Wetland restoration in an agricultural basin. Linking hydrologic response, optimal location, ecosystem services and stakeholder opinions

Abstract

Wetland restoration in agricultural basins with artificial drainage is seen as a promising strategy to improve water quality and reduce erosion. A case-study is conducted in the Le Sueur River Basin (LSRB), Minnesota, USA, using the Hydrologic Simulation Program Fortran. In the LSRB bluffs are the primary source of erosion governed by the stream flow. This simulation highlight that wetland restoration results in reductions in the stream flow for all years, most months and for all individual metrics studied. The reductions are largest in the months with currently the highest sediment concentrations making wetland restoration an efficient strategy. Furthermore, this research test the hypothesis that wetland restoration is most beneficial in late contributing, far upstream areas. However, the simulations show that this hypothesis has to be rejected and that actual downstream wetland restoration results in larger reductions in peak stream flow. The second part of this research is concerned with a broader framework for wetland restoration identifying stakeholder opinions and requirements and the synergies or trade-offs with costs and ecosystem service provision. The requirements set by stakeholders on wetland restoration actually create multiple opportunities synergies for both costs and several ecosystem services. However, an important dis-service provided by wetlands under anticipated future climate might be the effect on GHG-concentrations leading to an additional positive feedback loop in the climate system. Nonetheless, what is especially important is to not solely focus on the effect of wetland restoration on sediment concentrations but take into account and utilize the opportunities to achieve multiple policy goals and create multiple incentives for stakeholders through/for implementation of wetlands.