N/E) Topography (N) N = Necessary E = Typ. Estimated

Summary of Data Needs Salt and Nitrate Data Surface water quality (N) Groundwater quality (N/E) Point source quality (N/E) Land cover class (salt) loadings (E) Fertilizer rates (E) Land application rates (E)

Summary of Data Needs Process Parameters Plant uptake rates (E) Atmospheric deposition (N) Soil properties (N/E) Nitrification rate (M) Denitrification rate (M) Mineralization rate (M) Volatilization rate (M) Sorption rates (M) Phytoplankton processes (M) M = Model Value

Salinity Composition

Mass Balance – Surface Water TDS Input Inflows from Upstream 42% Inflows from Upstream 53% Imported Water 39% Inflows from Upstream 81% Imported Water 49% Output Diversion 17% Diversion 23% Outflow to Downstream 38% Outflow to Downstream 71% Diversion 61% Outflow to Downstream 77%

Mass Balance – Near-Surface Groundwater TDS Input Fertilizer/ Land App 35% Irrigation 32% Fertilizer/ Land App 47% Irrigation 72% Irrigation 44% Output Recharge to Deeper GW 47% Net Plant Uptake/ Rxn Decay 51% Recharge to Deeper GW 56% Outflow to Surface Water 24% Recharge to Deeper GW 72%

Mass Balance – Deeper GW TDS Input Recharge from Near-surface GW 100% Recharge from Near-surface GW 100% Recharge from Near-surface GW 100% Output Pumping for Irrigation 100% Pumping for Irrigation 95% Pumping for Mun/Ind 81%

Mass Balance – Surface Water Nitrate Input Inflows from Near-surface GW 45% Inflows from Upstream 51% Inflows from Upstream 63% Imported Water 46% Output Diversion 17% Diversion 19% Diversion 44% Outflow to Downstream 56% Outflow to Downstream 83% Outflow to Downstream 80%

Mass Balance – Near-Surface GW Nitrate Input Mineral weathering/ Rxn product 29% Fertilizer/ Land App 83% Fertilizer/ Land App 63% Fertilizer/ Land App 54% Output Net Plant Uptake/ Rxn Decay 36% Recharge to Deeper GW 32% Net Plant Uptake/ Rxn Decay 56% Recharge to Deeper GW 57% Net Plant Uptake/ Rxn Decay 84%

Mass Balance – Deeper GW Nitrate Input Recharge from Near-surface GW 100% Recharge from Near-surface GW 100% Recharge from Near-surface GW 100% Output Pumping for Irrigation 95% Pumping for Municipal/Industrial 84% Pumping for Irrigation 100%

Mass Balance Summary – TDS Principal TDS inputs to near-surface GW: irrigation and fertilizer/land application Other sources contributing >10 percent TDS to near-surface GW: Yolo and Modesto - atmospheric deposition Tule River - mineral weathering and reaction products TDS is accumulating in the near-surface and deeper GW in all three pilot areas.

Mass Balance Summary – Nitrate Principal NO3 inputs to near-surface GW: irrigation and fertilizer/land application. Other sources contributing >10 percent NO3 to near-surface GW: Yolo and Tule River - mineral weathering and reaction products NO3 accumulating in near-surface GW all three pilot areas and in the deeper GW in the Yolo and Modesto areas, but depleting in Tule River area as a whole.

Conclusions – Key Project Objectives Objective 4: Identify additional data that should be collected or developed. Data collected during study: Adequate to run models and perform mass balance calculations. Additional data: Likely to improve certainty and accuracy of results.

Conclusions – Key Project Objectives Objective 9: Select analytical tools and methods that work for the pilot areas as well as other parts of the Central Valley. Analytical tools and methods for study: Are applicable to all parts of the Central Valley. Primary data for mass balance calculation model: Required meteorologic, hydrologic, and land cover data (readily available for all regions). Other required data: Typically can be estimated.

Conclusions – Key Project Objectives Overall: ID/assemble input data for available models, then use the models to quantitatively relate salt and nitrate sources and sinks within representative pilot study areas. WARMF output: Demonstrates use as accounting method for tracking salts and NO3 on and beneath the land surface. GW models: Demonstrate how these provide complementary data to WARMF model application and insights regarding subsurface distribution of salts and NO3 in GW.

