CC 2024-01-23_09.f. Year 2023 Water Supply and Demand Update
Item 9.f.
MEMORANDUM
TO: City Council
FROM: Bill Robeson, Assistant City Manager/Public Works Director
BY: Shane Taylor, Utilities Manager
SUBJECT: Calendar Year 2023 Water Supply and Demand Update
DATE: January 23, 2024
SUMMARY OF ACTION:
The update reports the City’s total water supply and demand for Calendar Year 2023.
Current Lopez Reservoir level and projected levels are provided in the attachments.
IMPACT ON FINANCIAL AND PERSONNEL RESOURCES:
Approximately two (2) hours of staff time is required to prepare the report.
RECOMMENDATION:
Receive and file the Calendar Year 2023 Water Supply and Demand Update.
BACKGROUND:
On March 28, 2023, the City Council adopted a Resolution rescinding the declaration of
a State 1 Water Shortage Emergency and related water shortage restrictions and
penalties.
The City of Arroyo Grande’s water entitlements are calculated on a water year that begins
April 1st. The current water supply for water year 2023/2024 includes 2,290 Acre Feet
from Lopez Reservoir, 1323 Acre Feet of groundwater entitlement from the Santa Maria
River Groundwater Basin, and 160 Acre Feet from the City’s wells that draw from the
Pismo formation.
The predicted water use for 2023/2024 water year is 2,000 Acre Feet.
In 2023, the City’s water use was 1,935.7 Acre Feet with a per capita use of 98 gallons
per day/per person. The residential per capita use was 76 gallons per day/per person.
There was a total of 26.6 inches of rainfall at the City Corporation Yard gauge in 2023.
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Item 9.f.
City Council
Calendar Year 2023 Water Supply and Demand Update
January 23, 2024
Page 2
ANALYSIS OF ISSUES:
As of January 8, 2024, the United States Drought Monitor shows San Luis Obispo County
is not in a drought. Rainfall for the period of July 1, 2023, through December 31, 2023,
was 5.65 inches at the Corporation Yard rain gauge. Lopez Lake is 96% (47,445 Acre
Feet) as of January 8, 2024.
The deep well index for the fourth quarter of 2023 was completed on October 10, 2023,
and is 10.95 feet above sea level, which is 3.45 feet above the threshold value. The
current deep well index is 0.62 feet lower than July 2023, and 5.07 feet higher than
October 2022.
ALTERNATIVES:
The following alternatives are provided for the Council’s consideration:
1. Receive and file the report, or
2. Provide other direction to staff.
ADVANTAGES:
The report provides the City Council and the public with the current and projected
conditions of our water supply and demand.
DISADVANTAGES:
No disadvantages noted at this time.
ENVIRONMENTAL REVIEW:
No environmental review is required for this item.
PUBLIC NOTIFICATION AND COMMENTS:
The Agenda was posted at City Hall and on the City’s website in accordance with
Government Code Section 54954.2.
Attachments:
1. Monthly Operations report for December 2023
2. Lopez Reservoir Storage Projection
3. Yearly Water Use Comparison
4. Deep Well Index Levels
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PROJECT WATER
DELIVERIES
DURING SPILL
DELIVERIES
DURING SPILL
CONTRACTOR USAGE %USAGE %USAGE %USAGE USAGE %USAGE %USAGE %USAGE %USAGE USAGE %
AG 2290 0 0 2290 154.43 7%0.0 0%0.0 0%0.00 154.43 7%1117.4 49%0.0 0%0.0 0%405.05 1522.42 66%
OCSD 303 0 0 303 0.00 0%0.0 0%0.0 0%0.00 0.00 0%303.0 100%0.0 0%0.0 0%96.60 399.60 132%
GB 800 0 0 800 68.89 9%0.0 0%0.0 0%0.00 68.89 9%434.2 54%0.0 0%0.0 0%164.17 598.40 75%
PB 892 0 0 892 19.98 2%0.0 0%0.0 0%0.00 19.98 2%158.2 18%0.0 0%0.0 0%275.16 433.38 49%
CSA 12 245 0 0 245 3.83 2%0.0 0%0.0 0%0.00 3.83 2%46.4 19%0.0 0%0.0 0%19.90 66.26 27%
SM N/A N/A 0 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
TOTAL 4530 0 4530 247.13 5.5%0.0 0%0.0 0%0.00 247.13 5.5%2059.2 45.5%0 0.0%0.0 0%960.88 3020.06 67%
STATE WATER PROJECT WATER
DELIVERIES
THIS MONTH JANUARY TO PRESENT
ALLOCATION DIE AIE TOTAL ALLOCATION DIE AIE TOTAL
CONTRACTOR REQUEST USAGE %USAGE USAGE USAGE USAGE %USAGE USAGE USAGE CONTRACTOR [AF]
AG N/A 0.0 N/A N/A N/A 0.0 0.0 0.00 N/A N/A 0 0 0.00 AG 154.43
OCSD 187.5 0.0 62.5 50.46 26.9%0.0 0.0 50.46 175.8 94%0 0 175.76 OCSD 50.46
GB N/A 0.0 N/A N/A N/A 0.0 0.0 0.00 N/A N/A 0 0 0.00 GB 68.89
PB 1070.0 0.0 90.0 90.00 8%0.0 0.0 90.00 1037.5 97%0 0 1037.45 PB 109.98
CSA 12 96.0 0.0 7.5 6.99 7%0.0 0.0 6.99 89.9 94%0 0 89.93 CSA 12 10.82
SM 90.0 0.0 7.0 5.54 6%0.0 0.0 5.54 76.8 85%0 0 76.77 SM 5.54
TOTAL 1443.5 0.0 167.0 152.99 11%0.0 0.0 152.99 1379.9 96%0 0 1379.91 TOTAL 400.12
DAM & OTHER OPERATIONS GLOSSARY NOTES
THIS MONTH WY TO DATE MAX CAPACITY AIE: Agency Initiated Exchange 1) New Contract Changes effective October 1, 2022
LAKE ELEVATION (ft)520.37 N/A 522.6 DIE: District Initiated Exchange 2) On 12/31/22 there was an estimated 655.5 AF of District SSWPW remaining including approximately 46 AF of water lost to evaporation in 2022.
