The Unsustainable To Sustainable Development Environmental Sciences Essay

From Unsustainable to Sustainable development; Urban problems related to energy; Water conservation, rainwater harvesting, watershed management, Resettlement and rehabilitation of people; its problems and concerns. Case Studies; Environmental ethics: Issues and possible solutions; Climate change, global warming, acid rain, ozone layer depletion, nuclear accidents and holocaust. Case Studies; Wasteland reclamation; Consumerism and waste products; Environment Protection Act; Air (Prevention and Control of Pollution) Act; Water (Prevention and control of Pollution) Act; Wildlife Protection Act; Forest Conservation Act; Issues involved in enforcement of environmental legislation; Public awareness.

6.1 Unsustainable to Sustainable development

Sustainable development is not a new concept. It means living in harmony with the nature in full recognition of the needs of all other species. It is no just “the survival of the fittest”, we must help even the weakest of the species to survive because each species has a role to play that is ultimately beneficial to the earth and all its human population. Our forefathers preached us the need to coexist with the environment in a balanced manner. The needs of the people in different parts of the world may be different, but our dependence on the Nature is similar. The most important thing to remember is that we have only one earth and if we destroy it by our actions, our children will not have a place to live.

The first comprehensive definition of sustainable development was given by the Brundtland Commission in 1987:

“Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” [Brundtland, G (ed) (1987). Our Common Future: The World Commission on Environment and Development, Oxford: Oxford University Press].

Any development activity can be sustainable, if it is “.. a dynamic process which enables all people to realize their potential, and to improve their quality of life, in ways which simultaneously protect and enhance the Earth’s life support systems”. (Forum for the Future, Annual Report 2000).

In short, if we care for the comfort of the present generation only and do not think of the needs of the future generations, and we damage the environment by various development activities, these activities will be termed as unsustainable. In taking every action, small or big, the possible damages to the environment must be given full consideration and the action must not leave behind a degraded environment. Technically, sustainable development is defined as a path of development in which no permanent and irreparable damage is done to the environment and the resources are kept intact for the future generations. The earth has everything for each generation, but it depends on the proper use. The present generation can survive very well on the resources available, but they must also leave behind enough resources for the future generations. It is necessary that a sustainable development path do not have any negative factor that is responsible for causing adverse impacts on the environment. A sustainable development programme is friendly to the ecosystem in all respects and has the capacity to absorb abrupt changes of the present and the future. Sustainable development has also a strong element of socio-political development. Thus, sustainable development programme must have equal concern for all sections of the society with a balanced economic development and environmental protection. The programme should have a log-term view of future consequences of any action taken today. In short, sustainable development has become the cornerstone of development planning today and has also become a principal tool of negotiation in international aid packages to the countries.

The sustainable development can be broadly classified into three different kinds, viz., environmental sustainability (no permanent damage to the environment), economic sustainability (economy remains stable with equitable sharing of resources) and sociopolitical sustainability (maintaining social harmony and political stability).

Historical milestones

The Brundtland Commission, formally the World Commission on Environment and Development (WCED), known by the name of its Chair Gro Harlem Brundtland, was convened by the United Nations in 1983. The commission was created to address growing concern “about the accelerating deterioration of the human environment and natural resources and the consequences of that deterioration for economic and social development.” In establishing the commission, the UN General Assembly recognized that environmental problems were global in nature and determined that it was in the common interest of all nations to establish policies for sustainable development. The Commission was asked to focus mainly on the following:

To propose long-term environmental strategies for achieving sustainable development to the year 2000 and beyond;

To recommend ways in which concern for the environment may be translated into greater co-operation among developing countries and between countries at different stages of economic and social development and lead to the achievement of common and mutually supportive objectives which take account of the interrelationships between people, resources, environment and development;

To consider ways and means by which the international community can deal more effectively with environmental concerns, in the light of the other recommendations in its report;

To help to define shared perceptions of long-term environmental issues and of the appropriate efforts needed to deal successfully with the problems of protecting and enhancing the environment, and a long-term agenda for action during the coming decades.

