2013-03-21 / Front Page
New study looks at ‘degraded’ Malibu Creek watershed
SECOND OF TWO PARTS
But according to a study titled “Malibu Creek Watershed: Ecosystem on the Brink,” the 109- square- mile ecosystem overlapping Calabasas, Agoura Hills, Oak Park and Westlake Village remains vulnerable to pollution and urban encroachment.
Last week Heal the Bay, one of California’s leading environmental advocacy groups, released results of a 12-year study that assesses the habitat, water quality and flora and fauna of the watershed, which drains into Malibu Lagoon and Surfrider Beach in Malibu.
The study, a collaborative effort involving park agencies, local organizations and trained volunteers, shows how human activities impact the fragile ecosystem and how it can be safeguarded for future generations.
“Because 75 percent of the area (in the watershed) is undeveloped, we have an unprecedented opportunity to protect and improve the remaining natural resources,” Sikich said during a media tour of the area last week.
The tour included a stopover in Calabasas, where a section of Las Virgenes Creek along Lost Hills Road contains high bacteria levels; a trip to an unspoiled segment of Cold Creek, where California salamanders still breed; and a visit to Malibu Lagoon, which is being restored.
The lagoon project involves removing 7 feet of dead soil and trash and improving water flow to restore oxygen levels that can sustain aquatic life. The restoration will be completed next month.
According to Heal the Bay’s study, reducing seepage from septic tanks, horse ranches and fertilizers upstream will curb algae growth and improve oxygen levels in the water. Fertilizers contain nitrates and phosphates that promote excessive algal and microbial growth.
Although cities and local agencies are working to protect the habitat, Heal the Bay and the Santa Monica Bay Restoration Commission believe more regulations are needed to protect the streams and riparian areas from the effects of development.
To eliminate contamination, new developments should capture and reuse all runoff water. Existing properties can use native plants and drip irrigation to eliminate runoff.
Environmental advocates also hope to lower discharge levels at the Tapia Water Reclamation Plant in Malibu Canyon.
“Las Virgenes Water District has come a long way in reducing nutrient discharges in the creek,” said Mark Gold, former president for Heal the Bay and now director of the UCLA Institute of the Environment and Sustainability. “They have reduced nitrate discharges by about half, (though) nutrient levels are still too high.”
He suggested the water district build a recycled water reservoir to store excess water.
But customers in the water district already are saddled with rising fees and rates. Additional costs are being assailed.
According to the study, removing stream barriers such as the Rindge Dam will restore the natural water flow and prevent sedimentation, which would improve the habitat for native amphibians and fish such as the endangered Southern California steelhead trout.
Invasive plants and aquatic animals, such as crayfish and New Zealand mud snails are widespread throughout the watershed, strangling native habitat and crowding out native species.
Katy Delany, an ecologist with the National Park Service, said hikers can take steps to reduce the spread of invasive species. One suggestion was for hikers who have crossed streams to freeze their boots afterward to avoid spreading the mud snails to other areas.
While environmental groups are working with the EPA to strengthen regulations for the watershed, local water and sanitation officials are petitioning to block the new standards, saying they would be ineffective and costly to ratepayers.
“ Many of our goals are aligned with Heal the Bay, but we don’t agree on everything,” said David Pedersen, the new general manager for LVMWD.
“Heal the Bay has somewhat simplified its analysis on cause and effect in a very complex system. The science may be sound, but it has to be applied properly,” Pedersen said. “(This study) focused too much on the Tapia reclamation facility and in some cases dismissed some critical stressors affecting the watershed.” Among the stressors he mentioned was the oil-rich Monterey Formation, a specific type of rock which has outcroppings throughout the state.
Las Virgenes and Triunfo operate the Tapia sewer plant, which releases treated wastewater into the creek during the rainy season. District officials say the water out of the Tapia plant carries the same level of nutrients as those occurring naturally in the creek and the districts invested some $10 million to meet discharge standards that were established in 2003.
“ LVMWD is a pioneer in reuse, with recycled water systems and bio-solids composting. We’re very aware and sensitive to some of the issues and (have) made improvements to the Tapia plant to reduce nutrients, “Pedersen said.
District officials are also contemplating a recycled reservoir project, which they said would help eliminate the discharges into Malibu Creek. Costs to acquire land and build the reservoir and related pipelines would range between $114 million and $153 million. The district would seek federal and state grants to defray some of the expenses.
Heal the Bay’s Stream Team, made up of trained volunteers who collect environmental data in the watershed, hosted a workshop in Calabasas on Tuesday to encourage the public to safeguard the health of the watershed.