STORAGE [AF]47365 N/A 49200 96%N/A: Not Applicable 3) In March 2023, 5489 AF of water spilled resulting in loosing all of the District SSWPW, Agency SSWPW, and Stored PW.
MONTHLY RAINFALL [in]6.32 7.48 N/A PW: Project Water aka Lopez Water 4) 44.53 AF of March Project Water Deliveries will be credited to Stored PW at the end of the 2022//2023 water year (WY) due to March spill event.
(Annual: July 1- June 30)Surplus Water: Carry Over Water (LRRP)5) End of WY water credit of 44.53 AF was added to Stored PW. 44.53 AF of Stored PW was lost due to April spill event.
DOWNSTREAM RELEASES [AF]248.27 2934.50 4200.0 SWP: State Water Project 6) 364.03 AF of April Project Water Deliveries are reported in the "Deliveries During Spill" column due to April spill event.
LAKE TO TERMINAL [AF]221.3 3676.22 N/A SSWPW: Stored SWP Water 7) 426.5 AF of May Project Water Deliveries are reported in the "Deliveries During Spill" column due to May spill event.
SPILLAGE [AF] (WY)0.00 8968.15 N/A * Stored PW includes Surplus water declared 8) 170.38 AF of June Project Water Deliveries are reported in the "Deliveries During Spill" column due to June spill event.
AG WHEELING OCEANO WATER 1.42 N/A N/A ** Actual amount available is dependent on the State's (DWR) delivery %
*** Stored SWP water resulting from AIE
SURPLUS PW TOTAL USAGE
TOTAL
MONTHLY
DELIVERIESANNUAL
REQUEST**
CUMULATIVE
SSWPW
***
ENTITLEMENT STORED PW SURPLUS PW TOTAL ENTITLEMENT STORED PW
San Luis Obispo County Flood Control and Water District
Zone 3 - Lopez Project - Monthly Operations Report
December, 2023
AVAILABLE WATER (APR-MAR)DELIVERIES
ENTITLEMENT
STORED
PW*
SURPLUS
WATER
AVAILABLE
TOTAL
AVAILABLE PW
THIS MONTH APRIL TO PRESENT
Attachment 1
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0.43 0.34
2.03 1.91
1.31
12.71
4.39
11.56
0.39 0.39 0.10 0.37
6.32
3.12 2.98 2.84
0.98 0.36 0.07 0.35 0.67
1.84 2.24 2.76 2.98 3.01
0.98 0.41 0.35 0.67
1.84 2.24 2.76 2.98 3.01
0.98
0.41 0.35 0.67
1.84
0.00
5.00
10.00
15.00
20.00
25.00
0
10000
20000
30000
40000
50000
60000
1/1/20222/1/20223/1/20224/1/20225/1/20226/1/20227/1/20228/1/20229/1/202210/1/202211/1/202212/1/20221/1/20232/1/20233/1/20234/1/20235/1/20236/1/20237/1/20238/1/20239/1/202310/1/202311/1/202312/1/20231/1/20242/1/20243/1/20244/1/20245/1/20246/1/20247/1/20248/1/20249/1/202410/1/202411/1/202412/1/2024Storage (AF)Date
LOPEZ RESERVOIR STORAGE PROJECTION
Actual Precipitation Predicted Precipitation Storage Projection (SP)Reservoir Level (Actual)
Available Water (Storage Rights)SP (No Rain)20,000 AF
Attachment 2
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1989.7 1935.7
99 98
0
500
1000
1500
2000
2500
2022 2023
Yearly Water Use Comparison
Acre Feet Usage (gpcd)
Attachment 3
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