Building a potential wetland restoration indicator for the contiguous United States

Abstract

Wetlands provide key functions in the landscape from improving water quality, to regulating flows, to providing wildlife habitat. Over half of the wetlands in the contiguous United States (CONUS) have been converted to agricultural and urban land uses. However, over the last several decades, research has shown the benefits of wetlands to hydrologic, chemical, biological processes, spurring the creation of government programs and private initiatives to restore wetlands. Initiatives tend to focus on individual wetland creation, yet the greatest benefits are achieved when strategic restoration planning occurs across a watershed or multiple watersheds. For watershed-level wetland restoration planning to occur, informative data layers on potential wetland areas are needed. We created an indicator of potential wetland areas (PWA), using nationally available datasets to identify characteristics that could support wetland ecosystems, including: poorly drained soils and low-relief landscape positions as indicated by a derived topographic data layer. We compared our PWA with the National Wetlands Inventory (NWI) from 11 states throughout the CONUS to evaluate their alignment. The state-level percentage of NWI-designated wetlands directly overlapping the PWA ranged from 39 to 95%. When we included NWI that was immediately adjacent to the overlapping NWI, our range of correspondence to NWI ranged from 60 to 99%. Wetland restoration is more likely on certain landscapes (e.g., agriculture) than others due to the lack of substantive infrastructure and the potential for the restoration of hydrology; therefore, we combined the National Land Cover Dataset (NLCD) with the PWA to identify potentially restorable wetlands on agricultural land (PRW-Ag). The PRW-Ag identified a total of over 46 million ha with the potential to support wetlands. The largest concentrations of PRW-Ag occurred in the glaciated corn belt of the upper Mississippi River from Ohio to the Dakotas and in the Mississippi Alluvial Valley. The PRW-Ag layer could assist land managers in identifying sites that may qualify for enrollment in conservation programs, where planners can coordinate restoration efforts, or where decision makers can target resources to optimize the services provided across a watershed or multiple watersheds.

Estimating dominant runoff modes across the conterminous United States

“…Our simple approach comparing interpolated precipitation-frequency grids with national soils data provides a first approximation of the runoff processes most likely to occur naturally throughout the CONUS. Such (Easton et al, 2008), (c) denitrification zones (Anderson, Groffman, & Walter, 2015), (d) non-point source pollution hotspots for precision agriculture (Buchanan et al, 2013), and (e) areas of high wetland potential (Horvath, Christensen, Mehaffey, & Neale, 2017 to make a priori assumptions regarding the dominant runoff generating mechanism-often with little guidance. The importance of applying a valid runoff generating mechanism is underscored by the findings of numerous studies that show incorrect application of IE-based hydrologic, and water quality models in VSA dominated regions can lead to substantial errors in streamflow predictions, nutrient, and sediment transport and incorrect identification of runoff generating zones and critical source areas (Easton et al, 2008;Kan et al, 2017;Lyon, McHale, Walter, & Steenhuis, 2006;Schneiderman et al, 2007;Valeo & Moin, 2001).…”

Can Constructed Wetlands be Wildlife Refuges? A Review of Their Potential Biodiversity Conservation Value

“…Many of these biotas depend on wetland ecosystems to complete their life cycles [7]. Despite the recognized ecological value and services they provide, natural wetlands have been seriously degraded and have declined during the last few decades, either directly or indirectly as a result of human activities, such as land reclamation, hydrological alterations, and over-exploitation [8]. This has changed global ecological processes and led to significant negative impacts on sustainable development goals, especially biodiversity conservation all over the world [2,[9][10][11].…”

Remote Sensing and GIS Support to Identify Potential Areas for Wetland Restoration from Cropland: A Case Study in the West Songnen Plain, Northeast China

“…RS provides important data, covering a broad spatial extent and a long time series, while GIS has been widely used to develop data analysis and mapping [23,37]. Making spatial decisions is critical to wetland restoration at a regional scale [13]. In this study, we quantitatively documented the potential areas for converting cropland to wetland by integrating RS and GIS technologies.…”

“…Therefore, a comprehensive indictor system is necessary for wetland restoration. Soil drainage has been considered by Horvath et al [13] to identify potential areas for restoration. In our study area, we argue that all croplands are suitable from the perspective of soil property.…”

“…To perform effective wetland restoration, the first necessary step is to identify the potential areas. In past decades, multiple methods and indicators were used to do such work [13]. For example, O'Neill et al [14] employed a wetness index to develop a conceptual model for identifying restoration sites for riparian wetlands within the Upper Arkansas River basin in Colorado, United States.…”