Kajian Pengendalian Laju Sedimen Dengan Bangunan Pengendali Di DAS Hulu Batang Gadis Propinsi Sumatera Utara

Abstract

Hulu Batang Gadis Watershed is located in the district of Mandailing Natal province of North Sumatra . The rate of erosion in the watershed upstream Batang Gadis last 3 years has increased , it can be seen from the results of the analysis and calculation of the rate of erosion USLE method which in 2008 amounted to 307 285 tonnes / ha / year , in 2010 amounted to 318 482 tonnes / ha / year , Year 2012 of 385 336 tonnes / ha / year . This indicates an increase in the rate of erosion in 2008 - 2012 at 20:26% .. The rate of soil erosion hazard and criticality criteria of 1.41% Very Light , Light 10.92% , 17.76% Medium , Heavy and Very Heavy 49.59% ,20.32% . The results depend on the amount of sediment erosion in the watershed / sub-watershed .. Currently sediment issues have an impact on the downstream watershed upstream Batang Gadis ie the number of incoming sediment kesaluran irrigation and river silting . One attempt to overcome this problem is by building sediment control in the form of Check Dam . In this research study conducted as the proposed construction of sediment control 33 Check Dam . Successful achievement of development can reduce sediment control sediment 90.91% on average of all the bin capacity Chek Dam , while by means of sediment routing can reduce sediment by 97.39% with the operation of the check dam for 3 years . In addition to building pendali also recommended handling a land conservation treatment with a wide landing area function Buffer Zone 59.28% , Budi Region 4.57% Annual Plants , Cultivation Region Annuals 36.15% . The arrangement of the achievements of the region is a big impact on the land eroded soil erosion is very heavy 20.32% of basin area upstream Batang Gadis be 1.83% .

Keyword: Erosion, sedimentation, controle structure, conservation