Roughness coefficient and its uncertainty in gravel-bed river
Roughness coefficient and its uncertainty in gravel-bed river作者机构：River and Coastal Research DivisionKorea Institute of Construction Technology
出 版 物：《Water Science and Engineering》 (水科学与水工程（英文版）)
年 卷 期：2010年第3卷第2期
页 面：217-232页
核心收录：
学科分类：0707[理学-海洋科学] 08[工学] 081501[工学-水文学及水资源] 0815[工学-水利工程] 0813[工学-建筑学] 0824[工学-船舶与海洋工程] 0814[工学-土木工程]
主 题：roughness coefficient estimation field measurement gravel-bed river uncertainty
摘 要：Manning＇s roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge, and the applicability of various methods used for estimation of the roughness coefficient was evaluated. Results show that the roughness coefficient tends to decrease with increasing discharge and water depth, and over a certain range it appears to remain constant. Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that, although the field-measured values provide approximate roughness coefficients for relatively large discharge, there seems to be rather high uncertainty due to the difference in resultant values. For this reason, uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables. On average, a 20% increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity, but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach. Finally, the validity of estimated roughness coefficient based on field measurements was examined. A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation, but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%. Conversely, the necessity for roughness coefficient estimation by field measurement is confirmed.
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