PISMO BEACH COUNCIL AGENDA REPORT
Agenda Item #12.A
SUBJECT/TITLE:
2021 NORTHERN CITIES MANAGEMENT AREA (NCMA) ANNUAL REPORT AND
WATER SUPPLY UPDATE
RECOMMENDATION:
No action required; information only.
BACKGROUND:
This report to the City Council will serve as both an update on the Northern Cities Management Area (NCMA) Annual Report and the bi-monthly update on the status of the City’s water supply.
2021 Northern Cities Management Area (NCMA) Annual Report Due to a California Superior Court Ruling in 2008, the rights to the Santa Maria Groundwater Basin (SMGB) have been adjudicated to various agencies. Part of that ruling established three management areas, including the Northern Cities Management Area (NCMA), Nipomo Mesa Management Area (NMMA) and the Santa Maria Valley Management Area (SMVMA). Further, the ruling mandated that “a monitoring program be established in each of the three Management Areas to collect and analyze data regarding water supply and demand conditions,” and an annual report be filed with the Court within 120 days after the end of each calendar year.
The NCMA is comprised of four agencies: the Cities of Arroyo Grande, Grover Beach, and Pismo Beach, and the Oceano Community Services District. Through the NCMA Technical Group (TG), comprised of representatives from each agency, the member agencies work together to manage the SMGB and meet the annual reporting requirements of the Court Order.
The 2021 NCMA Annual Report, prepared by GSI Water Solutions, Inc. (GSI), was filed with the Court on April 29, 2022.
Discussion
The NCMA TG is facilitated by Water Systems Consulting, Inc. (WSC).
Together, the TG and WSC hired GSI to compile the data gathered during quarterly groundwater monitoring and to create the 2021 NCMA Annual Report. A copy of the full report is available for download from the Access Pismo1 public records portal or by scanning the QR Code to the right. A copy is also available upon request from the City Clerk’s Office.
1 Full URL:
https://accesspismo.pismobeach.org/WebLink/DocView.aspx?id=422908&dbid=0&repo=Laserfiche
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The following list is a summary of the report’s highlights and important information:
1. During 2021, water elevations generally decreased slightly in the NCMA portion of the SMGB in response to below-average rainfall in 2021. The relatively minor decrease in water levels throughout most of the area, despite the below-average rainfall conditions, is less than would be expected given the recent rainfall patterns.
The fact that the impacts are not greater is attributed to ongoing efforts by all NCMA agencies to minimize groundwater extraction and maximize surface water supply sources while maintaining the water conservation practices and requirements brought on by the current drought.
2. Ground Water Levels – The greatest threat to the groundwater supply in the area is seawater intrusion. An indicator of whether the NCMA agencies and other stakeholders are successfully averting the threat of seawater intrusion is the groundwater elevation in the NCMA sentry wells near the coastline. The average water elevations of three sentry wells—24B03, 30F03, and 30N02–make up the Deep Well Index. This index was developed by the NCMA in 2007 to gauge the ability of the aquifer to withhold potential landward migration of seawater. A Deep Well Index value above 7.5 feet North American Vertical Datum 1988 (NAVD 88) generally indicates that sufficient freshwater flow occurs from the east to the coastline to prevent seawater intrusion. History has shown that a prolonged period in which the Deep Well Index level is below 7.5 feet develops groundwater conditions that pose a risk of seawater intrusion. The following are evaluations of groundwater levels through the seasons in calendar year 2021.
Spring 2021 – In the mostly urbanized areas north of Arroyo Grande Creek, groundwater is extracted from the deep groundwater aquifers of the Paso Robles Formation and the Careaga Sand. The water elevation contours in the deep aquifer system in spring of 2021 generally showed a westerly to southwesterly groundwater flow. These groundwater flow gradients and positive (above mean sea level) groundwater elevations are developed and maintained primarily because the NCMA agencies have managed this portion of the basin through cooperative water management and conservation efforts. April 2021 groundwater elevations in the deep aquifer system main production zone along the coast ranged from 7.0 to 9.0 feet above sea level. By comparison the April 2020 groundwater elevations ranged from 8.0 to 12.0 feet.
