STAFF REPORT
Meeting Date: September 12, 2022
To: Honorable Mayor & City Council
From: Robert Welch, P.E., Utilities General Manager
Vince Damasse, P.E., Water Resources and Operations Manager Subject: Request by Vice-Mayor Gold, to Discuss Water Operations and Emergency Storage
Attachments: None
INTRODUCTION
Per the request of Vice-Mayor Gold, City Council is requested to review the management of the City’s water system operations and emergency water storage in preparation of the City Council reviewing the Cost of Service analysis. This fall, the City Council will be reviewing a Cost of Service analysis associated with the City’s water and wastewater operations.
DISCUSSION
The City owns, operates, and maintains the water system within the City’s service area.
The water service area includes the entire City of Beverly Hills plus a portion of the City of West Hollywood. The water system includes 10 storage reservoirs, 9 pump stations, 7 groundwater wells (5 currently permitted with 2 wells, Well 6 and LCW-1, pending permit amendment), approximately 170 miles of pipelines, approximately 10,800 water meters and the Foothill Water Treatment Plant (WTP), three (3) emergency interconnections with Los Angeles Department of Water and Power (LADWP) and imported water connections from Metropolitan Water District (MWD).
Operations of Reservoir System
The City has 10 Reservoirs with a maximum storage of 43 Million Gallons (MG). The City operates its current system in a way that enables our reservoirs to be 35% to full at all times. As one reservoir drains the others fill, so at no time are all reservoirs at a 35% level. The City also follows a reservoir top-off procedure where reservoirs are filled if there is a red flag day, for water supply interruptions, or emergency events. Staff is currently in the process of preliminary design for Reservoir Management Systems (RMS) at the three largest reservoirs. With the addition of the new RMS at Greystone (19.4 MG), Coldwater (8.3 MG) and Sunset (6 MG) reservoirs, which make up 77% of the total storage within the City, these reservoirs will be able to sustain a higher operational water level (ranging from 60% level to full) which will add approximately 8.5 MG of available Meeting Date: September 12, 2022
emergency storage at these three reservoirs. Also, most inspections and/or repairs to our reservoirs can be done without draining the reservoirs by the use of certified divers.
Water Distribution
The City receives water from MWD for distribution as well as water from the Water Treatment Plant. The average daily demand for water within the City is forecasted to be
9.8 MG. The City has five (5) wells currently permitted and operational. With the addition of two more wells (Well 6 at Burton and Foothill and LCW-1 within Los Angeles along La Cienega Blvd.) planned in 2022, the water treatment plant can provide up to
2.3 MG (approximately 25%) from local ground-water sources annually. Along with our MWD imported water connections, the City has three (3) LADWP Emergency Connections located at strategic points within the City that can supply water into our system.
Resiliency
Through the development of the City’s Integrated Water Resources Master Plan (IWRMP) (Nov. 2020), emergency resiliency was evaluated and in particular emergency storage. The emergency storage calculation performed in the 2020 IWRMP was a theoretical one and very conservative compared to industry standards. The analysis was conducted to determine the duration (days) of emergency storage available in the event that the MWD water supply is offline and no other emergency interconnections are available (the City has three emergency interconnections from LADWP). It is important to note that emergency storage duration is calculated based on above ground storage in reservoirs and groundwater supplies. For example, the Foothill WTP capacity will supply approximately 2.3 MGD of local supply, which is equivalent to a 2.3 MG above ground reservoir that can be refilled and replenished daily. Our groundwater wells serve as a renewable source of underground storage.
MWD Administrative Code § 4503 explains that, “Whenever repairs or maintenance of the District's system, … Each member agency shall have sufficient resources such as local reservoir storage, groundwater production capacity, system interconnections or alternate supply source to sustain: (1) A seven-day interruption in Metropolitan deliveries from raw and treated water distribution facilities based on average annual demands of the affected facility.”
As outlined in Appendix C of the IWRMP, the City took a conservative approach in its emergency storage evaluation and required that it provide a total of 7-days of storage based on peak summer month demands assuming all reservoirs were at a theoretical operating level of 25% with no additional contributions from the City’s other imported water connections or emergency interconnections.
