Water resources planning

WATER RESOURCES PLANNING

Water resources planning or management involves the development, control, regulation, protection, and beneficial use of surface and ground water resources. Water resources development and management have to plan for better utilization of water. The methods are,

• Inter-basin transfer

• Artificial recharge of ground water

• Desalination of brackish sea water

• Roof-top rain water harvesting

• Watershed management

Inter-basin transfer

Inter-basin, transfer refers to man-made conveyance schemes which move water from one river basin where it is available, to another basin where water is less available. The purpose of such schemes is to lessen water shortages in the receiving basin, to generate electricity, or both. There are dozens of large inter-basin transfers around the world, most of them concentrated in Australia, Canada, China, India and the United States.

Artificial recharge of ground water

Artificial recharge is the planned increase of groundwater levels using suitable civil construction techniques. It is the process of using water on the land (i) to increase the infiltration through the soil and percolation to the aquifer or (ii) to inject water by wells directly into the aquifer. Its basic purpose is to restore supplies from aquifers depleted due to excessive ground water usage.

Artificial recharge techniques address the following issues that in

(i) To restore supplies from aquifers depleted due to excessive ground water usage.

(ii) To conserve and store excess surface water for future requirements.

(iii) To improve the quality of existing ground water through dilution.

(iv) To remove bacteriological and other impurities from sewage and waste water so tha water is suitable for re-use.

When low quality water is used for recharge, the underground formations can act as natural filters to remove many physical, biological, and chemical pollutants from the water as it moves through. Often, the quality improvement of water is actually the main objective of recharge. The system is operated specifically using the soil and the aquifer to provide additional treatment to the source water. Systems used in this way are called soil-aquifer treatment (SAT), or geopurification systems.

Desalination of brackish sea water

Water seems to be a superabundant natural resource on the planet earth. However, only 0.3 per cent of the world's total amount of water can be used as clean drinking water. Huge amounts of drinking water are required every day. As natural fresh water resources are limited, sea water plays an important part as a source for drinking water. :

In order to use sea water, it has to be desalinated. Reverse osmosis and electro-dialysis are the preferred methods for desalination of brackish sea water.

Roof-top rain water harvesting

In urban areas, the roof top rain water can be conserved and used for recharge of ground water. This approach requires connecting the outlet pipe from roof top to divert the water to either existing well/tube wells/bore wells or specially designed wells/ structures. The urban housing complexes and institutional buildings have larger roof area. Hence, they can be utilized for harvesting the roof top rain water to recharge aquifers in urban areas.

Watershed management

Watershed management is carried out through the following methods:

• Soil conservation: This includes a variety of methods used to reduce soil erosion, to prevent depletion of soil nutrients and soil moisture, and to enrich the nutrient status of soil.

• Catchment area treatment: This involves treating the degraded areas of the catchment areas and forestation of catchment area.

• Construction of check-dams: Check-dams are small barriers built across the direction of water flow on shallow rivers and streams for the purpose of water harvesting. The small dams retain excess water flow during monsoon rains in a small catchment area behind the structure. Pressure created in the catchment area helps force the water into the ground.

The major environmental benefit is the replenishment of nearby groundwater reserves and wells. The water entrapped by the dam, surface and subsurface, is primarily intended for use in irrigation during the monsoon and later during the dry season. It can also be used for livestock and domestic needs.

 

1. WATER ALLOCATION PRIORITIES

Water allocation priorities for planning and operation of water resource systems are as follows:

Drinking water

Adequate safe drinking water facilities should be provided to the entire population both in urban and in rural areas. Irrigation and multipurpose projects should invariably include a drinking water component, wherever there is no alternative source of drinking water. Drinking water needs of human beings and animals should be the first priority on any available water.

Irrigation

Irrigation is the application of water to soil to assist in the production of crops. Irrigation water is supplied to supplement the water available from rainfall and ground water. In many areas of the world, the amount and timing of the rainfall are not adequate to meet the moisture requirements of crops. The pressure for survival and the need for additional food supplies are causing the rapid expansion of irrigation throughout the world.

Hydropower

Hydropower is a clean, renewable and reliable energy source. Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy. Hydroplants range in size from "micro-hydros" that power only a few homes to giant dams like Hoover Dam that provide electricity for millions of people.

Industrial demand of water

Industrial water consumption consists of a wide range of uses, including product-processing and small-scale equipment cooling, sanitation, and air conditioning. The presence of industries in or near the city has a greater impact on water demand. The quantity of water required depends on the type of industry. Thermal power plants, textile, chemical, paper and pulp, gasoline and oils, and iron and steel industries need maximum water.

Navigation

Navigation is the type of transportation of men and goods from one place to another place by means of water. The development of inland water transport or navigation is of crucial importance from the point of energy conservation as well.