Author(s): Kok Hou Ku, Claus Pedersen, Hans Christian Ammentorp, Yabi Yangkat, Vitalis Moduying
Linked Author(s): Kok Hou Ku
Keywords: Carrying capacity assessment, river bank erosion, exclusion zone mapping, sediment extraction rate
Abstract: The Segama River is located within the Districts of Lahad Datu and Kinabatangan, on the east coast of Sabah, Malaysia. This paper highlights an assessment to determine sustainable levels of sand mining in the river and describes the formulation of a resource management plan and guidelines for the mid-reaches of the Segama River. A river sediment transport model (MIKE 11 ST) is developed to assess the carrying capacity for river sand mining along the mid-reaches of Segama River. The sediment transport capacity is estimated to be approximately 70, 000 m3/year. This compares to an estimated sediment yield from the upper catchment estimated in the range of 250, 000 to 500, 000 m3/year with natural erosion/deposition within the river estimated to be approximately 130, 000 m3/year. The current river sand extraction at the rate of 100, 000 m3/year is in the same order of magnitude as the transport capacity and the natural erosion/deposition, and is significantly lower than the total sediment yield to the river system. Based on these findings, it is considered that the sediment yield from the catchment combined with sediment from natural erosion/deposition can replenish the extracted volumes without significant risk of causing regional deficit erosion within the river. The development of a Resource Management Plan and Guidelines was undertaken to manage river sand mining activities and prevent over exploitation and consequent environmental damage along the mid-reaches of Segama River. Sensitive areas (eg. fisheries spawning area, area experiencing river bank erosion and etc. ) are mapped and the river classified into zones (Permitted, Restricted, Prohibited and Prohibited (Subjected) ) that regulate the river sand mining activities. The findings of the study have been implemented into a GIS database and decision support system that enables the regulatory authority to better manage the sand resource in the future
Year: 2017