Wetlands: their Importance and Function

Wetlands range from springs, seeps, mires and bogs in the mountains, to midland marches and flood plains, to coastal lakes, mangrove swamps and estuaries. All wetlands are linked by rivers.

Water purification

• Plants and soils in wetlands play a significant role in purifying water.

• Many nutrients such as phosphorus and nitrogen, which are usually associated with agricultural runoff, are removed effectively by wetlands.

• High concentrations of these nutrients are therefore prevented from reaching groundwater supplies or other watersources that may be utilised for drinking purposes.

• Many wetland plants have the capacity to remove toxic substances such as pesticide residue, industrial effluent and seepage from mining activities.

Climate-change mitigation

• Wetlands protect coastal and inland areas against the effects of climatic changes such as increasing frequency of storms, changing rainfall patterns, rising sea levels and sea-surface temperatures.

• Wetlands have been identified as significant storehouses of carbon. Peatlands, such as those found in the Rietvlei Nature Reserve near Pretoria, are estimated to store more than 25 % of the soil carbon pool even though these areas cover only about 3 % of the world’s total land area.

• Drainage, conversion of land to agricultural use and degradation of wetlands will release large quantities of carbon dioxide as well as other greenhouse gases contributing to global warming.

Sediment and nutrient retention and export

Wetlands tend to slow down the force of water, promoting the deposition of sediments carried in the water. This results in the blocking of waterways. Nutrients such as phosphorus and nitrogen can, however, be deposited at the same time. These nutrients, which can come from agricultural sources, human waste or industrial effluent, may accumulate in the subsoil, be transformed by chemical and biological processes or taken up by wetland vegetation which can then be harvested and removed effectively from the system.

Flood control

• Wetlands often play a crucial role in flood control. However, loss of floodplains to agriculture and human habitation has reduced this capacity.
• The construction of levees and dams on rivers to improve flood control has often had the reverse effect.
• Flood-plain restoration and the removal of impeding structures partly solved the problem in many countries.

Recreation and tourism

• The natural beauty of wetlands and its diversity of animal and plant life make them popular tourist attractions. Many of the finest sites are protected as National Parks or World Heritage Sites.
• Recreational uses such as fishing, hunting and boating, involve millions of people who spend billions of rands on these activities.
• Wetland areas are also ideal locations for involving the general public and schoolchildren in hands-on learning experiences and to raise awareness of environmental issues in an essentially recreational atmosphere.

Cultural value

Although largely an unexplored, poorly-documented subject, wetlands are frequently of religious, historical, archaeological or other cultural significance at local or national level. For example, Lake Fundudzi in the Northern Province is of cultural significance to the Tshiavha clan as a place of worship and they believe that spirits of their ancestors inhabit the depths of the lake.

Reservoirs of biodiversity

• Freshwater wetlands contain more than 40 % of the world’s plant species and 12 % of all animal species.
• Some wetlands contain significant numbers of endemic species.
• Coral reefs rival tropical rainforests in terms of biodiversity; they may contain up to 25 % of all marine species. Reefs hold an estimated 4 000 species of fish and 800 species of reef-building corals. The total number of species associated with reefs may be more than a million.
• Wetland biodiversity is a significant reservoir of genes that have a considerable economic potential in the pharmaceutical industry and in the production of commercial crop plants such as rice.

Shoreline stabilisation and storm protection

Coastal wetlands play a critical role in many parts of the world in protecting the land from storm surges and other weather events. They reduce wind, wave and current action. Coastal vegetation helps to hold sediment in place.

Wetland products

The list of products from wetlands exploited by humans is immense. This occurs at all levels, from a commercial scale to cottage industries and subsistence level. Fish species, shrimp, and other marine animals are dependent on coastal wetlands for at least part of their life cycle. Rice, a wetland plant, forms the staple diet of 3 billion people.

Source: Department of Agriculture (RSA)

Rhode Island flooding

The current flooding on Rhode Island (USA) is due to a number of factors, many linked to human-induced environmental degradation. Most of the wetlands on Rhode Island have been severely degraded or lost completely and development has taken place in flood zones.  Floodwater attenuation by healthy, functioning wetlands could have mitigated the effects of heavy rainfall in areas like Rhode Island. Wetlands have been drained and polluted to the detriment of local ecology and people.  With increasingly extreme weather patterns, we will become acutely aware of the importance of wetlands for our survival.  Water Rhapsody supports the conservation and sustainable use of all our natural resources.

Water Rhapsody Mpumalanga’s water conservation products include water tanks (we are authorized South African JoJo Tank dealers and Atlas Plastics water tank suppliers), rainwater harvesting systems, rainwater tanks, grey water recycling systems, water-saving toilet flush mechanisms, swimming pool backwash recycling systems and other water saving devices.  Water and energy are linked and thus we have incorporated Yes Solar Mpumalanga (solar energy is ideal for the Lowveld, with Nelspruit having one of the highest irradiation rates in South Africa!).  Yes Solar is an official distributor for German-made Solsquare products that include a wide range of high quality solar panels, solar water heating systems, solar geysers and specific solar solutions customized to your needs.  Solsquare solar water geyser systems are Eskom-approved and are installed by Eskom-accredited solar installers (eligible for Eskom renewable energy rebate programme).

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