Fall 2021 – Groundwater elevations in the alluvial aquifer within the Cienega Valley in October 2021 were 1 to 14 feet lower than elevations at the start of the irrigation season in April 2021, which is a typical seasonal response to the irrigation season.
These conditions are consistent with the pumping depressions observed historically during the fall in the Cienega Valley. The alluvial groundwater elevation in the pumping depression in October 2021, at 11.6 feet below sea level, was 2.8 feet higher than in October 2020. October 2021 groundwater elevations in the deep aquifer system main production zone along the coast ranged from 3.8 to 7.0 feet above sea level.
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Deep Wells – In 2021, the Deep Well Index started the year above the 7.5-foot threshold value with an index number in January of more than 9 feet. It continued to rise, reached a high of nearly 10 feet during February, and then began to decline.
The index value dropped below the 7.5-foot trigger value by July and continued to fall to a low point of just over 6 feet in late October. A slow recovery occurred through November, followed by a more rapid recovery in December, coincident with above average monthly rainfall received in December. The index value continued to rise throughout the end of the year and finished 2021 at about 9 feet above sea level.
NCMA/NMMA Boundary – The water elevation in the San Luis Obispo County monitoring well (Well 32C03), which was installed to monitor aquifer conditions along the NCMA/NMMA boundary, typically exhibits regular seasonal fluctuations.
As in 2020, the water elevation in the well remained above sea level throughout all of 2021, in contrast to the 2013 through 2016 period when the water levels in the NCMA/NMMA boundary area typically dropped below sea level in August and remained at a low elevation until early October.
3. Change in Groundwater Storage – The change in groundwater in storage in the NCMA portion of the SMGB between April 2020 and April 2021 is estimated by comparing water level contour maps created for these periods and calculating the volume change from April 2020 to April 2021. Separate estimates of change in groundwater in storage were computed for both the deep aquifer system and for the alluvial aquifer and then summed to represent the total NCMA estimated change in groundwater in storage. Comparison of April water levels was chosen to comply with the California Department of Water Resources (DWR) reporting requirements under the Sustainable Groundwater Management Act (SGMA).
A decrease of groundwater in storage is a reflection of a net decrease in water levels across the aquifer. During the period of April 2020 to April 2021, the NCMA portion of the SMGB experienced a net decrease of groundwater in storage. The net decrease in groundwater levels represented a decrease of groundwater in storage from April 2020 to April 2021 of approximately 1,400 acre-feet (AF); that is, there was approximately 1,400 AF less groundwater stored in the NCMA portion of the SMGB in April 2021 than in April 2020.
4. Groundwater Quality – Analytical results of key water quality data (chloride, total dissolved solids (TDS), and sodium) in 2021 were generally consistent with historical concentrations and observed ranges of constituent concentrations. In general, no water quality results were observed that are a cause of concern.
5. Water Supply and Production/Deliveries
Urban Water Use – Urban water use in 2021 among the NCMA agencies was 6,073 AF, a slight increase from 2020. Urban water use in the past 20 years has ranged from 5,476 AF (2016) to 8,982 AF (2007). There has been an overall
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decline in urban production since 2007, although there have been slight increases since the low point in 2016. The decline in pumpage since 2013 was in direct response to a statewide order by the Governor to reduce the amount of water used in urban areas by 20 percent. That goal was achieved locally by conservation activities implemented by the NCMA agencies, and the relatively low urban water has been maintained since then.
Total Water Use – Total water use in the NCMA in 2021 (including urban use by the NCMA agencies plus agricultural irrigation and private pumping by rural water users) was 8,658 AF. Of this amount, Lopez Lake deliveries were 3,522 AF, California State Water Project deliveries totaled 1,772 AF, and groundwater pumping from the NCMA portion of the SMGB accounted for approximately 3,344 AF. The City of Arroyo Grande produced 20 AF from its Pismo Formation wells, outside the SMGB, in 2021. The breakdown is shown Table 1.
