Sustainable Water Resources Management - Safeguarding the Future

Transcription

1 Sustainable Water Resources Management - Safeguarding the Future Er. J. Lordwin Girisb Kumar Assistant Professor Dept!. ofsoil Water Land Engg & Mgt AllahabadAgricultural Institute - Deemed University Allahabad , U'P; India. ABSTRACT Water is the most widespread substance to be found in the natural environment. During recent decades natural variations in river runoff and quantitative and qualitative characteristics of renewable water resources have been much affected by a whole anthropogenic impacts. Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The vast water resource, both surface and sub-surface, has been subjected to over-exploitation or mismanagement. A study conducted by World Watch Institute (U.K.) revealed that by 2050 India as well as many countries in Asia and Africa would face acute water scarcity, which may result reducing the life span of its citizens. Therefore it is essential to develop reliable, economical viable and other input management strategies to save the water resources efficiently. It is not too late for us to focus our attention on protecting and respecting our water resources. Because by protecting our fresh water, we help ensure our future and our planet's long-term prospects. 1. INTRODUCTION Water resources occupy a special place among other natural resources. Water is the most widely distributed substance on our planet: albeit in different amounts, it is available everywhere and plays a vital role in both the environment and human life. The vast water resource, both surface and sub surface, has been subjected to over-exploitation or mismanagement. This has led to serious depletion of groundwater, salinization and pollution due to contamination with agricultural chemicals. By the year 2020, the world will have to support more than eight billion people. Despite the huge successes of world agriculture, some 800 million people are still hungry. This includes 180 million children from malnutrition. Calculations show that in the decades to come most of the Earth's population will face a critical situation with regard to water supply. This water deficit will become a factor depressing the living standards of populations and retarding the economic and social development in most developing countries of the world. Plenty of measures are possible for eliminating water resource deficits and which is very promising for the future is runoff regulation and territorial redistribution which has a course been in existence for a longtime. 496

2 1.1 Scenario of Global Water Resources During recent decades natural variations in river runoff and quantitative and qualitative characteristics of renewable water resources have been much affected by a whole complexity of anthropogenic impacts. They include those related directly to water intake from river systems for irrigation, industrial and domestic water use. They also include reservoir runoff control, river basin land use change such as afforestation and deforestation, field management, urbanization, and drainage. All these factors differently affect the total volumes of water resources, river runoff regime and water quality. However, estimation of global anthropogenic effects on water resources is based, primarily, on a consideration of the role of those factors related to direct water intake from water bodies and reservoir runoff control. These factors, causing unilateral decrease in surface and ground water runoff, are widely distributed, most intensively developed :and able to exert a pronounced effect on water resources in large regions.. 1.2World Water Balance The total quantity of water in the world is estimated to be about 1386 million cubic! kilometers (M krrr'). About 96.5% of this water is contained in the oceans as saline water. Some 'ofthe water on the land amounting to about 1% ofthe total water is also saline. Thus only about 35.0 M km' of fresh water is available. Out of this about 10.6 M krrr' is both liquid and fresh waterand the remaining 24.4 M krrr' is contained in frozen state as ice in the polar regions and on mountain tops and glaciers. The estimated world water quantities are shown in Table 1. Table 1. Estimated World Water Quantities. Item Area (Mkrn) Volume Percent total Percent fresh (M km'') water water 1. Oceans Ground water (a) Fresh (b) Saline Soil moisture Polar ice Other ice and snow Lakes (a) Fresh (b) Saline Marshes Rivers Biological water Atmospheric water a) All kind of water b Fresh water Source: Table from world water balance and water resources ofthe eartl() UNESCO,

