What is Rainwater Harvesting (RWH)?
“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."

Water requirements and Usage by a family. (in India)
Biggest usage takes place while flushing the toilet with pure drinking water, Gardening, Vehicle Servicing,etc.

Water Usage in the Urban City

WHY IT IS 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.

Benefits of rainwater harvesting

• 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 where...

• 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

System 1 - Roof top Rain water harvesting

• Roof top water collection
  Clean the roof first. Avoid keeping chemicals and other harmful materials. If there are nearby trees, clear the fallen leaves everyday particularly during the rainy season. The roof top of the Site is about 1000 sq feet then annually – (tenure of 55 days x 24 hrs) u can have around 94,900 liters of rain water.
   
• Drain pipe brings the water down
  There are 3 drainpipes that bring the roof water down at the Site. These drain pipes are typically 4” diameter in size and capable of 6 Kg of water pressure.
   
• First flush
  The first few liters of collected water when it starts raining may contain leaves and other contaminants. We try not to use this water. Once this section of the pipe is full, the excess overflows to the filter
   
• Filter
  The filter chamber is filled upto 1/3 its volume with 4 layers of different aggregates in between. After this filter, the water flows to the sump. Each drainpipe may have its own filter chamber or a group of drainpipes may share a filter chamber.
   
• Sump
  Rain Water flows from the filter chamber to the sump. Sump stores water for immediate consumption. With an existing motor you can pump this water to the overhead tank. Given the rainfall pattern in Bengaluru, you cannot design a sump large enough to hold water for the entire year. Most of the houses/flats in Bengaluru will have sumps for collecting Municipal / Bore well water.
   
• Dug Well
  The harvested rain water that overflows the sump / directly taken to the dug / open well, which percolates to the underground as well.

System 2 - Surface water harvesting

All the rainwater that falls around the house in open spaces can be harvested. Most house Pavements are designed to flow the water away from the house. If your house surface  area is covered with cement pavement, do not despair. We can collect all the water at the gate and recharge the underground.

Step 1. Collect

At the Site, the surface water flows to the gate.  There is 3.5 feet long, 1 feet deep gutter with a Reinforced concrete slab with holes. Inside the gutter there are pebbles. A small bump on the roadside just next to the gutter can make sure that no water flows to the street.

Step 2. Recharging well

Water from the gate gutter is taken to the recharge well. The recharge well is 3 feet in diameter, 10 feet in depth. The purpose of the recharge well is to collect the vast amount of water collected quickly when it rains. The depth of the recharge well corresponds with the depth of the clay soil layer. There is no filter media inside the recharge well. If you already have a working well, try to direct the water from the gate to the well.

Step 3. Percolation pit

Percolation pit is used if enough space for a recharge well does not exist. The percolation pit is about 2’ X 2’ X 2’. There is a bore well with a PVC pipe of 6” diameter and 10 feet depth. In a large house, you can put a number of percolation pits all around house. The percolation pit at the centre.

Percolation Pit

Recharging the Hand Pump

Recharging Abandoned Well

Percolation Pit

Storage cum Percolation Pit

Recharging Bore well Pattern

Recharging Bore Well

Recharging Bore well / Percolating system

Our profile includes as a RWH System Consultant & Implementer :

• Rain Water Harvesting & Ground Water Recharging works and Ground Water Development.
• Implementation of the recharge structures as given in the Consultancy report.
• Monitoring of Water Level.    
• Monitoring of Ground Water Quality.
• Ensuring proper maintenance and services for efficiency of the    constructed recharge structures.
• Conducting workshop for generating awareness on the subject matter.