The need to protect and enhance the human environment within a common framework and principles led to the Brundtland Report and subsequently, the United Nations Conference on Environment and Development (UNCED), more commonly known as the Earth Summit, took place in Rio de Janeiro, in 1992. This conference was designed to help governments to rethink economic development and find ways to stop pollution and the destruction of natural resources. The conference documents included:

Rio Declaration on Environment and Development

United Nations Framework Convention on Climate Change

United Nations Convention on Biological Diversity

Statement of Forest Principles

Agenda 21

Agenda 21 and Sustainable Development

At the Earth Summit in 1992, an agenda on worldwide sustainable development was formulated. This agenda, known as the Agenda 21, is a blueprint on how to make development socially, economically and environmentally sustainable into the next century. It addresses economic and development issues and the conservation and management of the world’s resources. The implementation of Agenda 21 has been made the responsibility of Governments, non-governmental organizations (NGOs), industry and also the general public. Agenda 21 provides a global framework for tackling global environmental problems like climate change, ozone depletion, biodiversity loss, desertification and deforestation.

The Earth Summit was followed by a conference in Johannesburg, South Africa in 2002 where the stakeholders from international institutions and corporations to national, regional and local governments have accepted that the principle of sustainable development will be at the core of all policy making. A few of the areas highlighted by the Agenda 21 are:

(i) Combating Poverty. Poverty and environmental degradation are directly related to one another and it is imperative on the part of the governments that they should focus on poverty alleviation in order to protect the environment. The national programmes should aim at sustainable use of resources and should enable the poor to earn a living without destroying the environment. It is envisaged that the people should have a say in the development process and that local groups should be involved in the planning and execution of anti-poverty programmes. In this way, the people will become a party to sustainable development and environmental protection.

(ii) Changing Consumption Patterns. Agenda 21 calls for a change in the existing patterns of production and consumption so that the damages to the environment may be minimized. For this purpose, the industrialized countries have been asked to play a leading role. National programmes should give more emphasis to more efficient production processes so that emissions and waste generation are brought down to minimum. All processes of production and consumption should conform to the principle of sustainable development – i.e. no harm to the environment. The Governments should discourage all production processes which are not environment-friendly and should levy taxes on goods that are produced through such processes. The use of eco-labels on appliances should be encouraged and efforts should be made to raise public awareness on energy efficiency and recycling of wastes.

(iii) Population and Human Health. The rapidly increasing population has created much pressure on natural resources, employment, social and health services. Sustainable development is not possible if the population is not appropriately controlled. Agenda 21 calls for the governments to adopt measures that take into account the links between population dynamics and sustainability, and identify carrying capacities. Poor health is often a result of poverty, especially in developing countries. Agenda 21 recommends that every national health programme should provide for the development of basic health care facilities with emphasis on training of doctors, nurses and other personnel, strengthen immunization programmes to control communicable diseases, and provide specific healthcare measures for the most vulnerable groups, including infants, women and indigenous peoples.

(iv) Human Settlements. Migration towards the urban centers has been continuously increasing and the towns and cities are overcrowded with people. Slums have expanded and basic facilities such as supply of clean drinking water, sanitation and sewerage facilities, healthy living conditions, etc., are becoming scarce. Traffic congestion, poor air quality, waste dumping and unhygienic conditions have multiplied in most cities. Agenda 21 calls for appropriate urban renewal projects and transportation strategies, the provision of access to land, and credit and low cost building materials for the poor. Migration to big cities can be reduced only by improving living conditions and employment opportunities in rural areas and Agenda 21 lays stress on the development of the rural areas.

(v) Atmospheric Protection. The atmosphere can be protected by reducing emissions to it. For this purpose, Agenda 21 calls for action in the energy production sector, transport and industry, through the promotion and development of energy efficient programmes, regional energy plans, public-awareness campaigns of environmentally sound energy systems, and research into more fuel-efficient transport systems.

(vi) Ecosystems. Ecosystem conservation and protection is considered as a major item in sustainable development. For this purpose, Agenda 21 calls for governments, business houses and NGOs to introduce programmes of afforestation, reforestation, and sustainable land use and water resource management. The education programmes should be reoriented towards environmentally sustainable resource management.

