[env-trinity] Trinity Journal: Worries over water storage in ‘dry’ year

[Tom Stokely]

http://www.trinityjournal.com/news/environment/article_667b4c70-e88d-11e4-a351-e36bd8b1c56c.html
Worries over water storage in ‘dry’ year
By AMY GITTELSOHN The Trinity Journal | Posted: Wednesday, April 22, 2015 6:15 am
River flow chart
Trinity River Restoration Program staff shared their recommendations for river flows in the 2015 water year to a skeptical group who argued those plans don’t reserve enough water to contend with the drought.The state Department of Water Resources is forecasting that 934,000 acre-feet of water will enter Trinity Lake for the 2015 water year running from Oct. 1, 2014, through Sept. 30, 2015. Although that amount is still on the low side bringing a “dry year” forecast for the basin, it’s far more water than last year.“We are all hopeful of a normal year,” said Robin Schrock, executive director for the restoration program, at the presentation held Thursday at the Trinity Public Utilities District office.While this seems at odds with reports on the meager snowpack, overall precipitation in the Trinity River Basin is not as grim.From the restoration program, hydraulic engineer Robert Stewart noted that about 800,000 acre-foot of water had flowed into the lake from Oct. 1 to April 1, a higher than average amount for the time period.“It’s all coming in the form of rain instead of snow,” he said, adding that most of the projected inflow is already in the reservoir.Although the reservoir is ahead in terms of the 2015 water year, because of low carryover storage it is only at 61 percent of average for this time of year, holding 1.2 million acre-feet.In addition to the amount that has already flowed into the lake, the DWR forecast includes some projected inflow from the small amount of snow in the mountains and anticipated rainfall for the remainder of the water year.Under the Trinity River Record of Decision that includes five water-year types ranging from extremely wet to wet, normal, dry and critically dry, the forecast of 934,000 acre-feet pegs this as a dry year with 453,000 acre-feet to be released to the Trinity River.Unlike the river release, there is no set amount of water from the reservoir diverted through tunnels for Central Valley Project purposes.Stewart noted that in the past the drier the water year the higher proportion of the inflow the CVP typically diverts. For example, in the critically dry year of 2014, 396,000 acre-feet of water flowed into the Trinity reservoir. The lake was drawn down as 435,300 acre-feet was released to the river and 618,000 acre-feet was diverted through the Carr tunnels for the CVP.“It’s not just water going down the river that causes the reservoir to go dry,” Stewart noted.At the recommendation of river restoration program staff, the Trinity Management Council recommended a flow schedule that was approved by Interior Department officials on Tuesday. The release to the river was to begin ramping up for a high spring flow today, April 22, and reach a high of 8,500 cubic feet per second released from Lewiston Dam on May 5 and 6. The spring spike meant to meet habitat and temperature objectives for fish is higher than that called for in the Record of Decision, which states that based on monitoring and studies the schedule for daily releases may be adjusted but the annual flow volumes could not be. The recommended spring peak takes water from the other parts of the schedule to use the same total volume of water.Several fishing guides and residents who live along the Trinity River were in attendance to voice concerns about the amount of water soon to be released.Jim Smith asked if it would be possible to take into account the effect of back-to-back dry years rather than basing releases on only the projection for the current year.He also noted that not sending water “over the hill” costs Trinity County in terms of lost power generation.“People aren’t considered at all in this equation,” Smith said.“We have no ability to make changes to that framework we got from the Record of Decision. None of the people here do,” said Ernie Clarke, science program coordinator for the restoration program.He noted that people and economics were considered in the National Environmental Policy Act document prepared in advance of the Record of Decision.Allen Houston of Weaverville asked how the program can justify sending more water down the river than is currently coming into the lake, adding he believes it’s for political reasons. Current inflow to the lake is approximately 1,000 cubic feet per second.It was noted that other alternatives were examined prior to the Record of Decision, including a release based on percent of inflow, but that led to temperature problems for fish.Program staff also noted that prior to the dam being put in the fish could go farther upstream in search of cool water.Stewart pointed out that the DWR’s projection of inflow is at the high end for a dry year — closer to reaching a normal year than dropping into a critically dry year.Fishing guide Travis Michel asked what the situation will be given the flows recommended by program staff if Reclamation again decides to do another high release in the fall and this year is followed by another drought.“That will depend on how they operate the dams,” Stewart said, and Michel added, “We don’t know what the Central Valley is going to want on top of that.”There was also a discussion of the program’s plans to add 1,700 yards of gravel to the upper river during the high spring release. The gravel is added to compensate for gravel that would otherwise come from above the dams, however, fishing guides have argued that it has filled pools in the river — deep spots used by fish to keep cool.While acknowledging that this has inadvertently occurred in the past, David Gaeuman, a physical scientist with the program, said changes have been made to “not repeat those errors” and “we’re going to keep looking at this stuff. It’s ongoing.”However, he also shared results of sonar studies indicating that almost all of the pools studied are deeper or have stayed the same.Smith responded that the data may show one thing, but “we’ll all line up and say you’re absolutely wrong.”Schrock said changes have been made due to Gaeuman’s research.Regarding the volume of the release to the Trinity River called for in the Record of Decision, she said Congress would have to take action to change that and “these three dry years may be the impetus for others who do have power to make changes.”Regarding the gravel recommendation, which is dependent on the spring high flow, she said “This is the best available science and in our jobs we’re obligated to use it.”Schrock added that as a fisheries biologist, she hoped the recommended high flow would be approved.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www2.dcn.org/pipermail/env-trinity/attachments/20150422/e92e0309/attachment.html>