Extra or optional slides/Bull Pen

Study Tools WARMF Model Groundwater Models Yolo – CVHM (USGS, 2009) Modesto – MODFLOW Model (USGS, 2007) Tule River – MODFLOW model (Harter) Particle tracking MODPATH Added surface model from Tule River

Mass Balance Calculation Elements Atmospheric Deposition Inflows Point Sources Land Application Diversion Irrigation Uptake Surface Water Near-surface Groundwater Lateral Flow Outflows Reactions Rxns Recharge Municipal Pumping Irrigation Pumping Deeper Groundwater

Recommendations – Other Analysis Tools Evaluate water, salt, and nitrate balances with whole-systems approach (current and future scenarios) Evaluate potential effects of future mass loadings on watersheds Recognize limitations of tools and data sets Evaluate sensitivity of tools to inputs and assumptions

Mass Balance – Surface Water TDS Process Yolo Modesto Tule R. Land Area 720,778 548,201 871,083 Total Inputs (lbs/d) 4,050,000 5,580,000 496,000 Total Inputs (lbs/acre/d) 5.6 10.2 0.6 Inflows from Upstream 1,710,000 4,510,000 259,000 Imported Water 1,970,000 408,000 194,000 Inflows from Near-surface GW 241,000 486,000 41,200 Point Sources 127,000 174,000 Reaction Product 765 1,700 1,380 Total Outputs (lbs/d) 3,890,000 5,810,000 519,000 Total Outputs (lbs/acre/d) 5.4 10.6 Bio.Uptake/Rxn Decay/Settling 165,000 2,350 4,250 Diversion 668,000 1,310,000 319,000 Outflow to Downstream 3,060,000 4,500,000 196,000

Near-Surface GW Loading to Surface Water by Land Use Class – Modesto Land Use / Source1 TDS Nitrate-N lb/d lb/ac/yr lb N/d lb N/ac/yr Orchard 155,000 653 1,710 3.6 Perennial forages 115,000 1,420 406 2.49 Other row crops 93,900 1,440 2,490 19.1 Warm season cereals/forages 60,000 817 3,220 21.9 Farmsteads 32,200 919 302 4.32 Grassland/Herbaceous 12,200 322 4.41 0.058 Winter grains & safflower 6,460 443 344 11.8 Urban landscape 4,060 427 52.9 2.78 Land constrained dairy land application 3,680 55.9 12.7 0.097 Unconstrained dairy land application 2,540 38.6 4.56 0.035 Urban residential 2,290 28.9 4.67 0.03 Total 486,000 8,600 1. Top 11 land use sources

Mass Balance – Near-Surface Groundwater TDS Process Yolo Modesto Tule R. Land area 720,778 548,201 871,083 Total Inputs (lbs/d) 1,720,000 2,330,000 2,450,000 Total Inputs (lbs/acre/d) 2.4 4.3 2.8 Atmospheric Deposition 197,000 423,000 119,000 Irrigation 1,230,000 1,030,000 785,000 Fertilizer / Land Application 221,000 807,000 1,160,000 Point Sources 7,680 22,500 44,000 Septic Systems 998 1,120 10,300 Mineral Weathering / Rxn Product 61,700 49,200 333,000 Total Outputs (lbs/acre/d) 1,670,000 2,050,000 1,890,000 2.3 3.7 2.2 Net Plant Uptake / Reaction Decay 130,000 406,000 959,000 Outflow to SW 241,000 499,000 41,200 Recharge to Deeper GW 1,300,000 1,150,000 889,000 Change in Storage (lbs/d) 48,000 280,000 565,000 Change in Storage (/ac/d) 0.1 0.5 0.6

Mass Balance – Deeper GW TDS Process Yolo Modesto Tule R. Land Area 720,778 548,201 871,083 Total Inputs (lbs/d) 1,300,000 1,150,000 889,000 Total Inputs (lbs/acre/d) 1.8 2.1 1.0 Recharge from Near-surface GW Total Outputs (lbs/d) 919,000 1,060,000 713,000 Total Outputs (lbs/acre/d) 1.3 1.9 0.8 Pumping for Irrigation 873,000 203,000 Pumping for Municipal/Industrial Use 46,000 860,000 Change in Storage (lbs/d) 381,000 87,000 176,000 Change in Storage (/ac/d) 0.5 0.2

Mass Balance – SW Nitrate Process Yolo Modesto Tule R. NO3-N Chloride Land Area 720,778 548,201 871,083 Total Inputs (lbs/d) 14,500 173,000 30,100 6,100 Total Inputs (acre/d) 0.02 0.24 0.05 0.01 Inflows from Upstream 3,720 90,300 19,100 3,130 Imported Water 6,670 44,700 415 52 Inflows from Near-surface GW 2,730 9,920 8,600 2,760 Point Sources 1,310 27,600 1,800 Reaction Product 39 191 161 Total Outputs (lbs/d) 14,700 175,000 30,700 6,170 Total Outputs (acre/d) 0.06 Biological Uptake / Rxn Decay / Settling 30 429 Diversion 2,510 39,500 5,950 2,710 Outflow to Downstream 12,200 135,000 24,300 3,460

