Abstract
Wetlands are multifunctional systems performing as nature-based solutions (NBS) for water management. This paper provides an overview of natural and constructed wetlands and their potential to support the regulation of hydrological fluxes and water quality. Wetlands can modulate peak flows by storing runoff and slowly releasing it over time, with positive impacts on soil moisture. They can also change the overall water balance by influencing evapotranspiration, infiltration, and groundwater recharge. They can enhance resilience of a catchment to floods and torrents, especially with relative low return periods (<50 years), and safeguard water availability during droughts. Wetlands may remove or reduce a number of organic and inorganic pollutants (e.g., nutrients, heavy metals, hydrocarbons, pesticides) by different physical, chemical, and biological processes developed between vegetation, microorganisms, soil/growth substrate, and water. They have proven to be efficient and effective in improving the quality of water from different sources, such as runoff from agriculture and urban areas, and domestic and industrial wastewater. The overall performance of wetlands is determined by their characteristics (e.g., size, design, type of vegetation), within-catchment position, type and amount of water and pollutants, and local conditions (e.g., climate). A focus on wetlandscape, rather than individual wetlands, is required for optimal water management and maximization of other ecosystem services.