(vii) Sustainable Agriculture and Rural Development. While agriculture should yield enough food for the rising population, the farming practices should not lead to land erosion, desertification and deforestation. Current methods of farming, particularly in developing countries, should be carefully examined and unhealthy practices should be discontinued. Agenda 21 urges the development of long-term land conservation and rehabilitation programmes, by encouraging people to invest for the future through land ownership.

(viii) Conservation of Biological Diversity and Management of Biotechnology. Habitat destruction, over-harvesting, pollution and introduction of foreign species are recognized as the main factors behind loss of biodiversity. Agenda 21 calls for governments to undertake national biodiversity assessment programmes and formulate strategies to conserve the existing biological diversity without further damage.

(ix) Protecting and Managing the Oceans and Fresh Water. Agenda 21 calls for nations to develop policies, which address unsustainable fishing practices, the creation of marine protection zones, and the surveillance and enforcement of fisheries regulations. The agenda further requires that the National water management practices are integrated into economic and social policies. Agenda 21 sets 2025 as the realistic target date for ensuring universal water supplies, and to develop low-cost services, which can be built and maintained at the community level.

(x) Managing Wastes. Agenda 21 calls for an international strategy to manage the production and disposal of wastes, including hazardous waste, solid waste and sewage, and radioactive waste. Governments should encourage and assist industry in achieving cleaner production technologies, and promote changes in lifestyles, production and consumption, through recycling and fund public education initiatives. Countries, which generate nuclear waste, should adopt an integrated approach to the safe management, transportation, storage and disposal of radioactive wastes.

(xi) Implementing Sustainable Development. All nations will have to make political, social and economic commitments to ensure that the Agenda 21 can be properly implemented and that necessary resources are available for the same. The Agenda asks international funding organizations such as the International Development Association and the Global Environment Facility to help developing countries in meeting additional expenses in implementing all measures required for sustainable development. Developed countries should help promote the transfer of technology to developing countries.

It is necessary to monitor the implementation of Agenda 21. Laws should be enacted to secure a balance between the needs for development and environmental protection. The main objectives should include: international standards in environmental protection taking into account the different situations and abilities of individual countries; review of all environmental laws making them more effective; and measures to avoid or settle international disputes.

Meeting the aims and objectives of Agenda 21 within the time frame established by the 1992 Earth Summit will pose great social, economic and technological difficulties, both for developing and developed nations. The development that has been witnessed during the 20th century has brought unprecedented changes to biodiversity, the atmosphere and global climate. These are to be reversed. The new challenge for today’s society is to ensure that future development and the use of the Earth’s resources is managed in a sustainable way, and in every action, the quality of life is preserved for generations of the 21st century and beyond.

For sustainable development, human population growth has to be controlled. Otherwise, no invention and development in science and technology will be able to prevent irreversible degradation of the natural environment and to alleviate continued poverty in large parts of the world. The natural and social sciences will be crucial in developing new options for limiting population growth, protecting the natural environment, and improving the quality of human life. These should be the perspectives in all short and long term planning for all governments so that the challenges of the present and the future can be adequately addressed.

6.2 Urban problems related to energy use

With massive urbanization occurring on a global scale, the state of the environment and human health in the cities of the world has become a prime concern. It is estimated that by the year 2025, over five thousand million people will be living in the cities. In the developing countries of the world, already more than 200 cities have populations of one million or more. Living in cities has many positive benefits, such as increased job opportunities and better access to essential services and facilities. However, many environmental, health and development problems have reached near-crisis dimensions in cities all over the world. Urban growth has exposed populations to serious environmental hazards and has outstripped the capacity of municipal and local governments to provide even basic amenities (water, sanitation, power) and essential health services. Millions of people in the urban areas of developing countries are living under life- and health-threatening conditions. Cities have a significant impact on the broader hinterland and global environment and the fate of cities will have a major influence on the fate of nations and of the planet.

