On Water

Link: http://www.malibutimes.com/articles/2009/09/09/news/news5.txt

A fish die-off in Malibu Creek is under investigation by the Resource Conservation District of the Santa Monica Mountains. Meanwhile, the study to remove Rindge Dam is on hold because of funding issues. It is believed that removal of the dam would help restore Southern California steelhead trout to the creek. Photo by Dave Lichten / TMT

The die-off mirrors a similar one in 2006. An emergency response team is investigating the cause.

By Melonie Magruder / Special to The Malibu Times

The Resource Conservation District of the Santa Monica Mountains will be meeting this week to discuss its rapid response team's effort to solve the mystery of the recent sudden decline in Malibu Creek's fish population, a phenomenon that appears to mirror a similar event three years ago.

In 2006, all the visible aquatic life in Malibu Creek between Rindge Dam and Malibu Lagoon died during a three-month period. At the time, conservation scientists attributed the die-off to a combination of high water temperatures, reduced dissolved oxygen, low water flow from the Tapia Water Reclamation Facility upstream, algal growth and the smothering presence of decomposing diatoms (microscopic, one-cell alga).

But
toxicity studies weren't performed until long after the fact,
conservation district spokeswoman Rosi Dagit said. Since then a rapid
response team was organized to hit the field and find immediate answers
in the event of a sequel.

“Fortunately, the fish population of
Malibu Creek [including the endangered California steelhead trout] came
back naturally,” Dagit said. “In fact, in 2008 we counted the highest
number of trout we've seen since we started keeping records. So what
has happened between then and now to cause the population to plummet?
That is the question we are trying to answer this week.”

The
RCDSMM rapid response team includes specialists in toxicology, water
quality and habitat restoration from a range of state and federal
agencies.

Creek surveys are conducted using both bank-side
observers and underwater snorkelers; and data is accumulated for
species counts, water levels and temperatures, bacterial contamination
levels, range of dissolved oxygen and the presence of toxins.

“We
had never observed the dramatic rise in the general fish population
that occurred between 2006 and 2008,” Dagit said. “The $64,000 question
is why? With this current die-off event in progress, we can figure out
what it isn't and what it is, and maybe prevent such an event in the
future.”

Steelhead trout live most of their lives in the ocean,
returning to their home creeks in early spring to spawn. The young stay
in the creek a few months until big enough to travel and head
downstream for the ocean around May.

Because of urban sprawl and
habitat degradation, Southern California steelhead trout populations
have declined so precipitously that Dagit figures there are perhaps as
few as 500 adults of this steelhead species left in the wild (there are
hefty $25,000 fines for taking steelhead trout from Southern California
watersheds, she said).

Dagit suspects the recent decline is due to similar reasons as those in 2006.

“The
most important thing is for us to come together and determine what
tests must be performed, what management strategies must be developed
so that we can prevent this from happening again,” she said.

One
barrier to restoration of Malibu Creek and all its fish populations is
the 83-year-old Rindge Dam, constructed three miles up the creek from
the lagoon to provide a water supply for May Knight Rindge's family and
livestock in the 1920s.

The 100-feet-high, 140-feet-wide dam
lost most of its function by the 1950s, due to a gargantuan
accumulation of sediment, and was decommissioned in 1967.

The
controversial efforts to remove the dam and restore the creek's natural
flow and habitat have been ongoing for years. The U.S. Army Corps of
Engineers and California State Parks have been engaged in a nearly $4
million study of the dam's removal and estimates on the project have
ranged from $31 million to $72 million, according to earlier coverage
of the issue by The Malibu Times.

Some people, including Ronald
L. Rindge, descendent of May Rindge, are opposed to the removal of the
dam, saying it would be a waste of money and that the conditions of the
creek are not suitable for restoration of the trout, which, he has said
in the past, is not necessarily native to the creek. Rindge has claimed
the trout were planted as game fish early in the 20th century.

Nevertheless, plans have continued for the study to remove it.

Jim
Hutchison, watershed studies group leader of the ACE, said he has
worked with a multi-agency group, including local stakeholders, to
develop an interim report and recommendation plan for the fate of the
dam.

“We are addressing issues we feel are vital to the
continuing health of the Southern California steelhead trout species
and have come up with a general recommended plan,” Hutchison said.
“Unfortunately, we are in a holding pattern because matching funds [of
approximately $150,000] from the state parks system to complete the
study have been cut off.”

Hutchison said the plan tentatively
recommends removal of the dam and accumulated 780,000 cubic yards of
sediment, restoration of habitat around the dam and smaller changes to
other upstream barriers like culverts and bridges.

“Removal of
the dam and restoration of the creek flow would open up another five
miles of stream habitat,” Hutchison said. “It's easy to focus
restoration efforts on spotlight species like steelhead, but this move
would benefit several species up- and downstream, including large
mammals, plants and other aquatic species.”

Hutchison emphasized
that initial estimates for costs and feasibility are preliminary, and
require more analysis and vetting from the public.

Elements that
affect cost are transport and final disposal of sediment and concrete,
but local construction companies could be invited to bid on the
project, benefiting local economies.

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