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DWP consultants offer ideas for river 02 worries

December 22, 2011

The Lower Owens River is beginning to show more signs of life with woody growth beginning to take root. River managers are planning to help the ecosystem along by re-tooling seasonal flows and reducing the number of beavers who feed on the young saplings that are sprouting up. Photo by L. Freilich/Inyo County

Public sentiment so far indicates satisfaction with – or at least the absence of objections to – the Los Angeles Department of Water and Power’s most recent Lower Owens River Project Report.
Representatives from Ecosystem Sciences, which compiled the 2011 report, met with residents Tuesday to discuss the data that was collected and receive questions and comments.
Consultants Mark Hill and Bill Platts said the goal for the LORP for the next year is to continue with adaptive management by monitoring the environment, vegetation and river flows to ensure a healthy habitat develops along the re-watered stretch of the Owens, “and if it goes the wrong way, we will put it back on track,” Hill said.
Currently, Hill said Ecosystem Sciences is planning to look at minor changes to the river flow in March that could help manage tule growth.
“We don’t want the tules gone,” he said. “They’re an important part of the ecosystem, but we don’t want them taking over the river.”
Platts said a change in the flow patters of the LORP could also improve oxygen levels, which currently fluctuate with habitat flows, creating concern about the health of fish in the river.
“Habitat flows year-round are putting a lot of pressure on the fishery,” Platts said. “It causes stress for the wildlife, and some died off in 2010.”
In hopes of finding a remedy to the oxygen level problem, Platts said he is recommending that seasonal habitat flows on the river begin no later than June 15, which will prevent the warm high desert temperatures from eliminating oxygen in the river.
Earl Wilson, a retired employee of the Great Basin Unified Air Pollution Control District, suggested the LADWP consider mechanically injecting oxygen into the river to help wildlife.
Platts said that would require “a lot of effort” and the oxygen that would be generated would be “eaten up too quickly.”
Platts also suggested that the LADWP experiment with different flows in the winter season in order to flush dead and decaying matter out of the river that would otherwise use up oxygen in the water.
“The river has to get that stuff out of its system,” Platts said.
Those flushes, he said, would also raise the water quality in the river.
Platts also said that he is recommending that the LADWP reinstate its beaver trapping program to ensure the non-native population does not begin eating away at the woody vegetation that is beginning to take root along the rehabilitated river.
Mark Bagley, speaking for the Sierra Club and Owens Valley Committee, wanted to know how many beavers had been counted on the Lower Owens River and what those numbers should be reduced to.
Platts said that it is nearly impossible to count the number of beavers living along a river that does not completely freeze over, so it is currently unclear how many there are.
He said monitoring of woody sites have turned up indicators that beavers are beginning to eat the new growth.
He said there is not a specific number of beavers that should be trapped and removed from the Lower Owens, and he is recommending only that the program be reinstated to bring the number of beavers down.
To pick up a hard copy of the 2011 LORP Report, go to the LADWP offices at 300 Mandich St. in Bishop. For a digital copy, visit http://www.ladwp.com/ladwp/cms/ladwp014936.js.
The Inyo County-Los Angeles Technical Group will meet to discuss the document Jan. 18.

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