Did the Construction of the Bhumibol Dam Cause a Dramatic Reduction in Sediment Supply to the Chao Phraya River?

Matharit Namsai,Supakorn Sirapojanakul,William C Burnett,Warit Charoenlerkthawin,Butsawan Bidorn

doi:10.3390/w13030386

Abstract

The Bhumibol Dam on Ping River, Thailand, was constructed in 1964 to provide water for irrigation, hydroelectric power generation, flood mitigation, fisheries, and saltwater intrusion control to the Great Chao Phraya River basin. Many studies, carried out near the basin outlet, have suggested that the dam impounds significant sediment, resulting in shoreline retreat of the Chao Phraya Delta. In this study, the impact of damming on the sediment regime is analyzed through the sediment variation along the Ping River. The results show that the Ping River drains a mountainous region, with sediment mainly transported in suspension in the upper and middle reaches. By contrast, sediment is mostly transported as bedload in the lower basin. Variation of long-term total sediment flux data suggests that, while the Bhumibol Dam does effectively trap sediment, there was only a 5% reduction in sediment supply to the Chao Phraya River system because of sediment additions downstream.

Highlights

Rivers are significant sources of freshwater, sediment, and nutrients to the oceans [1,2,3]
The high SSL at XP.12 was likely caused by the SSL supplied from the Mae Chaem River, which joins the Ping River 1 km upstream of Stations XP.12 and PU02
We have presented the characteristics and variation of sediment loads in the Ping River Basin, the largest of the four major river basins of the Chao Phraya River system, Thailand

Summary

Introduction

Rivers are significant sources of freshwater, sediment, and nutrients to the oceans [1,2,3]. Deforestation for agriculture, population pressures, water resources development, and dam construction are all factors that induce changes in river sediment loads [6,7,8,9,10,11,12]. Understanding the response of streamflow and sediment load to human activities is necessary for accurate ecological, geomorphological, and environmental studies [5,6,7,8,9,10,11,12,15,16,17,18] for better water resource and coastal engineering management [19]. A systematic assessment of human-induced changes in riverine sediment properties (sediment flux, concentration, grain size, and deposition/erosion) has only been done in certain cases [5]

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