Effect of watershed subdivision on swat flow, sediment, and nutrient predictions

被引:165
作者
Jha, M [1 ]
Gassman, PW
Secchi, S
Gu, R
Arnold, J
机构
[1] Iowa State Univ, Dept Civil Engn, Ames, IA 50011 USA
[2] Iowa State Univ, Dept Econ, Ctr Agr & Rural Dev, Ames, IA 50011 USA
[3] USDA ARS, Grassland Soil & Water Resource Lab, Temple, TX 76502 USA
来源
JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION | 2004年 / 40卷 / 03期
关键词
modeling; flow; sediment; nutrients; watershed subdivision; sensitivity analysis;
D O I
10.1111/j.1752-1688.2004.tb04460.x
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The size, scale, and number of subwatersheds can affect a watershed modeling process and subsequent results. The objective of this study was to determine the appropriate level of subwatershed division for simulating flow, sediment, and nutrients over 30 years for four Iowa watersheds ranging in size from 2,000 to 18,000 km(2) with the Soil and Water Assessment Tool (SWAT) model. The results of the analysis indicated that variation in the total number of subwatersheds had very little effect on streamflow. However, the opposite result was found for sediment, nitrate, and inorganic P; the optimal threshold subwatershed sizes, relative to the total drainage area for each watershed, required to adequately predict these three indicators were found to be around 3, 2, and 5 percent, respectively. Decreasing the size of the subwatersheds below these threshold levels does not significantly affect the predicted levels of these environmental indicators. These threshold subwatershed sizes can be used to optimize input data preparation requirements for SWAT analyses of other watersheds, especially those within a similar size range. The fact that different thresholds emerged for the different indicators also indicates the need for SWAT users to assess which indicators should have the highest priority in their analyses.
引用
收藏
页码:811 / 825
页数:15
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