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
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Presentation Overview
2020 Hydrology (Precipitation and Evapotranspiration)
2020 Water Demand
Groundwater Basin Conditions
Key Findings
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Santa Maria Groundwater Basin
Three management areas (NCMA, NMMA, SMVMA)
Mandated monitoring program and Annual Report
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Northern Cities Management Area
City of Arroyo Grande
City of Pismo Beach
City of Grover Beach
Oceano Community Services District
Private Users
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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
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NCMA Agricultural Land 2020
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Estimated Ag Pumpage - 2020
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NCMA Pumpage from SMGB - 2020
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NCMA Total Use - 2020
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Historical NCMA Production/Delivery
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Locations of Monitoring Wells
5 coastal well clusters
16 wells total
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Groundwater
Levels
Spring 2020
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Groundwater
Levels
Fall 2020
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Historical April Deep Well Index
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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
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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
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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
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Questions?
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Annual Precipitation 1950-2020
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