Impact of the Ithai Barrage on the Environment of Manipur: An Overview

H. Tombi Singh *

Ithai barrage was constructed in the downstream of Manipur River (Imphal River) as a part of the National Loktak Multipurpose Hydro-Electric Project, to maintain sufficient water volume in the Loktak Lake by making it a reservoir for maintenance of the project. The construction of the national multipurpose project was taken up by the Ministry of Irrigation and Power in 1971. The project was executed by National Hydro-Electric Power Corporation and commissioned in 1983 at an estimated cost of Rs. 115 crores. It was installed to generate 105 MW of power by 3 units (each producing 35 MW.) and to provide Life Irrigation facilities for 24,000 hectares of land.

In fact, the Imphal River is the only outlet of draining water from the central valley of Manipur, since all the rivers, streams and major water bodies in the valley are connected directly or indirectly through the Loktak Lake, and subsequently drained outside the state joining the Chindwin-Irrawaddy system of Burma.

Hence, Ithai barrage can be considered as the main gate which control quantity of water of Manipur Central valley, playing an important role in the environment of the valley as regards to the water supply, water storage, flood, drought, agriculture, fishery, irrigation, power production, aquatic flora and fauna etc. of Manipur central valley in particular and Manipur state in general. It appears that the barrage which was constructed as a part of the Loktak Hydro-Electric Project has now become a major problem for the socio-economic life and environment of Manipur.

With the construction of the Ithai barrage and initiation of Loktak Hydro-Electric Project, there have been certain changes in the climatic condition and socio-economic life of the people and environment of Manipur in general.

Environmental Impact of Ithai Barrage:

A preliminary survey on the environmental impact of the Ithai barrage has revealed certain points of merits and demerits of the project in the socio-economic and cultural life of the people of Manipur along with the changes in the environment of Manipur.

The Merits:

With the completion of Ithai barrage and commissioning of the multipurpose project there have been certain environmental changes, benefiting the people of Manipur which are really considered to be the merit points of the project as described below.

1. Preservation of the Lake and Conservation of Water:

The retention of constant water level of Loktak to 768.5 above mean sea level, with the help of the Ithai barrage, could be considered as a means for the preservation of the lake. It has stopped the usual practice of land encroachment in the peripheral areas of the lake. It helped in the accumulation of sufficient water volume to supplement water storage and water supply problem of the state, which are related to various environmental problems of the states e.g. flood, drought and buffering the climatic condition of the state.

There could be altogether a different scenario of Loktak Lake by now, if we leave the lake to continue the natural process with the increasing siltation and land encroachment in the past 2/3 decades. The existing areas of Loktak Lake (276 sq. km.) could have been reduced to a great extent by about 50 sq. km. only with an average depth of less than 1 metre if we did not take up the project.

2. Generation of Power:

The generation of 105 MW of electrical energy (in 3 phases of 35 MW each) has been a significant contribution of Loktak Lake. Out of the total production of 105 MW only 35 have been used for Manipur state and the rest 70 MW have been sold to other neighbouring states. Thus the state could earn in income of nearly 21-22 crores of Rupees per year (nearly 6 lakh rupees per day) from the power generation of Loktak project. In the year 1991-1992 the project could generate excess amount of energy increasing the income to about Rs. 30 crores in one year thereby increasing the power production by 17.3% over that of the previous year 1990-1991.

3. Irrigation Facilities:

In addition to the power generation Loktak Multipurpose Project has been able to provide water for lift irrigation of nearly 25,000 hectares of cultivated land area thereby giving the facilities for double-cropping in these areas.

4. Employment Opportunities:

The initiation of Loktak Hydro-Project has given employment to about 500 people directly as staff of the project itself. Besides, the project has given the opportunity for starting various small scale industries in the rural areas using the power generation to giving employment for at least 2,000 people.

5. Supply of Water for Loktak Down Stream:

Besides, the power generation from the Loktak project itself the project will be giving the water supply for the proposed Loktak down Stream Project also which is proposed to produce 96 MW of power supply for the state.

The Demerits:

Despite the various merit points of Loktak Project there are several points of demerit for the project affecting the socio-economic and cultural life of the people of Manipur and environment of the state as a whole as described below:

1. Flooding of the Agricultural and Land Surrounding the Lake:

One major impact of the Ithai barrage on the environment of Manipur is the flooding of several thousand hectares of agricultural land and around the Loktak Lake. The maintenance of constant water level of Loktak Lake due to the Ithai barrage of the project has flooded the agricultural land around the lake, which were previously utilized for cultivation. It is also reported that certain agricultural areas beyond the Ithai barrage on the other side of Loktak lake is also flooded with the water from Chakpi River since there is no counter current from Imphal river due to the blocks with Ithai barrage (Ibomcha Singh, ‘92).

It is estimated that nearly 20 hec. of agricultural areas have been submerged under the water spread of Loktak Lake due to Ithai barrage. In fact, Ibomcha Singh, (1992) reported an estimate of about 83,450 hac. of agricultural land affected by the Loktak project, and a loss of about 400 crores by the Loktak project, and a loss of about 400 crores of rupees from the products of the flooded areas.

