PISMO BEACH COUNCIL AGENDA REPORT
Agenda Item #9.E
SUBJECT/TITLE:
WATER SUPPLY UPDATE
RECOMMENDATION:
No action required; information only.
BACKGROUND:
On November 16, 2021 staff provided an update to the City Council on the City’s water supply and committed to return to the Council at the second meeting every other month to provide an update on the City’s water supply.
The staff report for that meeting can be found in the Access Pismo online public records portal1 or by scanning the QR Code at right.
Update on Water Supply
The City’s water supply portfolio is made up of three sources, State Water, Lopez Lake Water, and groundwater from the Santa Maria Groundwater Basin (SMGB).
Santa Maria Groundwater Basin
The SMGB is an adjudicated basin, and the City of Pismo Beach has the right to extract 700 acre-fee per year (AFY) from the basin.
The NCMA TG has established a “Deep Well Index Threshold” level of 7.5 feet as a level that can induce seawater intrusion into the basin if the basin remains below that level for an extended period of time.
Previous Index Level:
Data Collection Date: October 5, 2021
Deep Well Index Level (DWIL): 6.64 feet
0.86 feet lower than the Deep Well Index Threshold
Most Current Index Level:
Data Collection Date: January 4, 2022
DWIL: 9.36 feet
1.86 feet higher than the Deep Well Index Threshold
The current DWIL is 2.72 feet higher than the previous level and 0.08 higher than one year ago (January 2021).
1 Full URL:
https://accesspismo.pismobeach.org/WebLink/DocView.aspx?id=362819&dbid=0&repo=Laserfiche
9.E-1Council Agenda 3-15-2022
Lopez Lake
Lopez Lake is still operating under the Low Reservoir Response Plan (LRRP), and because the level in Lake Lopez is below 15,000 acre-feet (AF), Zone 3 agencies have reduced their entitlements by 10%. The full list of recommend reductions in municipal diversions under the LRRP are shown in Table 1.
Table 1: LLRP Recommended Municipal Diversion Reduction Targets
Amount of Water In
Storage (AF)
Recommended Municipal
Diversion Reduction
Targets
Recommended
Municipal Diversion
(AFY) Targets for Pismo
20,000 0% 892
15,000 10% 802.8
10,000 20% 713.6
5,000 35% 579.8
1,700 100% 0
Lopez Lake Levels:
Previous Lake Level
Measurement Date: January 12, 2022
Lake Level: 14,942.8 AF
Most Current Lake Level:
Measurement Date: March 9, 2022
Lake Level: 14,508.7 AF
The current lake level is 434 AF lower than it was on January 12, 2022.
Current projections show if the area receives “average rainfall” between now and January of 2023, that storage in the lake will be approximately 10,000 AF in the middle of September 2023, as shown in Figure 1 below.
9.E-2Council Agenda 3-15-2022
Figure 1: Lopez Reservoir Storage Projections
State Water
On December 1, 2021 the Department of Water Resources (DWR) set initial 2022 State Water Project (SWP) available supplies on a basis that ensures the SWP long-term water supply contractors can meet their outstanding minimum human health and safety demands for water (health and safety allocation). This allocation is based on minimum unmet water demands to meet domestic supply, fire protection, and sanitation needs during the year. These health and safety needs are determined to be not more than 55 gallons per capita per day (gpcd), consistent with the recent State Water Resources Control Board (SWRCB) emergency curtailment regulations. Agencies with stored water, or other sources of water will not receive a SWP delivery at this time.
On January 20, 2022 the DWR increased SWP deliveries to 15%. This means that the City of Pismo Beach can expect to receive 171 AF of Table A allocation and 186 AF of Drought Buffer for a total of 357 AF of State Water. However, the County of San Luis Obispo has agreed to make its subcontractors whole, meaning the City can take delivery of 1,240 AF of State Water from the County.
9.E-3Council Agenda 3-15-2022
The City’s current water supplies without additional State Water from the County are shown in Table 2, belowTable 2.
Table 2: Current Pismo Beach Water Supplies
Source
Full
Allocation
(AF)
Percent of
Allocation Allocation (AF)
SMGWB* 700 30% 210
State Water 1,140 15% 171
Drought Buffer** 1,240 15% 186
Stored State Water 0
Lopez Water# 892 80% 713.6
Lopez Surplus 314.0
Total 2,692 1,579.6
*Santa Maria Groundwater Basin
**Drought buffer is an additional allocation of water that can only be delivered when State Water Deliveries are less than 100%. The total amount of State Water delivered including drought buffer cannot exceed 1,240 AF in a given year.
#Lopez Lake is projected to drop below 10,000 AF in August of 2022. At that time allocations from the lake would drop to 80% retroactively, therefore for planning purposes an 80% allocation is assumed.
Taking into account the State Water the County has agreed to deliver to the City of Pismo Beach, the City’s total available water supply to 2,477.6 AF for 2022.
Precipitation
The City’s two local water supplies, Lopez Lake and the Santa Maria Groundwater Basin, are highly dependent on rainfall. Calendar year 2020 saw a significant short fall in precipitation, however and 2021 did see a small surplus of rain. So far 2022 has proven to be drier than both of the previous years. Rainfall data for these years is shown in Table 3, on the next page.
9.E-4Council Agenda 3-15-2022
Table 3: Average and Actual Rainfall from January 2020 to December 2021 Month
*Average
Rainfall
(in)
2020
Rainfall
(in)
Delta
(in)
2021
Rainfall
(in)
Delta
(in)
2022
Rainfall
(in)
Delta
(in)
Jan 3.59 0.61 -2.98 6.46 2.87 0 -3.59
Feb 3.87 0 -3.87 0.03 -3.84 0.08 -3.79
Mar 3.46 8.02 4.56 2.53 -0.93
Apr 1.13 1.72 0.59 0 -1.13
May 0.41 0 -0.41 0.1 -0.31
Jun 0.07 0 -0.07 0 -.07
Jul 0.03 0 -0.03 0.03 0
Aug 0.02 0 -0.02 0 -0.02
Sep 0.32 0 -0.32 0 -0.32
Oct 0.62 0.04 -0.58 1.95 1.33
Nov 1.7 0.49 -1.21 0.46 -1.24
Dec 2.57 1.21 -1.36 7.69 5.12
Total 17.79 12.09 -5.7 19.25 1.46 0.08 -7.38**
*Average rainfall from http://longrangeweather.com/
** total difference for only the months shown
Conclusion and Recommendation
On January 18, 2022 the City declared a Severely Restricted Water Supply Condition via Resolution R-2022-004 and the City’s water position has not significantly changed since the last report. Since the last report, the DWIL of the SMGB is 2.72 feet higher than the previous level, and Lopez Lake levels have decreased by 434.1 AF. Because the County has agreed to make its subcontractors whole with respect to State Water, there is no change in the amount of State Water available to the City despite the deliveries being increased from 0% to 15%.
Staff recommends that the City remains in a Severely Restricted Water Supply Condition and will continue to report back to the City Council at the second meeting of each month.
FISCAL IMPACT:
There is no direct fiscal impact from this report.
ALTERNATIVES:
1. Provide staff with direction on how to proceed.
ATTACHMENTS:
None
Prepared and Submitted by: Meeting Date: March 15, 2022 Benjamin A. Fine, P.E., Director of Public Works/City Engineer City Manager Approval:
9.E-5Council Agenda 3-15-2022