CC 2023-11-28 9.e. MonthlyWaterSupplyandDemandUpdateItem 9.e.
MEMORANDUM
TO: City Council
FROM: Shannon Sweeney, Interim Public Works Director
BY: Shane Taylor, Utilities Manager
SUBJECT: Monthly Water Supply and Demand Update
DATE: November 28, 2023
SUMMARY OF ACTION:
The update reports the City’s total water supply and demand for October 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 Monthly 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 2,2 00 Acre Feet.
In October 2023, the City’s water use was 179.7 Acre Feet with a per capita use of 105
gallons per day/per person. The residential per capita use was 81 gallons per day/per
person. There was a total of 0 inches of rainfall in the City in October 2023.
The rainfall total at the City Corporation Yard gauge for the season of 2023/2024 is 0
inches.
Item 9.e.
City Council
Monthly Water Supply and Demand Update
November 28, 2023
Page 2
ANALYSIS OF ISSUES:
The United States Drought Monitor, as of November 10, 2023, shows San Luis Obispo
County is not in a drought. Rainfall for the period of July 1, 2023, through October 31,
2023, is 0 inches at the Corporation Yard rain gauge. Lopez Lake is 95% (46,918 Acre
Feet) as of November 10, 2023.
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 directions 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
2. Lopez Reservoir Storage Projection
3. Monthly Water Use Supply & Demand
4. Deep Well Index Levels
PROJECT WATERDELIVERIES DURING SPILLDELIVERIES DURING SPILLRUSAGE % USAGE % USAGE % USAGE USAGE % USAGE % USAGE % USAGE % USAGE USAGE %AG 2290 0 0 2290 177.84 8% 0.0 0% 0.00% 0.00 177.84 8% 799.4 35% 0.0 0% 0.0 0% 405.05 1204.42 53%OCSD 303 0 0 303 55.32 18% 0.0 0% 0.0 0% 0.00 55.32 18% 280.9 93% 0.0 0% 0.0 0% 96.60 377.53 125%GB 800 0 0 800 64.84 8% 0.0 0% 0.0 0% 0.00 64.84 8% 300.5 38% 0.0 0% 0.0 0% 164.17 464.66 58%PB 892 0 0 892 12.21 1% 0.0 0% 0.0 0% 0.00 12.21 1% 137.4 15% 0.0 0% 0.0 0% 275.16 412.53 46%CSA 12 245 0 0 245 6.77 3% 0.0 0% 0.0 0% 0.00 6.77 3% 36.3 15% 0.0 0% 0.0 0% 19.90 56.15 23%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/AN/A N/A N/A N/A N/A N/A N/A N/ATOTAL 4530 0 4530 316.98 7.0% 0.0 0% 0.0 0% 0.00 316.98 7.0% 1554.4 34.3% 0 0.0% 0.0 0% 960.88 2515.29 56%STATE WATER PROJECT WATERDELIVERIESTHIS MONTH JANUARY TO PRESENTALLOCATION DIE AIE TOTAL ALLOCATION DIE AIE TOTALR REQUEST USAGE % USAGE USAGE USAGE USAGE % USAGE USAGE USAGECONTRACTOR [AF]AG N/A 0.0 N/A N/A N/A 0.0 0.0 0.00 N/A N/A 0 0 0.00AG 177.84OCSD 187.5 0.0 0.0 0.0 0% 0.0 0.0 0.00 94.6 50% 0 0 94.63OCSD 55.32GB N/A 0.0 N/A N/A N/A 0.0 0.0 0.00 N/A N/A 0 0 0.00GB 64.84PB 1070.0 0.0 120.0 120.0 11% 0.0 0.0 120.00 827.5 77% 0 0 827.45PB 132.21CSA 12 96.0 0.0 8.5 8.50 9% 0.0 0.0 8.50 75.4 79% 0 0 75.44CSA 12 15.27SM 90.0 0.0 7.0 10.57 12% 0.0 0.0 10.57 58.8 65% 0 0 58.80SM 10.57TOTAL 1443.5 0.0 135.5 139.07 10% 0.0 0.0 139.07 1056.3 73% 0 0 1056.32TOTAL 456.05DAM & OTHER OPERATIONSGLOSSARYNOTESTHIS MONTH WY TO DATE MAX CAPACITYAIE: Agency Initiated Exchange 1) New Contract Changes effective October 1, 2022LAKE ELEVATION (ft) 519.96 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] 46998 N/A 49200 96% N/A: Not Applicable3) In March 2023, 5489 AF of water spilled resulting in loosing all of the District SSWPW, Agency SSWPW, and Stored PW.MONTHLY RAINFALL [in] 0.10 0.10 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) 0.0 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] 321.01 1970.3 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]400.5 2608.6N/ASSWPW: Stored SWP Water7) 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 8968.1N/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 1.82** Actual amount available is dependent on the State's (DWR) delivery %*** Stored SWP water resulting from AIESan Luis Obispo County Flood Control and Water DistrictZone 3 - Lopez Project - Monthly Operations ReportOctober, 2023AVAILABLE WATER (APR-MAR)DELIVERIESENTITLEMENTSTORED PW*SURPLUS WATER AVAILABLETOTAL AVAILABLE PWTHIS MONTHAPRIL TO PRESENTSURPLUS PWTOTAL USAGEENTITLEMENTSTORED PWSURPLUS PWTOTALTOTAL MONTHLY DELIVERIESANNUAL REQUEST**CUMULATIVE SSWPW***ENTITLEMENTSTORED PWAttachment 1
0.4330.342.031.911.3112.714.393911.56560.390.390.103.1222.9882.844330.98480.3660.070.3550.67171.8431144442.2442.76762.9883.010.980.39339080.410.350.10050.6767671.8442.2442.7662.9883.010.9880.410.3550.671.840.005.0010.0015.0020.0025.0001000020000300004000050000600001/1/20222/1/20223/1/20224/1/20225/1/20226/1/20227/1/20228/1/20229/1/202210/1/202211/1/202212/1/20221/1/20232/1/20233/1/20234/1/20235/1/20236/1/20237/1/20238/1/20239/1/202310/1/202311/1/202312/1/20231/1/20242/1/20243/1/20244/1/20245/1/20246/1/20247/1/20248/1/20249/1/202410/1/202411/1/2024012/1/2024Storage (AF)DateLOPEZ RESERVOIR STORAGE PROJECTION Actual PrecipitationPredicted PrecipitationStorage Projection (SP)Reservoir Level (Actual)Available Water (Storage Rights)SP (No Rain)20,000 AFAttachment 2
16218095105020406080100120140160180200Oct‐22 Oct‐23Monthly Water Use ComparisonAcre FeetUsage (gpcd)Attachment 3
P:\Portland\672-Northern Cities Management Area\_Grapher Figures\Quarterly Rpt Figs Fig 6 NCMA_Q4_Deep_Well_Index_v2
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Water Elevation, feet NAVD88Deep Well Index Level
(Wells 24B03, 30F03 and 30N02)
Deep Well Index (Approximate)
Deep Well Index
Threshold: 7.5 feet
FIGURE 6Deep Well Index is the synoptic average of groundwater elevations
in the deep wells of Sentry Well clusters 24B, 30F, and 30N.
"Approximate" Deep Well Index elevations are based on
non-synoptic measurments, made during the same quarter.
Attachment 4