Assessment of Ma-a creek along Purok Kapundok : basis for diversion and design improvement

Abstract

Flooding has been a national concern in the Philippines, with high chances to occur during typhoons and may happen in the future due to rapid urban development. Flood risk reduction strategies can be enhanced by a diversion channel, increasing the waterway's capacity, or a closed diversion canal. The assessment of Maa Creek along Purok Kapundok: the basis for diversion or design improvement is a critical study that assesses the current state of the creek and the measures that can be taken to mitigate or reduce the flood discharge, even so, improve the functionality of the vicinity. The study gathered essential data, including the creek's geometry and dimensions, water flow data, and more. Following, HEC-RAS is utilized to simulate and compare the existing channel and the proposed diversion channel. The results of HEC-RAS steady flow modeling found that a diversion shortcut will further increase the water flow, thus, reducing the water elevation. Also, incorporating culverts in the diversion will add to the area's functionality. Simulating the flow that is critical for the creek, gathered hydrological data from the year 2018 is used for the unsteady flow. Here, it is found that water surface elevation reaches up to 3.12 meters high. In addition, results from sediment analysis of the proposed diversion show that invert siltation will increase by 0.95 meters in 1 year. In conclusion, a diversion shortcut with culverts reduces water surface elevation because of improved water discharge. Nevertheless, the design capacity is enough, and the future capacity may be reduced due to the siltation. It is essential to conduct regular monitoring and assessment of sediment build-up to sustain the correct water depth and prevent flooding.