ANALISIS EFISIENSI DAN KEHILANGAN AIR PADA SALURAN PRIMER DAN SEKUNDER DAERAH IRIGASI AIR LAIS (Studi Kasus Desa Sido Luhur – Kuro Tidur, Kecamatan Padang Jaya Kabupaten Bengkulu Utara)

Air Lais Dam is located in Kuro Tidur Village, Padang Jaya Subdistrict, North Bengkulu Regency, which is a dam that has primary and secondary networks. The Air Lais irrigation area experienced a lot of changes in both the condition of the network and the building so that, it experienced a decline in the function of the irrigation network which resulted in reduced water demand on agricultural land. This study aims to analyze the efficiency of water use in order to improve the management of effective and efficient irrigation networks in the irrigation area. Analysis of water efficiency and loss is carried out by the method of discharge and discharge. From the results of the efficiency analysis that has been done, obtained the average efficiency of the primary channel is 88.15% with a percentage of water loss of 11.85%. This result is not in accordance with the theoretical efficiency determined by KP-01 which is ≥ 90%. While for the average efficiency of the secondary channel is 57.93% with a percentage of water loss of 27.8%, this result is not in accordance with the specified theoretical efficiency of ≥ 90%. There are several other factors that cause water loss, namely evaporation and seepage. The value of water loss due to evaporation (evaporation) that occurs along the channel is 0.000429 m3/sec. The value of water loss due to the biggest seepage is 1.94 x 10-4 mm/day