CC 2021-01-26_08e Calendar Year 2020 Water Supply and Demand Update
MEMORANDUM
TO: CITY COUNCIL
FROM: BILL ROBESON, PUBLIC WORKS DIRECTOR
BY: SHANE TAYLOR, UTILITIES MANAGER
SUBJECT: CALENDAR YEAR 2020 WATER SUPPLY AND DEMAND UPDATE
DATE: JANUARY 26, 2021
SUMMARY OF ACTION:
The update reports the water supply and demand for Calendar Year 2020. 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:
It is recommended the City Council receive and file the Calendar Year 2020 Water Supply
and Demand Report.
BACKGROUND:
On April 25, 2017, the City Council, by Resolution, rescinded the Stage 1 Water Shortage
Emergency along with related emergency water conservation measures and restrictions.
During that public meeting, Council requested that staff continue preparing the monthly
water supply and demand updates. Council urged citizens to continue to practice
everyday water saving measures, and reiterated that the previously adopted water
conservation measures were to remain in effect.
In 2020, the City’s water use was 2,318.5 acre-feet with a per capita use of 117 gallons
per day/per person. There was a total of 10.4 inches of rainfall in the City in 2020.
ANALYSIS OF ISSUES:
The United States Drought Monitor, as of January 16, 2021, shows San Luis Obispo
County in a moderate drought. Rainfall to date for the period July 1, 2020, through
December 31, 2020, is 2.0 inches at the Corporation Yard rain gauge. Lopez Lake, as of
January 14, 2021, is at 39.7% capacity (19,631 acre-feet of storage).
The new water year began on April 1, 2020, and the City’s current total available supply
from Lopez is 2,290 acre-feet. In addition, the City has 1,323 acre-feet of ground water
Item 8.e. - Page 1
CITY COUNCIL
CALENDAR YEAR 2020 WATER SUPPLY AND DEMAND UPDATE
JANUARY 26, 2021
PAGE 2
entitlement from the Santa Maria Basin, 200 acre-feet from the Pismo Formation, and an
additional 111 acre-feet of surplus Lopez water. The deep well index of the Sentry Wells
along the coast on January 6, 2021, was 9.28 feet above sea level, which is 1.78 feet
above the threshold value of 7.5 feet. The current level is 1.41 feet lower than one year
ago (January 2020). The projected water use for water year 2020/21 is 2,375 acre-feet
based on current rainfall.
ADVANTAGES:
No advantages noted at this time.
DISADVANTAGES:
No disadvantages noted at this time.
ALTERNATIVES:
Not applicable 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. Lopez Monthly Operations Report for December 2020
1.a. Lopez Monthly Operations Report for March 2020
2. Lopez Reservoir Storage Projection
3. Yearly Water Use Comparison
Item 8.e. - Page 2
San Luis Obispo County Flood Control and Water District
Zone 3 - Lopez Project - Monthly Operations Report
December, 2020
208.20
Note: Deliveries are in acre feet. One acre foot = 325, 850 gallons or 43, 560 cubic feet. Safe yield is 8,730
acre feet.
"Year to Date" is January to present for State water, April to present for Lopez deliveries, and July to present for rainfall.
1790.71
April to Present
2.39
Arroyo Grande 177.2
Lopez Dam Operations
Lake Elevation (full at 522.37 feet)480.28
Storage (full at 49200 acre feet)19826
Rainfall 1.71
Downstream Release (4200 acre feet/year)332.67
Spillage (acre feet)0
This Month Year to Date
2286.94
0.00
911.00 177.20
Entl.Surplus
Water
Declared Usage
288.20
Total
Available
Water
Lopez Water Deliveries
511.20Oceano CSD 303 121.00 0.00624.00
592.00Grover Beach 800 318.00 64.56900.00
794.85Pismo Beach 892 355.00 104.481547.00
109.21CSA 12 245 98.00 9.52245.00
677.2760819.00
37.10402.23
60.00600.00
State Water Deliveries
3797.972417.2 1803.00 355.763604.20 894.7982825.76Total
Contractor
Difference (feet)-42.09
% Full 40.3%
Comments:
1) Oceano supplied water to Canyon Crest via Arroyo Grande's Edna turn out. A total of 1.96 AF delivered to Canyon Crest was
added to Oceano's water usage this month and 1.96 AF was subtracted from Arroyo Grande's usage this month.
