What is Rain Harvesting?

 

“CAPTURE RAIN WATER, STORE IT AND USE IT – IT IS AS SIMPLE AS THAT”.

   “Collect the rain water falling on house Roof tops, collection ponds, lakes, open areas with natural grading. Rain water is  naturally pure (except due to industrial pollution it becomes acid rain). Ground water could be saline."

The concept of RWH lies in tapping the rain water where it falls. A major portion of rain water that falls on the surface runs off from streams to river and finally into sea. An average of 8% of the total rainfall recharges the ground water aquifers.

Therefore most of the rainwater goes waste in the form of surface run off. The technique of rainwater harvesting involves catching the rain from localized catchments surfaces such as roof of a house, plain and sloping ground surface etc. the rain water that falls on these catchments is diverted into dugout pond, vessels or underground tanks to store for long periods.

In general RWH is the activity of direct collection of rain water which can be stored for direct use or can recharge into the ground water.

Why Rain Water Harvesting Required?

• To meet ever increasing demand for water in urban area.
• To reduce the runoff, which is choking the storm drains.
• To avoid the flooding of roads.
• To augment the ground water
• To reduce the ground water pollution.
• To improve the quality of ground water.

Rain is the first and primary source of water for us. River, lakes and ground water are all secondary sources of water in present times we depend mainly on such secondary sources of water in the process, it is forgotten that rain is the ultimate source that feeds all secondary source.

Water crisis occur only because effective collection and storage of rain water has been ignored.  The potential of rain to meet water demands are tremendous. Unless people are taught and involved in conserving rain water it would be difficult to meet the looming water crisis.

All local municipal bodies have understood its importance and have started marking RWH compulsory for all new projects and for existing old projects all Societies that have done RWH a rebate in the Municipal tax are provided.

How to do Rain Water Harvesting ?

Rainwater is considered the heaviest water available on earth since it has hardly any T.D.S. Bad water (example Sea Water) is counted as lightest water because it has very high TDS (over 40,000 mg/l). Rainwater is peculated into the subsoil, the bad water in and around rain water harvesting zone are driven away and rain water immediately replaces and occupies its place.

Due to this change in the subsoil the resultant is that after every rainy season the water quantity in one RWH will increase anywhere between 5,000 liters to 7,000 liters seasonally and its quality would be equivalent to the water supplied by corporation in parameters. This helps in saving a lot of money by becoming tanker free for which the quality of water and the frequency of supply is not known. It also helps in reducing the monthly water bill, reduce the demand on municipal water supply.

Benefits of Rain Water Harvesting ?

• 24 Hours or 365 days water supply for secondary use
• Reduces water bill
• Increase hygiene as water will not be stagnant at one place
• Increase ground water table
• Reduces storm water discharge
• Discount on Municipal Tax
• RWH helps in reducing flooding, erosion and contamination of surface water with sediments, fertilizers and pesticides in rainfall run offs
• Can supplement other sources of water supply such as groundwater or municipal water connections
• Ability to build or farm in areas with no other water supply
• High quality water - pure, free of chemicals
• Lower water supply cost
• Reduced flood flows and hence reduced topsoil loss
• The structures required for harvesting the rainwater are simple, economical and eco-friendly.

RWH is most suitable on...

• Groundwater is scarce
• Groundwater is contaminated
• Terrain is rugged or mountainous
• Seismic & flooding events are common
• The aquifer is at risk of saltwater intrusion
• Population density is low
• Electricity & water prices are rising
• Water is too hard or mineral laden

Cover inlets and drains with iron mesh