Quantifying future water environment using numerical simulations: A scenario based approach for sustainable water management plan in Medan, Indonesia

Water security and sustainable water management strategy are essential for socio-economic growth in Asia. This study uses hydrological modeling (Water Evaluation and Planning (WEAP) and Flo-2D/HEC-HMS models respectively) to predict the future water environment in Medan City, Indonesia. Various drivers were identified, and the results of this scenario-based approach show that that there will be a significant increase in flood inundation despite a wider flood diversion area. It was observed that the current status of water quality in rivers is very poor especially in downstream locations. This is due to the cumulative effects of waste disposal and an excess of untreated waste coming from upstream. The results of the business-as-usual scenario show that both climate change and population fluctuations severely affect water quality, a situation which is expected to deteriorate further by 2030. This chapter indicates that current management policies and near-future water resources management plans are not enough to control pollution levels and reduce flooding. Suggestions include carrying out transdisciplinary research to achieve more sustainable water management.