The Grizzly Flats Community Services District (GFCSD) provides domestic water service to 611 residential customers in a geographically remote foothill community in El Dorado County. The system is classified as a “Small Community Water System” by the Department of Health Services. The community is officially a Disadvantaged Community (DAC) with extremely limited financial resources. The community is served by a small two-source water system, which was originally constructed in the mid 1960’s through the mid 1970’s. Water for the community is derived from two local creeks, North Canyon and Big Canyon, which are tributaries to the Cosumnes River. These creeks are diverted and the water is transported roughly two miles via pipeline to a storage reservoir prior to treatment.
This project will substantially improve GFCSD water supply delivery system to a rural Disadvantaged Community with a water supply system that is over 40 years old. The various components of the project are described further below.
Air Release Valve (ARV): Eagle Ditch Pipeline, which is about 3 miles long, is GFCSD’s only water transmission line from their diversions to their raw water reservoir (which feeds GFCSD’s treatment plants). It used to be an open ditch but was piped using volunteer labor force in the late 1980s. In the last few years, GFCSD staff observed reduced flows coming from the pipe into the reservoir. They also noticed that the pipe is not taking all the water it should at the diversions. Using a camera, staff inspected approximately 3,000 feet of this pipe and found that roughly a third of it has air pockets trapped inside. Air pockets are known to reduce water flows to less than a quarter of the pipeline capacity. Water loss occurs when the air has to be removed and the system stopped.
Solution: Staff estimated that 20-25 ARVs needed to be installed to remove these air pockets.
Backwash Tank. The GFCSD system uses two backwash tanks that are over forty years old. The metal walls of these tanks were measured and results showed substantial thinning. As these tanks could fail due to thinning,
Solution: GFCSD staff determined that it will be best to replace the two tanks with one tank of equal or larger capacity. A newer, more efficient tank will allow GFCSD to reclaim water used for backwash and recycle it back into the reservoir for treatment more effectively. The new tank will also allow solids in the water to settle and be drained from the bottom of the tank, which is not possible with the old tanks. The clarified water could be returned to the reservoir. The project will include construction and installation of a new tank, piping for the recovery system and a pump.
Cathodic Protection: GFCSD’s 4 treated water storage tanks hold their total supply of treated water and keep water lines pressurized and operating correctly. They are a major component of GFCSD’s system reliability. The four tanks hold 600,000 gallons of water and they represent GFCSD’s only storage for treated water. A recent “Tank Coating Evaluation,” uncovered significant corrosion issues in the treated water storage tanks, which threaten the reliability of the system and could lead to leakage and water loss.
Solution: There are various alternatives to solve this corrosion issue, but they are all quite expensive. Replacing the tanks with new ones could cost anywhere from $150,000 – $300,000, depending on the size of the tank and on unavoidable issues that could occur during construction. Relining or recoating the tanks was estimated to be around $60,000 per tank. Cathodic Protection systems, however, are much more cost effective and cost about $12,000 per tank and will extend the life of the storage tanks by 10-15 years.
Leak Detection and Repair: The GFCSD water system is over 40 years old and consists of 25,248 feet, or approximately five miles, of one-inch to eight-inch pipeline that delivers water to over 600 residential accounts. The main lines are primarily asbestos cement and the service lines are thin-walled PVC with inadequate pressure ratings (less than Schedule 40). The pipelines were constructed with native backfill, without the benefit of engineered pipe zone material. As a result, point loads are a common cause of the ever increasing trend of waterline leaks and breaks, with three to five service or main line breaks per year. The critical issue facing the GFCSD is meeting domestic water demand and fire suppression needs, especially in the late summer and fall months when stream flows are at their lowest stages.
Solution: Timely detection and repair of water leaks will reduce treated-water losses, increase water use efficiency and optimize the use of GFCSD’s local water resources. Implementing a leak detection and repair program will provide efficiencies within GFCSD’s existing water infrastructure and ensure that treated water is reliable and consistently available to meet existing customer demands and fire suppression needs. While aleak detection and repair program is not expected to eliminate all leaks, it is expected to fix a substantial amount of leaks within GFCSD’s system. Conditions suggest that this project will realize a possible 20 percent in savings from the implementation of the leak detection and repair program.
Meter Replacement: GFCSD staff reviewed a global list of all 600 meters in their service territory and determined that about half of their meters are over 20 years old. This is problematic because meters on average have a 10-15 year life span. Many of these old meters provide inaccurate readings and they lack leak indicators.
Solution: Implementation of this project will replace roughly 300 meters to newer meters that not only provide accurate readings, but can detect leaks on properties. By replacing old meters, FCSD can ensure the accuracy of each customer’s water demand and will also help to better and more quickly identify leaks on the customer side, thus conserving water and preventing unnecessary water loss.
SCADA. In 2014, GFCSD staff worked cooperatively with Carlton Engineering to compile the GFCSD Water System Improvement Project (WSIP) PER, (pg 13) to comprehensively assess the GFCSD’s water system needs. This assessment determined that system monitoring at the treatment plant and in the distribution system is needed to detect large-scale water losses resulting from line breaks. Currently, the GFCSD physically monitors the potable water storage tank levels as often as possible. In the event of a major failure in the system, the GFCSD is notified by either customers calling the emergency line or by the auto dialer at the treatment plant.
Solution: The project will install a Supervisory Control and Data Acquisition (SCADA) control system to monitor and control the water treatment process and distribution system and to improve operational performance of the treatment plant. This system will allow operators and maintenance personnel to respond more quickly and appropriately to problems in the system. Ultimately, quick warning and easy access to system status will help reduce water waste, soil erosion, unauthorized discharge of chlorinated water into the environment, and public safety issues from water damage to roadways.
Residential Water Conservation: GFCSD’s Residential Water Conservation Program will provide performance measures to assist GFCSD in achieving the CABY region goal of Best Management Practices (BMPs) compliance. The Residential Water Conservation Program will focus on water use awareness, education and conservation savings. It will be designed to change lifestyle behaviors and the understanding of water as natural resource. While outreach and education programs do not have direct quantifiable water savings; however, consistent with the 20×2020 statewide per capita water reduction, it promotes water use efficiency to help achieve countywide 20% per capita water demand reduction.
Current Status (December 2016)
Planning and design is underway, and leak detection and prioritization of water system needs is ongoing. Construction is ramping up, and quarterly reporting and invoicing will continue.
Lead Agency: Grizzly Flats Community Service District
Contact: Jodi Lauther, General Manager, 630-622-9626, email@example.com
Measurable Physical Benefit: Water Supply, Water Quality
County: El Dorado