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Vanishing wetlands

Infilling of wetlands to build or expand malls, shops/residential buildings (commonly termed as urban sprawl in the US) in any city of Bangladesh could be costly and severely detrimental to the long-term environmental goals of Bangladesh. Local conservation commissions should be established in every township to enforce the Wetland Protection Act of the Department of Environment.

Albelee Haque
AN August 2 report in The Daily Star about waterlogging problem in Jhigatola area in the greater Dhaka city has motivated this article.
The time is appropriate for the CTG, NGOs, local communities and non-profit organisations in Bangladesh to collaborate more effectively and start working together towards a "cleaner Dhaka city," or to at least protect wetlands in Dhaka from the pressure of development to ensure desirable biodiversity. This writer was quite alarmed during a recent phone conversation with a relative, who was visiting Boston. It was alarming because my relative said that there were hardly any wetlands in Bangladesh that may be considered active.
Until recently, there was no Wetland Protection Act in Bangladesh. As a group, wetlands, bogs, vernal pools and salt marshes are all considered wastelands. Wetlands form a critical part of our ecosystem with diverse animal and plant life. Unfortunately, because of a lack of environmental consciousness and public education or awareness, wetlands such as haors, lakes, beels and marshes are systematically degraded and/or eliminated in Bangladesh through residential and commercial realestatedevelopment projects.
Wetlands carry out rather important functions, including flood protection. Their spongelike soil composition allows quick absorption of rainwater and can naturally prevent waterlogging, j^which is nowadays a bigger problem than flooding in Dhaka, Chittagong and other major cities.
The article indicated that Wasa Managirig Director Raihariul Abedin told the news agency that the waterlogging problem in Jhigatola area would be solved before the next monsoon as a part of the improvement of the sewerage system.
Infilling of wetlands to build or expand malls, shops/residential buildings (commonly termed as urban sprawl in the US) in any city of Bangladesh could be costly and severely detrimental to the longterm environmental goals of Bangladesh. Local conservation commissions should be established in every township to enforce the Wetland Protection Act of the Department of Environment.
Wetlands ensure biodiversity and provide a natural defense against flooding during storms. They also naturally filter nutrients and toxicants from polluted runoff from streets, parking lots, paved areas, building roofs and gutters or barnyards and farmland (in less urbanised districts) after rain passes through their special type soil. Overabundance of nutrients -- for example, nitrogen and phosphorus -- from human sources such as untreated sewage, commercial fertiliser, and dairy or confined animal feeding operations, can choke local rivers and ponds with unchecked algae growth. ’
Some algae certainly constitute an important part of the food chain in lakes, rivers and ponds. But algae proliferation can impose severe oxygen demand during nighttime respiration, and their death and decay can lead to the death of fish in warmer weather. Wetland attenuation of excess nutrients is a low cost, natural way
of keeping local water bodies Suitable for swimniing, fishirig andboating.
It is of utmost importance for the economy and environment of Bangladesh to save the wetlands, marshes and bogs, whether inland or in coastal areas. Without growing public consciousness and compliance/enforcement of environmental regulations, Bangladesh could lose most of its critical wetland systems to unplanned urban development projects. Of particular concern are the Ashulia and Kaliakor areas in Dhaka, that are threatened and endangered. There are dire environmental consequences to turning important wetland areas such as the above into commercial areas like Tejgaon without paying attention to nature.
The concept of low impact development (LID) entails preserving natural landscape, minimum land disturbance to control erosion, as well as soil amendment by adding compost to improve its hydrologic function. An assessment of Model Development Principle application in Virginia (USA) by the Center for Watershed Protection (2001) noted that, in comparison to conventional development, use of LID could save up to 49% in total infrastructure costs (including roads, gutters, sidewalks, landscaping and storm water best management practices). Studies by the American Forest Association indicated up to 40% savings in energy bills for homes and businesses that retained trees.
Urbanisation and impervious cover (IC) land induced changes in the natural water balance of streams, have physical impacts that ultimately affect water quality and biological diversity. The trend
of deviation from high water quality is almost inevitable at watersheds with an IC level higher than 25%. There is ample scientific data on the indirect impact of urbanisation on downstream receiving waters, revealing that suburban watersheds (15-35% IC) show signs of degradation and presence of pollution-tolerant species. However, the degradation of water quality and biodiversity is not as much as in urban watersheds (50% IC). One retrofit LID for renovation projects is disconnection of impervious areas by use of porous pavements, removing curbs, planting shrubs in traffic islands, etc.
Adopting a regional approach to LID or smart growth would be very beneficial. This may involve initiatives by law and policy makers in Bangladesh to evenly distribute economic development rather than intensifying density in Dhaka city alone. Otherwise, it will
be almost impossible to clean up the Buriganga River - one of the most polluted in the country.
According to Robert Zimmerman of the Charles River Watershed Association: "Nature was heeded when 8000 acres of wetlands were protected in the Charles River Reservation Area.” Because of this wetland conservation of land area in the Charles River Nature Valley Storage Area, despite frequent rains in the Boston area, there is no flooding in the watershed. Thus daily activities do not suffer, as they do in the Peabody area of Massachusetts; businesses are not closed like in Jhigatola, Dhaka. Therefore, adverse economic impact can be reversed by protection of remaining wetlands in Dhaka city.
Albelee Haque Is an environmental scientist in the Department of Environment in Boston, Massachusetts Email: albelee_haque@yahoo.com