Simulated environmental effects of wetland restoration scenarios in a typical Canadian prairie watershed

Abstract

Wetland conservation and restoration contribute to improved watershed functions through providing both water quantity benefits in terms of flood attenuation and water quality benefits such as retention of sediment and nutrients. However, it is important to quantify these environmental benefits for informed decision making. This study uses a ''hydrologic equivalent wetland'' concept in the Soil and Water Assessment Tool to examine the effects of various wetland restoration scenarios on stream flow and sediment at a watershed scale. The modeling system was applied to the 25,139 ha Broughton's Creek watershed in western Manitoba in Canada. As a representative prairie watershed, the Broughton's Creek watershed experienced historic wetland losses from 2,998 ha in 1968 to 2,379 ha in 2005. Modeling results showed that if wetlands in the Broughton's Creek watershed can be restored to the 1968 level, the peak discharge and average sediment loading can be reduced by 23.4 and 16.9%, respectively at the watershed outlet. Based on wetland and stream drainage areas estimated by the model and empirical nutrient export coefficients, the corresponding water quality benefits in terms of reductions in total phosphorus and nitrogen loadings were estimated at 23.4%. The modeling results are helpful for designing effective watershed restoration strategies in the Broughton's Creek watershed. The developed methodology can be also applied to other study areas for examining the environmental effects of wetland restoration scenarios.

Phosphorus Retention in Intact and Drained Prairie Wetland Basins: Implications for Nutrient Export

“…The Newdale soil series is characterized by an Orthic Black Chernozem solum on moderately to strongly calcareous, loamy morainal till of limestone, granitic, and shale origin (Podolsky, 1988). Agriculture is the dominant land use in the watershed (71.8%), followed by range land (10.8%), wetlands (9.5%), and forests (4.0%) (Yang et al, 2010). Historically, the Broughton's Creek watershed contained numerous depressions ranging from small potholes, to sloughs, to lakes that were left behind after the retreat of the Assiniboine glacial lobe between 20,000 and 12,000 BC (Yang et al, 2008).…”

Greenhouse gas emissions and carbon sequestration potential in restored wetlands of the Canadian prairie pothole region

“…Given the continued threat these systems face and their once prominent presence on the North American landscape (20 Million ponds, Euliss et al 2006) they are one of the most under-studied ecosystems in the world. Although we are starting to recognize the important ecological services provided by these systems, such as their role in regulating the flow and quality of water at the landscape level Yang et al 2010), they are still dramatically under-valued by society.…”

Patterns and drivers for wetland connections in the Prairie Pothole Region, United States

“…Depressional wetlands provide critical hydrological services including storing precipitation and hydrologic inflows (Winter and Rosenberry 1998), which reduces peak stream flows and potential downstream flooding (Vining 2002;Yang et al 2010). As depressional wetlands are typically non-channel connected (Tiner 2003), surface-water connections with other water bodies are usually not continuous.…”

“…During flood events or wet periods, depressional wetlands that become connected to streams or subsumed by lakes exchange water and materials, but may experience the temporary loss of wetland function until water levels recede (Junk et al 1989;Galat et al 1998;Mortsch 1998). Understanding landscape drivers for the abundance of wetlands that cyclically or variably contribute water to streams is important for accurately predicting stream flow, particularly during high flow events (Vining 2002;Yang et al 2010), as well as informing the process to determine the jurisdictional status of wetlands in compliance with the U.S. Clean Water Act. Yet, relatively little research into variable surface-water connections, in particular landscape patterns and drivers of such connections, has been done (U.S. EPA 2015).…”