日本地球惑星科学連合2018年大会

講演情報

[EE] ポスター発表

セッション記号 A (大気水圏科学) » A-HW 水文・陸水・地下水学・水環境

[A-HW20] 流域の物質輸送と栄養塩循環-人間活動および気候変動の影響-

2018年5月21日(月) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:齋藤 光代(岡山大学大学院環境生命科学研究科)、小野寺 真一(広島大学大学院総合科学研究科)、細野 高啓(熊本大学大学院先導機構、共同)、Adina Paytan(University of California Santa Cruz)

[AHW20-P28] Effects of Dam Construction on Suspended Sediment and Dissolved Solids Transport in the Ca River, North-Central Vietnam

*Phuong Thi Ho1,2Okubo Kenji2 (1.School of Chemical, Biological and Environmental Technologies, Vinh University, Vietnam、2.Graduate School of Environmental and Life Science, Okayama University, Japan)

キーワード:Suspended sediment transport, Dissolved solids transport, Ca River, Dam construction

The regime laws on hydraulic properties in the cross-section at two hydrological stations (Dua and Yen Thuong) along the Ca River, North-Central Vietnam are combined into the power functions with exponents of 1.46–1.85 by using the roughness coefficient (n) and the settling velocity or the particle size (D) to simulate suspended sediment load. Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS), and ratio of the root mean square error to the standard deviation of measured data (RSR) were used to evaluate the calibration process for a pre-dam priod (1994-2004) and the validation for a post-dam period (2005-2014). One of the effects of dam construction is a reduction in Manning’s roughness coefficient and in sediment particle size. As the results, the observed sediment load decreased after dam construction at both stations with the annual decrease rate of approximately 20-40%. The power function with exponents of 0.83 of dissolved solid load was applied to calculate long-term annual TDS. Average value of TSS/TDS decreased from 3.0 to 1.6 at Yen Thuong and from 2.4 to 1.8 at Dua after dam construction.