Poverty and health

Despite the unprecedented creation of wealth worldwide in the past two decades, the number of people living in absolute poverty is growing steadily. Poverty remains the number one killer, with the poor bearing a disproportionate share of the global burden of ill health. The poor live in unsafe and overcrowded housing, often in semi-urban and urban slums, with practically no access to safe water or to sewerage. These people are also exposed to pollution, traffic and industrial and other risks at home, at work or in their communities, much more than the wealthy people living in the same cities. They have insufficient food that too of poor quality from the point of nutrition.

Even in rich countries, the poor suffer worse health than do the better off. Children are particularly affected – in the poorest regions of the world, one in five children dies before his or her first birthday, mostly from environment-related diseases such as acute respiratory infections, diarrhea and malaria. Not only are children more heavily and frequently exposed to threats to their health in the environment, but also they are more vulnerable to the ill effects on health. For example, in the USA and parts of Europe, lead poisoning illustrates the unequal burden of risk borne by poor inner-city children, who are more heavily exposed to sources of lead in and around the home and are also more affected by the toxicity of lead.

Energy consumption

Compared to the rural areas, people in towns and cities consume large amount of energy. For example, the old type of Indian houses were made of wood, mud and unburnt bricks which required very little temperature adjustments and consequently very little energy was required for heating and cooling. The present buildings in towns and cities are mostly made of concrete, cement, steel, aluminium, marble, well-burnt bricks and glass. These materials are energy intensive and the houses made with them require a lot of power to keep them comfortable during the winter and the summer and also for lighting and decoration. The process of manufacture of these materials also consumes enormous amount of energy in different forms.

At earlier times, people used fuel wood or charcoal in kitchens for making food and also in the living rooms for heating. This did not create any environmental problem such as that of smoke because the houses had separate kitchens at a distance from the main living quarters and the houses were tall having provision of chimneys. This is no longer possible in today’s housing blocks where the living quarters are not separated from the kitchens; the RCC structure does not allow having tall roofs and also chimneys. Therefore the fuel type has to be changed as otherwise there will be serious smoke and associated health problems. Kerosene replaced firewood and charcoal as the favourite fuel for the urban homes. Later kerosene gave way to natural gas and electricity during the 1970s. The dependence on firewood has continued in the rural areas particularly for people living in the far-flung areas of the foothills and the forests. Newer tools of comfort came to be used in the urban centers. The use of electric fans during the summer has become a common practice but the effluent has gone for air-conditioning in their houses. As the houses have become almost like glass towers and since glass is a very bad conductor of heat, this has created problem of large temperature difference between outside and inside of a house requiring much energy to be spent on air-conditioning. Additional energy need has become necessary for running the lifts and operating a large number of other gadgets of modern life

The other major urban energy need is for transport. The towns and cities are roaming with buses, trucks, cars, two- and three-wheelers all of which depend on fossil fuels, namely petrol and diesel. The number of vehicles has increased at a very fast rate during the last few years despite the higher price of fuel. Small, narrow and improperly maintained roads and overcrowding have further aggravated the problem. Traffic congestion has become a serious problem in all urban areas. Slower moving vehicles burn more fuel and thereby the energy efficiency is further reduced. This has also given rise to problems of carbon monoxide pollution, smog and other environmental problems affecting people’s health particularly through various respiratory diseases. Time has come to design an efficient public transport system, which will lead to substantial energy saving, minimize congestion and reduce pollution problems.

6.3 Water conservation, rainwater harvesting, and watershed management

All living organisms need water, plants use it in photosynthesis, humans and other animals drink it, and aquatic plants and animals live in it. Water also plays an important part in many natural and human processes and is a critical component of countless physical and chemical reactions. It also supports many economic activities. The amount of water in the world has remained constant. In fact, water hasn’t changed in amount or nature for millions of years. It just keeps cycling and recycling from atmosphere to earth and back again. Freshwater is a precious resource as it makes up less than 3% of the earth’s total water resources. Because freshwater is so limited and plays such a key role in world health, economies, and environmental stability, it must be conserved and used in a sustainable manner.

The efficient use of water implies doing more with less. Efficiencies can be gained in all sectors, including agriculture, municipal, domestic, and industry. Central to a successful water conservation program are an understanding of

The water resource itself (baseline data and monitoring)

How, when, and why water is used (water audits and metering)

The full cost of providing water of suitable quality and disposing of wastewater

Alternative water-efficient technologies, processes, and practices

Attitudes and values related to water and the environment.

