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Life on the Earth

Wetlands of Assam

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The valley of the river Brahmaputra with its innumerable fresh water lakes (locally called beel), or ox-bow lakes (era suti), marshy tracts and seasonally flooded plains and hundreds of riverine sand_bars and islands was, till recently, an ideal wetland eco-system which contained specialised wetland animals like the fresh water dolphin, dugong and the great Indian one-horned rhino and reptiles like the crocodile, the winter monitor lizard and few species of turtles. All these creatures are either extinct or highly endangered at present. With the progressive destruction of the Brahmaputra valley wetlands since the advent of the British, along with these animals and others, we have lost yet another spectacular natural beauty – the hundreds of thousands of water birds all along the 800 km. of the river running through the plains of Assam.


The destruction of the Brahmaputra valley wetland system started with the arrival of the water hyacinth from Central America more than a century ago. Extensive growth of this fast growing weed can cut out sun light from the micro flora and also produces faster eutrophication by slowing down water current and depositing debris at the bottom. The second phase of enhanced eutrophication took place with the raising of earthen bunds along the banks of almost the entire length of the river and many of its tributaries after the 1950 earthquake. These artificial levees cut off, to a great extent, the periodic flushing out of the wetlands by the monsoon flood. The third and the final onslaught on the wetlands has taken place with the arrival of the human settlers in the sand bars and the minor riverine islands, mostly in the lower Assam. This has turned the wetlands into agricultural zones rich in rice and vegetables but totally denuded of wildlife. With the vanished wetlands, gone also are the rich supplies of fish, a compulsory item of the Assamese menu and a good source of protein for the rural mass. In spite of the presence of the mighty Brahmaputra, its numerous tributaries, and the large number of wetlands, Assam today imports 0.20 lakh tonnes of fish an anually to satisfy the domestic market. Out of this, 0.14 lakh tonnes is consumed in Assam. The total fish production from Assam’s wetlands is 1.55 lakh tonnes per year. Thus, a total of 1.69 lakh tonnes of fish is supplied from imports as well as local wetlands. The total demand for fish in the state, on the other hand, is estimated at 2.21 lakh tonnes per year, 6.68 percent of which met by imports from other states (source : Directorate of Fisheries, Government of Assam). As a result, there is a deficit of 0.52 lakh tonnes of fish every year and consequently the price of fish has rocketed up to such a height that the poor man simply cannot afford to buy it even once in a week. The production potential of wetlands in the state is estimated at 400-500 kg/ha/year after development. The progressive short supply of fish in Assam is a direct consequence of mismanagement and neglect of its wetland eco-system.
It is therefore felt to be an imperative need to conserve these wetlands and protect their unique biodiversity. If properly managed, the wetlands are going to be a source of immense wealth for this state leading also to enrichment of the quality of its environment.


