Clwa

Friends of the Santa Clara River and the Sierra Club appeal from the denial of their petition for writ of mandate alleging an urban water management plan for parts of the Santa Clarita Valley was adopted in violation of the Urban Water Management Planning Act (UWMP Act), Water Code section 10610 et seq. Among the many grounds for reversal asserted is the failure of the urban water management plan to assess the reliability of the water supply obtained from two layers of an aquifer contaminated with perchlorate.

Certain aspects of the urban water management plan concerning the effects of perchlorate contamination on the groundwater supply can be summarized as follows. If there is a dry stretch, the districts plan to take more water from the Saugus Formation. If the perchlorate contamination impairs the supply of water taken from the Saugus Formation in dry years, the districts plan to restore full production capacity by treating the contaminated water. While the treatment facilities are being built, the districts have no plan to cover the reduction in water available from the Saugus Formation.

Thus, the plan’s description of the perchlorate contamination and the method…