2) OCSD revised their annual State Water Delivery Request on September 10th from 150 AF to 60 AF.
April to Present Lopez Entitlement+Surplus Water Usage
0
50
100
150
200
250
Jan '20 Feb '20 Mar '20 Apr '20 May '20 Jun '20 Jul '20 Aug '20 Sep '20 Oct '20 Nov '20 Dec '20Acre FeetAG GB OCSD PB CSA12
January to Present State Water Usage
0
20
40
60
80
100
120
Jan '20 Feb '20 Mar '20 Apr '20 May '20 Jun '20 Jul '20 Aug '20 Sep '20 Oct '20 Nov '20 Dec '20Acre FeetOCSD PB CSA12 SanMig
San Miguelito 120.421204.53
This Month
%
Total
January to Present
Usage
This Month
% of
Annual
Request
Usage % of Annual
Request
177.2
Total Water
Deliveries
This Month
54.82
64.56
123.48
11.75
4.53
436.34
Annual
Request
0.00
Usage
54.82
0.00
0.00
0.00
%
0.00
208.20
0.00
0.00
0.00
1790.71
303.00
592.00
794.85
109.21
3589.7754.82 704.00
SWP
Deliveries
SWP
Deliveries
Change in
Storage
21 -4.76
1265.46This Month Stored State Water
17.5%
100.0%621.3%
0.0%81.9%
8.1%65.8%
11.7%51.4%
3.9%44.6%
3.1%111.4%
5.6%92.8%
0.0%100.0%
14.7%105.4%3.1%108.1%
3.8%100.4%
0.0%
17.1%
0.0%
0.0%
0.0%
0.0%
64.9%
0.0%
0.0%
0.0%
1010.6%
100.0%
74.0%
89.1%
44.6%
148.5%4.6%
Entitlement Surplus
Usage %Usage %
Entitlement Surplus
Usage %
1270.22Last Month Stored State Water
Surplus
Requested
111.00
321.00
100.00
655.00
0.00
1187.00
Wednesday, January 13, 2021 Page 1 of 1Report printed by:AdminData entered by:D. Bravo
ATTACHMENT 1
Item 8.e. - Page 3
San Luis Obispo County Flood Control and Water District
Zone 3 - Lopez Project - Monthly Operations Report
March, 2020
727.00
Note: Deliveries are in acre feet. One acre foot = 325, 850 gallons or 43, 560 cubic feet. Safe yield is 8,730
acre feet.
"Year to Date" is January to present for State water, April to present for Lopez deliveries, and July to present for rainfall.
2122.35
April to Present
14.31
Arroyo Grande 2290
Lopez Dam Operations
Lake Elevation (full at 522.37 feet)490.87
Storage (full at 49200 acre feet)25472
Rainfall 5.37
Downstream Release (4200 acre feet/year)207.46
Spillage (acre feet)0
This Month Year to Date
2736.22
0.00
378.00 139.74
Entl.Surplus
Water
Declared Usage
2290.00
Total
Available
Water
Lopez Water Deliveries
624.35Oceano CSD 303 50.00 0.00624.35
787.22Grover Beach 800 132.00 64.00820.00
1297.65Pismo Beach 892 147.00 0.001297.65
86.34CSA 12 245 40.00 7.19245.00
97.27112023.84
5.92272.04
0.002270.00
State Water Deliveries
4917.914530747.00 210.935277.00 132.28150135.14Total
Contractor
Difference (feet)-31.50
% Full 51.8%
Comments:
Available Surplus Water is shown and as designated per BOS May 14, 2019 Declaration of Surplus Water. Beginning with July 2019
report, Surplus Water Requested is amount purchased by each agency. Surplus Water used is based on Surplus Water Requested.
