Solar heat evaporates water into the air from the Earth's surface. Land, lakes, rivers and oceans send up a steady stream of water vapour. Condensation then occurs higher up in the atmosphere, whereby water vapour turns into tiny droplets of water and thereafter clouds form. The clouds then precipitate.
Following are the two important approaches to water conservation
Rain is the major source of water to the surface of earth. Part of the rain water percolates to soil and add to the ground surface that is ultimately lost to the oceans this is called surface run water
Collecting rain water by different method & minimizing its loss through surface run-off is called rain water harvesting.
Surface water is adequate to meet our demand and we have to depend on ground water.
Due to rapid urbanization infiltration of rain water into the sub – soil has decreased drastically and recharging of ground water has diminished.
Over – exploitation of ground water resources has resulted in declined in water levels in most part of the country.
To enhance availability of ground water at specific place and time.
To arrest sea water ingress.
To improve the water quality in aquifers.
To improve the vegetation cover.
To raise the water levels in wells & bore wells that are drying up.
To reduce power consumption.
The components of a typical urban rainwater harvesting system are as follows :
Roof Water Harvesting Rooftops of houses are excellent collection centers for rainwater. If properly diverted from rooftops and used for artificial recharge, rainwater will augment the groundwater table to a sufficient extent In Roof water Harvesting, the roof is connected to the well through a network of pipes and filtering system Rainwater that lands on roofs and elevated platforms is likely to be contaminated by foreign elements, such as dust, leaves and bird droppings. These foreign elements can be prevented from entering the well by flushing
It is an hand bore made in the soil with the help of anaugar and filled up with pebbles and river sand on top. The depth of these pits will be between 4 to 9mts depending upon the nature of the soil .if the soil is clayey the pit has to be dug to depth till a reasonably sandy stratum is reached . These pits will be 25cm a square /circular collection chamber will still arrestor is provided at the top.
DCB is a type of percolation pit with a large chamber and deeper in well bore. If necessary, more than one shaft is installed in the same recharge well. Conventional filter media is used to filter the recharge water. Coir packing can also be provided to achieve maximum efficiency in filtering the recharge water. If the area is prone to flooding, it is advisable to provide necessary air vent to the DCB
MAAS is a unique artificial recharge structure, which is ideally suitable for open areas, particularly low-lying areas. Besides open areas, this structure is suitable for junctions of roads; street corners; parks; stadiums; playgrounds; bus terminuses; theatres; and open areas of public buildings, schools and colleges.
It provides an essential reserve in times of emergency and/or breakdown of public water supply systems, particularly during natural disasters.
· The construction of a rooftop rainwater catchments system is simple, and local people can easily be trained to build one, minimizing its cost.
Helps to conserve ground water .
Saves money & energy.
Minimize urban flooding .
Provides control over water source.
Inexpensive & simple technology .
Disadvantages of rain water harvesting The success of rainfall harvesting depends upon the frequency and amount of rainfall; therefore, it is not a dependable water source in times of dry weather or prolonged drought. · Low storage capacities will limit rainwater harvesting so that the system may not be able to provide water in a low rainfall period. Increased storage capacities add to construction and operating costs and may make the technology economically unfeasible, unless it is subsidized by government.
Maintenance Tips for Rainwater harvesting structures .
Always keep the surroundings of the tank clean and hygienic. Remove Algae from the roof tiles and asbestos sheets before the monsoon.
Drain the tank completely and clean from inside thoroughly before the monsoon.
Clean the water channels (gutters) often during rainy season and definitely before the first monsoon rain.
Avoid first 15 or 20 minutes of rainfall depending on the intensity of rain. Use the first flush arrangement to drain off this first rainwater.
Change the filter media every rainy season Cover all inlet and outlet pipes with closely knit nylon net or fine cloth or cap during non-rainy season to avoid entry of insects, worms and mosquitoes.
Why is watershed management planning important?
Watershed management planning provides opportunities for communities to address water quality and habitat issues within the physical boundaries of a watershed rather than political boundaries. It is an inclusive approach to support environmental protection, quality of life issues, and economic development —using the watershed as a holistic planning framework.
Soil management techniques: Tillage during the off-season or in pre-rainy season helps with rain water intake by breaking the hard soil and making the soil surface more permeable. This allows water to seep to the deeper soil layers and keeps the soil wet for longer time. The result is the soil will have more moisture during sowing the crop. Tillage also controls weeds which depletes the soil moisture. Off-season tillage also destroys the offs, cocoons and larvae of some pests by exposing them to the sun which otherwise affect the already stressed crop plants.
Crop management techniques : Avoid growing of drought prone crops like maize, cotton etc. Growing drought resistant grain crops like sorghum, pearl millet, finger millet, fox tail millet etc. Growing drought resistant legume crops like pigeon pea, green gram, horse gram etc. Growing of oil seed crops like castor, sunflower, Niger, sesame, safflower etc.
Intercropping systems Intercropping refers to growing more than one crop in the same land area in rows of definite proportion and pattern. Intercropping system provides insurance against total crop failure in drought prone areas .
Surface Mulching: Surface mulching either by timely inter cultivation or by covering the soil surface with plant residues benefits the crops Reduce water evaporation from soil Reduces water runoffs from the cropped fields. Help control weeds. Adds organic matter to the soil and improves soil quality .
Use soaker hoses or drip irrigation wherever possible.
Practice Xeriscaping. This method of landscaping uses plants which are native to your area or are naturally drought resistant.
Replace grasses with groundcover whenever possible. Groundcover requires much less water than lawn grasses do.
How as infrequently as possible, and when you do mow set the mower on its highest setting. Cutting the grass too short causes stress when the summer heats up forcing the roots to work harder and use more water .
Conserving water can extend the life of your septic system by reducing soil saturation, and reducing any pollution due to leaks. Overloading municipal sewer systems can also cause untreated sewage to flow to lakes and rivers. The smaller the amount of water flowing through these systems, the lower the likelihood of pollution. In some communities, costly sewage system expansion has been avoided by communitywide household water conservation.
The most important step in the direction of finding solutions to issues of water and environmental conservation is to change people's attitudes and habits¾this includes each one of us. Conserve water because it is the right thing to do. We can follow some of the simple things that have been listed below and contribute to water conservation