Contemporary and restorable wetland water storage: A landscape perspective

Authors: JONES, N. - Virginia Polytechnic Institution & State University; EVENSON, G.R. - Environmental Protection Agency (EPA); MCLAUGHLIN, D. - Virginia Polytechnic Institution & State University; VANDERHOFF, M.K. - Environmental Protection Agency (EPA); LANG, M.W. - Fisheries & Wildlife; McCarty, Gregory; ALEXANDER, L. - Environmental Protection Agency (EPA)

Submitted to: Ecological Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2017
Publication Date: 3/15/2017
Citation: Jones, N., Evenson, G., Mclaughlin, D., Vanderhoff, M., Lang, M., McCarty, G.W., Alexander, L. 2017. Contemporary and restorable wetland water storage: A landscape perspective. Ecological Applications. https://doi.org/10.1002/hyp.11405.
DOI: https://doi.org/10.1002/hyp.11405

Interpretive Summary: Wetlands are important features on the landscape because they store water, which enables a suite of hydrologic, biogeochemical, and biological functions. While wetland definitions widely vary (e.g., from broad descriptions that highlight the persistence of inundation or saturation to more stringent requirements for regulation all implicitly include wetlands’ ability to store water. Historically, artificial drainage is one of the most common techniques used to fully convert or otherwise hydrologically alter wetlands for agricultural or urban land uses. In the US, this tradition can be traced back to colonial agricultural practices. Today, extensive drainage systems are still widely used for agricultural production throughout the Midwest and Eastern US, where their prevalent use reduces wetland water storage and subsequent functions at local to landscape scales. Current tools for quantifying wetland storage capacity include estimates using available topographic data and either empirical relationships or contour-based approaches. High-resolution, airborne Light Detection And Ranging (LiDAR) is becoming more readily available across landscapes, enabling catchment and even regional topographic analyses. We apply this approach to the Delmarva Peninsula, quantifying both contemporary wetland storage capacities and potential storage capacities that could be achieved through hydrologic restoration. We then investigate the spatial distribution of wetland storage capacities across a single watershed, further highlighting the potential utility of this approach to target wetland conservation and restoration efforts. We estimated both current and restorable storage capacities of 2.2 and 3.8 cm, respectively, across the entire peninsula.

Technical Abstract: Surface water storage in wetlands drives ecosystem function from local to landscape scales. In many regions, hydrologic modifications have significantly reduced wetland storage capacity and subsequently diminished wetland functions. While the loss of wetland area has been well documented across many landscapes, few studies have quantified the loss and potential gain of wetland storage capacity. Here, we present a raster based method to quantify the storage capacity of individual wetlands in highly modified landscapes. We demonstrate the utility of this method by applying it to the greater Delmarva Peninsula, a region punctuated by both depressional wetlands and agricultural drainage ditches. We estimated both current and restorable storage capacities of 2.2 and 3.8 cm, respectively, across the entire peninsula. We then examined the spatial distribution of the storage capacity within a single watershed. Vertically, 88 and 93% of both contemporary and potential storage capacity was found within 1 m of the stream elevation, respectively. Horizontally, more than 60% of potential storage capacity can be found within 20m of a drainage feature, highlighting both ubiquitous nature of ditching and potential for hydrologic restoration. With high resolution LiDAR data becoming more available, the presented method represents an effective and novel tool to quantify the effects of hydrologic modification, and to optimize wetland restoration and conservation efforts at landscape scales.