In:
JAWRA Journal of the American Water Resources Association, Wiley, Vol. 53, No. 2 ( 2017-04), p. 365-381
Abstract:
The curve number ( CN ) method is used to calculate runoff in many hydrologic models, including the Soil and Water Assessment Tool ( SWAT ). The CN method does not account for the spatial distribution of land cover types, an important factor controlling runoff patterns. The objective of this study was to empirically derive CN values that reflect the strategic placement of native prairie vegetation ( NPV ) within row crop agricultural landscapes. CN s were derived using precipitation and runoff data from a seven‐year period for 14 small watersheds in Iowa. The watersheds were planted with varying amounts of NPV located in different watershed positions. The least squares and asymptotic least squares methods (LSM) were used to derive CN s using an initial abstraction coefficient ( λ ) of 0.2 and 0.05. The CN s were verified using leave‐one‐out cross‐validation and adjustment for antecedent moisture conditions ( AMC ) was tested. The asymptotic method produced CN values for watersheds with NPV treatment that were 8.9 and 14.7% lower than watersheds with 100% row crop at λ = 0.2 and λ = 0.05, respectively. The derived CN s produced Nash‐Sutcliffe efficiency values ranging from 0.4 to 0.7 during validation. Our analyses show the CN s verified best for the asymptotic LSM, when using λ of 0.05 and adjusting for AMC . Further, comparison of derived CN s against an area weighted CN indicated that the placement of vegetation does impact the CN value. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series .
Type of Medium:
Online Resource
ISSN:
1093-474X
,
1752-1688
DOI:
10.1111/jawr.2017.53.issue-2
DOI:
10.1111/1752-1688.12510
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
2090051-X
SSG:
14