Table 1. Water Production by Source (AF)
Agency Lopez
Lake
State Water
Project
SMGB
Groundwater
Other
Supplies1 Total
Urban Area
Arroyo Grande 2,158 0 129 20 2,307
Grover Beach 795 0 482 0 1,277
Pismo Beach 406 1,302 63 0 1,771
Oceano CSD 163 470 85 0 718
Urban Water Use Total 3,522 1,772 759 20 6,073
Non-Urban Area
Agricultural Irrigation
Applied Water 0 0 2,457 0 2,457
Rural Water Users 0 0 82 0 82
Non-potable Irrigation
by Arroyo Grande 0 0 46 0 46
Total 3,523 1,772 3,344 20 8,658
6. Threats to Water Supply – Total groundwater pumping (urban, agriculture, and rural domestic) from the SMGB in the NCMA was 3,344 AF in 2021, which is 35 percent of the court-accepted 9,500 acre-feet per year (AFY) long-term safe yield of the NCMA portion of the SMGB.
When pumping is less than the safe yield of an aquifer, groundwater in storage should generally increase and result in rising groundwater levels. As such, groundwater elevations throughout the NCMA portion of the SMGB should rise
12.A-4Council Agenda 5-3-2022
significantly if several consecutive years of groundwater pumping occurs at 30 to 40 percent of the safe yield, which has been the case in the NCMA for the past decade. However, as illustrated by the decline in groundwater levels during 2021, the data show that the aquifer is still in a tenuous position with respect to the threat of seawater intrusion.
Historically, groundwater flowed from higher elevations inland westward toward the ocean, thereby acting to prevent seawater intrusion. In recent years, the well- documented pumping depression in the deep aquifer system near Black Lake Canyon within the NMMA appears to have reversed the groundwater gradient. The apparent development of a landward gradient in the southern portion of the NCMA, because of the pumping depression in the NMMA, likely reduces the historical recharge volume of subsurface inflow into the NCMA from Nipomo Mesa. This reduction of subsurface inflow to the NCMA creates conditions more likely to result in seawater intrusion in the NCMA and NMMA.
During 2021, there were no indications of seawater intrusion, but any increase of groundwater pumping or decrease in rainfall may quickly result in a greater risk of seawater intrusion
Update on Water Supply
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 portal2 or by scanning the QR Code at right.
Current Status
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: January 4, 2022
Deep Well Index Level (DWIL): 9.36 feet
1.86 feet higher than the Deep Well Index
Threshold
2 Full URL:
https://accesspismo.pismobeach.org/WebLink/DocView.aspx?id=362819&dbid=0&repo=Laserfiche
12.A-5Council Agenda 5-3-2022
Most Current Index Level:
Data Collection Date: April 5, 2022
DWIL: 7.98 feet
0.48 feet higher than the Deep Well Index
Threshold
The current DWIL is 1.38 feet lower than the previous level and 1.08 lower than one year ago (April 2021).
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 2.
Table 2. 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: March 9, 2022
Lake Level: 14,508.7 AF
Most Current Lake Level:
Measurement Date: April 8, 2022
Lake Level: 14,148.1 AF
The current lake level is 360.69 AF lower than it was on March 9, 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 late September of 2022, as shown in Figure 1 below. This date is 11 days later than the previous prediction.
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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%, however on March 18, 2022 the DWR reduced SWP deliveries to 5% due to the lack of rain and snowpack. This means that the City of Pismo Beach can expect to receive 57 AF of Table A allocation and 62 AF of Drought Buffer for a total of 119 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.
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The City’s current water supplies without additional State Water from the County are shown in Table 3, below.
Table 3. Current Pismo Beach Water Supplies
Source
Full
Allocation
(AF)
Percent of
Allocation Allocation (AF)
SMGWB* 700 30%210
State Water 1,140 5%57
Drought Buffer** 1,240 5% 62
Stored State Water 0
Lopez Water#892 80%713.6
Lopez Surplus 314.0
Total 2,692 1,347.6
*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 that the County has agreed to deliver to the City of Pismo Beach, the City’s total available water supply is 2,463.6 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 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 4, on the next page.
