Geographically isolated wetlands and watershed hydrology: A modified model analysis

JOURNAL OF HYDROLOGY

卷:529

Article

Evenson, Grey R.¹  Golden, Heather E.²  Lane, Charles R.²  D'Amico, Ellen³ 

[1] US EPA, Oak Ridge Inst Sci & Educ, Off Res & Dev, Natl Exposure Res Lab, Cincinnati, OH 45268 USA

[2] US EPA, Off Res & Dev, Natl Exposure Res Lab, Cincinnati, OH 45268 USA

[3] CSS Dynam Corp, Cincinnati, OH USA

关键词: Geographically isolated wetlands;    Non-floodplain wetlands;    Non-adjacent wetlands;    Hydrologic connectivity;    Watershed model;    Soil and Water Assessment Tool (SWAT);   

DOI  :  10.1016/j.jhydrol.2015.07.039

来源: Elsevier

【 摘 要 】

Geographically isolated wetlands (GIWs) are defined as wetlands that are completely surrounded by uplands. While GIWs are therefore spatially isolated, field-based studies have observed a continuum of hydrologic connections between these systems and other surface waters. Yet few studies have quantified the watershed-scale aggregate effects of GIWs on downstream hydrology. Further, existing modeling approaches to evaluate GIW effects at a watershed scale have utilized conceptual or spatially disaggregated wetland representations. Working towards wetland model representations that use spatially explicit approaches may improve current scientific understanding concerning GIW effects on the downstream hydrograph. The objective of this study was to quantify the watershed-scale aggregate effects of GIWs on downstream hydrology while emphasizing a spatially explicit representation of GIWs and GIW connectivity relationships. We constructed a hydrologic model for a similar to 202 km(2) watershed in the Coastal Plain of North Carolina, USA, a watershed with a substantial population of GIWs, using the Soil and Water Assessment Tool (SWAT). We applied a novel representation of GIWs within the model, facilitated by an alternative hydrologic response unit (HRU) definition and modifications to the SWAT source code that extended the model's pothole representation. We then executed a series of scenarios to assess the downstream hydrologic effect of various distributions of GIWs within the watershed. Results suggest that: (1) GIWs have seasonally dependent effects on baseflow; (2) GIWs mitigate peak flows; and (3) The presence of GIWs on the landscape impacts the watershed water balance. This work demonstrates a means of GIW simulation with improved spatial detail while showing that GIWs, in-aggregate, have a substantial effect on downstream hydrology in the studied watershed. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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