Public education and awareness are necessary in implementing water conservation. However, they may need to be supplemented by appropriate legislation and regulations and economic incentives and disincentives, including consumption-based pricing.

Demand for more water has been very common. This demand can be reduced by careful planning. This involves the following measures:

More-efficient irrigation systems

Drought-resistant cultivars and crop rotations

More-efficient livestock watering systems

Water metering and charging for water

Use of effluent and wastewater for irrigation

Household water conservation.

The water resources have to be carefully managed through the following steps:

Dividing water resources into various divisions for effective supply

Laying a network of supply pipelines

Building reservoirs for storing water

Increasing water availability through groundwater extraction

Treatment of wastewaters and making arrangement for their reuse

Reducing losses through seepage and evaporation.

Managing Excess Water. Sometimes, more water is available than the actual need. In such cases, the management of the excess water can be achieved by taking it to deficient areas through drainage:

Many agricultural areas are low lying or located in flood plains and require drainage to be profitable. Good drainage improves plant growth and crop productivity, helps to reduce soil salinity and erosion, and allows farmers a wider selection of crops and a longer growing season, all of which help to reduce the costs of production.

There are two types of artificial drainage system: surface and subsurface. Surface systems may contribute to declining water quality in watercourses by releasing drainage water containing sediments, nutrients, and chemicals. Subsurface systems release substances that leach through the soil, such as nitrate, pesticides, and bacteria.

Drainage systems can also alter the environment by draining wetlands, removing riparian zones, increasing runoff, and changing a region’s hydrology. Proper design and maintenance of drainage systems may alleviate some of these effects, but lost riparian and wetland systems are usually difficult and expensive to replace.

On-farm drainage systems are not able to handle large volumes of stormwater received from developed uplands. Properly designed regional drainage systems may be needed to protect lowland agricultural areas. Even so, damage from major floods cannot always be prevented.

Maintaining Reliable Water Supplies

A sufficient supply of good quality water is needed for agricultural activities such as irrigation and livestock watering, as well as for domestic, municipal, industrial, recreational, and other uses. Water needs to be conserved for the lean periods such as drought. Droughts are very common but difficult to predict. They occur most often in dry regions, but other regions may also have shorter, less serious periods of drought. Drought threatens both crop and livestock production. With the potential threat of global warming and increasing trends in population, urbanization, and consumptive use, the impacts of drought can become more serious.

The development of storage reservoirs is essential for maintaining adequate year-round supplies, particularly during the dry season. Groundwater is an important source of water and although the groundwater level goes down during the dry season, sufficient water can be extracted for meeting different needs. Sustainable use of groundwater resources depends on withdrawing water at rates that do not exceed recharge rates. Deep aquifers recharged only by water filtering through overlying materials are particularly at risk of over-withdrawals.

Measures have been taken throughout the world for reuse of wastewater at least for irrigation and other non-drinking uses. An adequate supply of good-quality water available round the year is essential for all human activities. Concerns continue to mount regarding the availability of water as demands and competition for water grow in all sectors of society. Management of water supplies must consider all competing uses of water, including those associated with agriculture, industry, municipalities, recreation, and aquatic ecosystems.

Drought

Drought is a prolonged period of abnormally dry weather that depletes water resources. Because most human activities and ecosystems are dependent on reliable and adequate water resources, the impacts of drought are far reaching. Drought affects our lives by

Putting stress on water and food supplies

Degrading the environment through poorer water quality and more forest fires, soil erosion, and insect infestations

Affecting the economy by reducing the capacity for agricultural production, power generation, transportation, and manufacturing,

Causing soil moisture deficit in farmland soils and thereby threatening both crop and livestock production resulting in severe financial losses to farmers.

Global warming scenarios predict that unless the warming is controlled, the frequency and severity of drought will increase and the occurrence will be unpredictable with respect to time and location.

Three basic types of drought may occur separately or simultaneously:

Meteorological drought occurs when precipitation is significantly below normal over a long period.