3 Annual water balance studies of the sub areas of the world indicate interesting facts. The water balance of the continental land mass is shown in Table 2. It is interesting to see from this table that Africa, inspite of its equatorial forest zones, is the driest continent in the world with only 20% of the precipitation giving as runoff. On the other hand North America and Europe emerge as continents with highest runoff Extending this type of analysis to a smaller landmass, viz., the Indian sub continent, the log term average runofffor India is found to be 46%. Table 2. Water balance of continents mm/year Continent Area (Mkm.l) Precipitation Total runoff Runoff as % of precipitation Africa Asia Australia Europe N. America S.America Evaporation Source: Table from world water balance and water resources ofthe eartl() UNESCO, Water for Agriculture Land has been practised for millennia through the necessity to maximize food supply for humanity but the dramatic expansion in irrigated land has mainly taken place during the 20 th century, with irrigation becoming the principal water use in many countries. Indeed, agriculture is now reckoned to be the largest consumer of water, accounting for some 80% of total water use. In the modern world, population growth proceeds at a great rate and at the same time there is an acute food deficit being experienced by almost two-thirds of the world's population. Irrigation therefore plays a major role in increasing arable production and cattle breeding efficiency, with irrigated farming expected to continue to develop intensively in the future, mainly in those countries with extremely rapid population growth and sufficient land and water resources. Considerable water economy through the use of the best and up-to-date engineering methods and watering techniques such as sprinkler, drip irrigation etc, which helps to increase crop productivity and decrease the volume of irrigation water required. 1.4 Future Water requirements At present, agriculture receives 67% of total water withdrawal and accounts for 86% of consumption. The global irrigated area was 254 million ha in By 2010 it is expected to grow about 290 million ha and by 2025 upto 330 million ha. However, in future, the proportion of water used for agriculture is likely to decrease slightly, mainly at the expense of more intensive growth in other water demands such as industry and public water supply. In summary, agriculture is expected to increase demands by 1.3, industry by 1.5 and global public supply by 1.8 times. On the Asian continent, the greatest volume of water withdrawal occurs in the Southern regions - India, Pakistan, Bangladesh. The dynamics of growth in water use up to 2025 differ considerably by region. In developed countries and in those countries with limited water 498

4 resources, water withdrawal is expected to rise by 15-35%. In developing country regions with sufficient water resources, the water withdrawal growth could be %. 1.5 Potential of new technologies and improved management The water deficit will become a factor depressing the living standards of populations and retarding the economic and social development in most developing countries of the world. It is already clear that in the first halfofthe century water issues will be the most important, even among other global problems facing humankind such as adequate food and power productions. It is therefore essential to formulate an efficient, reliable and economically viable water and other input management strategies in order to irrigate more land area with existing water resources and to enhance crop productivity and quality of high value crops such as vegetables, fruits and commercial flowers for local consumption as well as for export. The future irrigation water demand can be met through advanced irrigation system management like sprinklers, drip irrigation etc, which helps to increase crop productivity and decrease the volume of irrigation waterrequired. 1.6Policy reforms needed A crucial pre-condition for all the measures is reform in water policy. Saving water depends on such reforms/activities and it will not be easy to carry out but action should be initiated in a big way to overcome the water problem. The key elements of water policy reforms should be Creation of price incentives for saving water that is water should be considered as an economic good and not a free good as it is contemplated. Management of the irrigation system by a water users association, that is, turn over irrigation system. Encouragement of inter-state cross-border cooperation in water resources. Therefore, utmost care in management is necessary to utilize water judiciously and economically by various means such as conservation, development, storage, distribution reclamation and reuse for sustainable food security. 2. CONCLUSION At the present time and for the foreseeable future, the most realistic and efficient measures will be taken economically in the use of and protection of water resources by a drastic decrease in specific water consumption, especially in irrigated land use and industrial sector. Among all the measures possible for eliminating water resource deficits and which is very promising for the future is runoff regulation and territorial redistribution which has a course been in existence for a long time. It is our firm belief that we shall succeed in our mission of having a sustainable water resource management to save our future generation. 499

5 REFERENCES Davis, TJ. and Schirmer, LA. (Eds) Sustainability issues in Agricultural Development, Proc. Seventh Agriculture Sector Symposium, World Bank, Washington, D.C. Katyal J.C. and Balaguru, T (1997). India's Natural Resources vis-a-vis research priority setting. Paper presented in the Institutionalizing Agricultural Research Priority Setting, Monitoring and evaluation in the Indian NARS', held at New Delhi, July Ministry of Water Resources (1993) India: Proposal for technology research in irrigation and Drainage. Panell, DJ. and Schilizzi, S. (1999). Sustainable agriculture: a matter of ecology, equity, economic efficiency or expedience, Journal ofsustainable Agriculture, 13(4), 1999,