Kajian Saluran Irigasi Tersier di Desa Namu Ukur Utara Daerah Irigasi Namu Sira-Sira Kecamatan Sei Bingei Kabupaten Langkat

Abstract

Vikri Novandi Akbar : Study of Tertiary Irrigation Canals in Namu Ukur Utara Village in The Irrigation Areas of Namu Sira-sira Sei Bingai District of Langkat Supervised by SUMONO and AINUN ROHANAH. The distribution of irrigation water on the field of Namu Ukur Utara village is done through tertiary canal which is a soil canal. This can affect the lossing of water through evapotranspiration, percolation and seepage so that the efficiency of water distribution is reduced. This research was aimed to review and design an appropriate canal dimensions to prevent scour and sedimentation at 2 tertiary irrigation canals in Namu Ukur Utara village in the Irrigation Areas of Namu Sira-sira Sei Bingei District of Langkat. The results of the research showed that the average flow velocity was smaller than the critical speed so that sedimentation occured in the canals, therefore redesigning of the dimensions on the both canals was needed. The efficiency of the distribution on canal 1 at a distance of 45 m was 73% and on canal 2 at a distance of 35 m was 75%. However the efficiency of distribution at a same distance (35 m) with the assumption of losing the water on every meters was the same, was 83,87% on canal 1 and 75% on canal 2. The best design of tertiary canal dimensions for the canal 1 was: width of the canal (B) was 0,37 m and depth (D) was 0,17 m with a slope of 0,04%, and for the canal 2 was: width of the canal (B) was 0,52 m and depth (D) was 0,24 m with a slope of 0,04%