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2012 – 2013

Submitted by:

SASHI KANT KURMI

Roll No.: 429, Reg. No.: 122-1121-0381-10 B.COM. HONS. IN ACCOUNTING & FINANCE

CITY COLLEGE OF COMMERCE & BUSINESS ADMINSTRATION

Rainwater Harvesting

ACKNOWLEDGMENTS

I am thankful to all respected Professors and Teachers for advice and computation, with their guidance and supervision I have been able to complete this project. The project taught me a lot about Rainwater harvesting and ways to preserve it. I am thankful to my Professor Mrs. Vineeta Gupta for giving me this topic. I have been able to lean a lot about it

Contents:

1. Introduction

2. Need for rainwater harvesting

3. Reasons for rainwater harvesting

4. Advantages and disadvantages

5. Objectives

6. Methods

7. Current Status

8. Observation & Findings

9. Conclusion

10. Suggestions

11. Bibliography

1.Introduction

Millions of people throughout the world do not have access to clean

water for domestic purposes. In many parts of the world conventional

Piped water is either absent, unreliable or too expensive. One of the

biggest challenges of the 21st century is to overcome the growing water

shortage. Rainwater harvesting (RWH) has thus regained its importance

as a valuable alternative or supplementary water resource, along

with more conventional water supply technologies. Much actual or

potential water shortages can be relieved if rainwater harvesting is

Practiced more widely.

People collect and store rainwater in buckets, tanks, ponds and wells. This is commonly referred to as rainwater harvesting and has been practiced for centuries. Rainwater can be used for multiple purposes ranging from irrigating crops to washing, cooking and drinking

Rainwater harvesting is a simple low-cost technique that requires minimum specific expertise or knowledge and offers many benefits. Collected rainwater can supplement other water sources when they become scarce or are of low quality like brackish groundwater or polluted surface water in the rainy season. It also provides a good alternative and replacement in times of drought or when the water table drops and wells go dry. One should, however, realize that rainfall itself cannot be managed. Particularly in arid or semi-arid areas, the prevailing

climatic conditions make it of crucial importance to use the limited amount of rainfall as efficiently as possible. The collected rainwater is a valuable supplement that would otherwise be lost by surface run-off or evaporation.

During the past decade, RWH has been actively reintroduced by local organizations as an option for increasing access to water in currently underserved areas (rural or urban). Unfortunately decision-makers, planners, engineers and builders often overlook this action. The reason that RWH is rarely considered is often simply due to lack of informal introduction

on feasibility both technical and otherwise. During the past decade the technology has, however, quickly regained popularity as users realize the benefits of a relatively clean, reliable and affordable water source at home .

In many areas RWH has now been introduced as part of an integrated water supply, where the town water supply is unreliable, or where local water sources dry up for a part of the year. But RWH can also be introduced as the sole water source for communities or households.

The technology is flexible and adaptable to a very wide variety of conditions. It is used in the richest and the poorest societies, as well as in

the wettest and the driest regions on our planet.

2. Need for rainwater harvesting

Due to pollution of both groundwater and surface waters, and the overall increased demand for water resources due to population growth, many communities all over the world are approaching the limits of their traditional water resources. Therefore they have to turn to alternative or ‘new’ resources like rainwater harvesting (RWH). Rainwater harvesting has regained importance as a valuable alternative or supplementary water resource. Utilization of rainwater is now an option along with more ‘conventional’ water supply technologies, particularly in rural areas, but increasingly in urban areas as well.

RWH has proven to be of great value for arid and semi-arid countries or regions, small coral and volcanic islands, and remote and scattered human settlements.

Rainwater harvesting has been used for ages and examples can be found in all the great civilisations throughout history. The technology can be very simple or complex depending on the specific local circumstances.Traditionally, in Uganda and in Sri Lanka rainwater is collected from trees, using banana leaves or stems as gutters; up to 200

litres may be collected from a large tree in a single rain storm.With the increasing availability of corrugated iron roofing in many developing countries, people often place a small container under their leaves to collect rainwater. One 20-litre container of clean water captured

from the roof can save a walk of many kilometres to the nearest

clean water source. Besides small containers, larger sub-surface andsurface tanks are used for collecting larger amounts of rainwater.

3. Reasons for rainwater harvesting

The reasons for collecting and using rainwater for domestic use are plentiful and varied:

Increasing water needs/demands

The increased need for water results in lower groundwater tables

and depleted reservoirs. Many piped water supply systems fail. The use of rainwater is an useful alternative.

Variations in water availability

The availability of water from sources such as lakes, rivers and

shallow groundwater can fluctuate strongly. Collecting and storing rainwater can provide water for domestic use in periods of water shortage. Rainwater may also provide a solution when the water quality is low or varies during the rainy season in rivers and other surface water resources (for example in Bangladesh).

Advantage of collection and storage near the place of use

Traditional sources are located at some distance from the community.

Collecting and storing water close to households improves the

accessibility and convenience of water supplies and has a positive

impact on health. It can also strengthen a sense of ownership.

Quality of water supplies

Water supplies can become polluted either through industrial or

human wastes or by intrusion of minerals such as arsenic, salt

(coastal area) or fluoride. Rainwater is generally of good quality.

4.Advantages and disadvantages When considering the possibility of using rainwater catchment systems for domestic supply, it is important to consider both the advantages and disadvantages and to compare these with other available options. RWH is a popular household option as the water source is close by, convenient and requires a minimum of energy to collect. An advantage for household systems is that users themselves maintain and control their systems without the need to rely on other members of ‘the community. Since almost all roofing material is acceptable for collecting water for household purposes, worldwide many RWH systems have been implemented successfully.

