Author(s): Wan Ruslan Ismail, Mohd Nazrul Ibrahim, Sumayyah Aimi Mohd Najib
Linked Author(s): Wan Ruslan Ismail
Keywords: Land use changes, sediment load, sediment budget, Merbok River catchment, Kedah
Abstract: Merbok River catchment situated in the Kedah State receives its input from Bongkok River and Puntar River flowing down and joining Sg. Lalang River to flow down to the Merbok Estuary. The Merbok catchment (440 km2) is experiencing several degrees of complex land use activities that affect the suspended sediment production of the Merbok River. A study is conducted to investigate the suspended sediment loading of rivers draining the Merbok catchment from January to December 2013. Suspended sediment budget of the Merbok catchment is estimated. The river SSC and SS loads increase during wet season compared to dry season. The SS loads increase from upper catchment to the river mouth. The sediment loadings are divided into three segments- the upstream, middle segment and lower segment. The SS loads increase from 10 t/yr in the upper part of Bongkok river to 3336 t/yr in the upper segment. The sediment loading then increases to to 4299 t/yr in the middle segment of the catchment (at Bongkok 4), and then exiting the Merbok Estuary, as the lower segment, with a total amount of sediment output estimated at 7156 t/yr. Based on the findings, Merbok River catchment is experiencing a lot of sediment removal. Most of the sediment sources originate from the tributaries; Bongkok River, Puntar and Lalang River, which is much higher than its proportion in terms of its length and drainage area. As a conclusion, the inconsistency of SSC in the river is influenced by the various anthropogenic activities (especially agriculture and urbanization activities) in the catchment area which necessitate future land use and sediment control to avoid sediment and possible nutrient loading into the estuary
Year: 2017