Water Resources and Ecological Balance
Water Resources and Ecological Balance
Er. Mohammad Ashraf Fazili
Life on earth is made possible by joint venture of Lithosphere, Hydrosphere, Atmosphere and Solar Energy. In the sphere of life called Biosphere, all the organisms are interdependent and each in turn depends upon the physical environment of the area in which they live. In the natural environment there is perfect balance between the various organisms in the biosphere, called ecological balance.
To maintain the food chain in balance, the small weaker organisms are more numerous and reproduce at a faster rate than the larger and the stronger ones. Under natural conditions also, due to change in physical environment on the earth, during different geological periods, some plant and animal species, which were not able to adapt themselves suitably to the changed environmental circumstances died out. In some cases new species came into existence. This process is continuous one and scientists estimate that 90 percent of all species (both animal and plant) have virtually vanished since life began. However, the rate of extinction has increased considerably since last century. About 20000 plant species and over 1000 animal species are at the verge of extinction. This rapid rate of extinction is not due to natural change but the man is responsible for destroying and transforming the nature.
For the sake of meeting the requirement of his food, fodder, shelter etc., man has dislodged the food chain, the ecological balance by raking and misuse of natural resources such as coal, petroleum and natural gas for power production. Industrialization and transport systems, have further aggravated the situation and created atmospheric and water pollution.
Pollution of water in seas, river, lakes, springs and other water bodies is increasing to abnormal proportions due to effluents, urban waste, use of insecticides and pesticides, etc. Organisms living in water and those dependent on water are sufferers; land resources are mistreated without any remorse. The fertile soil is being wasted and drawn to deep oceans, along with precious water by faulty cultivation, removal of vegetable cover and by the process of mining.
Our strategy must be to formulate answers to these questions through an open dialogue within and beyond the community. Specific activities will include the convening of workshops and open science symposia, preparation of pre-received publications and policy beliefs, assembly and testing of data sets and model inter comparison exercises. Education and capacity building aimed at training the next generation of GWS scientists/ engineers must also be a part of the effort.
Human interaction with water has created a global significant impact on the land-based hydrological cycle, its resident biota (all plants and animals in a region) and material transports to the ocean. The humans have begun to affect the Global Water System without adequate understanding of how that system functions. The world’s 45000 dams convey a substantial human signature on continental runoff, with impounded waters increasing seven-fold the storage of water in river channels and tripling the residency time of continental runoff. Improvement likely traps one-third or more of global sediment destined for the world’s coastal zones.
Deforestation is likely to have nearly halved the evaporative power of vegetation on a global scale. DECD countries have destroyed 70 percent of their wetlands. The integrity of aquatic ecosystems is endangered by the management of surrounding unplanned system, such as from poor agricultural practices, which create siltation changes in discharge regime and eutrophication in receiving waters.
Water is a limited resource, which needs to be carefully managed. Its natural abundance, in a region and how it is collected, stored and distributed has a major impact on a country’s economy, determining what crops can be grown and whether there is sufficient to meet domestic and industrial demands. The establishment of some of the first civilizations in the Middle East was due to the inspired use of the Nile floodwater for irrigation.
If water is to be made available on demand all the year round, it needs to be collected and stored. How this is done varies around the world, according to climate and geography in regions of Asia, Tropical Countries, European Temperate Zones, North America, South America, Africa and Australia. Some areas have plentiful water all the year round, some have marginal water in the growing seasons and some have markedly seasonal water supplies and there are constant water deficit areas.
More than 90 percent of world’s water consumption goes to agriculture. Domestic use accounts for less than 3 percent, with only a little more being consumed by industry. The pattern of water use varies in different parts of the world. In the developed world- Western Europe and North America- industry often makes just as much if not more demand on water resources than agriculture.
UNESCO estimates that nearly half the world’s crop production, in terms of value, comes from the irrigated land. Within India, a consciousness of the importance of the subject of water led to the establishment of National Commission of Water Resource Development Plan, which submitted its report in the year 1999.
The annual runoff has been estimated as 1953 cu.kms (including both surface and ground water resources). The annual ‘usable’ water resources of the country are 690 cu.kms of the surface water and 396 cu.kms of ground water making a total of 1086 cu.kms. The present quantum of use is put around 600 cu.kms. The National Commission has come to the conclusion that by 2050 the demand will catch up with the supply. There will be a difficult situation, provided that a number of measures on the demand and supply sides are taken in time.
