The Analysis of Large Dam Impacts on Sediment Grain Size Distribution in a Tropical River System

Mohammad Haroon Hairan (1) Water Resource Laboratory, Department of Environment, Faculty of Forestry and Environment, Universiti Putra Malaysia (UPM), Serdang, Malaysia. 2) Department of Natural Resources Management, Faculty of Environment, Kabul University, Jamal Mena, PD.)
Nor Rohaizah Jamil (1) Water Resource Laboratory, Department of Environment, Faculty of Forestry and Environment, Universiti Putra Malaysia (UPM), Serdang, Malaysia. 3) Aquatic Ecosystem and Management Laboratory, International Institute of Aquaculture and Aquatic Scien)
Mohammad Noor Amal Azmai (4) Department of Biology, Faculty of Science, Universiti Putra Malaysia (UPM), Serdang, Malaysia. 5) Aquatic Animal Health and Therapeutics Laboratory, Institute of Bioscience, Universiti Putra Malaysia (UPM), Serdang,)
Ley Juen Looi (3) Aquatic Ecosystem and Management Laboratory, International Institute of Aquaculture and Aquatic Sciences (i-AQUAS), Lot 960 Jln Kemang 6, Port Dickson 71050, Negeri Sembilan, Malaysia. 6) Department of Environment, Faculty of Forestry and Environm)
Ahmad Zaharin Aris (3) Aquatic Ecosystem and Management Laboratory, International Institute of Aquaculture and Aquatic Sciences (i-AQUAS), Lot 960 Jln Kemang 6, Port Dickson 71050, Negeri Sembilan, Malaysia. 6) Department of Environment, Faculty of Forestry and Environm)
Mohd Hafiz Rosli (Laboratory of Food Safety and Food Integrity (FOSFI), Institute of Tropical Agriculture and Food Security (ITAFoS) Universiti Putra Malaysia (UPM), Serdang,)

Civil Engineering Journal
Vol 9 (2023): Special Issue "Innovative Strategies in Civil Engineering Grand Challenges"

Sedimentation is a natural phenomenon of rivers that is enhanced by modification of the river basin. The presence of dams delays the exchange of sediments, nutrients, and organisms between the terrestrial and aquatic environments. This article assesses the impact of the Selangor dam on the sediment grain size distribution and its association with river velocity and discharge. The fieldwork for sampling is conducted in the normal and rainy seasons. The samples were analyzed through a sieve analysis procedure to determine the particle size of the sediments. After the sieve analysis technique, GRADISTAT analysis was performed on the output. The GRADISTAT analysis classifies the sediments between sandy gravel and sand, and the median grain size (D50) ranges from 4.00 to 0.18 mm. The spatial distribution of the D50 shows that the bed-load sediments of the upper Selangor River are becoming fine-grained downstream. The skewness of the sediments differs from 0.86 to 8.44, which indicates that the sediments are poorly to moderately well sorted. The Spearman's correlation of the D50 and river velocity and discharge determine no association of the D50 with river velocity and discharge. The stations near Selangor Dam have high slopes and receive "sediment hungry" water that washes small-sized sediments; therefore, the upper stations have a more significant amount of gravel and large sand. Doi: 10.28991/CEJ-SP2023-09-02 Full Text: PDF