Entropy model to assess sediment resuspension probability and trap efficiency of small dams  

作　　者：Francisco Jairo Soares Pereira Antonio Viana da Silva Filho José Wellington Batista Lopes José Carlos de Araújo 

机构地区：[1]Department of Agricultural Engineering,Federal University of Ceará,Campus Do Pici,Bloco 804,60.450-760,Fortaleza,Brazil [2]Rural Federal University of Pernambuco,Serra Talhada,Brazil [3]Federal University of Piauí,Bom Jesus,64900-000,Brazil

出　　处：《International Journal of Sediment Research》2022年第5期675-686,共12页国际泥沙研究（英文版）

基　　金：support of the Brazilian Coordination for the Improvement of Higher Education Personnel—CAPES,the Brazilian National Council for Scientific and Technological Development(Grant No.CNPq/407999/2016-7);the PiauíResearch Foundation(Grant No.021/2019 PPP/FAPEPI/CNPq)。

摘　　要：In the Brazilian drylands,there are tens of thousands of small dams.Despite their paramount importance to the rural population,they are rarely monitored.Water demand increases with time while,simultaneously,siltation reduces reservoir water capacity and availability.Reservoir siltation models are,therefore,mandatory to manage the numerous ungauged small dams in these drylands.The objective of the current study is to improve sediment trap efficiency(TE)modeling by including resuspension as a key probabilistic process.The Shannon entropy was used to estimate the sediment resuspension probability,which was merged with the Camp model and generated the RETSED entropy model.To validate the RETSED model,an experimental check dam(ECD,300 m^(3)),located in the Gilbu es desertification site,Brazil,was monitored hourly during one hydrological year(July 2018-July 2019).Measurements show that the annual volumetric decline of the check dam was 12%;and that the average trap efficiency equaled 86%.Only 9.5%of the hourly sediment concentration outflow exceeded the average plus one standard deviation,showing that the reservoir is well mixed;a fact which highlights the relevance of the resuspension process.Three empirical models failed to mimic the experimental results:Churchill(TE=99%),Brune(TE=75%),and Maryland(TE=94%).According to the RETSED entropy model,the resuspension probability during the experiment was 10%and TE=81%,a value only 6%below the measured one.The Camp model simulated TE=89%,only 3%higher than the measured value,but confirmed the Camp model’s tendency to overestimate TE due to a disregard of resuspension.The deterministic model showed low sensitivity concerning the hydrodynamic effects,whereas the entropy formulation proved to be more consistent with physical behavior:the resuspension probability clearly increased and trap efficiency decreased with rising reservoir discharge.

关 键 词：EROSION Check dam SEDIMENTATION Ungauged basins Camp model 

分 类 号：TV64[水利工程—水利水电工程] TV142