Study- Rain water Harvesting in bangaluru city

INTODUCTION

Water, water everywhere but not a drop to drink indeed potable drinking water will soon be a rare commodity for all with water pollution on the rise; the day is not far when water will be sold at a premium in the world including India. It would not be an exaggeration to hold that if

ever the third world war occurs. It will be for water. The UNDP’s human development report 2006 focuses on one of the most serious problems facing humanity today. The global water cries. More than a billion people have no access to safe drinking water and nearly two million children die every year for want to clean water and sanitation facilities. The pressure on finite sources is mounting every day owning to poor water resources management high population growth. rapid urbanization and increasing demand horn competing uses for drinking agriculture, industry and

energy. Climate change is also affecting the hydrological cycle more importantly the fresh water production and its distribution. India’s huge and growing population is putting a serious strain n the country natural resources. The World Bank has repeatedly warned that India will face a

severe water crisis in 20 yrs, if the government does not change its ways,

and clashes are already taking place because the resource is so scarce.

Management system in place, its ground water is disappearing and river bodies are turning into marks hit sewers. Estimates reveal that by 2020, India’s demand for water will exceed all sources of supply even today in metro cities such as Chennai, Bangalore. Some localities relay on private water tankers for their daily water needs.

Even through the rate of urbanization in India is among the lowest in the world the nation has more than 250 million city dwellers. Experts predict that this number will rise even further and by 2020, about 50% of India’s will be living in cities. This is going to put further pressure on the already strained centralized water supply system of urban area.

The urban water supply and sanitation sector in the country is suffering from in adequate levels of service an increasing demand supply gap, poor sanitation conditions and deteriorating financial and technical problems.

In most cities centralized water supply system depend on surface water sources like rivers and lakes Chennai for instance has to bring in water from a distance of 200 km whereas Bangalore gets its water from the cauvery river, which is 95 km away, where surface water sources fail to meet the raising demand, groundwater resources are being tapped, often to unsustainable levels.

In Bangalore with a population of 5,686,000, it is India’s fifth largest city. As per the estimates of the Bangalore water supply and sewage board [BWSSB], the total demand of water is 840 million liters per day [MLD].

In order to conserve water and ensure ground water recharge, in Karnataka government in February 2009 announced that buildings, constructed in the city will have to compulsorily adopt rainwater harvesting facility. Residential sites, which exceed an area of 2400 sq ft (40 x 60), shall create rain harvesting facility according to the new law.

Rainwater harvesting is the accumulating and storing, of rainwater for reuse, before it reaches the aquifer. It has been used to provide drinking water, water for livestock, water for irrigation, as well as other typical uses given to water. Rainwater collected from the roofs of houses, tents and local institutions can make an important contribution to the availability of drinking water. It can supplement the sub soil water level and increase urban greenery. Water collected from the ground, sometimes from areas which are especially prepared for this purpose, is called Storm water harvesting. In some cases, rainwater may be the only available, or economical, water source. System of collection rainwater and conserving for future needs has traditionally been practiced in India. The traditional system was time tested wisdom of not only appropriate technology of rainwater harvesting, but also water management systems, where conservation of water was the prime concern. Traditional water harvesting system were bawaries stepwells, jharies, lakes, tanks etc. there were the water storage bodies to domestic and irrigation demands. People were themselves responsible for maintenance of water resources and optimal use of water that could fulfill their needs.

System of collection rainwater and conserving for future needs has traditionally been practiced in India. The traditional system was time tested wisdom of not only appropriate technology of rainwater harvesting, but also water management systems, where conservation of water was the prime concern. Traditional water harvesting system were bawaries stepwells, jharies, lakes, tanks etc. there were the water storage bodies to domestic and irrigation demands. People were themselves responsible for maintenance of water resources and optimal use of water that could fulfill their needs.

Rainwater harvesting systems can be simple to construct from inexpensive local materials, and are potentially successful in most habitable locations. Roof rainwater can't be of good quality and may require treatment before consumption. As rainwater rushes from your roof it may carry pollutants in it such as the tiniest bit of mercury from coal burning buildings to bird feces. Although some rooftop materials may produce rainwater that is harmful to human health, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars; these uses alone halve the amount of water used by a typical home. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 200 mm (7.9 in) per year, and no other accessible water sources (Skinner and Cotton, 1992). Overflow from rainwater harvesting tank systems can be used to refill aquifers in a process called groundwater recharge, though this is a related process, it must not be confused with Rainwater harvesting.

It is worth bearing in mind that RHW is not the definitive answer to household water problems. There is a complex set of inter-related circumstances that have to be considered when choosing the appropriate water source. These include cost, climate, hydrology, social and political elements, as well as technology, all play a role in the eventual choice of water supply scheme that is adopted for a given situation.

The reason that RHW is rarely considered is often due to lack of information-both technical and otherwise. In many areas where RWH has been introduced as part of a wider drinking water supply programme, it was at first unpopular, simply because little was known about the technology by the beneficiaries. In most of these cases, the technology has quickly gained popularity as the user realizes the benefits of a clean, reliable water at the home, the town supply is unreliable or where local water resources dry up for apart of an integrated water supply system, where often used as the sole water source for a community or household. It is a technology that is flexible and adaptable to a wide variety of conditions, being used in the richest and poorest societies on our planet, and in the wettest and driest regions of the world.

Given the current crisis in India as well as the world over, water harvesting is needed in urban and rural areas by the rich and poor and by industrialized as well as developing countries.

