Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

RAIN WATER HARVESTING

155 views

Published on

Water: water is renewable resource. Three- fourth of surface is covered with water but only a small proportion of it accounts for freshwater fit for use.
Some facts about water
Only 2.5% of the world’s water is fresh water and most of this are in the form of polar ice-caps.
Water use as increased by 70% since 1970.
A recent report by credit issues stated that by 2025 18 will
countries experience water demand beyond supply capabilities.


Published in: Education
  • Be the first to comment

RAIN WATER HARVESTING

  1. 1. Water: water is renewable resource. Three- fourth of surface is covered with water but only a small proportion of it accounts for freshwater fit for use. Some facts about water Only 2.5% of the world’s water is fresh water and most of this are in the form of polar ice- caps. Water use as increased by 70% since 1970. A recent report by credit issues stated that by 2025 18 will countries experience water demand beyond supply capabilities.
  2. 2. Life is possible on earth due to the presence of water. Nearly three-fourths of the earth's surface is covered with water. Water is also found below the earth's surface. It is present in air in the form of water vapor. About 70 per cent of the human body is water. The bodies of all plants and animals contain water.
  3. 3. In the past few years, there was not even enough rain. Everything had dried up there. There was no water for drinking, for growing crops, or for animals. People had to leave their village and go to nearby towns for some work. During dry and hot weather periods, it is common to find dry and cracked earth without even a single shed of water or wet areas. Lakes, rivers, and streams may as well run dry. Well, these are the typical earth conditions that define drought.
  4. 4. Introduction: Harvesting Rainwater for saving drinking water has gained enormously in significance as modern water saving sanitary technique. This can be used for private and public buildings as well as for many industrial areas. Due to the storage (retention) and the usage of rainwater the water flowing off housing estates in both reduced and delayed
  5. 5. What is Rainwater Harvesting ? Water is our most precious natural resource and something that most of us take for granted. We are now increasingly becoming aware of the importance of water to our survival and its limited supply, especially in such a dry continent as Australia.
  6. 6. Why is it Important? The harvesting of rainwater simply involves the collection of water from surfaces on which rain falls, and subsequently storing this water for later use. Normally water is collected from the roofs of buildings and stored in rainwater tanks. This is very common in rural Australia. Water can also be collected in dams from rain falling on the ground and producing runoff.
  7. 7. Methods of Rainwater Harvesting Broadly there are two ways of harvesting rainwater. •Surface runoff harvesting •Roof top rainwater harvesting
  8. 8. Surface runoff harvesting In urban area rainwater flows away as surface runoff. This runoff could be caught and used for recharging aquifers by adopting appropriate methods.
  9. 9. Roof Top rainwater harvesting •It is a system of catching rainwater where it falls. In rooftop harvesting, the roof becomes the catchments, and the rainwater is collected from the roof of the house/building. It can either be stored in a tank or diverted to artificial recharge system. •This method is less expensive and very effective and if implemented properly helps in augmenting the ground water level of the area.
  10. 10. Components of the roof top rainwater harvesting The illustrative design of the basic components of roof top rainwater harvesting system is given in the typical schematic diagram.
  11. 11. Components of roof top rainwater harvesting system •Catchment •Transportation •First flush •Filter •Storage •Usage •Recharge
  12. 12. Catchment • The surface that receives rainfall directly is the catchment of rainwater harvesting system. •It may be terrace, courtyard, or paved or unpaved open ground. The terrace may be flat RCC/stone roof or sloping roof. •Therefore the catchment is the area, which actually contributes rainwater to the harvesting system.
  13. 13. Transportation •Rainwater from rooftop should be carried through down take water pipes or drains to storage/harvesting system. •Water pipes should be UV resistant (ISI HDPE/PVC pipes) of required capacity. •Water from sloping roofs could be caught through gutters and down take pipe. •At terraces, mouth of the each drain should have wire mesh to restrict floating material.
  14. 14. Gutters •Gutters are channels all around the edge of a sloping roof to collect and transport rainwater to the storage tank. •A carefully designed and constructed gutter system is essential for any roof catchment system to operate effectively. •When the gutters are too small considerable quantities of runoff may be lost due to overflow during storms. •The size of the gutter should be according to the flow during the highest intensity rain. It is advisable to make them 10 to 15 per cent oversize.
  15. 15. First Flush •First flush is a device used to flush off the water received in first shower. The first shower of rains needs to be flushed-off to avoid contaminating storable/rechargeable water by the probable contaminants of the atmosphere and the catchment roof.
  16. 16. Filter •There is always some skepticism regarding Roof Top Rainwater harvesting since doubts are raised that rainwater may contaminate groundwater. • There is remote possibility of this fear coming true if proper filter mechanism is not adopted.
  17. 17. Storage Harvested rain water can be stored in sub-surface ground water reservoir by adopting artificial recharge techniques to meet the household needs through storage in tanks.
  18. 18. Recharge structures Rainwater may be charged into the groundwater aquifers through any suitable structures like dug wells, Bore wells, recharge trenches and recharge pits.
  19. 19. Advantages of RWH RWH systems provide water at or near the point where water is needed or used.  Rainwater is relatively clean and the quality is usually acceptable for many purposes with little or even no treatment.  System is independent and therefore suitable for scattered settlements.  Local materials and craftsmanship can be used in construction of rainwater system.  Ease in maintenance by the owner/user  Provides a water supply buffer for use in times of emergency or breakdown of the public water supply systems.
  20. 20. Disadvantages of Rainwater Harvesting. 1. Unpredictable Rainfall: Rainfall is hard to predict and sometimes little or no rainfall can limit the supply of rainwater. 2. It is not advisable to depend on rainwater alone for all your water needs in areas where there is limited rainfall.
  21. 21. Rain water harvesting is a technique of collection and storage of rainwater into natural reservoirs or tanks, or the infiltration of surface water into subsurface aquifers (before it is lost as surface runoff). One method of rainwater harvesting is rooftop harvesting
  22. 22. Water is a limited resource. What each of us does in the world, how we live, does make a difference. As we learn the value of clean, safe water and how scarce it truly is, we can take steps to protect it and to get it to people who lack access today. Did you know that nearly 1 billion people, mostly in the developing world, have no access to safe water? More than double this number - about 2.4 billion - have no access to any form of improved sanitation facilities. They could use your help to get it.
  23. 23. How to save water: 10 tips for saving water around the home The majority of household water use comes from toilets, washing machines, showers, baths, faucets and leaks, but what you can do to save water is fairly simple. These 10 water-saving tips will put you on the path to conserving water in your house hold. Turn off the tap while brushing your teeth. Turn off the tap while washing your hands. Fix your leaks. Re-use your pasta cooking liquid. Don’t run the dishwasher or washing machine until it’s full. Flush with less. Water outdoor plants in the early morning. Use less electricity. Skip the shower from time to time

×