2. Damage to the Naturally Fishery of Manipur:

A recent survey on the disappearance of several indigenous fishes of Manipur e.g. Ngaton, Khabak, Pengba, Tharak, Ngara, Ngatin, etc. indicated the Ithai barrage as one of the major cause for the disappearance of the fishes and loss of our natural fishery. It has been observed that these fishes migrated from the Chindwin-Irrawady system of Burma to the course of Imphal/Manipur River for breeding in the adjoining lakes and streams of Manipur valley.

In the past, these natural fisheries constituted about 60% of the fish products in the state since the culture fishery was not common in Manipur till 1960. With the construction of Ithai barrage the migratory route of these fishes were blocked and they could not reach the valley and disappeared from our waters. This caused a great loss in our state fishery and economy.

3. Damage to Aquatic Plants of Flood and Commercial Importance:

The increase in the water level of Loktak Lake due to Ithai barrage has caused a great damage to the production of aquatic plants of food and commercial importance. As for instance the production of about 23 aquatic food plants e.g. Heikak, Thangjing, Tharo, Thambal, Loklei and Pulei etc. has been significantly reduced due to the failure in the germination and extension of their roots to the bottom soil of the lake.

On the other hand, the water level in the southern part of Manipur river beyond Ithai barrage has been greatly reduced due to the blockade of water flow by Ithai barrage, caused the failure in the growth of ‘Nungsam’ which normally grew on the pebbles under the water current. These also caused a great loss in the economy of our state. Besides the food plants a number of plants of commercial importance like, Tou, Singnut, Imom, Charot etc. of commercial importance have also been disappeared or greatly reduced due to the increase in the water level of Loktak lake. These caused a heavy loss in the state’s economy.

4. Affecting the Ecology of the National Park:

The maintenance of constant water level of Loktak Lake due to the Ithai barrage has a serious effect on the ecology and existence of the seriously endangered Brow-Antlered Deer of the floating Wild Life National Park of Keibul Lamjao. The seasonal floating and sinking of the Phumdies in the National Park which play an important role in the nutritional cycle of the vegetations in the National park has not been possible due to the constant water level of the lake.

The vegetations which serve as the food and shelter of the seasonal sinking of the Phumdies to get the nutrients from the bottom soil of the lake. Further, the Phumdies become thinner in the peripheral areas of the park and small factions got detached from the main body of the phumdies thereby decreasing the area of phumdies for existence of the deer. Many deer are also killed when they are carried away along with the Phumdies which get dettached from the main mass of phumdi.

5. Increasing Siltatiion Rate of the Loktak Lake:

The blockade of water current in the outlet of Loktak Lake through Imphal River due to Ithai barrage has affected the usual removal of the silt with the current of water from Loktak Lake. Then it helped in depositing the silts to Loktak Lake itself from different inlets of the catchment areas of the lake. This led to the increase rate of siltation in the lake thereby raising the lake bottom.

6. Increasing Accumulation of Phumdies Inside the Lake:

The blockade of water current in the outlet of the Loktak Lake through Imphal River due to Ithai barrage also blocked the floating away and removal of the phumdies from Loktak Lake to Imphal River. This caused the increased mass of phumdies inside the lake itself which covered nearly 75% of the surface of the lake. This is another problem for increasing the water level of the lake due to the floating mass of phumdies of nearly 1-2 metres in thickness. The increasing phumdies have spoiled the normal ecosystem and beauty of the lake. The removal of these phumdies at least 50% will be very necessary in the management of the lake.

7. Grazing Ground of the Cattle:

The peripheral areas of Loktak Lake and several elevated areas inside the lake which was used as the grazing areas inside the lake which was used as the grazing ground of cattle in the past have become inundated due to the maintenance of constant water level of Loktak Lake by Ithai barrage. This caused a great destruction in the grazing grounds of the cattle that cattle rearing and buffalo rearing in the villages in and around Loktak Lake has become difficult. Subsequently, the number of cattle and buffaloes has been reduced to a great extent in the past 5/6 years.

8. Unemployment Problems of the People:

With the inundation of peripheral areas of Loktak Lake several thousands of hectares of land could not be used for agriculture and it caused the loss of the employment opportunities for more than one lakh people. Apart from the failure in agriculture, cattle’s rearing was also not possible since there is no grazing ground of the people. The indigenous technique of Phoom fishing in Loktak Lake also becomes difficult due to the constant rise of water level in the lake. Hence, the Ithai barrage caused unemployment to more than one lakh people in and around the lake.

Conclusion

From the observations of our preliminary study on the impact of Ithai barrage on the environment of Manipur it appears that there has been several points of demerits, of Ithai barrage causing serious environmental problems in general especially with regards to agriculture, fishery and socio-economic aspects of the people in the state. These could have been avoided to some extent if we could have taken up an environmental impact assessment of the project before its initiation.

Now, it is expected that the Loktak Development Authority would take up certain management plans as remedial measures with due consideration of the maintenance of the natural ecosystem of the lake as much as practicable.

The primary objective of the management plan could be
(1) control of flood in the agricultural areas around the lake;
(2) to improve the natural fishery and fish production of the lake;
(3) to retain the power generation and irrigation facilities from the lake;
(4) to improve the ecology of Keibul Lamjao Wild Life National Park as far as practicable;
(5) to take up special measures to stop any further process of siltation, eutrophication and encroachment of the lake;
(6) to improve the natural fishery and fish production of the lake; and
(7) to retain the natural ecosystem of the lake as far as possible.

These could be possible through a dialogue between the local administrators, expert members and representative of the inhabitants in and around the lake, with advice and suggestions from external experts.