Agricultural drought occurs when low soil moisture and scarce water supplies stunt crop growth, reduce crop yields, and endanger livestock.

Hydrological drought occurs when a lengthy meteorological drought causes a sharp drop in the levels of groundwater, rivers, and lakes.

The timing of a drought may determine its effects. For example, summer drought usually causes more problems because it coincides with the time of highest water demand. It is to be noted that drought is the result of several factors such as

Below normal precipitation

Extended hot dry air

Already low soil moisture.

Because of this complexity, a large range of climatic and hydrological variables are needed to monitor and detect drought, including temperature, precipitation, soil moisture, stream flows, and water supply conditions. The serious impacts of drought call for an integrated effort from the physical, biological, and social sciences to develop effective responses.

Surface water management

Surface water management requires effective measures to control the extremes of floods and droughts, while maintaining a reliable water supply to meet the basic needs of human life and the demands of economic development. Because of the high degree of variability of precipitation, water storage is a must to provide a year-round supply of water. The storage in the form of reservoirs, dams, dugouts, and natural lakes has been a common practice. A significant challenge to water managers is locating surface water supplies relative to that of water users. Water users (domestic, municipal, agricultural, and industrial) usually require a number of resources and services and are not always located near the water sources. Providing a reliable supply of water to users often requires distribution networks consisting of canals and pipelines.

Wetlands

Wetlands are areas saturated with water for long enough to significantly alter soil and vegetation and promote aquatic processes. The five main types of wetlands-bogs, fens, swamps, marshes, and shallow water-are characterized by

A seasonal or permanent covering of shallow water

A water table at or near the surface for most of the growing season

Saturated organic soils, or peat, the productivity of which depends on the nutrient status and the pH of the site

Water-loving plants, such as cattails, rushes, reeds, sedges, dogwood, willows, and cedars.

Wetlands provide a number of environmental benefits, i.e. they

provide habitat for wildlife,

improve water quality by serving as biological filters and mechanical settling and filtering ponds, which help to remove impurities from the water,

recharge groundwater,

augment low flow in watercourses,

serve as a buffer against drought,

reduce the risk and damage of flooding by storing large volumes of water during heavy rainfall, rapid thaws, or runoff events, and

stabilize shorelines.

The other important services rendered by wetlands are (a) they provide recreational, educational, and economic opportunities, through canoeing, fishing, hunting, ecotourism, school trips, and the harvesting of resources (e.g., wild rice), (b) the wetlands support a large number of waterfowl species that use wetlands for nesting habitat, protective cover, or sources of food, (c) wetlands are equally important to non-avian wildlife as they provide essential breeding habitat for many amphibian and reptile species, (d) they are also the prime locations, along with lakes and rivers, for a large number of freshwater fish seeking shallow waters for cover, spawning, and nurseries, (e) wetlands serve as primary habitat to mammals adapted to aquatic conditions (e.g., beavers and musk-rats), and secondary habitat for other upland species that occasionally use these areas to escape predators, reproduce, or forage (e.g., raccoons, shrews, and moose).

The wetlands thus hold considerable biodiversity because of the unique combination of water and land. The wetlands have high productivity as they are the breeding and feeding grounds for thousands of invertebrate species at the base of food chains. Directly or indirectly, the invertebrate communities support species of birds, mammals, amphibians, and reptiles, as well as numerous other fish and plant species, including endangered or threatened species. The wetlands also contribute significantly to the biological diversity beyond their borders. For example, deer or moose commonly use a hardwood forest in winter when thick conifers, commonly associated with swamps, are nearby to provide thermal cover.

Encroachment, expansion of human habitats and building of roads and railways across the wetlands, establishing industries have caused substantial loss of wetlands in the last few decades. Wetlands sustain many ecosystems and even if a part of the wetland is destroyed, it may lead to elimination of important ecosystems.

