Post-Project Concrete Lining Seepage Analysis

Abstract

The Imperial Irrigation District conserves water for various water conservation and watertransfer programs. Post-project concrete lining ponding tests and seepage analysis are completedshortly after construction, three years later, and 13 years later to determine the amount of waterconserved by canal and lateral concrete linings. The seepage rate, determined by analysis ofponding test measurements, is used to calibrate a seepage inference model that estimates seepagerates in canals and laterals. Concrete lined and earth canal/lateral sections of the water deliverysystem are modeled to compute water losses due to evaporation, water level variations, andseepage. This report presents ponding test and seepage rate analysis information.<br><br>Ponding test methods used in 2004 are the same methods used in the early 1990s post-projectponding tests. After reviewing the early 1990s ponding test methods it was determined to follow thesame methods in 2004. By following the same method the 2004 test results can be compared to theearly 1990s test results. Ponding tests are completed at previously tested sites to compare seepagerate values.<br><br>Ponding tests are conducted on representative canals and laterals for all canal lining projects. Theestimated volume of water conserved from canal seepage is calculated as the difference betweenobserved pre-project and post-project seepage. It is expected and determined that the post projectponding tests values involve a narrow range of post project seepage rates.