NCMA 2025 Annual Report
Ag Representatives
Meeting
GSI Water Solutions, Inc.
Presented to Agricultural interests: August 10, 2026
Presented to City of Arroyo Grande: August 25, 2026
Presentation
Overview
Introduction
Goal: Coordination with Ag Reps
2025 Hydrology (Precipitation and
Evapotranspiration)
2025 Water Use
Groundwater Basin Conditions
Key Findings
2 Santa Maria
Groundwater
Basin (SMGB)
Three management areas:
1. Northern Cities Management Area
(NCMA)
2. Nipomo Mesa Management Area
(NMMA)
3. Santa Maria Valley Management
Area (SMVMA)
Court ordered monitoring program
and Annual Report (Santa Maria
Groundwater Basin Adjudication)
3 Northern Cities
Management
Area
City of Arroyo Grande
City of Pismo Beach
City of Grover Beach
Oceano Community Services District
Private Users
Agricultural Irrigation
Rural Use
4 2025 Hydrology 5
Average annual rainfall –
15.6 inches
Rainfall in 2025: 14.12 inches
Above average rainfall in
5 of 12 months
ETo1 exceeded rainfall in 10 of 12
months
1 – Reference Evapotranspiration (ETo)
recorded at Nipomo CIMIS Station
NCMA
Agricultural
Land in 2025
6 7
Estimated Agricultural Pumpage in 2025
NCMA
Pumpage
from
SMGB in
2025
8 NCMA
Total
Water Use
in 2025
9 Historical
NCMA
Production/
Delivery
10 Locations of
Monitoring
Wells
5 coastal well clusters
15 wells total
Deep Well Index:
Average of water levels in
3 coastal wells:
(24B03, 30F03, and 30N02)
11 Groundwater
Levels
Spring 2025
12 Yellow Contours:
Alluvial Aquifer (Cienega Valley)
Blue Contours:
Deep Aquifer System
Groundwater
Levels
Fall 2025
13 Yellow Contours:
Alluvial Aquifer (Cienega Valley)
Blue Contours:
Deep Aquifer System
Historical
Deep
Well
Index
14 Deep Well Index at
end of 2025 was 10.5 ft,
3 feet higher than
threshold value.
Key Findings
Total 2025 NCMA Water Use – 8,053 AF
(7,783 AF in 2024)
Lopez Lake – 4,095 AF (4,173 AF in 2024)
State Water Project – 581 AF
(661 AF in 2024)
Groundwater – 3,377 AF (2,949 AF in 2024)
Other Groundwater – 0 AF
(0 AF in 2023)
Total Urban Water Use – 5,477 AF
(third lowest in 20 years!)
Total Agricultural Irrigation – 2,447 AF
Groundwater pumping is 36% of 9,500 AFY safe
yield
Estimated decrease of 1,149 AF of groundwater
in storage (April 2024 to April 2025)
15 Questions?