Co‐design of Constructed Wetlands to Mitigate Pesticide Pollution in a Drained Catch‐basin: A Solution to Improve Groundwater Quality

Abstract

The European Water Framework Directive enjoins its members to retrieve the good ecological status of their water resources. In France, it has resulted in the regulation of entrants' reduction plans which aim at halving the quantities of pesticides. This plan matches standard situations of non‐point pollution sources, where the water infiltrates towards the underlying aquifer. However, numerous situations exist in France in which groundwater is imperfectly protected by a shallow impervious layer in the topsoil, meaning that sinkholes may connect the surface water and relay pollution directly to the aquifer. These impervious layers induce subsurface drainage demand and construction so that the effluent can be collected at outfalls of drainage systems, and be processed in constructed wetlands before falling down the sinkholes, thus decreasing net pollution. The Champigny aquifer corresponds to this description, and has been shown to be highly vulnerable. The mission of AQUI'Brie, a non‐profit organisation, is to protect this groundwater, which is one of the water resources of Paris. Although well aware of the benefits of buffer zones, but at this time without incentives to implement them, AQUI'Brie started a co‐construction process of constructed wetlands, involving all the stakeholders of a small catchment located upstream from a sinkhole. This paper describes the co‐construction from the first meeting to the final structures in a context of high land use pressure. It shows that the number and area of constructed wetlands has diminished beyond the threshold for which the performance of depollution process may fail. In 2011, a performance assessment programme was set up to determine if the co‐constructed wetlands comply with the new current regulations. Copyright © 2012 John Wiley & Sons, Ltd.

Identifying Feasible Locations for Wetland Creation or Restoration in Catchments by Suitability Modelling Using Light Detection and Ranging (LiDAR) Digital Elevation Model (DEM)

“…They will show the best nitrate-N removal performance. This can also support the practical side of wetland management: one large, collectively managed wetland, could be more practical than several smaller ones in some cases [53]. In our study, the wetland at the very lower part of the watershed (W6) belonged to five different cadastral parcels, meaning that managers of these five areas must collaborate in creating and managing the wetland.…”

Disentangling the Complexity of Groundwater Dependent Social-ecological Systems

“…These efforts might include focusing on enhancing ecosystem services provided by soil and vegetation. In practice several types of these levers exist, such as ditch networks and artificial wetlands (Stehle et al 2011;Tournebize et al 2012). The principle is either to treat the flux directly, or to divert it into parts of the ecosystem that can mitigate aspects of poor water quality.…”

Adaptation Options for Land Drainage Systems Towards Sustainable Agriculture and the Environment: A Czech Perspective

“…Well known are studies that report different types of controlled drainage and its positive effects on reducing drainage runoff and mitigating solute concentrations both in tiles and surface drainage ditches [22,24,34,39,53,54]. Other measures for improving drainage water quality include various denitrification bioreactors, constructed or natural wetlands, changes in fertilization and tillage management, planting of catchcrops, or grassing the drained land [55][56][57][58][59][60][61][62]. In short, the efforts principally aim to: i) Decrease the input of nutrients or plant-protective compounds from soil to water and promote the natural processes of binding the nutrients in soil (reducing mineralization of organic matter, increasing denitrification, augmenting sorption) ii) Enhance water retention time in soil and thus increasing the consumption of nutrients by plants or soil biota.…”