Tiga Dihaji Dam Access Route Plan Alternative using Geographic Information System (Cost Distance Method)

The Tiga Dihaji dam access route function is destined for heavy equipment during the dam construction period. It is located on Tiga Dihaji sub-district, Ogan Komering Ulu Selatan district, South Sumatera, Indonesia. The Tiga Dihaji access route supervisor stated that the planning justification was done using expert judgement based on contour map and local land cover. This method is considered less measurable. Therefore, the Geographic Information System method is offered in this paper to determine the most suitable Tiga Dihaji dam access route. The parameters considered are landslide vulnerability, land cover and construction factors. These parameters are overlaid based on weights determined by the Public Works Department then validated by expert judgement. The new route is proposed using the cost distance method. Based on the analysis, it can be concluded that the cost distance method is more measurable than the planned method, but this method produces a less suitable route in terms of civil engineering.