South San Joaquin Irrigation District and the City of Manteca have hammered out a storm drainage agreement amendment that will slash the cost of installing flow metering devices to monitor storm run-off from $4.5 million to $400,000.
At the same time the amendment to the 2006 agreement will allow developing areas south of the 120 Bypass that wasn’t previously included to drain into existing SSJID canals. SSJID has partnered with Manteca for decades allowing the city to use irrigation canals to ferry storm water to the San Joaquin River instead of having to build a separate system.
The flow meters and accompanying remote monitoring of levels of water in storm drain basins and control of when water is released to flow into canals as originally delineated were expected to cost the city $4.5 million.
That was the cost estimated to install the needed equipment at the city’s existing 78 storm drain pump stations. Manteca’s Public Works Department and SSJID engineers took a different approach. Instead of having the equipment at all 78 locations, they will be placed only where drains and laterals discharge into the SSJID’s French Camp Outlet Canal. That reduces the points needing the equipment to 22.
 At the same time the SSJID will install  the equipment instead of the city hiring a private contractor to do so. The district has developed expertise iver the past several years installing similar devices on its drains and laterals as well.
The city’s share of the $400,000 cost will be $200,000.
Besides being  able to control water flow into the canals to make sure the system isn’t overwhelmed and providing basic filtering, the flow meters allow the district and the city to keep track of runoff. That data could become critical in the coming years as groundwater recharge mandates and other water-related issues come up. Some communities such as Los Angeles are already harnessing storm water to recharge groundwater basins.
The city’s extensive use of placing storm retention basins in neighborhood parks — one of the first Central Valley communities to do so — is credited with virtually wiping out perennial flooding of local streets that was commonplace in Manteca up through the early 1990s
Water going down storm drains enter into pipes that will flow to the retention basis during significant storms. The water will sit there until such time capacity is available in laterals to take the water to the outlet canal and into the San Joaquin River.
The council will consider adopting the amendment when they meet Tuesday at 7 p.m. at the Civic Center, 1001 W. Center St.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com