Restoration of instream flows was identified in the Walla Walla Subbasin Plan as a critical limiting factor that must be addressed to achieve recovery of ESA-listed Mid-Columbia steelhead and bull trout and ensure the success of reintroduced spring Chinook salmon in the Walla Walla Basin.  Consistent with the recommendations of the Subbasin Plan, Stuart Durfee, Manager of the Gardena Farm Irrigation District (GFID), proposed the design and construction of the South Lateral Pipeline, which was intended to be the first in a series of projects culminating in a fully piped conveyance system for the GFID which experiences seepage losses estimated to be between 33% and 42% of the water diverted or up to 30 cfs.  The GFID subsequently requested the assistance of the WWCCD which has successfully installed pipelines for other irrigation districts in the Walla Walla Basin.  

The strategy for installing the 27 miles of pipeline on the GFID was to start at the downstream end of the the ditch and work back toward the diversion. The South Lateral Pipeline, which is the downstream end of the southern branch of the GFID conveyance system, would convert approximately 6 miles of open ditch conveyance to a gravity pipeline and save approximately 4.5-5.0 cfs of water that is presently lost to seepage and evaporation.  The GFID agreed that saved water will be returned to instream flow and protected through Ecology's Trust program.  This project was subsequently combined with other capital projects into 2007-396-00, funded and scheduled for completion during the period 2007-09.  In 2007 approximately 1.2 miles of the ditch was piped by GFID.  In March, 2009, the GFID Board of Directors decided that their interests would be better served by working cooperatively with WWCCD and they requested that WWCCD assume responsibility for completion of the South Lateral Pipeline project which involved reducing the scope of contract 40082 with GFID and initiating this contract (CR-117078) with WWCCD.

The South Lateral Pipeline project was designed to tie into the North Lateral Pipeline which is the next phase of the GFID pipeline to be completed.  When the design and construction of the South Lateral Pipeline is finalized and resources become available, the WWCCD and GFID will transition as seamlessly as possible to the design of the North Lateral Pipeline which has been funded in part by WA Dept of Ecology.  Construction of the North Lateral Pipeline  is tentatively planned for July-October, 2010.

The GFID has the largest WA water right in the Walla Walla Basin.  The GFID point of diversion is at the Burlingame Diversion, which is located within a designated priority reach on the Walla Walla River at RM 36.7 .  The Walla Walla Subbasin Plan identifies three imminent threats including "..areas of the stream that seasonally go dry..." and recommends that they be the highest priority for restoration "...regardless of whether they are located in a priority geographic area."  The water saved by piping the Gardena ditch will be of immense value in terms of the Walla Walla subbasin restoration effort.

Because of its location, size and the potential for substantial water savings, considerable work has been done by other entities to facilitate and encourage the piping of the GFID ditch.  A Comprehensive Irrigation District Management Plan (CIDMP) which estimated the seepage and evaporation losses of the various components of the ditch was completed in 2003.  Under contract 40082, GFID contracted with IRZ Irrigation, a very experienced and competent consulting firm located in Hermiston, OR, to design the remainder of the Gardena South Lateral pipeline.  We plan to implement the IRZ design and use the CIDMP's seepage and evaporation estimates to determine the amount of Trustable water saved by the project.