[This report is based on the personal observations made by Dr. Arvind Kumar, President of Water India Foundation, New Delhi, during his recent to the North-eastern states of India from 30 December 2008 to 6 January 2009. apart from personal observations about the water situation, the report has also relied upon available supporting material in order to highlight the water-related problems and put them in a proper perspective so that efforts to resolve these problems are put in place.]
Water Situation in North Eastern Region
The North Eastern Region (NER), consists of the eight Indian states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura. This region is endowed with abundant water resources carried by its several rivers originating mainly from the Trans-Himalayas, Middle-Himalayas and the Sub-Himalayas on the north, Patkai-Purbachal hills on the north-east and east and Karbi-Jaintia-Meghalaya-Garo hills on the southern fringe. The Brahmaputra in the northern part and the Barak, also known as Meghna, flowing through the southern margins along with their various tributaries are the two main river systems that have been instrumental in establishing a very vibrant and powerful hydrologic regime in the region. The Irrawaddy, a third river, passing through Myanmar at the easternmost flanks of the region also drains a part of it mainly through some of its tributaries like the Chindwin.
The Brahmaputra stemming from the Tibetan plateau, and passing through Arunachal Pradesh and Assam, finally merges with the Bay of Bengal in Bangladesh. The Barak River, originating at the Manipur-Nagaland border, flows through the southern part of Assam and outfalls in the Bay of Bengal after merging with the Brahmaputra by the name of the Meghna. The Irrawaddy, stemming from Myanmar, flows entirely through Myanmar and outfalls in the Bay of Bengal in the vicinity of Andaman and Nicobar islands. Thus all the three major rivers of the region and many of their tributaries are international in character with their courses lying in more than one country and their basins shared by several countries.
Viewed in a broad spectrum, the basins of the Brahmaputra, the Barak and the Irrawaddy rivers occupy 68.42 per cent (1, 74,528 km2), 16.36 per cent (41,723 km2) and 7.27 per cent (18,539 km2) of the region respectively. Together they constitute 92.04 per cent (234790 km2) of the region’s geographical area. However, the Brahmaputra and the Barak, two main rivers of the region, jointly claiming 84.78 per cent (216251 km2) of the North Eastern Region, are undoubtedly the most dominant hydrological systems having the greatest impact on the environment and lives of the people of the region. According to broad estimates, the surface water resources available in the region amount to 652.8 billion cubic meters that gives it the highest (34%) share in the country’s total surface water resources potential although the region represents only 8 percent of the total Indian landmass. The per capita and per hectare availability of water in this region is the highest in the country.
Flood Scenario
Annual floods and soil erosion are the recurring phenomena in the Brahmaputra and Barak (Meghna) basins, especially in Assam. These not only cause havoc bringing misery to the people but also wreck the fragile agro-economic base of the region every year. About 40 per cent of Assam’s land surface is vulnerable to flood damage. It is worth mentioning here that Brahmaputra valley in Assam represents one of the most acutely hazard-prone regions in the country, having a total flood prone area of 3.2 million hectares. Broadly speaking, a combination of natural and anthropogenic factors causes floods in Assam. According to one expert, the unique geo-environmental setting of the basin vis-à-vis the eastern Himalayas, the highly potent monsoon regime, weak geological formation, active seismicity, accelerated erosion, rapid channel aggradations, massive deforestation, intense land-use pressure and high population growth, especially in the floodplain belt, and ad hoc temporary flood control measures are some of the dominant factors that cause and/or intensify floods in Assam.
The state of Assam has experienced major floods in the years 1954, 1962, 1966, 1972, 1977, 1984, 1986, 1988, 1998 and 2004. According to one opinion, it was in the aftermath of the Great Earthquake of 1950 that the damage due to and intensity and frequency of floods increased progressively.1 The floods of 1988, 1998 and 2004 were the worst in recent memory. It is noteworthy that breaching of embankments has become a key factor in causing intensification of the flood-related problems in recent years. At a broader level, structural measures in the form of construction of embankments have been harnessed as the only answer to tackling floods. Of the total embankments built thus far in the entire India (15, 675 km), about one-third of them have been built in Assam (5,027 km). This shows that floods pose a grim situation for Assam and a well-concerted policy is called for to tackle this recurring phenomenon.
Rain-Water Harvesting
North Eastern Region falls in the highest rainfall zone of the country and enjoys typical monsoon climate, with conditions varying from tropical to temperate. The fast pace of changes in topography culminates in climatic changes within short distances. For instance, the average annual rainfall reaches a peak of 13,390 mm in the Cherrapunji–Mawsynram region in the Meghalaya plateau, while the northern and adjoining central areas in the same plateau that fall in the rain-shadow region need irrigation during most part of the year.2 The pre-monsoon showers (March–May) account for 25 per cent of annual rainfall, while bulk of the rainfall (67%) occurs during June–September, which constitutes the monsoon season.