Lakes and ponds

Lakes and ponds provide a diversity of aquatic habitat. The littoral zone of these water bodies is defined as that portion where sunlight can reach the bottom, usually in shallow areas near the shore (up to 5 meters deep, depending on turbidity). This is the most productive part of lakes and ponds, and it supports a variety of waterfowl and shorebirds, fish, amphibians, reptiles, mammals, and plants. Most fish, cold- and warm-water species alike, rely on the littoral zone for their early life stage requirements (for spawning, larval, and juvenile stages). Nutrient enrichment of lake and pond water can promote eutrophication, as it does in streams and rivers. Pesticides that enter ponds and lakes have the potential to disrupt the metabolism of organisms at all levels of the food chain in the aquatic system.

Floodplains

Floodplains are the low-lying flat lands that border streams and rivers. When a watercourse reaches its capacity and overflows, such as during continuous heavy rains, the excess water is accommodated by the floodplain. The floodplains serve to

receive sediments that settle out of flood waters,

absorb and store water during floods and rainfall which later becomes available to plants, including agricultural crops, during the dry months,

provide large expanses of wildlife habitat that supports diverse plant and animal communities, and

help fish to survive during high flood by providing low velocity refuge areas.

If the water drains out rapidly, the floodplain does not have enough time to soak up water. This lowers the water table and correspondingly, the groundwater availability during the dry months decrease. This normally happens in urban and residential areas due to creation of impervious built-up surfaces when the runoff volume increases and causes waterlogging in low lying areas. These reduce the natural flood plain area and contribute to greater flow, erosion, and damage downstream.

Problems created by impervious surfaces

Urban development creates large areas of impervious cover, such as roofs and pavement that cannot absorb rainfall. As forests are removed or low-lying lands are filled up to increase habitat area, water-retaining capacity of the soil declines, and the surface runoff increases in volume. It becomes difficult to manage the increased runoff and the low lands suffer from problems of excessive water accumulation for a long time. In the flat and fertile agriculture lowlands of a watershed, the runoff affects agriculture seriously causing loss of valuable crops, livestock, machinery, and structures. Construction of barns, feedlots, and greenhouses has increased the areas under impervious surface even in the agricultural areas, further reducing the capacity of soils to absorb water.

Limits on Water use

Use of water for different purposes is gradually increasing and the demand is expected to rise several folds in the immediate future. This may even give rise to conflicts among localities, people and nations. While agriculture remains the chief water-user, competition is likely from such sectors like thermal power generation, manufacturing, and municipal water use. Water management has become a prime responsibility of the nations. If water is not available, both agriculture and livestock production will be affected. Drought is a severe problem in many countries and its effective control involves proper water management. It is predicted that climate change processes will increase both flood and drought, and the countries are required to plan for the future assuming severe water shortages. Alternative farming practices that are not solely dependent on water availability have also to be developed.

Thermal power generation

Thermal power generation withdraws much more water than agriculture. Production of one kilowatt-hour of electricity requires 140 liters of water for fossil fuel plants and 205 liters for nuclear power plants. Conflict may arise between agriculture and the thermal power sector if thermal plants are located in agricultural areas.

Manufacturing

The manufacturing industry withdraws more water than agriculture, but consumptive use is higher for agriculture. The trend to expand value-added processing of agricultural products may increase the competition for water between agriculture and manufacturing industries.

Municipal water use

Municipal water use and population are projected to grow in unison, possibly conflicting with agricultural growth in areas short of water. Towns and cities may compete for water supplies needed by agriculture, particularly in irrigated areas. Conflicts may also arise if water destined for municipal use is polluted as a result of agricultural activity.

Water use by Fish and wildlife

Pollution of fishery waters as a result of agriculture could give rise to conflict between agriculture and the fisheries sector and potentially limit the growth of agriculture. A demand for more land for developmental work may exert pressure on wetlands and other habitats of fish and wildlife. This could seriously affect availability of water for fish and wild animals.

Water allocation

Whatever water is available should be distributed and used properly and all governments should initiate actions for allocating water for different sectors. The drinking water needs of the people must be met but there should also be adequate allocation for agriculture. Serious conflicts have arisen all throughout the world (also in India) for allocation of water from the rivers during the lean months. Inter-state conflicts on water continue to take up a lot of attention of the Central Government and the judiciary in India.

