Water Management: Wetlands

Wetlands are regions which have water systems mixed with marsh or fen lands. The water may be mobile or static and may be fresh or brackish (slightly saline) in nature. The depth of the water at low tide (since wetlands typically adjoin the sea) should not be more than six metres (for more details on wetlands, see here).

Wetlands are particularly important areas of land for several reasons. The first of these is the opportunity it provides for wildlife, both animals and plants. This is true not just as a permanent habitat but as a means of offering a stopping point for migrating birds. For example, large numbers of Siberian Cranes stop at the Lake Poyang Basin in China every year – without these options, bird migration patterns might be seriously affected.

Since the wetlands unite land and water (and also abut the sea), they represent zones where two different ecotones (i.e. land and river or sea) join together and these are vital areas in providing two different sources of food. As a survival strategy, living in a region where two ecotones exist is a good idea because the sources or food are diversified and so risks reduced: if there is a problem with the land, then maybe the water will provide a different type of food.

It is the seasonal presence of migratory birds and the year-round presence of a wide variety of flora and fauna that make many wetlands important natural resources for tourism. Environmental tourism of this sort van be both a threat and an opportunity: it is a threat if excessive tourism damages the land and the wildlife it supports; it is an opportunity if income derived from carefully-managed tourism enables wetlands managers to improve the sustainability of the area.

Wetlands can also be important areas for water purification purposes. Owing to the large number and variety of animals and plants living in wetlands areas, the ecosystem has become accustomed to dealing with quite a large amount of waste products and material in the system. While taking care to ensure that this capability is not damaged, it may be possible in some cases to use wetlands to help purify certain types of wasterwater – mostly the greywater which is not the most contaminated form of household or industrial waste.

Substances which may be harmful might be taken up by plant roots and then converted into less harmful forms when released back into the environment. The same can happen with substances that are deposited in the soil, which may come into interaction with bacteria which then convert them into forms which are less harmful. Of course, these are not automatically beneficial processes and may not be sustainable if overused. Consequently, careful evaluation, monitoring and management of wetlands areas s required.

Wetlands areas are vulnerable not just to overuse but also climatic phenomena such as storms, hurricanes, tsunamis and other disasters. The importance, in various categories, of the mangrove swamps of Southeast Asia which have been damaged in recent years indicates the need to conserve and maintain such areas in all parts of the world.