Stop our wetlands from fast disappearing

Wetlands contribute significantly to the earths climate system, resilience to water scarcity, and a range of ecosystem services. Climate change is now likely to have a significant effect on wetlands worldwide due to rising global temperatures and unpredictable rainfall patterns. Nearly 90% of the worlds wetlands have degraded since the 1700s, and the rate of deterioration is three times greater than that of forests, according to the UNFCCC COP-28 report. In cities, the situation is significantly worse, especially in third-world countries.

In Bangladesh, as a third-world country and a nation experiencing a rise in urbanization, wetlands are decreasing rapidly and have become a major concern in urban areas, particularly in Dhaka, the nations capital. Already, several environmental challenges have persisted in Dhaka City, worsening the climate and environment. An issue that eludes the attention of the relevant authorities, including academics and environmental stakeholders, is the rapid decrease of wetland areas encompassing the city of Dhaka. In light of this concern, Dhaka will face increased vulnerability to heat stress and frequent waterlogging in the foreseeable future as a result of the adverse consequences of climate change, particularly an inadequate supply of surface water.

Because of Dhaka Citys persistent expansion in all directions, the number of wetlands has gradually reduced and has recently fallen even more rapidly. Because of this decline, there is insufficient stormwater flow from the urban upstream to the natural reservoir. In 2005, wetlands accounted for only 16.9% of Dhakas total land area. However, in 2009, the wetland area dropped and reached 9.75%, while in 2014, it reached 6.95%.
Research titled "Wetlands of Dhaka Metro Area: A Study from Social, Economic, and Institutional Perspectives" found that if the present alarming rate of wetlands degradation continues, all of Dhakas temporary wetlands will disappear by 2035. A report by Rajdhani Unnayan Kartripakkha (RAJUK) titled Detailed Area Plan 2022 revealed the presence of 3464 ponds under its 1528 square kilometer authority. Among them, 205 are located in the central Dhaka region. Between 2010 and 2019, Dhaka lost 3440 acres of flood flow zones, water retention areas, and water bodies out of the total 9556 acres. This loss has strained the citys water supply and sparked major concerns about the sustainability of our water security. Urban planning specialists emphasize that water bodies should encompass 12-15 percent of Dhakas territory based on its population, although the actual coverage is only about five percent.

The most significant factors contributing to the reduction of wetland areas in the city of Dhaka are the following: encroachment, river banking, tie-channel reclamation, river damming, and disruption of hydrological and ecological connectivity; irregular high and low water pulses; unplanned urbanization; a lack of coordination between government agencies; system maintenance; and the application of relevant laws. All of these factors have adversely affected the wetlands in Dhaka city.

Over the last three decades, wetlands have been steadily disappearing, causing lasting harm to the environment, ecosystem, and society as a result of the vital ecosystem services they offer. This loss affected the wetland biota, as wetlands are essential habitats for a significant number of fragile or endangered species in the city and surrounding areas. Additionally, the extensive exploitation of water plants has harmed the survival of aquatic life by degrading wetlands. A wide variety of plant and animal species, comprising fisheries, food crops, wildlife, and forest resources, are also threatened with extinction. In addition to the aforementioned issues, the decline of wetlands has given rise to many other problems, including the depletion of natural soil nutrients, the reduction in water storage capacity, and the associated benefits.

As we all know, Dhaka is one of the most polluted cities in the world, and it is becoming unlivable as a result of heavy traffic, a large population, and challenges relating to air and water with unplanned urbanization. The government, city corporation authority, RAJUK, and other concerned authorities should prioritize the protection of wetlands as well as the restoration of internal canals and surrounding rivers. Though city administrators are attempting to revitalize the canals, they should also work to recover the ponds and wetlands, as they play an important role in maintaining local climate and water cycles, regulating temperature extremes, promoting disaster risk reduction, and improving water and environmental management. Therefore, the city governments first and foremost priority should be to ensure the minimum proportion of wetlands existence. Following the establishment of an adequate proportion of wetlands, the distribution of wetlands, their spatial-temporal changes, integration, and coordination must be addressed in urban development.

The writer is working at the Centre for Sustainable Development (CSD), ULAB