Rainwater Harvesting Basics

Gathering or accumulating rain-water and storing it for multiple uses is rainwater harvesting. This method is also implemented to provide drinking water for domestic use, irrigation and re-charging ground water. Rain water collected from the roof-tops during rain is significant and very economical for further usage. If not conserved, it is lost to the atmosphere through evaporation. A huge down-pour causes soil erosion, you can prevent it by channeling the rain water in the ground. Rain water can be stored either in the ground or on the roof depending on the space and method used.

Roof-Top Rain Water Harvesting

Natural and man made water tanks are very effective in storing water. Man made ponds and lakes can be used for conservation of water. Simple design techniques can be employed to provide an adequate slope from the collecting area to storage with reduced ground water absorption. Elevated tanks to collect rain water can be installed. The barrels or storage tanks are specifically designed to store potable water and are ultra-violet stabilized to prevent it from cracking when placed in the sun. Alternatively for ground storage, the outlet pipe from the roof of the house can be diverted to wells, tube wells or bore wells. The pipelines or conduits carry rainwater from the catchment or rooftop area and are made of materials commonly available like polyvinyl chloride (PVC) or galvanized iron (GI).

Cleaning the Rain Water

Rain water gets contaminated due to the force of the wind and has tendency to collect dry leaves, twigs, plastic and atmospheric pollutants. For treatment of the rain water, it is first stored into a temporary storage called recharge-well, located close to the destination well or tank. A filter with gravel, sand and mesh is used to remove floating impurities. This filter has to be cleaned regularly. The rain water is taken through an additional bore on the land and led into the water strata for removing impurities. Care should be taken to prevent the rainwater linking to the underwater drainage system.

Using Home Made Filter for Rain Water Purification

Home made sand water filter is easier to build and cost effective. The collected rain water has to be slowly flowed through several layers for purification in order. Here is an outline of the various layers -

 

• Place a layer of stones or medium size clean boulders.
• Place a second layer over the first one with big jelly stones.
• Place a third layer over the second one with small jelly stones.
• Place a fourth layer of charcoal.
• Repeat the process by placing a fifth layer comprising of big jelly stones.
• Place a sixth layer again of small jelly stones.
• Over that place a seventh layer of nylon curtain.
• Place eighth layer of sand at the top.

 

Overall this home made filter has eight layers. The contents of the various layers of the filter should be changed after five years. Bird excreta, organic matter and any other external impurities are treated by charcoal. You can also treat the water with alum for additional purification. Alum is cheap and available at any chemist's drugstore. It removes germs, ptomaines and organic matter very efficiently. The purified water should be stored in a special tank that can withstand sun and reaction with external atmospheric conditions.

Rain water harvesting for the Herb Garden

Design and plan small drainages to the outdoor herb garden from the storage tank. Water tanks and barrels come with taps. You can connect the tap to the pipe and let go the water in the neatly arranged plant rows in your herb garden. For indoors, use a water can or sprinkler to water the herbs. Water is the hub of life and elixir for the plant. Conserve and recycle water, your herb garden will bloom with beautiful flowers and dense foliage with rain water harvesting.