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Wednesday, March 06, 2013

Recurring Rindge Dam Removal Proposals Provoke Strong Community Reactions

• Stakeholders Prepare to Hold Fast to Their Concerns as Public Feasibility Study Nears Completion

BY BILL KOENEKER

Longtime Malibu residents recognize that the discussion about removal of the Rindge Dam, currently surfacing as possibly the next hot topic, has been circulating for a very long time.
In 1995, the U.S. Bureau of Reclamation published its appraisal report on options to remove Rindge Dam.
In 1996, California’s statewide steelhead recovery plan, identified removing Rindge Dam as the single best restoration approach.
In 1997, the southern steelhead trout was listed as endangered by National Marine Fisheries Service under the federal Endangered Species Act.
The U.S. Army Corps of Engineers conducted its reconnaissance study to determine federal interest in the restoration of Malibu Creek in 1998.
Two years later, the Corps had begun ways to address fish passage issues by undertaking the Malibu Creek Environmental Restoration Feasibility Study in partnership with the California Department of Parks and Recreation. The first scoping meeting was held on May 29, 2002.
One of the driving forces behind the removal is a group known as the Southern California Steelhead Coalition, which claims a membership of 224,000.
There was additional research carried out nearly 25 years ago that suggested there was something special about the southern run of steelhead.
In 2000, there was a study that determined that steelhead would be tolerant of high sediment loads in the stream and such events following a large wildfire in the watershed do not degrade the species or the creek’s vegetation and instream habitat.
The following year, a Heal the Bay study reportedly showed that water quality during a series of monitoring tests in the upper sections of Malibu Creek demonstrated good conditions for steelhead trout habitat.
Further studies suggested that the Bureau of Reclamations’ recommendation to excavate the sediment behind the dam and transport it elsewhere by trucks could be rendered infeasible by the traffic restrictions and increasing congestion on Malibu Canyon Road.
The Rindges, the last family to own the entire Malibu Rancho, finished building the dam in 1926, reportedly using railroad materials from the abandoned Rindge Railroad for at least a portion of the building materials.
The dam was constructed in two parts around a natural stone pier. It is a 102-foot-tall, 140-foot- wide steel reinforced concrete arch dam.
The two components are the thin arch retaining wall built to impound Malibu Creek flows and its spillway. The spillway is prominent, with the dam’s construction date stamped in the concrete and original metal spillway gate structures still intact, according to various reports.
Rindge Dam was built for agricultural water supply and originally impounded 574 acre-feet of water with the spillway gates raised, according to sources.
It was owned by the Rindge family and operated by the Marblehead Land Company from 1933 to 1946.  The dam is said to impound approximately 800,000 cubic yards of sediment.
The reservoir was completely filled with sediment by 1955. In the early 1960s water deliveries stopped and the California Department of Water Resources decommissioned the dam in 1967, according to various sources.
A SCSC comment to The Corps study in 2002 had this to say. “Rindge Dam provides no flood storage, no hydroelectric generation and no water supply. Thus the dam is obsolete, providing no beneficial functions, and has been a barrier to the upstream migration of fish for over seventy-five years.”
Rindge descendants have publicly stated they would like the dam to remain as an historic monument
An early suggestion to The Corps feasibility study for a dam removal operation would be to remove the thin arch retaining wall while preserving the spillway for historic reference. This method is described as less costly while still offering upstream enhancement and leaving some historical aspect of the dam intact.
Today, the upper dam consists of a small wetland ecosystem that supports arroyo willow, rushes and tules.
Why so much interest in a fish that is worth spending maybe close to hundreds of millions of dollars?
Proponents say because the steelhead is not just an endangered species, but is what experts call the Southern California Evolutionary Significant Unit, a biological unit of steelhead that was listed as endangered under the federal Endangered Species Act in August 1997.
Southern California Steelhead have had to adapt over hundreds of years to the climate of the Southland and are thought to possess unique ways to remain healthy in the highest range of water temperatures for the species throughout its entire range along the Pacific coast.
Rising temperatures caused by global warming could pose a threat to all kinds of species of fish that use freshwater waterways.
If that is so, Malibu Creek steelhead may be important as genetic stocks that are better adapted to warmer water conditions than more northerly populations.
Proponents argue that the Southern Steelhead could provide an opportunity to preserve steelhead throughout the Pacific Coast Range.
Thus, the argument goes that increasing the 2.6 mile stretch of stream from Malibu Lagoon to Rindge Dam could offer good cover and what is called appropriate stream morphology—shade and deep pools—to offer adequate summer habitat, which is usually found in the headwaters of coastal streams not in the lowermost mainstream reaches as is now the case with Malibu Creek.
In 1996, the Steelhead Restoration and Management Plan for California concluded that removing Rindge Dam is the key to Malibu Creek steelhead recovery.
They insist it is a numbers game.
In a 1989 study by Franklin and Dobush, they concluded that major benefits for recovery could be realized by providing access above Rindge Dam, potentially tripling the existing population.
They found that over 86 percent of the potential spawning habitat and 65 percent of the potential rearing habitat lie above Rindge Dam. The assumption is that if steelhead gained access to this habitat, spawning and rearing habitat would  increase 590 percent and 180 percent, respectively over what is currently available to steelhead.
Most of the argument seems to center on some of those assumptions about steelhead historical habitat.
Many critics assert that the upper reaches above the dam were never steelhead habitat.
The argument goes that before development in the upper reaches of the 105-square mile Malibu Creek watershed, there was never enough water to keep the steelhead alive.
Much of the water today is provided by the discharge of treated water by Tapia sewage treatment plant during much of the year and the extensive use of recycled water to provide irrigation for landscaping throughout the watershed.
Serra Retreat residents, who live on the banks of Malibu Creek, have expressed concern about how any kind of dam removal might impact their flood-prone properties and say they might have the most to lose if operations were to go awry.
Surfers point out that any attempt to send the sediment downstream offers the potential to impact the cobblestone reef that has made surfing so popular on the beach at the end of the watershed.
Currently there is a steelhead restoration project underway in Solstice Canyon Park. Restoration proponents hope to create habitat suitable for a steelhead run.
Hundreds of thousands of dollars have already been spent to remove barriers and concrete culverts, to enable the fish to swim upstream to the deeper shady pools where they could potentially spawn.

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