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Effects of spatial data resolution on runoff predictions by the BASINS model
Chang, C.L. & Chao, Y.C.
Abstract
The BASINS model, developed by the United
States EPA, is a popular simulation tool for predicting
watershed responses, such as runoff, pollution exports, and
water quality. It requires large amounts of data to set
parameters. Many studies state that model input is a major
source of model uncertainty. Thus, improvements to the
quality and completeness of the data will improve the
certainty of the model. The objective of this study is to
discuss the effects of spatial data, including digital elevation
models (DEMs) and spatial rainfall records, on predictions
of runoff from the BASINS model. The result
shows that both DEMs and rainfall data can significantly
influence peak flow and runoff volume. Rainfall input has
more influence on the curve shape of hydrograph than
DEM resolution. DEM resolution can have more impact on
peak flow predictions than rainfall input. Because the
model uncertainties from DEMs and rainfall records
influence each other, the prediction error does not always
decrease when DEM resolution increases. The present
results show that the BASINS model produces reliable
answers in the case area when the grid size is less than
100 m × 100 m and the precipitation records from the
Bihu Rainfall Station are correct and complete.
Keywords
BASINS; Runoff; Spatial data; Uncertainty
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