Read this article to learn about the water resources: meaning, source of fresh water, causes of depletion and management of water resources!
Water is the most important element of the biosphere which is essential for the existence of all forms of life. Water is a renewable resource and its availability depends upon the climate, geographical and physical conditions, affordable technological solutions and the efficiency with which water is conserved and used. In a civilized society, the human activities and economic development are dependent upon water.
Out of the total water resources, 97% remains in oceans as salty water, 2% remains as ice and rest 0.6 to 1.0% remains as fresh water either on surface or as ground water. That is, the available fresh water resources are very limited.
The fresh water is used by living organisms for their different activities. Of the three major uses of water that is domestic, agricultural and industrial, agriculture is the greatest consumer of water (65% of total consumption). Industries consume 25% and 5% is used for domestic purpose.
Source of fresh water:
The fresh water required for the human beings is obtained from two natural sources:
(a) Ground Water:
The water present under the surface of the earth is known as ground water. The average magnitude of the total round water content is about 210 billion m3 including recharge through infiltration, seepage and evapotranspiration.
The storing of ground water occurs by the passage of water molecules through the intermolecular spaces between the soil, rock, sand and gravel particles. The downward flow of water stops when it Caches the rock without porosity.
These water molecules get collected at different, zones giving ground water. Similarly a part of the river water or streams can pass through the voids (inter Article spaces) giving ground water. Due to good quality and non polluted nature of ground water, it can be used for drinking other uses of human beings.
It can be withdrawn for human consumption by the following ways:
(i) Wells (dug well or bore well);
(ii) Spring intake chamber and
(iii) Infiltration galleries,
(b) Surface water:
The water present over the surface of earth in rivers, lakes, ponds, streams, etc. is known as surface water. The freshwater bodies may be lotic (i.e., running water as spring, stream, rivers, etc.) The river water system serves about 80% of the total population of the country.
The surface water contains a lot of pollutants, micro-organisms, and mineral nutrients for the feeding of bacteria and virus. The surface water gets polluted by the run of water from agricultural fields containing pesticides and fertilizers, soil particles, waste chemicals from industries and sewage from cities and rural areas. However, the surface water can be purified and reused.
The fresh water can be used for different purposes as given below:
(i) Domestic use for drinking, cooking, cleaning sanitation etc.
(ii) Irrigation for agriculture
(iii) Industrial use for cooling, processing, cleaning etc.
(iv) For fisheries and aqua-culture.
(v) For waste disposal
(vi) For power generation
(vii) For recreation
The personal water use by an urban Indian is given in table 4.3
Causes for the Depletion of water resources:
The depletion of water resources is attributed to the following causes:
1. High demand for water:
Coupled with population explosion, the rapid industrialization and technological development require large quantity of water for their maintenance.
2. Poor storage facility and careless attitude towards conservation:
Due to poor storage facility and careless attitude, a lot of rain water is carried to the seas and oceans.
3. Poor ground water resources:
The ground water resources are declining due to overgrazing and deforestation which cause soil erosion and make the soil unable to permit water infiltration.
4. Over-exploitation of ground water:
In order to meet the demand of increased population, the ground water is withdrawn by suitable mechanism and it is overexploited.
5. Bad water management:
Due to bad water management and ignorance, a lot of water is lost.
6. Evapo-rational loss:
The water stored in large reservoirs undergo evaporation and due to such process, a lot of water is lost.
7. Loss by seepage:
During the passage of water in long canals a part is lost due to seepage.
8. Dumping of pollutants:
The usability of the available water decreases with dumping of different pollutants in water bodies.
9. Siltation of bodies of water:
The degradation of vegetational cover in the hills and catchment areas, there is siltation of water bodies.
Management of water resources:
In order to avoid water stress and water scarcity, the following steps should be taken for the better management of water resources.
(i) Treating and recycling of municipal waste water effluents of industries and sewage for agricultural use.
(ii) Effective rain water harvesting in urban and rural areas.
(iii) Maintaining river systems effectively without disturbing their original paths.
(iv) Constructing small water reservoirs instead of big dams.
(v) Protection of wet lands.
(vi) Preventing over exploitation of ground water.
(vii) Checking overgrazing and deforestation.