The impact of hydraulic load and aggregation on sedimentation of soil particles in small constructed wetlands

被引:31
作者
Braskerud, BC [1 ]
Lundekvam, H
Krogstad, T
机构
[1] Norwegian Ctr Soil & Environm Res, N-1432 As, Norway
[2] Agr Univ Norway, Dept Soil & Water Sci, N-1432 As, Norway
关键词
D O I
10.2134/jeq2000.00472425002900060039x
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
Loss of soil particles from arable land to streams and lakes negatively affects mater quality. When initiatives to mitigate soil erosion are insufficient or fair, constructed wetlands (CWs) could be a Inst buffer to mitigate pollution. The objectives in this study were to (i) determine the influence of aggregation on clay sedimentation in CWs and (ii) evaluate the prediction performance of two commonly used retention models, based on hydraulic toad and particle sedimentation velocity. Retention was measured three ways, with (i) water now proportional sampling systems in the inlet and in the outlet, (ii) sedimentation traps, and (iii) sedimentation plates. Surface area of the CWs was 0.03 to 0.07% of the watershed, which consisted of silty clay loam (18-33% clay). Some runoff episodes, usually at high runoff rates, accounted for a relatively high proportion of total sedimentation. Thus 80% of the particles were retained from less than 44% of the total runoff. Constructed wetland performance increased with increased hydraulic load or decreased detention time. The clay content in the CW sediment reflected the clay content in the arable soil. Actual CW sediment exceeded model estimates 2.5 to 8.2 times, depending on CW size and runoff. The probable reason for the prediction error is clay particles entering the CWs as aggregates. Constructed wetlands should be located in small streams to avoid break up of aggregates and a reduction in retention efficiency.
引用
收藏
页码:2013 / 2020
页数:8
相关论文
共 24 条
[1]  
BRASKERUD B, 1996, VANN, V2, P328
[2]  
Braskerud BC, 1998, PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON COMPREHENSIVE WATERSHED MANAGEMENT (ISWM-'98), P493
[3]  
CAMP TR, 1946, T AM SOC CIV ENG, V111, P895
[4]  
Chen C.-N., 1975, Proceedings of the national symposium on urban hydrology and sediment control, July 28-31, P285
[5]   NONPOINT POLLUTION AND MANAGEMENT OF AGRICULTURAL AREAS - PHOSPHORUS AND NITROGEN TRANSFER IN AN AGRICULTURAL WATERSHED [J].
DORIOZ, JM ;
FERHI, A .
WATER RESEARCH, 1994, 28 (02) :395-410
[6]   FLOCCULATION OF SUSPENDED SEDIMENT IN RIVERS OF SOUTHEASTERN CANADA [J].
DROPPO, IG ;
ONGLEY, ED .
WATER RESEARCH, 1994, 28 (08) :1799-1809
[7]  
ELONEN P, 1971, ACTA AGRAL FENN, V122
[8]  
FENNESSY MS, 1994, ECOL ENG, V3, P409
[9]  
Haan C T, 1994, DESIGN HYDROLOGY SED
[10]  
HAZEN A, 1904, T ASCE, V53, P43