Can't believe CIdco is part of such a wonderful paper but working just opposite.
Extract from paper published by CIDCO & TERI in 2009 & presented in Wuhan, China
3. Wetlands are not wastelands
3.1 Impact of wetland degradation on Mumbai Wetlands, the transitory area between the hydrosphere and the land are very important with respect to; ecological aspects and its resource potential.
In MMR, wetland makes up 1.12% of the total land area. Mumbai enjoys an average rainfall of 250-300 cm which is much higher than the national average of 120
cm. The consistent rainfall results in maintaining the steady level of ground water table as well as the water
level of the wetlands. However, from satellite imageries, it is reasonable to assume that wetland areas have declined considerably in the recent years [13]
. The condition of wetlands in India is not different than the other countries. Due to lack of awareness, wetlands have been indiscriminately and deliberately destroyed
with a short sighted outlook for instant gains. For example, 60 % of wetlands worldwide and up to 90 % in Europe have been destroyed over the past century,
due to agriculture, pollution, development of dams, canals, groundwater pumping, urban development and peat extraction [14]
. In summary, wetlands are globally becoming a threatened landscape.
Degrading wetlands can lead to serious
consequences, such as increased
flooding, extinction of species, and poor
water quality. The catastrophic deluge
which engulfed Mumbai on 26, July
2005 bringing the city to a stand still is
a self explanatory example (Fig. 3).
The impact of the floods was
manifested in a variety of ways:
Large numbers of people were stranded
on the road for more than two days, thousands lost their homes. The death
toll was more than 1000. The reports suggest that the floods caused a direct loss of about $100 million [15]
.
Experts have expressed that the situation would not have been that harsh had the coastal wetlands been preserved. Besides this, reclamation along the Mithi River, encroachment of land by rapacious builders, old drainage and sewage system are found to be other key reasons that lead to water-logging in Mumbai in monsoon.
3.2 Exploring the resource potential of wetlands
MMR is naturally gifted with numerous fresh water wetlands and these can be exploited as decentralized sources of potable water. Navi Mumbai has more than 70 villages and around 150 lakes. Most
of the villages purchase potable water supplied through water tankers in summer. The villages could be made self sufficient if wetlands could be properly explored.
For instance, it has been estimated that, on an average, a medium sized freshwater wetland has a holding capacity of almost 5 million litres. With a per person potable water consumption of 20 lpcd, the wetland
could cater to the requirements of a village with an average population of 2,000 for more than four months of the year including the most critical summer months when water shortages are acute.
But there are still many practical challenges pertaining to the preservation of man made or natural wetlands and its effective use in Navi Mumbai [16]
. The challenges are mainly an interwoven network of anthropogenic, administrative and geographical hindrances. The practical problems encountered by the CIDCO in the course of developing the twin city of
Mumbai are summarized in the following sections.
4. Challenges in preserving Wetlands in
Navi Mumbai
4.1 Climate change and sea level rise
LECZ (Low Elevation Coastal Zone).are regions which fall under 10 metres of coastal elevation.
Approximately 81 000 sq. km of land in India falls under LECZ, housing a population of over 60 million.
50% of this population reside in urban regions comprising approximately 31 million people [17]
.
Navi Mumbai falls under the category of LECZ and is highly vulnerable to the impact of climate change. It is developed in a low lying-area through reclamation at a height of 2.2 metres which is just equal to the mean sea level. The average high tide level
of Navi Mumbai is 3.5 metres as compared to that of 5 metres of Mumbai.
According to the IPCC (Intergovernmental Panel on Climate Change)
[18], the sea level is expected to rise at the rate of 2.4 mm (millimetre) per year. By the
middle of the century the rise will be 38 cm. A one-metre sea-level rise will inundate 6000 sq km in India,
of which Mumbai, Kolkata and Chennai will be the most affected. This would mean a loss of billions of dollars in infrastructure, social, physical assets and capital through inundation of low-lying areas, drowning of coastal marshes and wetlands, erosion of
beaches and flooding and increase in the salinity of rivers, bays and groundwater.
Link to get full report :