[env-trinity] Revised FAQ on Winter Storms

[Tom Stokely]

This is a revised version of the document that I recently posted on the env-trinity list server.  

TS


            P.O. Box 1300, 1313 South Main Street, Weaverville, California  96093

            Telephone: 530-623-1800, Fax: 530-623-5944
           
        
            Trinity River Restoration Program

           
        


 

 

Frequently Asked Questions:  Winter Storms 2006

 

 

 

Q: How big is this next storm going to be?

                                         

A: The National Weather Service provides rainfall and river flow storm predictions for the Trinity River at Burnt Ranch and the Trinity River at Hoopa. The predictions are updated twice daily. 

 

Trinity River at Burnt Ranch:

http://www.cnrfc.noaa.gov/graphicalRVF.php?id=BURC1 

 

Trinity River at Hoopa

http://www.cnrfc.noaa.gov/graphicalRVF.php?id=HOOC1 

 

Q:  What is the current streamflow?

 

A:  Real-time streamflow information for all rivers in California (including the Trinity River) can be obtained from one of the following two websites:

 

California Data Exchange Center (CDEC): 

http://cdec.water.ca.gov/river/rivcond.html 

 

U.S. Geological Survey (USGS):

http://waterdata.usgs.gov/ca/nwis/rt 

 

Q:  What are the current conditions (inflow, outflow, storage) at Trinity Lake?

 

A:  This information can be obtained from the CDEC website at: http://cdec.water.ca.gov/river/res_CLE.html 

 

Q:  What are the current and scheduled flow releases from Lewiston Dam into the Trinity River? 

 

A:  Real-time flow releases are measured by the U.S. Geological Survey and reported at http://waterdata.usgs.gov/ca/nwis/uv?site_no=11525500.  The annual release schedule developed by the Trinity River Restoration Program to benefit Salmonid recovery is posted at: http://www.usbr.gov/mp/cvo/vungvari/trinsch.pdf.  Other scheduled releases, such as for Safety of Dams, are posted at:  http://cdec.water.ca.gov/cgi-progs/queryRES?lew - then click on the "Get last month of data" button. Please note that Safety of Dams releases are scheduled in response to storm events and typically have no more advance warning than several days.

 

Scheduled release changes at Lewiston for the Trinity River can also be obtained by calling the "River Release Recording" phone number.  The phone message is updated daily, but only with the current release and any "scheduled" changes.  "Scheduled" changes are those officially transmitted by Central Valley Operations, and therefore, occur usually only a couple of days to several hours before changes are made, depending on the circumstances.  The recording lists the Keswick release for the Sacramento River first, so those interested in Trinity River releases need to wait for the Trinity portion of the recording.  The phone number is 530-246-7594.

 

Q: How does the Bureau of Reclamation decide to make higher flow releases to the Trinity River during the winter?

 

A: During the winter, the Bureau of Reclamation maintains lower levels in Trinity Reservoir to provide a buffer in the event of an extremely large winter storm. The quantity of that buffer is based on several factors, and primarily references many years of hydrologic record for the basin.  Maintaining storage space is a very important aspect of flood control operations, and is fundamental in protecting areas downstream of Trinity Dam, as well as the dam itself.  As winter storms fill Trinity Reservoir, the Bureau of Reclamation may need to increase releases to the Trinity River to maintain the lower lake levels. Because these elevated winter releases help protect the dam, they are commonly called "Safety of Dams releases" and may or may not occur in conjunction with actual winter storms. Safety of Dams releases are typically no greater than 6,000 cfs, but may go higher if conditions warrant.

 

Q:  WINTER STORMS caused trees and other woody debris to fall into the river near my house. does the Trinity River Restoration Program plan to remove the debris from the river? 

 

A:  The Trinity River Restoration Program has no authority, and is not responsible, for removing woody debris from the river. Private landowners and public land management agencies make decisions about removing debris that might impair public safety, threaten the integrity of bridges or other structures, or increase the likelihood of local flooding.  If landowners elect to remove debris, we urge that landowners are cautious and follow safe work practices.

 

If left within the watercourse, fallen trees and bushes do play an important role in the juvenile life stages of fish in the river. Large woody debris provides cover, shade, and structure for fish. It also causes local scour that refreshes gravel, and increases the number and size of pools or holes for fish to utilize during low flow periods. Large woody debris contributes to the geomorphic processes, resulting in the creation and maintenance of the complex river habitats required by Chinook and Coho salmon and steelhead.

 




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