Interactive effects of damming, forest loss and climate change on the hydrology of the Baleh River, Malaysia

Xin Yi Chong, Xin Yi Lum, Ramon J. Batalla, Damia Vericat, Alex M. Lechner, Karen Suan Ping Lee, Fang Yenn Teo, Christopher Gibbins

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review


This paper combines empirical and modelling studies to assess historic and future changes in the hydrological regime and sediment yield of the Baleh River, Malaysia. In the most recent 50-year period, the river has experienced a reduction in flow magnitude, mainly as a result of changes occurring in the wet season. Simulations using the Soil and Water Assessment Tool (SWAT) suggested that annual rates of forest loss even less than those currently witnessed in other parts of Malaysia may result in increases in sediment yield of more than 300% in some sub-catchments of the Baleh over the next 50 years. However, the lower rainfall and higher temperatures expected under climate change were predicted to result in reductions in flow and increases in sediment yield of more than 100%. A new dam currently under construction was predicted to trap approximately 95% of sediment and affect flood frequency and magnitude up to 90 km downstream. Multivariate analyses of the historical flow regime show that several identifiable types of high flow event (defined by their shape) occur naturally in the river, with some of these having distinct temporal patterns of occurrence. Efforts are needed to develop an operational regime for the dam to mimic the most functionally important of these events, although designing this regime is complicated by changes in flow and sediment loads anticipated due to climate and landcover change. An adaptive approach to dam operation is therefore needed.

Original languageEnglish
Title of host publicationProceedings of the 39th IAHR World Congress
EditorsMiguel Ortega-Sánchez
Place of PublicationSpain
PublisherInforma UK (International Association of Hydraulic Engineering and Research (IAHR))
Number of pages9
ISBN (Print)9789083261218
Publication statusPublished - 2022
EventCongress of IAHR, the International Association of Hydro-Environment Engineering and Research 2022: From Snow to Sea - Granada, Spain
Duration: 19 Jun 202224 Jun 2022
Conference number: 39th (Proceedings)

Publication series

NameIAHR World Congress Proceedings
ISSN (Print)2521-7119
ISSN (Electronic)2521-716X


ConferenceCongress of IAHR, the International Association of Hydro-Environment Engineering and Research 2022
Abbreviated titleIAHR 2022
Internet address


  • Damming
  • Flow regime
  • Landcover change
  • Sediment yield
  • Tropical rivers

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