Cotati City Council
Agenda Staff Report
Item type: CONSENT CALENDAR (ACTION)
To: City Council
Subject: MAIN CLEANING AND WATER TREATMENT SERVICES
FOR THE WATER DISTRIBUTION SYSTEM
Date: February 13, 2024
Written by: Craig Scott, Director of Public Works/City Engineer Recommendation
It is recommended the City of Cotati City Council by motion approve a Standard Service Agreement with No-Des, Inc., to complete water main flushing services.
Background
The City owns and operates a public drinking water system and is regulated by the State Water Resources Control Board. Proper maintenance of the water system requires regular flushing of the distribution system and particularly the pipelines with low points and dead ends. The flushing maintains water clarity and discharges sediment that may collect in the system.
Analysis/Discussion
With the increased frequency and severity of droughts, and the increased costs of treating and delivering drinking water, owners and operators of public water systems are increasingly using closed system flushing techniques, instead of flushing water, to conserve water. The City used the closed system technique in 2016, and 2023, and is again proposing its use.
The closed system flushing method consists of hiring a service which provides a trailer mounted water filtration system, real time water quality measurement and pumping equipment to draw water from one hydrant, treat the water, and return the treated water to the system via a second hydrant. Strategically shutting water valves enables cleaning many thousands of feet of main with a single set up location for the treatment system. Ther treatment system uses filters which remove sediment, not harmful to customers, but does lead to discoloration and has the potential to clog water meters.
The City has researched providers of this service and have only found the one provider, No-Des, Inc. Some cities, Petaluma for instance, have chosen to purchase and operate their own trailer mounted treatment unit. Their system is large enough for a crew to be kept busy year-round operating the unit. This may be an option for the City in the future, but the infrequency of the cleanings, and the high cost of the units, has made this option cost prohibitive.
City Staff requested and No-Des, Inc. provided a quote to provide the treatment trailer, replacement filters, appurtenant equipment including hoses and fittings, and a crew of two for approximately a two-week period. The process begins with “burndown” of the equipment which sanitizes the trailer mounted equipment prior to use, then the flushing operation including moving from one location to another, and replacement filters. City Staff expects this year’s operation to be similar to last year where 5.7 miles of pipeline were cleaned which is about 20% of the system.
Financial Considerations
The City’s adopted FY23/24 Budget includes $100,000 for main flushing contract services which was based on a prior quote received in 2023. The updated quote for services attached from No-Des, Inc. is for an amount of $99,721.26, which is within the budgeted amount and no budgetary adjustments or actions are required from the City Council at this time.
Environmental Issues
This action is found to qualify for a Class 1 Categorical Exemption under CEQA Section 15301 in that the project consists of the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of the existing or former use.