Evaluation of Economic in Concrete Linings of Irrigation Canals in Cold Climatic Condition Area

Apply of suitable lining in irrigation canals to enhance conveyance and distribution efficiency, is one of effective methods to control of water and capital losses in part of agriculture.Different kinds of materials were used as lining to control water loss. Therefore its necessary that in different area all various lining are evaluated and suitable lining are chsen based on durability and economic. The aim of this research was to study economic effect of concrete lining in main irrigation canals based on reduction of water seepage loss, area of extentable irrited cultural and extention expence of lining in cold area of Hamadan province. Total length of concrete-lined irrigation canals in this province is 500 km. 12 main lined and unlined canals with total length of 26 km were chosen to study in this area. Water seepage in these canals was measured by the inflow-outflow method. While water velocity was determined using a current-meter. extention expences were determined in unlined and concrete lining of canals. The volume water losses through seepage at unlined and concrete-lined canals was determined 9.4 MCM and 5.19 MCM respectively. So with usage of concrete lining in earth irrigation canals, the seepage water loss has been reduced about 4.21 MCM. With this volume of water about 430 hac. of agriculture areas will be irrigated. Totall extention expences of 13.47 km of concrete lined-canals was 8355 million rials. Benefit-cost ratio in studied unlined and concrete-lined was 315 and 23 respectively. So with usage of concrete lining in earth canals benefit-cost ratio has been redused to 1/14. application of concrete lining in this cold area is not economic. It’s becouse of cracking and destruction of concrete linings in such a this cold climate condition.