Investigation of Natural Sealing Effects in Irrigation Canals.

摘要

Results of a three year study on the factors contributing to natural sealing of irrigation canals and reservoirs are presented. Laboratory evaluations of the effect of sedimentation,microbiological activity and soil-water chemical reactions on the hydraulic conductivity of soils were performed. Particular emphasis was on the Portneuf silt-loam soil of southern Idaho. Techniques for determining and predicting the sediment entrapment in soils from hydraulic conductivity measurements in laboratory columns are presented. Application of a method utilizing soil clay content,exchangeable sodium percentage,and total salt concentration of irrigation water to predict hydraulic conductivity is evaluated. The effect of microbiological activity in the benthic area of canals and reservoirs on seepage rates is discussed. Field tests in an operating canal to monitor soil moistur tension,soil moisture and seepage rates during an irrigation season are outlined. (Modified author abstract)