Perhitungan Nilai Nisbah Hantaran Sedimen Dengan Menggunakan Kurva Sedimen Dan Model Erosi Tanah

Prolonged soil erosion and sedimentation have negative effect on land quality showing by decreasing land productivity, in addition, sedimentation process may cause decreasing function of hydrologic infrastructures. In watershed scale it is important to monitor both important processes. The relationship between the amount of onsite erosion and sedimentation at the watershed outlet is formulated in the Sediment Delivery Ratio (SDR). SDR is the ratio between the erosion that occurs in the entire basin with the amount of sediment in the outlet of a watershed. This study aimed to calculate SDR value of two watersheds which have different topographic condition and land cover types composition. The study was conducted in two sub-watersheds namely Tapan and Ngunut I. Erosion calculation used USLE formulae while prediction of water discharge and sediment discharge utilized rating curve and sediment rating curve. The study shows that (1) SDR of Tapan is higher than SDR of Ngunut I, it indicates that there are others source of sediment beside sheet erosion which is transported to the outlet of watershed, (2) The value of SDR fluctuate according to fluctuations in monthly rainfall and runoff, (3) SDR is less sensitive to land cover types rather than of topographic factor (slope, drainage density an watershed area)

VARIASI DAN KARAKTERISTIK MODEL AGROFORESTRI

agroforestri is a new technical term while its practice have been executed byfarmers for a long time. Farmer's responses to the stress of land condition and life needs have urged the creation of local innovation on agroforestri system. Local innovation will change the land use system which has variety of local agroforestri system. The aim of this study were to dig out the information of variation and characteristic of localagroforestri models,find out the supporting factors that emerged the variation models basedon land slope,and discover the information of agroforestri models development. The method of this. research was by surveying and interview. &quo