There are variations in the availability of water in the country depending upon the rainfall period and its intensity. There is a wide range of precipitation from 100 mm in Rajasthan to 11000 mm in Cherranpunji. Sixty percent of water resources of India are to be found in the Ganga, Brahmaputra and Meghna rivers systems, which account for 33 percent of the geographical area of the country, 11 percent in the West flowing rivers south of Tapti covering 3 percent of the area and the balance 29 percent in the remaining river system spread over 64 percent of the land area.
The Himalayan rivers are snow fed and perennial, whereas the peninsular rivers are dependent on the monsoons and therefore seasonal. Again the North and the East are well endowed with water, whereas the West and the South are water short. Besides desert areas of Rajasthan, there are drought prone areas in parts of Gujarat, Maharashtra, Karnatka, Andhra Pradesh and Tamil Nadu and the eastern parts of the country experience devastating floods from time to time.
Various solutions have been suggested for storing and transfers from surplus areas to water short areas. Gravity link canals and tapping of rivers continues to haunt the minds of water planners. Interlinking of rivers like Mahanadi, Godavari and Krishna, the Punnar and the Cauvery is under consideration despite opposition of the concerned states.
The National Commission talks about demand, management economy in water use, resource conservation, etc., and local harvesting and water shed development projects which are regarded as the primary answer to the future needs of a growing population, besides financing of the projects and the contributing role of private sector participation in the massive effort envisaged.
There seems to be wide spread agreement on the regional, national and international level that:
a) Considering the projected water needs of the future, an important part of the answer lies in the water Resource Development Projects.
b) The financial constraints and managerial limitations of Government, a significant part of that development will have to come from the Private Sector.
Numbers of projects are envisaged for hydro electricity and irrigation and flood moderation in some cases in Nepal, Karnali, Pancheswar, Sepatakosi. Bangladesh being interested in these and other projects in Nepal from the point of view of augmenting the lean season flows of the Ganga. In India the Tehri Hydroelectric Project in Himalayas is being built despite opposition. Several projects have been formulated in Brahmaputra, besides the idea of transfer of waters from Brahmaputra is still live. In Bhutan, Mamas and Sankosh projects are to come up. In Tripura, the Tipaimukh project in Magna/Barak has been proposed. On the Teesta, a tributary of Brahmaputra, both India and Bangladesh have built barrages and overcome inadequacy of water, the idea of building a dam has been mooted.
The NWDA has been studying the possibility of transfer of waters from the Mahanadi to Godavari and thence to Krishna, the Pennar and the Cauvery involving building of a number of dams and links. The idea of transfer from the Himalayan rivers to the Peninsular rivers is also on the anvil. The state governments of Maharashtra, Karnatka and Andhra Pradesh may embark on many projects, with a view to establishing or improving their respective claims under the Awards of Tribunals on the shared rivers. On the Narmada, apart from the major projects (Sardar Sorovar, Narmada Sagar), a host of other projects, big and small are envisaged in the over all plan. Finally there is the idea of diversion of some West flowing peninsular rivers eastwards. In J&K State long term perspective of utilization of water resources have to be:
(a) To irrigate remaining areas within the Indus Water Treaty limits in Leh, Kargil, Jammu & Kashmir Divisions.
(b) To have water harvesting moisture/soil retention measures to make the barren hill slopes productive.
(c) To exploit identified hydro potential of 9935 MW in entire State.
However not many of these projects are likely to materialize due to financial constraints and strong opposition to the projects. Assuming most of these materializing, there will be an additional irrigation potential and consequent enhancement of agricultural production, some flood moderation and possibly an addition to navigation facilities
There will also be adverse impacts (environmental, social and human) and there can be no assurance that the benefit will outweigh their costs. Even if the gain will exceed costs, the totality of the project taken together will constitute a massive onslaught on nature.
In spite of all these advantages, it is established that future needs cannot be met without massive “Water Resource Development” that is large storage (dam and reservoir) projects, local rainwater harvesting and water shed development, for which a major push needs to be given to these activities. The need for large projects can be minimized (if not eliminated) and the environmental, social and human impacts will be correspondingly reduced.
The author is retired Chief Engineer and can be mailed at firstname.lastname@example.org