1) Oceano supplied water to Canyon Crest via Arroyo Grande's Edna turn out. A total of 1.5 AF delivered to Canyon Crest was
added to Oceano's water usage this month and 1.5 AF was subtracted from Arroyo Grande's usage this month.
On 2/7/2020 Pismo requested the remaining 127 AF of surplus water (SurW) in addition up to 90 AF of Oceano’s SurW if needed for
March, 2020. In March, Pismo used 78.65 AF of Oceano's remaining SurW.
Pismo Surplus = 200 AF (original) + 127AF (Total remaining SurW) + 78.65 (Oceano's remaining SurW Requested) = 405.65 AF.
San Miguelito 29.091279.26
This Month
%
Total
January to Present
Usage
This Month
% of
Annual
Request
Usage % of Annual
Request
139.74
Total Water
Deliveries
This Month
48.07
64
102.49
9.23
9.26
372.79
Annual
Request
0.00
Usage
48.07
0.00
78.65
0.00
%
0.00
321.35
0.00
405.65
0.00
2122.35
303.00
787.22
892.00
86.34
4190.91126.72 136.00
SWP
Deliveries
SWP
Deliveries
Change in
Storage
1459.97This Month Stored State Water
97.3%
6.1%92.7%
0.0%100.0%
8.0%96.0%
0.0%100.0%
2.9%35.2%
2.1%8.7%
7.6%21.9%
0.0%0.0%
4.7%93.2%2.3%8.8%
7.3%22.9%
0.0%
15.0%
0.0%
19.4%
0.0%
0.0%
100.0%
0.0%
100.0%
0.0%
92.7%
100.0%
98.4%
100.0%
35.2%
92.5%17.0%
Entitlement Surplus
Usage %Usage %
Entitlement Surplus
Usage %
Last Month Stored State Water
Surplus
Requested
0.00
321.35
20.00
405.65
0.00
747.00
Friday, April 3, 2020 Page 1 of 1Report printed by:AdminData entered by:D. Bravo
ATTACHMENT 1a
Item 8.e. - Page 4
5.44
0.54
0.00
4.70
2.14
0.24 0.00 0.00 0.00 0.00 0.00 0.52 1.42
3.59 3.87 3.46
1.13
0.41 0.44
0.99
2.17
3.61
4.35 4.15
3.20
1.41
0.07 0.07 0.04
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
0
5000
10000
15000
20000
25000
30000
35000
40000
1/1/20202/1/20203/1/20204/1/20205/1/20206/1/20207/1/20208/1/20209/1/202010/1/202011/1/202012/1/20201/1/20212/1/20213/1/20214/1/20215/1/20216/1/20217/1/20218/1/2021Storage (AF)Date
LOPEZ RESERVOIR STORAGE PROJECTION
Actual Precipitation Predicted Precipitation Actual Storage
20,000 AF Storage Projection Storage Projection (No Rain)
1. Storage projection is based on predicted rainfall from longrangeweather.com, inflow based on predicted rainfall, 20-21 downstream release requests, and municipal usage.
2. Municipal Usage is based on Jan 2010-Dec 2019 average monthly deliveries.
3. Predicted inflow is based off of historical precipitation and storage data. Antecedant moisture conditions are factored into the model.The first rainstorms after months without
rain will cause less inflow than rainstorms during the rainy season. If the average daily rainfall for the previous three months is below 1 inch the model will multiply the predicted
inflow by 0.1, if the average is above 1 inch the inflow is multiplied by 1.25.
ATTACHMENT 2
Item 8.e. - Page 5
2,1382,31910811705001,0001,5002,0002,5002019 2020Yearly Water Use ComparisonAcre FeetUsage (gpcd)ATTACHMENT 3Item 8.e. - Page 6