Southwest Kings GSA Southwest Kings GSA Water Budget PRELIMINARY Southwest Kings Groundwater Date: 7/11/2018 Sustainability Agency Presented by: Joe Hopkins
PRELIMINARY 2
Water Budget Purpose • Summarize all water sources and uses – Sources – Surface water, precipitation, groundwater – Uses – Irrigation, municipal, industrial PRELIMINARY • Summarize hydrological interactions ― Land Surface – Groundwater interactions Recharge, pumping, deep percolation ― Land Surface – Atmosphere Interactions Precipitation, evaporation, evapotranspiration • Compare to Basin-wide Model ― Period of Record: 1990-2016 to match AMEC’s model 3
4 PRELIMINARY Water Budget Diagram
Data Sources • Farmers/Landowners – Cropping data, pumping/irrigation data, water levels, water quality, PRELIMINARY system/operational data • Public Databases ― Water levels, precipitation, evapotranspiration, soils, historic land use/cropping • Publications ― Recharge rates, specific and sustainable yield, historic land and water use, deep percolation rates 5
Southwest Kings GSA Water Budget Diagram Southwest Kings GSA WATER BUDGET DIAGRAM 1990-2016 (9) (1) (10) (11) (8) (7) (2) (12) (26) (25) (28) Other Supply: Surface Water - Crop ET - Applied Crop ET - Effective Surface Water - Evap.- Evaporation - Spill Inflows Precipitation ET - M&I Operational Spills Irrigation Water Prec. M&I Reservoir/Basin Channels PRELIMINARY 58,200 AF 0 AF (13) 90,400 AF 74,600 AF 29,100 AF 0 AF 0 AF 100 AF 200 AF 6,700 AF 0 AF Other Consumptive (27) Precipitation - Use: Evap and Runoff 0 AF 29,100 AF Agricultural Lands (30) Reservoirs and Recharge Municipalities and Urban Areas Canals and Pipelines Irrigation Efficiency = 82% Basins Other Losses: Agency Area = 89,689 Acres Irrigated Area =47,328 Acres 0 AF (15) (23) (16) (17) (20) (19) (22) (21) (18) Deep Perc. - Deep Percolation - Deep Percolation - Recharge - Urban Seepage - Intentional Local Stream and Seepage - Other Recharge Irrigation Precipitation M&I Stormwtr Reservoirs Recharge River Recharge Canal/Pipeline 21,100 AF 13,100 AF 300 AF 0 AF 22,400 AF 0 AF 0 AF 100 AF 0 AF 0 AF 0 AF 0 AF 20,700 AF GW Pumping - Irr. GW Pumping - GrW Pumping - GW Pumping - Agency Private Irr. M&I Agency M&I Private (3) (4) (5) (6) (24) Groundwater (14) Outflow Change in Groundwater Storage N/A Groundwater Inflow 8,700 AF (inflow and outflows) (29) N/A N/A (change in groundwater levels) Groundwater Export 0 AF 6
Output: Evapotranspiration • Evapotranspiration numbers were obtained from ITRC – Wet, Dry, Average Water Year types PRELIMINARY Southwest Kings • ITRC uses the CIMIS ET Zone Map GSA • Southwest Kings GSA is located in Zone 16 7
Output: Consumptive Use • Water Needs – Irrigation Cropping data was gathered from growers and PRELIMINARY supplemented by USDA- Cropscape and DWR Survey All crops are assumed mature – Minor Domestic/Industrial Limited data, assumed to be negligible – Municipal Kettleman City Community Services District: 300 AF/Year 8
Water Sources • Groundwater (Output ) – Least used water source – Unmetered – Calculated using water budget spreadsheet PRELIMINARY • Precipitation (Input ) – Using Kettleman City CIMIS Station – Effective precipitation assumed to be 50% of annual precipitation • Surface Water (Input ) – Primary water source – Use data is still limited, some sources are not metered 9
10 PRELIMINARY Inputs: Water Sources
Inputs: Groundwater Recharge • Deep Percolation – From Irrigation Systems – Overall irrigation was assumed to be 82% efficient on average, resulting in 18% of water deliveries going to deep percolation PRELIMINARY – From Precipitation – Assumed to be 0% of annual precipitation The Williamson Method determined that annual precipitation of less than 9.69 inches in the Central Valley results in no groundwater recharge (Williamson et al. 1989). 7.77 inches average annual precipitation from 1990-2016 in Southwest Kings GSA (CIMIS, Kettleman Station) • Seepage – Canals – Major canals assumed to have operated for 365 days/year – Pipelines – Assumed no leaks – Reservoirs – Negligible seepage contributions from DRWD 820 acres of ponds and RD 761 evaporation ponds Limited percent of time filled 11
Change in Groundwater Storage • Method – Check Book Balance – Uses all inputs and outputs from Water Balance PRELIMINARY Workbook • Insufficient data to complete a groundwater level/specific yield comparison 12
Assumptions and Uncertainty 1. Cropping Patterns – Years with data gaps were filled with similar water year conditions’ data PRELIMINARY 2. Groundwater Pumped Back-calculated in spreadsheet – 3. Surface Water Imports – Years with data gaps were filled with similar water year conditions’ data 4. Irrigation Methods 5. Groundwater Inflows and Outflows 13
Key Take-Aways 1. SWKGSA is essentially in balance. 8,700 AF surplus 2. Future efforts to inventory cropping, groundwater pumping, surface water deliveries and irrigation methods will be helpful PRELIMINARY 3. Seepage benefits from the channelized flow contributed almost as much as deep percolation of residual irrigation water 4. Will need to share this data with Wood to refine model 14
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