Rapid growth of urban area is threatening the watershed. As a consequence water problems such as drought and flood are emerging, and then the sustainability of flowing water is decreasing. A conventional approach including frequency analysis doesn't take into consideration the water storage capacity in the watershed as important parameters to mitigate overcome this problem. Therefore in this research, the watershed retention capacity approach was applied to identify the possible counter measures and to understand the behavior of the problems. The water balance were employed to check the reasonability data, to analyze watershed retention capacity, and then to identify the solution for flood and drought. With 40% of the total rainfall becomes river discharge, 76% becomes evapotranspiration, and only -16% becomes storage (groundwater), the hydrologic data at Johor River Watershed is considered as reasonable. Then, the Johor watershed retention capacity was calculated as 9427mm, and it requires another 1060 mm reservoir capacity to maintain the river discharge fluctuation at its moving average. The current histogram of Johor River discharge shows that the droughts are more frequent as compared to floods. It is found also that a dam/reservoir is the best option to control flood and mitigate drought, in term of volume. Considering the discharge moving average still has 7% drought, different scenarios of discharge control were conducted to control flood and mitigate drought completely. As result, a reservoir with capacity of 998 mm (1371MCM), 1212mm (1665MCM), 1317mm (1810MCM), 1228mm (1687 MCM). This discharge range is suitable to fulfill the Johor River Watershed requirements as well as the water requirements of Singapore.
Watershed retention capacity, water management, reservoir, drought and flood
How to Cite This Article
Ali, Rawshan Othman and Heryansyah, Arien
"WATERSHED RETENTION CAPACITY APPROACH FOR IDENTIFYING WATER RESOURCE PROBLEMS-CASE STUDY FROM MALAYSIA,"
Polytechnic Journal: Vol. 8:
1, Article 9.