METRO Light Rail Uses StormCapture® System to Harvest Rainwater

Santa Monica, California

Highlights

Engineering

Maintenance Design Group

Pasadena, California

The Problem

Landscape irrigation, vehicle washing and other water needs required an estimated 5,500 gallons per day at the new facility. Focusing on “green” building and energy efficiency, METRO officials sought a Low-Impact Development (LID) design with zero stormwater runoff. Poor soil conditions precluded soil infiltration to replenish aquifers. As a result, the best option was a stormwater harvesting system for non-potable uses to reduce reliance on city water.

The Design

Oldcastle Stormwater assembled a team to provide the total stormwater management system including a 400,000 gallon StormCapture cistern, an upstream pre-treatment unit, and a downstream stormwater harvesting system from Water Harvesting Solutions (WAHASO). The Murray Company installed the pre-treatment and StormCapture systems during the spring of 2014. The harvesting equipment was later installed in August 2014. The facility finally became operational in May 2015.

The Solution

The system was designed to minimize maintenance by onsite personnel. Sediment and other debris captured by the pre-filter must be periodically evacuated to keep the cistern free of sediment and organic matter, especially first-flush debris after major rain events. In the filtration skid, bag filters are typically changed every four to eight weeks and the UV bulbs are replaced every 10,000 hours, which equates to a year of continuous use.
“The stormwater management techniques are set to contribute from one to four points toward a LEED gold rating,” says Renee Azerbegi, president and project manager for Ambient Energy, a consultant engaged by Maintenance Design Group for LEED project facilitation. “Because of the drought, water conservation issues are being significantly heightened,” notes Wong. “Technology for pre-treatment, post-treatment and storage is available today. Stormwater treatment and management is certainly here to stay.”

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