Need for Rainwater Harvesting
Rainwater Harvesting is the collection and storage of rain,Water is perhaps the most fundamental prerequisites for the presence of living creatures. Surface water and groundwater are two significant wellsprings of water. Because of overpopulation and higher utilization levels of water in metropolitan regions, water supply offices are incapable to adapt to request from surface sources like dams, stores, streams, and so forth This has prompted the burrowing of individual cylinder wells by house proprietors. Indeed, even water-supply offices have depended on groundwater sources by diving tube-wells all together to increase the water supply. Renewal of groundwater is radically decreased because of the clearing of open zones. Unpredictable abuse of groundwater brings about bringing down of water table delivering many bore-wells dry. To defeat the present circumstance bore wells are penetrated to more noteworthy profundities. This further brings down the water table and in certain territories, this prompts a higher grouping of risky synthetics, for example, fluorides, nitrates, and arsenic. In seaside territories like Chennai, overexploitation of groundwater brought about seawater interruption consequently delivering groundwater bodies saline. In country regions additionally, government strategies on the sponsored power supply for rural siphons and channeled water supply through bore wells are bringing about a decrease in the groundwater table. The answer for every one of these issues is to recharge groundwater bodies with rainwater by man-made methods.
Advantages of rain water harvesting
- Promotes adequacy of underground water
- Mitigates the effect of drought
- Reduces soil erosion as surface run-off is reduced
- Decreases load on storm water disposal system
- Reduces flood hazards
- Improves ground water quality / decreases salinity (by dilution)
- Prevents ingress of sea water in subsurface aquifers in coastal areas
- Improves ground water table, thus saving energy (to lift water)
- The cost of recharging subsurface aquifer is lower than surface reservoirs
- The subsurface aquifer also serves as storage and distribution system
- No land is wasted for storage purpose and no population displacement is involved
- Storing water underground is environment friendly
Annual water harvesting potential
Consider a building with flat terrace area (A) of 100 sqm located in Delhi. The average annual rainfall (R) in Delhi is approximately 611mm. The runoff coefficient (C) for a flat terrace may be considered as 0.85.
from 100 m2 roof = A x R x C
= 100 x 0.611 x 0.85
= 51.935 cum
= 51, 935 liters
Rainwater storage Arrangements
The minimum capacity of the storage tank
- Office/Business – 50 litres/sq.m of floor area
- Educational – 50 litres/sq.m of floor area
- Medical/Hospital – 50 litres/sq.m of floor area
- Assembly – 50 litres/sq.m of floor area
Frequently asked questions
Most frequent questions and answers
What is rainwater harvesting ?
The process of collecting this water after rain for use for productive purposes is called rainwater harvesting. In other words, rainwater harvesting is the process of collecting rainwater falling on your roof in a normal way and purifying it.
Why Rain Water Harvesting is Necessary ?
Today, lack of quality water has become a cause of concern. Although pure and good quality rainwater runs out very quickly. But if it is collected then water crisis can be controlled. In view of the current water crisis, this is the only option left by which we can get a solution to the water crisis.
What is the suitable location for Rain Water Harvesting ?
Generally, rainwater harvesting can be done anywhere, but for this those places are very suitable where the flow of water is fast and the rainwater flows away quickly. This type of rainwater harvesting is suitable for the following locations: 1. Low groundwater sites, 2. Contaminated groundwater sites, 3. Hilly/heterogeneous water sites, 4. Drought or flood affected sites, 5. Polluted water sites. , 6. Sites with low population density, 7. Sites with high mineral and salt water, and 8. Sites with expensive water and electricity,
What What is the use of rain water harvesting ?
Generally rain water is pure water and it can be used for all works, however its use is completely suitable for the following tasks:
1. Cleaning of utensils, 2. Bathing and washing clothes, 3. Toilet work etc., 4. for irrigation, 5. for drinking, bathing etc. for cattle, and 6. industrial work, after checking the quality of rain water, if found suitable, it can also be used for drinking water and cooking.
What is the surprising truth of rainwater harvesting ?
The International Water Institute has described the rainwater received from the roof as better than the water received from other sources. According to the report of the chemical lab, this water is free from all kinds of harmful salts. It also does not contain harmful bacteria and its pH is low. The value is also the ideal 6.95. The pH value shows how natural and normal the water is. Water with a pH value between 6.5 and 8.5 is considered fit for normal use.
Rainwater Conservation Measures
Following measures can be taken to store rainwater. Through these measures, the falling water level inside the ground can be raised.
- Directly underground: Under this method rainwater is discharged directly into the ground water reservoir through a pit.
- Recharging by making a trench: In this method, water is lowered underground by making large drains (recharge trenches) along with the boundary wall in the campuses of large institutes. This water goes down into the ground and helps in maintaining balance in the ground water level.
- Unloading water in wells: Rainwater is discharged from the roofs of the houses through pipes into a well in or near the house. In this way not only is the well recharged, but the water from the well also goes underground. This water raises the groundwater level inside the ground.
- Unloading water into tubewells : Rainwater is stored on the roof of buildings and directly discharged into the tubewell through a pipe. In this it becomes necessary to install a filter between the pipe connecting the tubewell to the ceiling. Due to this, the water of the tubewell always remains the same.
- Storage in the tank : Apart from recharging the ground water reserves, rainwater can be stored in the tank to meet our daily needs. By this method rain water can be used for a long time.