NEED FOR THE STUDY ON RAINWATER HARVESTING

The scarcity of water is the well known fact. In spite of higher average annual rainfall in India (1,170 mm, 46 inches) as compared to the global (800 mm, 32 inches) it does not have sufficient water. Most of the water falling on surface tends to flow away rapidly, leaving very little for the recharge. As a result, most parts of India experience lack of water for domestic uses. Surface water sources fail to meet the raising demands of water supply in urban areas; groundwater reserves are being tapped and over exploited resulting into decline in groundwater levels and deterioration quality. This precarious situation needs to be rectified by immediately recharging aquifers. With massive concreting and asphalting of ground areas, the soil exposed for rainwater infiltration has decreased, leading fall in the groundwater table and disappearance of open wells. In last 30 yrs, Bangalore has experienced five years of severe drought and three years of moderate rainfall. The quest for water has resulted in over exploitation of groundwater. On an average, the ground level has progressively declined by 10 mts between 1978 and 2003. Consequently, the quality of run-off water in the storm drains has increased tremendously. Rainwater harvesting is all about conserving this water, thereby, supplementing the present supply.

Hence, this study was undertaken to gather information regarding the advantage and disadvantage, extend of use, type of system and satisfaction derived out of rainwater harvesting installation used by selected families in Bangalore.

DEFINITION OF RAINWATER HARVESTING

According to Shagufta (2010), Rainwater harvesting is a gathering, accumulating and storing of rainwater. It has been used to provide drinking water, water for life stock and water for irrigation or refill aquifers in the process called groundwater recharge.

Hattum and Worm (2006), Opines that rainwater harvesting is a simple low coat technique that requires minimum specific expertise or knowledge and offers many benefits, collected rainwater an supplement other water source.

In the words of Anidita (2009), Rainwater harvesting is an age old method to collect rainwater on the rooftops and then using it directly or storing it for use when the rainy season is over.

According to Anisfeld (2010), the basic factors the drives dam building the need to overcome the temporal and spatial variability in rainwater has also the millennium, driven a variety of small scale, decentralized approaches and the principal behind them, have now been united under the term rainwater harvesting.

In the words of Chatterjee (2008), rainwater harvesting is a simple, economical and affordable process by which rainwater that collects or falls on roofs, terrace, cotter yards and pavements etc is directed to storage tanks or well which recharge the groundwater. The recharge technique includes collection of water and passing it through pipes and other means to groundwater table which is normally lie below the ground.

Shivkumar (2005) states that, rainwater harvesting is that process of collecting and storing rainwater in scientific and controlled manner for further use.

According to Vishwanath (2006), the collection and storage of rainwater for later productive use is defined as rainwater harvesting.

BENEFITS OF RAINWATER HARVESTING

Ø According to Shivkumar (2005), the following are some of the benefits of rainwater harvesting:

ü Environmental friendly and easy approach for water requirements.

ü An ideal solution for water requirements in areas have inadequate water resources

ü Increase groundwater level.

ü Mitigates the effects of drought.

ü Reduce the runoff, which otherwise floods storm water drains.

ü Reduces flooding of roads low lying areas.

ü Reduces soil erosion.

ü Cost effective and easy to maintain.

ü Reduces water and electricity bill.

Ø U.N Habitat, listed the following benefits of rainwater harvesting:

ü Improvement in quality of groundwater.

ü Rise in water levels wells and bore wells that are drying up.

ü Mitigating of effects of drought and attainment of drought proofing.

ü An ideal solution to water problems in areas having inadequate water resources.

ü Reduction in soil erosion as the surface run of reduced in the choking of storm water drains and flooding of roads.

ü Saving of energy to left groundwater, meter rise in water level saving 0.40 kilo watt hour of electricity.

Ø Benefits of rainwater harvesting in the opinion of Shagufta (2010):

ü Water is free the only cost is for collection and use.

ü The end use of harvested water is located close to the source, eliminating the need for complex and costly distributed system.

ü Rain water provides a water source when groundwater is unacceptable or unavailable, or it can augment limited groundwater supply.

ü The zero hardness of rainwater helps prevents scale on appliances, extending their use, rainwater eliminates the need for water softener and the salt added during the softening process.

ü Rainwater is sodium free, important for persons for low sodium diets.

ü Rainwater is superior for landscape irrigation.

ü Rainwater harvesting reduces flow to storm water drains and also reduces non point source pollution.

ü Rainwater harvesting helps utilities reduce the summer demand peak and delay expansion of existing water treatment plant.

ü Rainwater harvesting reduces consumer’s utility bills.

Ø According to Norma Khoury-Nolde (2000), benefits of rainwater harvesting are:

Rainwater harvests in urban and rural areas offers several benefits including provision of supplemental water, increase soil moister level for urban greenery, increasing the underground water table via artificial recharge, mitigating urban flooding and improving the quality of groundwater. In homes and buildings, collected rainwater can be used for irrigation, toilet flushing and laundry. With proper filtration and treatment harvested rainwater can also be used of showering, bathing or drinking. The major benefits of rainwater harvesting are summarized below:

ü Rainwater is a relatively clean and free source of water.

ü Rainwater harvesting provides a source of water at the point where it is needed.

ü It is owner-operated and managed.

ü It is socially acceptable and environmentally responsibility.

ü It promotes self-sufficiency and conserves water resources.

ü Rainwater is friendly to landscape plants and gardens.

ü It reduces storm water runoff and non point source pollution.

ü It uses simple, flexible technology that is easy to maintain.

ü Offers potential cost savings especially with raising water cost.

ü Provides safe water from human consumption after proper treatment.

ü Low running costs.

ü Construction, operation and maintenance are not labor-intensive.