World Wetlands Day is annually observed on the 2nd of February in effort to foster global public awareness on the importance of wetlands for a sustainable environment – environmentally, socially and economically spoken. Although wetlands are found in a variety of settings, sustainable and functional wetlands have identifiable soil, plant, hydrological and river settings and features. Wetland function ability is severely hampered by wetland alteration due to land use changes and urban development. What are the functions of wetlands, and why are these so important?
Commonly recognised wetland functions include the following:
- Water storage;
- Protection of water quality and pollution control;
- Elimination of excess nutrients; (read more about nutrient pollution of water here);
- Flood intervention;
- Ecological habitats (especially safe nursing grounds for a number of bird, fish and smaller mammal species); and
- Recreational facilities for communities including hiking and walking, fishing, bird and wildlife watching.
Some of these functions such as the storage of water, ecological habitats and recreational amenities are easy to see, but what about water quality protection, flood intervention? To understand these functions, we need to dig a bit deeper:
Wetlands are often described as the kidneys of the natural environment. This is based on the observation that wetlands fulfil the same role for the natural environment as kidneys fulfil for the human body. Through the complex biological nature of wetlands, they are able to filter pollutants and foreign chemical substances, re-circulating these substances and often breaking it down into nutrients that are favourable for the surrounding biological environment. The biological ability of wetlands to purify water is often recreated through artificial wetlands. By mimicking the natural filtering function offered by wetlands, artificial wetlands can purify urban and waste water enabling this water to safely feed into river systems without pollution threats.
Wetlands are furthermore described as functioning similar to sponges. It can take up significant volumes of water and then release the water over a period of time. This is how wetlands intervene with floods and effectively slow down floodwaters intensity. This wetland function is of substantial importance particularly for urban environments. Continued alteration of natural environments and urban development are contributing to increasing surface areas being taken up by hard and compacted surfaces, and this accelerates the speed of floodwaters. Storm water passing through wetlands is temporarily captured, preventing immediate and high intensity flood damage at a lower level. The purified, cleaner floodwaters return back into the environment, slowly.
In the global quest for a sustainable environment, wetlands will continue to offer these and other extremely valuable functions, but only if the global community continues to recognise, and act on the vitality of wetlands.
Source: US Geological Survey, National Water Summary on Wetland Resources (1997), USGS Water Supply Paper 2425
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