Wetlands: Going, Goings ... Gone?

Article excerpt

We neglect swamps and bogs at our own peril.

The ongoing loss of wetlands throughout the world is undermining water quality, worsening the impact of natural disasters, and reducing biological diversity according to researchers at the Worldwatch Institute.

Wetlands are areas that are saturated with water for part of the year--freshwater sites such as swamps, bogs, and marshes, and saltwater systems that include mangroves and coral reefs. Intact wetlands provide essential services, including the recharging of groundwater supplies on which drinking water depends. They also shield ecosystems from pollutants such as the nitrogen and phosphorus contamination that results from crop field drainage.

Wetlands are often drained or filled when dam construction projects alter the frequency of water flows; deltas and coastal ecosystems far downstream can also be harmed. Draining wetlands can cause water tables to fall and increase the likelihood of salinization of soils, water shortages, and flood-related disasters.

Water disruptions in South Africa led to extreme flooding in neighboring Mozambique in 2000. About half of South Africa's wetlands have been drained for agriculture; this loss of the wetlands' flood control capacity, along with high runoff resulting from overgrazed grasslands in South Africa's portion of the Limpopo River watershed, made the flooding in Mozambique especially severe. Wetlands loss in the U.S. Mississippi River basin also disrupted natural flood control, resulting in $19 billion in property damage during floods in 1993. …