Lakes / Ponds:
In Assam, there are 690 lakes and ponds as recorded through the study. These lakes /ponds cover an area of 15494.00 ha which constitutes 0.20 percent of the total geographical area of the state and 15.30 percent of the total area under wetlands. The smallest of them measures 2.50 ha while the largest one has 882.50 ha of area coverage. Majority of this type of wetlands have water with low turbidity. An analysis of aquatic vegetation in these lakes / ponds indicates that most of them have no vegetation or are partially vegetated. Highest number of lakes / ponds are observed in Golaghat district (113 number) followed by Dhubri (73 number) and Nagaon (68 number) districts. But areawise, the highest area under this category is observed in Kamrup district (15705.00 ha) followed by Nagaon (2175.50 ha) and Dhubri (1816.50 ha) districts. Some of the important wetlands under this category are Deepar beel in Kamrup district, Dhir beel in Dhubri district, Tamaranga beel and Dalani beel in Bongaigaon district.
Table : District- wise distribution of wetlands in Assam
District
Number
Area (ha)
Barpeta
97
3301.00
Bongaigaon
100
3158.50
Cachar
340
7188.00
Darrang
103
3515.00
Dhemaji
139
3960.00
Dhubri
233
6459.70
Dibrugarh
86
2752.50
Goalpara
165
3832.50
Golaghat
330
5467.50
Hailakandi
47
840.00
Jorhat
109
2108.50
Kamrup
352
11407.00
Karbi Anglong
77
897.00
Karimganja
70
5719.50
Kokrajhar
85
1578.40
Lakhimpur
151
3033.50
Morigaon
183
11658.00
Nagaon
379
11295.50
N.C. Hills
10
2552.50
Nalbari
68
1988.00
Sibsagar
109
2135.00
Sonitpur
206
3651.00
Tinsukia
74
2732.50
Total
3513
101231.60
Source: AssamRemote Sensing Application Centre, Assam
Table : Size wise distribution of wetlands in Assam
Area Class (Ha)
Total Number
Total Water spread Area (Ha)
Total Vegetation Area (Ha)
Total Wetland Area (Ha)
1.0-100.0
3341
52878.1
1920.5
55821.5
100.1-200.0
100
12921.5
947.5
13869.0
200.1-300.0
36
7979.5
537.0
8527.0
300.1-400.0
14
4505.0
328.0
4823.0
400.1-500.0
4
1815.0
0.0
1815.0
500.1-600.0
6
2625.0
602.5
3227.5
>600.1
12
13068.0
70.0
13148.0
TOTAL
3513
96818.10
4405.5
101231.6
Source: AssamRemote Sensing Application Centre, Assam
Ox-bow Lakes / Cut-off Meanders:
A total 861 number of ox-bow lakes/cut-off meanders are observed throughout the state of Assam, covering an area of 15460.60 ha which constitutes 0.20 percent of the total geographical area of the state and 15.27 percent of the total area under wetlands. The smallest of them measures 5.0 ha while the largest one has 582.50 ha of areal coverage. Majority of this type of wetlands have water with low turbidity. An analysis of aquatic vegetation in these ox-bow lakes / cut-off meanders indicates that most of them are either without vegetation or partially vegetated. Highest number of ox-bow lakes / cut-off meanders are observed in Golaghat district (104 number) followed by Nagaon district (71 number) and Dhubri district (68 number). But area wise, the highest area under this category is observed in Morigaon district (2143.00 ha) followed by Nagaon (1746.00 ha) and Golaghat (1563.00 ha) districts. Some of the important wetlands under this category are Morikolong and Patoli beel in Nagaon district, Mer Beel in Golaghat district and Guruajan in Morigaon district.
In Assam, a total of 1125 number of waterlogged areas are observed which are distributed unevenly covering an area of 23431.50 ha which constitutes 0.30 percent of the total geographical area of the state and 23.15 percent of the total area under wetlands. The smallest of them is 2.5 ha while the largest one has 3010.00 ha of areal coverage. Majority of this type of wetlands have low turbidity. An analysis of aquatic vegetation in these wate-logged areas indicates that most of them are free from aquatic vegetation. Highest number of water(c)logged areas are observed in Cachar district (231 number) followed by Nagaon district (138 number) and Sonitpur district (110 number). But area wise, the highest area under this category is observed in Cachar district (4869.50 ha) followed by Karimganj (4667.00 ha) and Nagaon (2559.50 ha) districts. Some of the important wetlands under this category are Son beel in Karimganj district and Raumari beel in Darrang district.
These water-logged areas play significant role in the region’s economy as they are present in large numbers in the rural areas containing good amount of fishes and other aquatic fauna and providing habitat to a variety of migratory as well as domestic birds. Besides they have remarkable potential for supplying irrigation water to the nearby agricultural fields during the dry periods. There are some waterlogged areas which can be developed for recreational purposes and as tourist spots such as the Sonbeel in Karimganj district.


Swampy/Marshy areas :
These swampy/marshy areas constitute another major group of wetlands in Assam. These are identifiable on satellite imagery by their reddish tone indicating the presence of vegetation, associated with dark blue tone inferring to the presence of water and their occurrence in the low lying areas. Due to the presence of varied quantities of minerals in the water, these swampy/marshy areas are either moderately or highly turbid. In most cases, there is no feeder channel to control the inflow or outflow of water.
In Assam, as many as 712 number of swampy/marshy areas have been identified from satellite data which cover an area of 43433.50 ha constituting 0.55 percent of the total geographical area of the state and 42.91 percent of the total area under wetlands. The smallest of them is 2.5 ha while the largest one has 1350.00 ha of areal coverage. Majority of this type of wetlands are with low turbidity. An analysis of aquatic vegetation in these lakes / ponds indicates that most of them are partially vegetated. Highest number of swampy/marshy areas are observed in Kamrup district (155 number) followed by Nagaon (92 number) and Goalpara (68 number) districts. But area wise, the highest area under this category is observed in Kamrup district (8109.50 ha) followed by Morigaon (7051.00 ha) and Nagaon (4764.50 ha) districts. Some of the important wetlands under this category are Nandan-Sonai beel in Morigaon district, Batha beel in Darrang district and Urpad beel in Goalpara district.
Unlike the water-logged areas, the swampy/marshy areas don’t have much contribution to the state’s economy. But with the help of proper developmental schemes by converting them into utilizable form, these may boost up the economy of the state to a significant level.
Reservoirs :
Reservoirs are artificial impoundments of water for irrigation, flood control, municipal water supplies, hydro-electric power generation and so forth. There are as many as 10 number of reservoirs covering an area of 2662.5 ha which constitutes 0.03 percent of the total geographical area of the state and 2.63 percent of the total area under wetlands. The smallest of them covers 17.50 ha while the largest one has 930.00 ha of areal coverage. Majority of this type of wetlands contains water with low turbidity. An analysis of aquatic vegetation in these reservoirs indicates that most of them are either free from vegetation or partially vegetated. Highest number of reservoirs is observed in N.C.Hills district (4 nos.) followed by Golaghat and Nalbari districts (2 nos. each). But area wise, the highest area under this category is observed in N.C.Hills district (2365.00 ha) followed by Kamrup (220.00 ha) and Golaghat (37.50 ha) districts. Some of the important wetlands under this category are Garampani and Umrangsu in N.C.Hills district.
Tanks :
Assam has several thousands of family owned small size tanks, these have not entered into reckoning as far as this report is concerned because of the scale factor. In Assam, a total of 115 number of tanks are identified from satellite data. These tanks occupy an area of 749.00 ha which constitutes 0.01 percent of the total geographical area of the state and 0.74 percent of the total area under wetlands. The smallest of them covers 2.5 ha while the largest one has 55.00 ha of areal coverage. Majority of this type of wetlands have low turbidity. An analysis of aquatic vegetation in these tanks indicates that most of them are free from vegetation. Highest number of tanks are observed in Sibsagar district (20 number) followed by Kamrup (18 number) and Sonitpur (16 number). But area wise, the highest area under this category is observed in Sibsagar district (267.00 ha) followed by Sonitpur (83.50 ha) and Kamrup (80.00 ha) districts. Some of the important wetlands under this category are Gaurisagar Pukhuri, Sibsagar Pukhuri and Joysagar Pukhuri in Sibsagar district. Besides providing water to the people of the nearby areas, these tanks can also be used for rearing fishes and raising plantation crops like coconut, arecanut, cashewnut etc. along the sides of the ponds. Ornamental gardens can also be developed on the banks of the ponds.

