NID to spend $7.9 million for water storage

The covered reservoirs at the Nevada Irrigation District’s Banner-Taylor reservoir site will be replaced by a pair of modern storage tanks, under a $7.9 million construction contract awarded June 13 by the NID Board of Directors.

The design-build contract was awarded to Gateway Pacific/DYK/Bennett Engineering, a group that submitted the lowest among five proposals received by the district.

The new concrete-treated water-storage tanks – 4.6 million gallons and 5.9 million gallons – will replace two earthen reservoirs that store treated drinking water within a synthetic rubber liner made of Hypalon.

Water from NID’s adjacent Elizabeth L. George Water Treatment Plant is stored in the covered reservoirs and supplied in wide areas of Nevada County, including the nearby Brunswick Basin.

NID project engineer Doug Roderick said the Hypalon liners were installed in 1992 and are failing “at an exponential rate.” He said the liners are showing significant wear and tear, have been subject to acts of vandalism and need continued maintenance. The covered reservoirs have been likened to large water beds.

NID studies examined water-quality protection and safety, emergency and reliability needs as well as three different levels of storage at the site:7.6 million gallons, 9.2 million gallons and 10.5 million gallons.

The staff recommendation for 10.5 million gallons was deemed most cost-effective and adequate for a 20-year or longer period. The board voted unanimously to support the staff recommendation.

Roderick said the two tanks will be built within the existing reservoir berm and be partially buried, limiting visual impacts to surrounding neighborhoods. The tanks will be built separately so adequate storage is preserved during construction. The site is large enough to accommodate a third tank in the future, he said.

The reservoir site is just off Banner Lava Cap Road, near Boreham Lane, about two miles southeast of Nevada City. Construction is expected to begin this summer and be completed in about 18 months.