Table 6 below indicates the results of the calculation assuming all reservoirs operating at 25% of operating capacity with peak summer month demand. Note that the City currently operates its system in a way that enables our reservoirs to be 35% to full at all times. As one reservoir drains the others fill, so at no time are all reservoirs at only a 35% level. The City also follows a reservoir top-off procedure where reservoirs are filled if there are any indications of fire hazards, high winds, water supply interruptions, or other emergency events. For reference, the City’s recent daily water use demand was in the last two months approximately 9.4 MGD. Also, note that the total available supply from the Water Treatment Plant will not be realized until La Brea well is brought online later this year.
Meeting Date: September 12, 2022
Table 7 below is the result of the calculation assuming all reservoirs operating at a full operating capacity with peak summer month demand. This chart more accurately represents how the City operates the reservoir system since we would fill reservoirs to full capacity prior to any outage.
As shown in Table 7, even with a conservative average summer demand and the WTP online, the emergency storage ranges from 4.2 days to 8.3 days with various levels of conservation (assuming 2021 Scenario). Please note that the City’s average water use per day in July 2022 was 9.1 MG and is a 26.7% reduction in water use from the measured baseline from August 2013. For comparison, the City used 10.0 MG in July 2020 and 10.4 MG in July 2021.
Fire Suppression
Working with the Fire Department, staff prepared an analysis to ensure the water system can fight structure fires, in the event there was a loss of MWD imported water connections and no contribution from LADWP’s emergency connection. Please note that this analysis was for structure fires only and was not intended to simulate a wildfire.
The analysis was performed assuming four (4) simultaneous structure fires in the hills (Zone 8) with a fire flow demand requirement of 1,250 gpm for 2 hours. Other assumptions made for this analysis included that it was during the hottest summer day Meeting Date: September 12, 2022
with the most water demand in the City, our reservoirs were full to start, and both MWD and LADWP water connections were unavailable. Reservoirs start full due to our continued coordination with the Fire Department. The results of the analysis indicate that the Fire Department could fight four (4) simultaneous structure fires, for 2 hours, and repeat this for two (2) days. Note, that with the imported connections from MWD, the Fire Department could sustain this scenario indefinitely.
A second analysis was performed that had all the same assumptions above, but included the future ultimate Cabrillo Reservoir (4.3MG) maximum storage. The results of the analysis indicate that the Fire Department could fight four (4) simultaneous structure fires, for 2 hours, and repeat this scenario for 2.5 days. Again, with the imported connections from MWD, the Fire Department could repeat this scenario indefinitely.
All of the City’s reservoirs, pump stations, imported connections and wells can be operated remotely from the Water Treatment Plant through a SCADA control system.
This software is also available on our operator’s laptops allowing for even more mobility.
The reservoirs, pump stations and imported connections are equipped with backup generators that will automatically power on during a power outage. The City also regularly inspects our pump stations, wells, and reservoirs, removing vegetation as a preemptive fire protection measure. Also, all site locations are equipped with CCTV camera’s that are available to the operators remotely at the Water Treatment Plan.
Staff is in the process of to initiate a project for Advanced Metering Infrastructure (AMI) for the City’s water meters. This program will be replacing all existing meters with new meter technology allowing for real time meter reading and remote operational options.
In regards to fire suppression, the existing water system has been developed to fight structure fires and has the ability to provide for the necessary demand for fire suppression for structure fires. When discussing wildfires, Vegetation Management, Fuel Modification, and Home Hardening are just a few of the programs that provides a means of property / home protection. These programs are made to give their homes a fighting chance when they are told to evacuate.
FISCAL IMPACT
No impact to the City’s budget at this time. A water and wastewater Cost of Service analysis will be brought forward to City Council this fall that anticipate future water infrastructure improvements (e.g. Cabrillo Reservoir).
RECOMMENDATION
This report is provided to City Council regarding the operation of the City’s water system and emergency water storage in preparation of the City Council’s upcoming review of the Cost of Service analysis.
Shana E Epstein,
Director of Public Works
Approved By