Concrete Steps Needed To Save These Water Bodies from Extinction
Assam, the northeastern state of India is endowed with wetlands rich in eco-diversity. But degradation, human settlement and industrialization are posing threats to them.
Assam, the northeastern state of India, is endowed with varied landscapes abounding in hills, mountain ranges, rivers, valleys and what not. Among them, the wetlands occupy a pride of place. But wanton human settlement, improper waste-management and lack of awareness has reduced these places to mere dumping grounds posing a serious threat to the ecology, environment and the very existence of these transitional habitats between deep water aquatic system and terrestrial system.

Assam – A Treasure Trove of Wetlands

The state of Assam comprises around 1, 00,000 hectares of wetlands, the largest in the northeastern region of the country. This is also more than double of the wetlands in neighboring West Bengal which has 42,500 hectares of wetland.
These water systems help mankind in various ways, such as improving the quality of water, conservation of bio-diversity and also providing livelihood for the rural populace. But ironically most of the wetlands of Assam’s flood plains of the two major rivers – the Brahmaputra and the Barak – are degrading both for natural reasons and most often man-made hazards.

Wetlands and Their Potential

There are around 3,500 different types of wetlands in Assam that, according to satellite data, constitute 1.29 per cent of the total geographical area of the state. These wetlands can be classified into fresh water lakes, oxbow lakes, marshy tracts and seasonally flooded plains apart from the hundreds of riverine sandbars and islands in both Brahmaputra and Barak valleys.·
  • These wetlands play a significant role in the state’s economy as they provide a variety of fishes and other aquatic fauna. However, the potential for fisheries is not well-tapped. Ninety percent of the population of Assam eats fish, yet the state imports almost half of its fish from other states. As such, developing these wetlands into fisheries can well be a viable proposition. ·
  • They also act as ideal natural habitat for both migratory birds and domestic. The wetlands are also home to hundreds of aquatic animals and reptiles. It might also be a better choice for these wetlands to be systematically converted into wildlife conservation locations, avian parks, bird sanctuaries and recreation centres promoting eco-tourism.·
  • Significantly, these wetlands also make up the shortage of irrigating water into the agricultural fields during the lean season.
  • These wetlands can also act as reservoirs of flood waters that otherwise bring untold miseries by destroying human settlements and agricultural lands, as well as causing loss of precious human and animal lives.
Assam Wetlands in Dilapidated State

However, the wetlands of Assam are fast shrinking due to both natural and man-made causes.

  • The extensive and uncontrolled growth of water hyacinth and the raising of dykes and embankments along the river banks are thought to be the main causes of the deteriorating condition of these wetlands.
  • These wetlands are subjected to harsh organic processes caused by debris from floating vegetation and silt carried by rain water.
  • Another alarming cause is rampant human settlements, industrial developments and other economic activities that disturb the ecological balance and lead to the loss of these wetlands.

(Data quoted from Environmental Information System – Assam, The official mouthpiece of Assam Science Technology and Environment Council, envisassam.nic.in)

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