Disinfection Byproduct Reduction Project

The project involves comprehensive upgrades to the Westhaven Community Services Districts water system to enhance treatment processes, replace aging infrastructure, increase storage capacity, and improve fire flow reliability across the service area. Key improvements include installing waterlines and electrical conduit from the 4th Avenue Well to the Water Treatment Plant (WTP) site, replacing existing water meters and meter boxes near 4th Avenue, and installing new fire hydrants along 4th Avenue. At the WTP site, construction will include a new treatment building, a septic tank and leach field, two propane tanks, an emergency backup generator, a Battery Energy Storage System, a hydropneumatic tank, and a 200,000-gallon glass-fused bolted steel water tank with an aluminum domed roof. To address groundwater intrusion at the new tank site, a 6-inch sub-drain trench will be installed along its southwest side, with overflow routed through a dechlorination diffuser into a rock-filled concrete cylinder that discharges into a newly constructed bioswale. The slow sand filters will have their media replaced, and associated piping, drainage, and electrical systems will be upgraded. A Supervisory Control and Data Acquisition (SCADA) system will be implemented, and photovoltaic solar panels will be mounted on the WTP building’s roof. The Humboldt crossing on Two Creek will be removed, and the existing single-phase electrical alignment will be converted to 480V three-phase, requiring replacement of PG&E power poles and overhead lines, plus extension of an overhead line to a new pole at the WTP site. Environmental compliance is central to this project, governed by the California Environmental Quality Act (CEQA) through a Mitigated Negative Declaration and an associated Mitigation Monitoring and Reporting Program. Contractors must adhere to a series of enforceable mitigation measures, including daily biological surveys for special-status species like the northern red-legged frog and Pacific tailed frog prior to any earth-disturbing activity near the Humboldt crossing, mandatory training for all workers on species protection and regulatory compliance, and strict avoidance of wetland boundaries marked during construction. Wildlife entrapment prevention requires trenches deeper than one foot to be backfilled daily or equipped with escape ramps, and pipes must be inspected before burial. Tree removal is conditioned on either acquiring a conservation easement on two or more acres of redwood forest, funding a third-party easement, or paying a compensation fee to a CDFW-approved fund to protect three or more acres. Vegetation clearing is