PHYSICAL MODELING OF PROPOSED POROUS DRAINAGE SYSTEM TO SOLVE INUNDATION PROBLEM

Post rain inundations that occurred in Prambanan Temple yard interfere the visitor’s mobility and heavy equipment that operated for restoration activities in the temple. A typical porous drainage system was proposed using waste material from Merapi eruption to reduce the inundations. Research on the characteristics of the waste material becomes important due to the availability of so many supplies from these materials and it has not been utilized optimally. A full scale of physical modeling experimental test, with a modified equipment to determine the performance of the porous drainage system, was proposed in this study. Physical modeling of the porous drainage system is expected to represent the actual conditions in the field. The groundwater level was designed in two conditions, deep groundwater level based on the natural field condition and shallow groundwater level that is an extreme condition that may occur in the field. In this test, rainfall simulator was built to flow the discharge constantly into this physical modeling. The effectiveness of this system amounted to 20% of the drainage capacity in natural field condition during the rainfall duration of 2.183 hours. In the extreme condition, the effectiveness of the system amounted to 75% of the drainage capacity during the rainfall duration of 2.383 hours. It shows that the porous drainage system is quite effective when applied at Prambanan Temple yard that has an average rainfall duration of 2.375 hours. The proposed porous drainage system is expected to solve the inundation problem in Prambanan Temple yard.