Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A catchment modeling approach - Part 2

In-Young Yeo; Sangchul Lee; Megan W Lang; Omer Yetemen; Gregory W McCarty; Ali M Sadeghi; Grey Evenson

doi:10.1016/j.scitotenv.2018.11.237

Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A catchment modeling approach - Part 2

Sci Total Environ. 2019 Feb 25:653:1557-1570. doi: 10.1016/j.scitotenv.2018.11.237. Epub 2018 Nov 20.

Authors

In-Young Yeo¹, Sangchul Lee², Megan W Lang³, Omer Yetemen⁴, Gregory W McCarty⁵, Ali M Sadeghi⁵, Grey Evenson⁶

Affiliations

¹ School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia; Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA. Electronic address: In-Young.Yeo@newcastle.edu.au.
² Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA; US Department of Agriculture - Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA.
³ Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA.
⁴ School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia.
⁵ US Department of Agriculture - Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA.
⁶ Department of Food, Agricultural and Biological Engineering, The Ohio State University, Columbus, OH 43210, USA.

PMID: 30527888
DOI: 10.1016/j.scitotenv.2018.11.237

Abstract

In Part 1 of this two-part manuscript series, we presented an effective assessment method for mapping inundation of geographically isolated wetlands (GIWs) and quantifying their cumulative landscape-scale hydrological connectivity with downstream waters using time series remotely sensed data (Yeo et al., 2018). This study suggested strong hydrological coupling between GIWs and downstream waters at the seasonal timescale via groundwater. This follow-on paper investigates the hydrological connectivity of GIWs with downstream waters and cumulative watershed-scale hydrological impacts over multiple time scales. Modifications were made to the representation of wetland processes within the Soil and Water Assessment Tool (SWAT). A version of SWAT with improved wetland function, SWAT-WET, was applied to Greensboro Watershed, which is located in the Mid-Atlantic Region of USA, to simulate hydrological processes over 1985-2015 under two contrasting land use scenarios (i.e., presence and absence of GIWs). Comparative analysis of simulation outputs elucidated how GIWs could influence partitioning of precipitation between evapotranspiration (ET) and terrestrial water storage, and affect water transport mechanisms and routing processes that generate streamflow. Model results showed that GIWs influenced the watershed water budget and stream flow generation processes over the long-term (30 year), inter-annual, and monthly time scales. GIWs in the study watershed increased terrestrial water storage during the wet season, and buffered the dynamics of shallow groundwater during the dry season. The inter-annual modeling analysis illustrated that densely distributed GIWs can exert strong hydrological influence on downstream waters by regulating surface water runoff, while maintaining groundwater recharge and ET under changing (wetter) climate conditions. The study findings highlight the hydrological connectivity of GIWs with downstream waters and the cumulative hydrological influence of GIWs as hydrologic sources to downstream ecosystems through different runoff processes over multiple time scales.

Keywords: Hydrological connectivity; Remote sensing; Watershed modeling; Wetland hydrologic function; Wetlands.