Effects of agriculture on water

Agricultural practices have undergone tremendous changes during the last 50 years due to the technological advances taking place. Productivity has increased because of the use of modern mechanized agriculture and use of fertilizers and pesticides to maintain production levels. These new techniques have also contributed to some degree of environmental degradation, including the decline of water quality. Water pollution is one of the consequences of modern agriculture.

The main pollutants coming from farmland to water are sediments, nutrients (especially nitrogen and phosphorus), pesticides (including insecticides, herbicides, and fungicides), bacteria, and salts. The presence of these substances can make water unfit for uses by humans and wildlife. The quality of freshwater resources is the first to be affected by agriculture. However, the impact is also felt in some estuarine, coastal, and marine waters that receive runoff from agricultural fields.

The construction of dams and reservoirs, distribution of irrigation water, drainage of wet soils, including wetlands, and sedimentation of streams and lakes are also very likely to alter the water quality. These activities completely change the esthetic appeal of the countryside, affect wildlife habitat and give rise to conflict with other users of water.

Rainwater Harvesting

To meet water demand during the lean seasons, people have taken to rainwater harvesting when they store the rainwater for use later. Rainwater harvesting (RWH) is a method of collecting, storing and conserving roof top water runoff and local surface water runoff. In industrialized countries, sophisticated RWH systems have been developed with the aim of reducing water bills or to meet the needs of remote communities or individual households in arid regions.

In countries like Uganda and Sri Lanka, rainwater is collected from trees, using banana leaves or stems as temporary gutters; up to 200 liters may be collected from a large tree in a single storm. Many individuals and groups have taken the initiative and developed a wide variety of RWH systems throughout the world.

RWH has come to mean the control or utilization of rainwater close to the point where rain reaches the earth. In practice, the RWH may be divided into two categories

RWH for domestic use, and

RWH for agriculture, erosion control, flood control and aquifer replenishment.

RWH is a possible source for meeting water demand in some areas, but is often overlooked by planners, engineers and builders. In many areas, where RWH has been introduced as part of a wider drinking water supply programme, it was at first unpopular, simply because little was known about the technology by the beneficiaries. In most of these cases, the technology has quickly gained popularity as the user realizes the benefits of a clean, reliable water source at the home, when the supply is unreliable or inadequate, or where local water sources dry up for a part of the year. In many cases, RWH has been introduced as part of an integrated water supply system. It is a technology that is flexible and adaptable to a very wide variety of conditions, being used in the richest and the poorest societies in the planet, and in the wettest and the driest regions of the world.

Rain water harvesting is essential because

Surface water is inadequate to meet our demand and we have to depend on groundwater,

Due to rapid urbanization, infiltration of rainwater into the sub-soil has decreased drastically and recharging of groundwater has diminished,

Over exploitation of groundwater resources has resulted in decline in water levels in most part of the country,

To enhance availability of groundwater at specific place and time,

To arrest sea water ingress,

To improve the water quality in aquifers,

To improve the vegetation cover,

To raise the water levels in well and bore-well,

To reduce power consumption.

Rainwater harvesting depends on end use application such as

Roof top rainwater captured from the roofs of buildings on residential property can be used for various needs such as domestic use, irrigation of flower gardens, car washing, etc.

Rainwater harvesting may be used for inducing, collecting, storing and conserving local surface runoff for using in irrigation, reducing soil moisture deficit and for ground water recharge.

Rainwater conservation has four phases. The four phases are:

Rainfall induces surface flow on the runoff area.

At the lower end of the slope, runoff collects in the basin area.

The major portion of water collected infiltrates and is stored in the root zone of the soil.

After infiltration has ceased, the conservation of the stored soil water follows.

In Orissa, for example, the average annual rainfall is around 1500 mm, which is quite high in comparison to world’s average rainfall (i.e. 800 mm.). But this rainfall occurs for a very short period. As a result, maximum amount of rainwater flows away very rapidly with poor recharge of ground water. So, scarcity of water for domestic purpose is a common phenomenon in most parts of Orissa. This problem can be reduced if the excess rainwater is harvested and stored for use during the lean period.