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Table 4. 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 .05 -3.54
Feb 3.87 0 -3.87 0.03 -3.84 .10 -3.77
Mar 3.46 8.02 4.56 2.53 -0.93 1.08 -2.98
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 1.23 -10.29**
*Average rainfall from http://longrangeweather.com/
** total difference for only the months shown
Past Actions
The City is currently in a Severely Restricted Water Supply Condition. On June 1, 2021, City Council declared a Moderately Restricted Water Supply Condition via Resolution R- 2021-049 in response to the current drought. Then on January 18, 2022 the City Council declared a Severely Restricted Water Supply Condition via Resolution R-2022-004 in response to the continued drought conditions and dropping levels in Lake Lopez.
Building Restrictions
The current triggers for the building restrictions are that on May 1st of each year the City’s water supply is evaluated and if the water supply as of May 1st is 15% greater than the previous year’s production, no building restrictions are called for, as shown in Figure 2 on the next page. The City’s current water supply is greater than 15% of last year’s and staff does not recommend that building restrictions be considered at this time. However, because the City’s water supply is in a deficit without additional water from the County, staff is including the building restriction flow chart to provide the Council with an opportunity to review and discuss the building restriction flow chart.
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Figure 2: Flow Chart Illustrating Triggers for the Three-Tier Building Restriction System
Is total Water
Supply above
1,630 AF?
Is Lopez
above
10,000 AF?
Is State
Water Above
20%?
Is Lopez
above 5,000
AF?
Is Lopez
above 4,000
AF?
Tier I Tier II Tier III
Is State
Water Above
15%?
Is State
Water Above
10%?
Y
Y
Y Y Y
Y Y
N
N N N
N N
Is total Water
Supply above
1,130 AF?
Is total Water
Supply above
850 AF?
Y Y
N N N
SMGB below
trigger level for
6 consecutive
quarters?
SMGB below
trigger level for
10 consecutive
quarters?
SMGB below
trigger level for
3 of 4 previous
quarters?
N
Y
N
Y
N
Y
Y
N
Evaluate on May 1st of each year.
Is
total water
supply
15% above previous
year’s
production?
No Restrictions
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In 2021 the City produced 1,770.8 AF of water which was made up of 62.52 AF from the SMGB, 283.36 AF from Lopez Lake, 263.24 AF from Lopez Lake Surplus and 1,161.7 AF from the SWP. From Table 3, above the City’s available water supply is 1,347.6 AF without additional water from the County. Following the building restriction flow chart, shown in Figure 2 above, without consideration of County Stored State Water, the Council may wish to consider Tier III Building Restrictions. However, when considering County Stored State Water the City’s available water supply is 2,463.6 AF, meaning that no Building Restrictions would need to be considered per the Council’s current policy.
Conclusion and Recommendation
Given the fact that Lopez Lake is at 14,148.1 AF, SWP deliveries are set at 5% (and could be adjusted back to 0%) and that without County Stored State Water the City’s water supply is only 1,347.6 AF, staff recommends that the City Council consider declaring a Critical Water Supply Condition pursuant to section 13.24.060 of the City’s Municipal Code.
A Critical Water Supply Condition has the same water use restrictions as a Severely Restricted Water Supply Condition, with that added condition that, “the City Council may impose any water rationing requirements as it deems appropriate to protect public health, safety, welfare, comfort and convenience.” Some water use restrictions the Council may wish to consider could include:
Prohibition on washing vehicles except at a commercial facility that recycles wash water
Extending the prohibited hours for outdoor irrigation from 10 a.m. to 4 p.m. to 8 a.m. to 6 p.m.
Limit outdoor irrigation to one day per week
Mandate that all water users cut their water consumption by 10% as compared to a given baseline (the previous year, another given year, etc.) Mandate that all water leaks be repaired within 72 hours of notification by the City Other restrictions the City Council deems necessary to reduce water consumption Should the City Council wish to declare a Critical Water Supply Condition or enact building restrictions, staff recommends that the City Council provide direction on what restrictions should be enacted and staff will return at the next meeting with a resolution that reflects the direction of the City Council.
FISCAL IMPACT:
There is no direct fiscal impact from this report.
ALTERNATIVES:
Provide staff with direction on how to proceed.
ATTACHMENTS:
None
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Submitted by: Meeting Date: May 3, 2022
Benjamin A. Fine, P.E., Director of Public Works/City Engineer City Manager Approval:
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