CC 2022-08-09_11b NCMA PP PresentationNCMA 2021 Annual Report
City Council Meeting
Nate Page
GSI Water Solutions, Inc.
August 9, 2022
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Presentation Overview
2021 Hydrology (Precipitation and Evapotranspiration)
2021 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 2021: 13.2 inches
Below average rainfall in
9 of 12 months
ET exceeded rainfall in 10 of 12 months
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NCMA Agricultural Land 2021
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Estimated Ag Pumpage - 2021
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NCMA Pumpage from SMGB - 2021
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NCMA Total Use - 2021
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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 2021
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Groundwater
Levels
Fall 2021
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Historical April Deep Well Index
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Key Findings
Total 2021 NCMA Water Use – 8,658 AF (8,577 AF in 2020)
Lopez Lake – 3,522 AF (4,740 AF in 2020)
State Water Project – 1,772 AF (737 AF in 2020)
Groundwater – 3,344 AF (3,064 AF in 2020)
Other Groundwater – 20 AF (36 AF in 2020)
Groundwater pumping is 35% of 9,500 AFY safe yield
Estimated decrease of 1,400 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 pumping on the Mesa above the estimated safe yield
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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