IMPACT OF DEVELOPMENT ON THE MANGROVE COVER IN THE MUMBAI METROPOLITAN REGION
Guest Post by Ar. Anita Shyam
This article first appeared in the COA Magazine.
Coastal Resources constitute an important component of natural resources, particularly in a country like India which is surrounded by sea on all three sides. Coastal regions, where land and water meet, are unique eco regions which attract large number of economic activities like trade and ports, ship building activities, defence, fisheries, industries and human settlements. These economic activities appear to promote economic growth but in turn cause loss in terms of coastal and marine resources
IMPORTANCE OF MANGROVES FOR MUMBAI
Mumbai is a reclaimed island along its entire shoreline. The wave action has increased in the North Western area and has eroded the 16 km long coastline by about 500 ms in the past 35 years. Only mangroves can provide a natural control for the eroding shoreline. Also Coastal biodiversity including the million migratory birds that visit Mumbai are housed by the mangroves.
THREATS TO MANGROVES IN MUMBAI
Large demographic pressure is exerting tremendous stress on the coastal environment. The major causes of mangroves degradation are land reclamations and industrial effluents
Systematic dumping of all kinds of waste and debris in the mangrove areas destroys them.
This waste/debris creates a barrier preventing the sea water from entering the mangroves and eventually kills the mangroves. In many instances, this is done intentionally to reclaim land for construction activity. Hence it is important to control and finally stop this systematic degradation of mangroves.
• Land reclamation- Most industrial houses, developers; builders are reclaiming the mangrove lands illegally.
• Pollution – There are over 200 non point sources of industrial and domestic waste discharges that pollute entire water around the city- 6 times more than the assimilation capacity.
• Under the name of “development” creeks, rivers and other water bodies are altered in shape, size and course.
• Every year, over 1000 tons of mangrove wood is cut for fuel wood and to meet other timber demands.
The other threats to mangrove cover are port development, dumping of all kinds of Waste and Debris, over harvesting of marine resources and reduced natural regeneration.
MANGROVES AS COASTAL RESOURCES ALONG THE MAHARASHTRA COAST
The total length of the Maharashtra coast is 720 km long. The Maharashtra coastal zone falls under five districts from South to north namely, Thane District, Sindhudurg District, Ratnagiri District, Raigad District and Bombay District.
CHANGE IN MANGROVE COVER IN MUMBAI
From the time of the Evolution of the city the area under mangroves has decreased and it is taken over by built up.
BUILT UP AGAINST WETLAND
The above images show clearly that as the city grew the wetlands have slowly been replaced by built up
ASSESSMENT OF CHANGE IN MANGROVE COVER- MMR
The following maps generated indicate the change in the mangrove cover in the MMR. The mangroves are categorized into Dense Sparse and mudflats.
The mangrove cover map 2005 shows that dense mangrove areas near the thane creek have been converted to mudflats. Detailed analysis of the cover change for each creek is given below.
The analysis of mangrove cover change in MMR shows that there has been an overall decrease in the mangrove area in MMR. The decrease in the dense and sparse mangrove has been maximum in the Thane creek area west side followed by Manori, Malad respectively.
ASSESSMENT OF IMPACT OF DEVELOPMENT ON MANORI CREEK AREA
The Manori Creek area is divided into two zones Mangrove zones (marked in green) and Influence zones i.e area around the mangrove that impacts the mangrove zones.(marked in orange)
These are further divided into smaller zones with respect to Ward boundary, High tide lines, and the Major roads in the area for assessment and to identify.
1. Deterioration levels of mangroves (to identify zones where mangrove deterioration is maximum)
2. Areas of High Development pressure (Zones where development pressure is maximum which in turn effects the mangroves)
DETERIORATION LEVELS OF MANGROVES
CATEGORIES OF MANGROVE DETERIORATION
TYPE AREA(Sq km)
dense to extinction 5.73
dense to sparse 0.48
dense to mudflats 0.14
sparse to extinction 2.4
sparse to mudflats 3.39
The extent of deterioration of mangroves in each zone
The final output map showing the zones in which maximum mangrove deterioration has taken place with respect to the above parameters. The areas highlighted are the ones with maximum deterioration
DEVELOPMENT PRESSURES AROUND THE CREEK
The analysis for Development pressures are indentified with respect to the parameters given below. The parameters considered were selected as these parameters have an effect on the development pressures which in turn would have an impact on the mangroves.
