Namsai, M.; Bidorn, B.; Mama, R.; Charoenlerkthawin, W. A Half-Century of Human Impact on Nan River Runoff and Sediment Load Supplied to the Chao Phraya River. Water2024, 16, 148.
Namsai, M.; Bidorn, B.; Mama, R.; Charoenlerkthawin, W. A Half-Century of Human Impact on Nan River Runoff and Sediment Load Supplied to the Chao Phraya River. Water 2024, 16, 148.
Namsai, M.; Bidorn, B.; Mama, R.; Charoenlerkthawin, W. A Half-Century of Human Impact on Nan River Runoff and Sediment Load Supplied to the Chao Phraya River. Water2024, 16, 148.
Namsai, M.; Bidorn, B.; Mama, R.; Charoenlerkthawin, W. A Half-Century of Human Impact on Nan River Runoff and Sediment Load Supplied to the Chao Phraya River. Water 2024, 16, 148.
Abstract
It was believed that the construction of large dams in the upper tributary basin of the Chao Phraya River (CPR) has caused sediment load reduction in the CPR system by 75–85%. Based on historical and observed river flow and sediment data measured during 1922–2019, we investigated the effects of three large dams, the Sirikit, Naresuan, and Khwae Noi dams, on river runoff and sediment loads supplied to the CPR using Mann-Kendall (MK) test and the double mass curve (DMC). Results from this study revealed that the Nan River contributed approximately 40% and 57% of the runoff and total sediment load (TSL) to the CPR, respectively. The water regulation by the Naresuan diversion dam has mainly caused the reduction on annual runoff and TSL downstream of each dam. The results from this study also reveal that the sediment load observed at the headwater (C.2) of the CPR still increased after the construction of the Sirikit dam due to the expansion of irrigation areas downstream of the dam and the channel improvement in the lower reach of Nan River. After the three major dams were operated, the sediment load at C.2 reduced by 31% compared that discharging during the pre-construction period.
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