Mass Balance – Near-Surface GW Nitrate Process Yolo Modesto Tule R. NO3-N Chloride Land Area 720,778 548,201 871,083 Total Inputs (lbs/d) 45,700 94,100 85,300 205,000 Total Inputs (lbs/acre/d) 0.06 0.13 0.16 0.24 Atmospheric Deposition 1,290 3,960 584 2,550 Irrigation 7,890 77,500 9,070 33,400 Fertilizer / Land Application 28,800 9,960 71,900 109,000 Point Sources 43 2,280 495 184 Septic Systems 0* 245 Mineral Weathering / Rxn Prod. 7,650 200 3,320 60,200 Total Outputs (lbs/d) 40,300 89,400 71,000 133,000 Total Outputs (lbs/acre/d) 0.12 0.15 Net Plant Uptake / Rxn Decay 14,500 22 40,000 111,000 Outflow to Surface Water 2,730 13,300 8,610 2,760 Recharge to Deeper GW 23,000 76,100 22,400 19,000 Change in Storage (lbs/d) 5,460 4,700 14,300 Change in Storage (/ac/d) 0.01 0.03 0.08

Mass Balance – Deeper GW Nitrate Process Yolo Modesto Tule R. NO3-N Chloride Land Area 720,778 548,201 871,083 Total Inputs (lbs/d) 23,000 76,100 22,400 19,000 Total Inputs (lbs/acre/d) 0.03 0.11 0.04 0.02 Recharge from Near-surface Groundwater Total Outputs (lbs/d) 9,920 89,100 19,800 34,600 Total Outputs (lbs/acre/d) 0.01 0.12 Pumping for Irrigation 9,440 84,000 3,100 Pumping for Mun/Industrial Use 481 5,100 16,700 Change in Storage (lbs/d) 13,100 -13,000 2,600 -15,600 Change in Storage (/ac/d) (0.02) 0.00

Trend Analysis: NO3-N Tule (MODPATH) WARMF Model Download URL: ftp://systechwater.com username: cvsalts password: nitrate Questions –  Contact: Joel Herr Systech Water Resources, Inc. joel@systechwater.com Trend Analysis: NO3-N Tule (MODPATH) Nitrate concentration in the source zone (near water table and areas impacted within 50 years at specified depth below water table. Note: Groundwater nitrate data averaged and extrapolated across large sub-watersheds. Very coarse-scale approximation. Source Concentration (here: measured GW data)

List of Data Sources Data Source No. Data Source 1. WARMF Model (default and calibrated values) 10. Central Valley RWQCB 2. 11. SWRCB – Calif. Integrated WQ System (CIWQS) 3. DWR Land Cover Data 12. Hilmar SEP Report 4. USGS Land Cover Data 13. Web H2O 5. Dairy CARES 14. Nat’l Atmos. Deposition Program (NADP) 6. UC Coop. Extension 15. Clean Air Status and Trend Network (CASTNET) 7. Western United Dairymen 16. DWR Hydrologic data 8. Co. Ag Commissioners 17. DWR WQ Data 9. CA Dept. of Food & Ag 18. EPA-STORET

List of Data Sources No. Data Source 19. California Data Exchange Center (CDEC) 29. CA Department of Public Health (CDPH) 20. Bay Delta and Tributary Project 30. Integrated Groundwater Surface Water Model (IGSM) – Yolo County Area 21. U.S. Bureau of Reclamation 31. USGS Central Valley Hydrologic Model (CVHM) 22. California Irrigation Management Information System (CIMIS) 32. USGS Water Quality Data 23. Surface Water Ambient Monitoring Program (SWAMP) 33. Water Resources Information Database (WRID) – Yolo County 24. USGS Hydrologic Data 34. CA SWRCB – Geotracker 25. Local Irrigation and Water Districts 35. USGS Digital Elevation Models (DEM) 26. U.S. EPA NPDES Database 36. Modesto Local MODFLOW Model 27. SWRCB – (GAMA domestic and LLNL) 37. Harter Tule River Basin MODFLOW Model 28. NAWQA 38. Yolo County Flood Control District

Pilot Area Selection Criteria Major Central Valley hydrologic basins represented (Sacramento River, San Joaquin River, and Tulare Lake) Advanced application status of WARMF model for the area (previously applied, partially applied, or not currently) Range of land use classes (including various urban, industrial, commercial, and agricultural) Relatively advanced status of GW flow models applied Available GW quality data