Viewed in meteorological terms, the entire North Eastern Region is grouped under the Homogeneous Rainfall Region. With a mean annual rainfall of 2070 mm and mean summer monsoon rainfall of 1420 mm (69% of annual mean), the NER is the wettest of all the five homogeneous rainfall regions of India. The rainfall characteristics of NEI are distinctly different from those of other regions of India as well as the All India rainfall in several important aspects viz. variability and trends in annual and seasonal precipitation and conformity to the El Nino Southern Oscillation (ENSO) events.
The abrupt withdrawal of monsoon from the Northeast by the last week of September; followed by scanty rainfall in post-monsoon period (October–December) and winter season, the scope for agricultural activities during the rabi season gets limited.3 Delayed pre-monsoon rainfall and slow onset of monsoon along with partial distribution of rainfall not only entails the potential of leading to serious dislocations, but can also cause damage to the crops and also severe water shortage. On the other hand, excessive precipitation causes rapid run-off on steep slopes, resulting in heavy soil loss as well as siltation of riverbeds.
The rainfall regime of the region is characterized with high spatial and temporal variability. While temporal variability is determined largely by fluctuations in the monsoon and pre-monsoon circulations, spatial variability is controlled overwhelmingly by the physiography of the region. Rainfall in large portions of this hilly region is generated and distributed orographically which augments the contrasts in rainfall distribution that usually remain eclipsed by the seeming abundance of rain and water, but actually have far reaching consequences for local climates, agriculture and environment.4
All this only underscores the need for a scientific and technical approach towards water management, with focus on harvesting and multiple uses of water. Viewed in a broad perspective, rainwater harvesting, has so far been largely ignored in the region (with the only exception of Mizoram) mainly due to the existing perception that the region has enough of rainfall and surface and ground water everywhere. However, the prevailing agro-meteorological ground situation negates this myth and necessitates promotion of rainwater harvesting along with rejuvenation of all other traditional water harvesting systems in the region.
In this regard, it has been observed that rainwater harvesting can be implemented as a viable alternative to conventional water-supply schemes in the region, considering the fact that any land anywhere can be used to harvest rainwater. Rainwater harvesting besides helping meet the ever-increasing demand for water, helps reduce run-off which is choking storm drains, reduce flood hazards, augment the groundwater storage and control the decline in the water level, improve quality of groundwater and reduce soil erosion. This is considered to be an ideal solution for water problem, where there is inadequate groundwater supply or where surface resources are either not available or insufficient. Rainwater is bacteriologically pure, free from organic matter and soft in nature.
The structures for harvesting rainwater are simple, economical and eco-friendly. The subsistence agriculture in the hilly northeastern region can be successfully changed into a profit-earning enterprise by tapping and utilizing rainwater in limited quantities. Rainwater harvesting, irrespective of the technology used, essentially means harvesting and storing rainwater in days of abundance, for use during the lean days.
Storing of rainwater can be done in two ways: (i) in an artificial storage and (ii) in the soil media as groundwater. A demand–supply analysis is required while designing water-collection tanks. Factors such as amount and frequency of rainfall, run-off coefficient of the collecting surface, number of users, daily requirement and dearth period are important for calculating the size and capacity of the storage tank.
In domestic rooftop rainwater harvesting systems, rainwater from the roof of a house is collected in a storage vessel or tank for use during the periods of scarcity5. Usually these systems are designed to support the drinking and cooking needs of the family at the doorstep. Such a system usually comprises a roof, a storage tank and guttering arrangement to transport water from the roof to the storage tank. In addition, a first flush system to divert the dirty water during the first rains and a filter unit to remove debris and contaminants before water enters the storage tank are also provided.
Rainwater can be collected in large quantities in lined ponds. Generally, big ponds are constructed and subsequently lined with non-permeable sheets like agrifilm, silpaulin, HDPE or nylon, or with a semi-permeable coating of clay to reduce the seepage losses. The roof water, run-off water (after filtration, for potable/household purposes) or spring water may be diverted to the pond. A large quantity of water, generally 50,000–20,00,000 can be harvested using such ponds, which in turn may be used for irrigation or household purposes. Moreover, it is durable and easy to construct with less maintenance cost.
Normally three types of ponds, viz. embankment type, excavated (dugout) and dugout-cum-embankment type are constructed for collection of excess run-off. Embankment type and dugout-cum-embankment type of ponds are feasible in hilly and undulating topography. Embankment type of ponds are made by constructing a small length of dam across a water course, whereas dugout-cum-embankment type of ponds are made by excavating a site surrounded by hillocks from two or three sides and making the embankment from the excavated soil on the remaining sides. In flat areas, where these two types of ponds are not feasible, dugout ponds are constructed.
Inland Water Transport
Viewed in a broad spectrum, Inland Water Transport (IWT) is often considered as cost effective, relative fuel efficient, environment friendly and more employment generating mode of transport. Many countries are now undertaking initiatives to make better use of the existing capacity and making investments in IWT. Several development projects aimed at enhancement of IWT infrastructure and operations are underway not only in the European and Western countries but also in Asian countries like China, Myanmar, Bangladesh and India.
