Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A geospatial modeling approach - Part 1

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

doi:10.1016/j.scitotenv.2018.11.238

Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A geospatial modeling approach - Part 1

Sci Total Environ. 2019 Feb 25:653:1546-1556. doi: 10.1016/j.scitotenv.2018.11.238. Epub 2018 Nov 20.

Authors

In-Young Yeo¹, Megan W Lang², Sangchul Lee³, Gregory W McCarty⁴, Ali M Sadeghi⁴, Omer Yetemen⁵, Chengquan Huang²

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 Geographical Sciences, University of Maryland, College Park, MD 20742, USA.
³ 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.
⁴ US Department of Agriculture, Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA.
⁵ School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia.

PMID: 30527818
DOI: 10.1016/j.scitotenv.2018.11.238

Abstract

Headwater wetlands affect ecosystem integrity of downstream waters; however, many wetlands - particularly geographically isolated wetlands (GIWs) - continue to be at risk. A significant portion of US federal policy is based on the jurisdictional status of wetlands, which is partly determined by the relationship between wetlands and downstream waters, including the cumulative impact of wetlands on those waters. We present a novel multi-phase geospatial modeling method to help elucidate hydrological relationship between GIWs and downstream waters at the landscape scale. The presented approach in this study used inundation maps derived from time series remotely sensed data between 1985 and 2010, weather and hydrological records, and ancillary geospatial data including information from the US Fish and Wildlife Service National Wetlands Inventory (NWI). The study site was a headwater catchment (292 km²) of the Choptank River Basin, located in the Mid-Atlantic region of USA, which contained a large number of Delmarva bays. The results showed inundation extent within GIWs varied, in aggregate, in response to weather variability (r = 0.58; p-value = 0.05), and was well correlated with streamflow (r = 0.81; p-value < 0.01) and base flow (r = 0.57; p-value < 0.1) conditions. The relationship between inundation patterns and stream discharge also varied with NWI hydrologic modifiers. The GIWs with water regime characterized by longer durations of flooding exhibited stronger correlations with stream discharge, but those GIWs with shorter durations of flooding were less correlated with stream discharge. This analysis suggests the mutual reliance (i.e., connection) of wetlands and streams on groundwater. GIWs appeared to function in aggregate, and it is likely that the combined effect of these wetlands significantly influenced the functioning of downstream waters.

Keywords: Catchment hydrology; GIS; Geospatial modeling; Hydrological connectivity; Remote sensing; Wetlands.