Hydrological value
Wetlands greatly influence the flow and quality of water, thus providing benefits to humans.
- Wetlands act as like sponges. They store and slowly release surface water, rain, snowmelt and flood waters. Wetland vegetation also impedes the movement of flood waters and distribute them more slowly over floodplains.Thus wetlands reduce the likelihood of flood damage to homes, businesses, and crops in agricultural areas. Flood storage and shoreline erosion control might be more and more important in a context of climate change; sea-level rise as well as an increase in the frequency of heavy rain events are expected in the Mediterranean. Wetlands can help human societies to lessen the impacts of these changes, especially in highly constructed areas like the Mediterranean coast.
- Like sponges, wetlands store water during a definite time. Thus, some wetlands maintain stream flow or at least soil humidity during dry periods. This may be of great use to human beings as for instance it allows having good pastures during summer in the Mediterranean. Others also replenish groundwater, as the water seep into the soil. Many of us depend on this groundwater for drinking and gardening.
- Moreover, wetlands help improving water quality, including that of drinking water, by intercepting surface runoff and removing or retaining inorganic nutrients, processing organic wastes, and reducing suspended sediments before they reach open water. However, the capacity of wetlands to clean water is not unlimited. It depends on the species they host, their interactions and the structure of the ecosystem. Too much surface runoff carrying sediments, nutrients, and other pollutants can thus degrade wetlands and, consequently, the societal services they provide.
- Finally one of the most important services is the supply of clean water for drinking but also for agriculture and industries. This issue is of particular importance at the beginning of the 21st century as water shortage is a key challenge to address in the Mediterranean development process.
