Groundwater-dependent wetlands

Abstract

From the biological point of view wetlands are highly productive areas. They are of growing interest not only for wildlife, scenic landscape and recreation, but as a source of income and as a bioreserve. The times when wetlands were considered unhealthy and undesirable areas are fortunately over. However, in Europe and other regions many of them have already been desiccated, often by public initiative. Many wetlands or parts of them depend on groundwater contribution. This means less fluctuating situations than when they depend only on surface water, and physico-chemical characteristics are more stable. Associated vegetation is resistant to drought conditions when there is groundwater available at shallow depth. Not only is groundwater discharge to land surface important, but underground discharge as well, since this plays an important role in the water balance and especially in salinity and solute concentrations of local water. Groundwater-dependent wetlands can vary from small spots to large, elongated areas, from vegetation-rich areas to impoundings of spring water, and they may contain water from fresh to briny and with precipitated salts. Aquifer development may interfere (and often does) with groundwater availability to wetlands. Then there is an environmental conflict. Its solution means a trade-off between development and conservation, which is often a difficult one. This requires compromises by initially very diverse interests, as well as overcoming deeply entrenched myths. Obtaining reliable data and adequate monitoring is a necessary step.