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CC 2021-08-24_11a NCMA Annual Report_2020_PP PresentationNCMA 2020 Annual Report Arroyo Grande City Council Paul Sorensen and Nate Page GSI Water Solutions, Inc. August 24, 2021 1 Presentation Overview 2020 Hydrology (Precipitation and Evapotranspiration) 2020 Water Demand Groundwater Basin Conditions Key Findings 2 2 Santa Maria Groundwater Basin Three management areas (NCMA, NMMA, SMVMA) Mandated monitoring program and Annual Report 3 Northern Cities Management Area City of Arroyo Grande City of Pismo Beach City of Grover Beach Oceano Community Services District Private Users 4 Hydrology Average annual rainfall – 15.6 inches Rainfall in 2020 – 10.0 inches Below average rainfall in 10 of 12 months ET exceeded rainfall in 11 of 12 months 5 5 NCMA Agricultural Land 2020 6 Estimated Ag Pumpage - 2020 7 7 NCMA Pumpage from SMGB - 2020 8 8 NCMA Total Use - 2020 9 9 Historical NCMA Production/Delivery 10 Locations of Monitoring Wells 5 coastal well clusters 16 wells total 11 Groundwater Levels Spring 2020 12 12 Groundwater Levels Fall 2020 13 13 Historical April Deep Well Index 14 14 Key Findings Total 2020 NCMA Water Use – 8,577 AF (8,296 AF in 2019) Lopez Lake – 4,740 AF (4,385 AF in 2019) State Water Project – 737 AF (567 AF in 2019) Groundwater – 3,064 AF (3,320 AF in 2019) Other Groundwater – 36 AF (24 AF in 2019) Groundwater pumping is 32% of 9,500 AFY safe yield Estimated decrease of 500 AF of groundwater in storage 15 15 Why Aren’t Water Levels Higher? Continued effects of drought, unequal distribution of rainfall events Reduction of recharge from east Not because of overpumping in NCMA 16 16 Threats Continued reduction in underflow from the east Sea water intrusion Potential increased groundwater demand in NCMA Threat to Lopez Lake supply Threat to SWP deliveries 17 17 Questions? 18 Annual Precipitation 1950-2020 19