Facing stricter standards regarding the discharge of treated wastewater into Malibu Creek, the Tapia Water Reclamation Facility is looking at expensive alternatives to redirect its surplus of reclaimed water.
By Melonie Magruder / Special to the Malibu Times
Every year, the Tapia Water Reclamation Facility in Calabasas is permitted to discharge a surplus of treated wastewater into the Malibu Creek watershed between the wet weather months of November through April. Although Tapia officials say the water has been purified to the point where “you can go swimming in it,” there are many, from surfers to environmental groups, who believe the discharges into the Malibu Creek cause higher levels of nutrients causing degradation to the quality of water in the creek and ocean water at the mouth where the creek empties. Last year, the Los Angeles Region of the California Regional Water Quality Control Board voted unanimously in favor of implementing a revised permit for the Tapia Water Reclamation Facility. Under the revised permit, facility officials are required to lower nutrient levels in the treated water from 10 milligrams to 8 milligrams of nitrogen per liter and increase monitoring of treated water. The Tapia facility, which is owned by the Las Virgenes Municipal Water District, is also required to adhere to stricter standards regarding the discharge of treated water into Malibu Creek. Tapia officials were given until 2011 to reach the targeted amount of nitrogen per liter outlined in the revised permit.
Anticipating a time when its discharge permit might be denied year-round, the Joint Powers Authority, the public agency that operates Tapia, commissioned a yearlong study of alternatives to Malibu Creek discharge.
Serving the Las Virgenes Municipal Water District that includes Malibu, the Tapia facility reclaims 33 to 44 million gallons of wastewater a day on maximum-flow days, cleaning and converting it to a resource for irrigating parks, highway medians and open spaces. Most of the treated water Tapia produces is used in public and agricultural irrigation during the summer months.
“This is purely an engineering study,” said Randal Orton, acting director for resource conservation and outreach for the Las Virgenes Municipal Water District. “There are no plans to implement any of these alternatives right now, but it is best to be able to provide full information to the public and to interested agencies, so we are ready if the time comes.”
After determining 13 potential projects to deal with treated outflow, the comprehensive study used five, equally weighted criteria to evaluate the four most likely options. The criteria includes the relative ease of implementation and permitting, the costs, the environmental impact on water quality and habitat, the effect on property values, public health and aesthetic values, and long-term viability in relation to regulatory compliance.
Alternative A, the least expensive at a cost of $54.8 million, would dispose of unused recycled water through an ocean outfall. It would require construction of a pump station at the Tapia facility, a force main (which would bypass Malibu Creek altogether) and a gravity flow pipeline through Malibu Canyon. According to the study, “Construction would likely require extensive rock cutting in the Malibu Canyon right of way and possible suspension of the pipeline off canyon walls.”
The volume of discharged water into Santa Monica Bay would not increase and strict water quality standards would be maintained. The downside would be a complex permitting process from agencies such as Los Angeles County, the Army Corps of Engineers, and the U.S. Fish and Wildlife Services. But once in place, the permits would likely be extended indefinitely. The outfall (where the treated water would go into the ocean off Malibu’s coast) would need to be approved by the Coastal Commission and the State Lands Commission.
Alternative B, at a cost of $65.5 million would construct a 14-mile pipeline to transport Tapia’s recycled water to the Los Angeles River, upstream. This plan would require alteration of the TMDLs (Total Maximum Daily Loads) for discharges into the L.A. River and could negatively impact the river environmentally. Though the projected lifetime of the pipeline is 50 to 100 years, future regulatory changes could alter the viability of such a project.
Alternative C, estimated to cost $141.8 million, would expand recycled water use and construct a reservoir at Donnell Ranch in the Santa Monica Mountains. While encouraging more use of recycled water for residential irrigation, construction of some pipeline extensions, such as Decker Canyon to serve the Malibu Country Club golf course, will likely be costly compared to increased demand in recycled water, and construction of a reservoir’s dam would introduce a substantial visual element in an otherwise natural setting. Once a market for recycled water is secured and infrastructure completed, few problems are anticipated in sustaining a new reservoir. However, interagency contracts, subject to periodic review, could lead to eventual cancellation.
Alternative D, the most expensive at $191.7 million, would expand recycled water use and storage at the Chatsworth Reservoir. Because of the high costs of pumping water to the Chatsworth Reservoir and the geological hazards presented by the site of the reservoir after the 1991 Sylmar earthquake, this option seems the least desirable. Two new dams would have to be constructed in a site that is currently considered sensitive by state and federal resource agencies and the whole project would be subject to likely opposing reviews by a multitude of local agencies.
None of the four alternatives can readily fit in to the district’s existing infrastructure and all would pose environmental challenges. However, future population and wastewater growth will require comprehensive, and inevitably expensive, problem solving.
“We encourage recycling as much as possible,” Orton said, “So that there is less waste water to store or discharge.”
The sentiment was echoed by Tracy Egoscue of Santa Monica Baykeeper.
“There is this huge stigma attached to recycled water,” she said, “But the fact is we can minimize our usage of imported water dramatically. Why store or discharge the treated water from Tapia? There is no reason not to use it.”