North East India is endowed with many large and small rivers providing facilities for water transport, especially in its plain parts and in flat river valleys. From the ancient period until the roads were constructed, the rivers of the Brahmaputra and Barak plains were commonly used as the mode for transportation of goods and passengers. During the British period the Brahmaputra River and Barak-Surma-Kushiyara-Meghna river systems were extensively used for transport and trade between north-east India and the Kolkata port.
It is estimated that the north-eastern region has about 1800 km of river routes that can be used by steamers and large country boats. The inland water transport departments of both the state and central governments have been trying to improve the water transport system in the region. The river Brahmaputra now has several small river-ports like Sadiya, Dibrugarh, Neamati, Tezpur, Guwahati, Jogighopa and Dhubri.
Besides, there are more than thirty pairs of ferry-ghats on the Brahmaputra, transporting men and materials. The River Barak also has small ports at Karimganj, Badarpur and Silchar and ferry services at several places across it. The major tributaries of Brahmaputra namely Lohit, Dhansiri and Subansiri, rivers of Tripura namely Gumti and Haora, Tizu river in Nagaland, Kolodyne river in Mizoram are having immense navigation potential and it can be developed for better utilization of both cargo and passenger movements.
With the renewed focus on IWT development and the completion of the ongoing programme and projects it is expected that it would be a full fledged waterway with all the necessary infrastructure facilities within a short time frame. With this the IWT can compete with other modes namely rail and road in terms of cargo transportation to/from the Kolkata/ Haldia ports through the Indo-Bangladesh Protocol route and NW-2. The development of river routes like Subansiri, Dhansiri and Lohit will accelerate the development of the hinterland as well as the opening up of new business opportunities along these rivers
Besides the existing Indo-Bangladesh Protocol route, opening of the new inter country IWT routes namely (i) River Tizu- Chindwin- Irrawady system- this will make interconnectivity between Nagaland and Myanmar to the port of Yangoon (Rangoon) (ii) River Nengpui- Chimtupui- Kolodyne system –this will make interconnectivity between Mizoram and Myanmar to the port of Sittwe and (iii) River Gumti- Meghna system- this will make interconnectivity between Tripura and Bangladesh to Dacca and other locations, will accelerate trade and commerce between India and its neighboring countries.
Suggestions
On the basis of above brief descriptions and my personal observations made during the tour of the North Eastern Region, I offer following broad suggestions to tackle the water-related problems in the North East India.
• In order to provide a viable long-term solution to the chronic flood problem, a judicious combination of structural and non-structural measures aimed at reducing vulnerability and risks of the people and places to the hazards of flooding and erosion must be a component of Integrated Water Resource Management systems.
• Thus far the entire emphasis has been put on structural measures such as embankments, spurs, dykes, porcupines, bamboo cribs, permeable screens etc. Of late multipurpose storage reservoirs seem to have caught the imagination of the planners as a single window solution to moderate flood peaks as well as to generate power. Non-structural measures such as flood plain zoning watershed management, soil conservation, afforestation, real-time flood forecasting, reduction of susceptibility to flood hazards and damage, enhancing coping capability of the affected people to floods etc. are yet to be encouraged and adopted in reality. Catchment treatment plans that include massive afforestation both in upstream highlands and downstream flood plains are needed to stabilize the channels of the tributaries of the rivers and reduce silt load in the flow.
• The concerned authorities should draw up plans to tackle situations of wider disparity in rainfall and water availability for agriculture, irrigation and other purposes in the North Eastern Region.
• It will be in the fitness of things to introduce financial incentives in rural areas to motivate people to adopt rainwater-harvesting. While doing so such projects should also be partially financed by the Central or concerned State governments under some schemes to sustain the interest of the villagers.
• Construction of large and small ponds to collect rain water should be accorded priority.
• Inland Water Transport system should be implemented without delay.
• Campaigns for water conservation, rainwater-harvesting etc., should be launched continuously and its feedback should be monitored periodically.
Notes
1. For further details see, D.C. Goswami and P.J. Das, “Hydrological impact of earthquakes on the Brahmputra river regime, Assam: A study in exploring some evidences”, in Proceedings of the 18th National Convention of Civil Engineers, 9-10 November 2002, Institution of Engineers (India), Assam State Centre, Guwahati, pp. 40-48.
2. Government of India, Basic Statistics of the North-East, N.E.C., New Delhi: Ministry of Home Affairs, 1995, p. 40.
3. R. K. Singh, T.D. Lama, U.S. Saikia and K.K. Satapathy, “Economics of rainwater harvesting and recycling for winter vegetable production in mid-hills of Meghalaya”, Journal of Agriculture Engineering, No. 143, 2006, pp. 33-36.
4. For more details see, D.C. Goswami and P.J. Das, “The Brahmputra River, India: The eco-hydrological context of water use in one of the world’s most unique river systems”, Ecologist Asia, Vol. 11, No. 1, January-March 2003, pp. 9-14.