1. Population Density
2. Population growth rate
3. Accessibility
a. Proximity to main roads
4. Land use Characteristics
a. Residential
b. Slums
c. Commercial
d. Amenities
5. Activity pattern (Human Impact)
a. Solid waste dumping
b. Upcoming projects (conversion of mangrove cover to another land use)
c. Pumping stations
6. High tide and low tide levels
With the help of assigning Scores depending upon the impact of development pressure in each zone for each parameter following maps generated for each parameter.
Accessibility:
Growth Rate:
High Tide Line:
Land use:
Population Density:
Influence Zone Proximity:
The map below is the final output map generated by summing up all the scores of individual parameters. The map shows that there are three patches where the impact of development pressures will be high
FINAL MAP SHOWING AREAS OF HIGH DEVELOPMENT PRESSURESThe analysis of Manori creek shows the zones identified that have high development pressures which can have an impact on the mangrove area. The area all around the creek shows high development pressures is due to all the above parameters. Hence the development pressures are due to the high impact of development and human interference.
The mismatch between supply and demand of land is one of the main reasons for the disappearnce of environmentally fragile land like mangroves.
RECOMMENDATIONS AND CONCLUSION
The conservation of a mangroves has not been completely successful and they are fast disappearing owing to rampant construction and lack of governmental will for their protection. Hence the measures to be taken should be of two kinds one which is at policy level and the other is setting up guidelines in terms of physical planning intervention.
Physical planning
Intervention can be done by giving 500 m buffers adjoining the mangrove area so that there is clear demarcation of mangrove area and the adjoining area.
Network of roads should be provided so that there is a physical delineation after the buffer so that the development does not penetrate into the mangrove areas.
High density commercial should be restricted near the mangrove area and the density of development should decrease as the distance from the city and the mangrove area increases.
Policy recommendation
Detail Separate plans for the individual areas- Specific Plans Showing the physical attributes in detail so that planning for such environmentally fragile land is easier.
The CRZ regulations should be strengthened by detailing the regulations with respect to the area and Transfer of Development Rights can be given for mangrove area so that if any mangrove land is privately owned the ownership can be transferred to the government.
CONCLUSION
Mumbai can boast of some very unique and varied environments, ranging from coastal belts, creeks and mangroves, to many hills, forests, streams, lakes and ponds, all of them in a state of intense stress and marginalization today. The analysis of the mangrove cover change in MMR clearly shows that the mangrove cover has deteriorated on the whole. Development could be one of the main reasons for it. The dense and sparse mangroves have decreased whereas the mudflats have increased. The mangroves have decresed either due to environmental conditions or due to human impact on them.
The mismatch between supply and demand of land is one of the main reasons for the disappearnce of environmentally fragile land like mangroves. The rapid and haphazard trend of urbanisation in Mumbai and its suburbs has extended relentlessly beyond its administrative boundaries. This explosive growth of urban areas has brought about fundamental changes, to the physical landscape
The pressures of rapid haphazard development, high and growing population density, relaxation of the building restrictions of no-development zones, along with the growth of pollution, encroachments, deforestation for fuel and economic gains, and destruction of natural land-forms for real estate development lead to the catastrophic depletion of the largest and most precious of the vanishing green zones of the city
Over the years, excessive built up area intentionally strangulated the city’s open spaces, wetlands, mangroves and salt-pan lands for commercial purposes. This loss and subsequent commercialization and concretization of open spaces has meant that water, which previously could seep into the soil has practically nowhere to go, leading to flooding.
Conservation of the mangroves which is still existent in the city and an initiative to safeguard them with the help of controlled development in the areas around the mangrove is one of the possible measures to help preserve them.
LIMITATIONS OF THE STUDY
Some areas which come under mangrove area have already started developing with development projects coming up on them. No measures can be taken up in such areas.
Converting the Secondary data into digitised form could involve human errors
REFERENCES
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