Why Rain Water Harvesting?
Water supply in urban area is always short against the total demand. Surface water is inadequate to meet our demand and we have to depend on ground water. Due to rapid urbanization, infiltration of rainwater into the subsoil has decreased drastically and recharging of ground water has diminished. This scenario requires an alternative source to bridge the gap between demand and supply. Rainwater, which is easily available and is the purest form of water, would be an immediate source to augment the existing water supply by “catching water wherever it falls”.
Rainwater Harvesting has emerged as a viable alternative to traditional perennial sources of water in hilly areas, in places where the level of fluoride and arsenic is above permissible limits and in urban areas facing water shortage and flooding during monsoons.
Traditional Water Harvesting in Hyderabad city underlines the importance of step wells, lakes, tanks, channels etc., as water storage bodies, the basic purpose of which was to establish a chain of water storage structures. However, a vanishing “Lake Culture” due to urbanization and industrialization has caused these systems to be neglected.
Need for rainwater harvesting
Water harvesting is an activity of collection of rainwater and storing in containers for direct use or can be recharged in to the ground.
- 1.As water is becoming scarce, it is the need of the day to attain self-sufficiency to fulfill the water needs
- 2.As urban water supply system is under tremendous pressure for supplying water to ever increasing population
- 3.Groundwater is getting depleted and polluted
- 4.Soil erosion resulting from the unchecked runoff
- 5.Health hazards due to consumption of polluted water
Rainwater Harvesting (RWH) is the process of collecting and storing rainwater in a scientific and controlled manner for future use. Rainwater Harvesting in urban areas include
- 1. Roof top rainwater harvesting
- 2. Rainwater harvesting in paved and un-paved areas (open fields, parks, pavement landscapes etc.)
- 3. Rainwater Harvesting in large areas with open ponds, lakes, tanks etc.
Quality of rainwater harvested
- 1. As the primary source of water, rainwater is the purest form of water. Rainwater harvesting not only solves the problem of availability of water, but also provides good quality water.
- 2. However, certain precautions need to be taken to ensure that the stored water is not polluted.
- 3. Keep the roof or the water collection area clean before the rains.
- 4. Flush the rainwater collected in the first few minutes.
- 5. Store the collected rainwater in a closed container (avoid sunlight).
- 6. The quality of water deteriorates in the presence of sunlight and air.
- 7. Water can be kept clean over a period of five to six months in a clean container stored in an enclosed area protected from sunlight.
RWH has the following unique advantages
- 1. Capturing rainwater in-situ and augmenting supply water at a marginal cost
- 2. Replenishing groundwater through recharging of rainwater by using the soil column, Increase in ground water level, Mitigates the effects of drought.
- 3. Reducing pollution and contamination, Improves the ground water quality.
- 4. Reducing the water bill for the state exchequer
- 5. Providing clean and safe water
- 6. Least capital investment with maximum benefits to households and Reduces electricity bills
- 7. Reduces the runoff, which other wise flood storm water drains.Reduces flooding of roads and low-lying areas, Reduced soil erosion.