| Abstrak | In Indonesia, the serious problems of degradation water quality from nonpoint source pollution was not yet many applied on watershed. Agrecultural activities such ass cultivation and applicaation of ferlizer and pesticide will influence water quality, with activities in runoff-producing zones and near streams having a greater effect than those elsewhere. Water quality integates all suorces of pollutants . Nonpoint sources, by definition, are diffuse and not easily identified. The control technologies and best management pratice available are generally expensive tobe implemented. ANGPS model is as model hydrology that shuold used to identify and quattify the nonpoint suorce pollution from watershed. The ANGPS is an event- based model that simulates surface runoff, sediment, and nutrient transport primarily from agricurtural watersheds. In iddition, the model considers point source of water, sediment, nutirents, and chemical oxigen demand (COD) from animals feedlots, and spring. The model has the ability to output water quality characteristics at intermediate points througthout the watershed network. Seven parameter were selected out of twenty two parameters based on their signifiacancde in sensitivity to hydrology eroisoin ang sediment, and nutrient yield output. That seven paramaters concist of SCS curve number, manning's roughness coeffiecient, cover and management factor ,land slope , channel sedislope, practice factor and fertization available factor.Omitted parameters in the hypothetical scenario formulationt were either parameters of uncontrollable naature such as rainfall, El30, soil erobility, parameters that had least signifcant sensensitvity such asd rainfall, slope length and channel slope. The sirmulaation with BMP system has been conducted from the parameters adjustment for seven parameters. The BMP scenario was most effecttive in reducing the degree of volume and peak runoff rate by 32,08% and 29,66% from the base value of 0,53 inches and 118,51 cfs. All erosion and sediment related nonpoint sopurce pollunts were significantly reduce by 66,36% from the base valuie of 135,67 tons by altering the cover and mangement factor (C- factor) and the pratice factor (P-factor ) at theee time that ,total N dan P were significantly reduced by 56,85% and 57,92% from the base value of 11,15 lbs /care with that same of methods. |
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