2. .ppt (2)
1. WHAT IS RAINWATER HARVESTING?
2. WHY RAINWATER HARVESTING?
3. HOW TO HARVEST RAINWATER?
4. DESIGN CONSIDERATIONS
5. STORAGE
6. RWH-METHODOLOGIES
7. OPERATIONAL PROCEDURES
3. .ppt (3)
RWH technology consists of simple systems to collect, convey, and
store rainwater. Rainwater capture is accomplished primarily from roof-
top, surface runoff, and other surfaces.
RWH either captures stored rainwater for direct use (irrigation,
production, washing, drinking water, etc.) or is recharged into the local
ground water and is call artificial recharge.
In many cases, RWH systems are used in conjunction with Aquifer
Storage and Recovery (ASR). ASR is the introduction of RWH collected
rainwater to the groundwater / aquifer through various structures in
excess of what would naturally infiltrate then recovered for use.
4. .ppt (4)
Why Rainwater
Harvesting?
>Conserve and supplement existing water resources
>Available for capture and storage in most global locations
>Potentially provide improved quality of water
>Supply water at one of the lowest costs possible for a
supplemental supply source.
>Capturing and directing storm water (run-off) and beneficially
use it
>Commitment as a corporate citizen - showcasing
environmental concerns
>Public Mandate (India)
>Replenishing local ground water aquifers where lowering of
water tables has occured
6. .ppt (6)
Rain Water as Source Water
Design Considerations
1 Roof
2 Screen
3 Discharge of water
4 Pre-filter
5 Storage tank
6 Flow meter
7 Storm water discharge
7. .ppt (7)
Storage
• Storage devices may be either above or below ground
• Different types include
Storage Tanks
Water Containers
Lagoons or Lined Ponds
Infiltration Ponds
• Size based on rainfall pattern, demand, budget and area
8. .ppt (8)
•Roof Rain Water Harvesting
• Land based Rain Water Harvesting
• Watershed based Rain Water harvesting
• For Urban & Industrial Environment
• Roof & Land based RWH
• Public, Private, Office & Industrial buildings
• Pavements, Lawns, Gardens & other open spaces
The collection device usually represents the biggest capital investment of an RWH system. It therefore requires careful design- to provide optimal storage capacity while keeping the cost as low as possible.
While above-ground structures like tanks are easily purchased or made with a variety of designs, and water extraction is in many cases by gravity; they also are expensive, require more space and are prone to attack from the weather.
Below-ground structures like cisterns, lagoons etc. are generally cheaper due to lower material requirements and unobtrusive. However, water extraction often requires a pump, contamination is more common, and present a potential danger to children and small animals if left uncovered.