However, RWH has some disadvantages. The main disadvantage of RWH is that one can never be sure how much rain will fall. Other disadvantages, like the relatively high investment costs and the importance of maintenance, can largely be overcome through proper design,

ownership and by using as much locally available material as possible to ensure sustainability (and cost recovery). The involvement of the local private sector and local authorities can facilitate upscaling of RWH. Some advantages and disadvantages are given .

Advantages of rainwater harvesting: ~

Relatively cheap materials can be used for construction of containers and collecting surfaces

Construction methods are relatively straightforward

Low maintenance costs and requirements

Collected rainwater can be consumed without treatment providing a clean collecting surface has been used

Provides a supply of safe water close to homes, schools or clinics, encourages increased consumption, reduces the time women and children spend collecting water, reduces back strain or injuries from carrying heavy water containers.

Simple construction: Construction of RWH systems is simple and local people can easily be trained to build these themselves.This reduces costs and encourages moreparticipation, ownership and sustainability at community level.

Good Maintenance: Operation and maintenance of a household catchment system are controlled solely by the tank owner’s family. As such, this is a good alternative to poor maintenance and monitoring of a centralized piped water supply.

Relatively good water quality: Rainwater is better than other available or traditional sources (groundwater may be unusable due to fluoride, salinity or arsenic).

Low environmental impact: Rainwater is a renewable resource and no damage is done to the environment.

Convenience at household level: It provides water at the point of consumption

Not affected by local geology or topography:Rainwater collection always provides an alternative wherever rain falls.

Flexibility and adaptability of systems to suit local circumstances and budgets, including the increased availability of low-cost tanks (e.g. made of Ferro cement, plastics or stone/bricks).

Disadvantages of rainwater harvesting: ~

Supplies can be contaminated by bird/animal droppings on

catchment surfaces and guttering structures unless they are cleaned/flushed before use.

Poorly constructed water jars/containers can suffer from algal growth and invasion by insects, lizards and rodents.

They can act as a breeding ground for disease vectors if they are not properly maintained

High investment costs: The cost of rainwater catchment systems is almost fully incurred during initial construction. Costs can be reduced by simple construction and the use of local materials.

Usage and maintenance: Proper operation and regular maintenance is a very important factor that is often neglected. Regular inspection, cleaning, and occasional repairs are essential for the success of a system.

Water quality is vulnerable: Rainwater quality may be affected by air pollution, animal or bird droppings, insects, dirt and organic matter.

Supply is sensitive to droughts: Occurrence of long dry spells and droughts can cause water supply problems.

Limited supply: The supply is limited by the amount of rainfall and the size of the catchment area and storage reservoir.

5. Objectives of Rainwater Harvesting

Rainwater harvesting is a way of capturing and storing water during rainy periods for use in times when there is little or no rain available. In certain regions of the world, rainwater harvesting can be the difference between having a plentiful crop and dried up vines. There are several objectives behind rainwater harvesting.

Increase Available Water During Dry Season Many ecosystems have wet and dry seasons. Because the dry seasons can consist of weeks or months of little to no rain, it is important to capture during the rainy season and have it available for use during the dry season. Rainwater harvesting enables you to store rain when it is prevalent to be used when there is no rain.

Reduce Flooding and Erosion By capturing and storing large amounts of rainwater in reservoirs, it is possible to reduce the amount of runoff and limit the impact on the land of large rainfalls. By capturing rainwater you are basically reducing the

amount of water that is flowing across the land, which reduces flooding chances and the impact of erosion.

Prevent Over use of Aquifers

As cities and towns grow the need for water increases. Many municipalities rely upon aquifers deep below the ground for this water supply. The problem is it takes a long time to replenish an aquifer if it is quickly drained. By harvesting rainwater for later use, the demand on aquifers is reduced, which enables them to remain full.

Save Money

Pumping water up from underground aquifers can be a fairly expensive operation. It is estimated that for every one meter rise in water level, there is a reduction of 0.4 KWH of electricity usage. So by having water closer to the surface, or at the surface in reservoirs, less electricity is needed to pump it so

less money is spent

6.Methods of Rainwater Harvesting Catchment :

Any surface or the paved areas can be treated as catchment. Even the footpaths and roads can act as the catchment, as these areas too receive the direct rainfall. Rooftops are the best among them because of the large coefficient of run off generated from them and there are less chances of contamination of water.

Conveyance :

Conveyance system basically includes rain gutters and down pipes which collects the rain water from catchment to the storage tank. These rain gutters are usually built during the time of construction. They need to be designed appropriately as to avoid the loss of water during the conveyance process.

Storage :

The most important part of the rain water harvesting is the storage system. The storage system is designed according to the amount of water that is to be stored. The design and site (location) of the storage or the recharge system should be properly chosen. The areas which receives the rainfall frequently, there a simple storage system could be constructed, to meet the daily water requirements. Otherwise the areas which receive the lesser rainfall, there the storage systems are quite essential. Rain barrels, underground or open slumps are mostly used to collect rain water. Make sure that the storage system is properly sealed and does nor leak. Use Chlorine from time to time to keep the water clean.

7.Current Status Currently in China and Brazil, rooftop rainwater harvesting is being practiced for providing drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. Gansu province in China and semi-arid north east Brazil have the largest rooftop rainwater harvesting projects ongoing.

In Bermuda, the law requires all new construction to include rainwater harvesting adequate for the residents.

The U.S. Virgin Islands have a similar law. In Senegal and Guinea-Bissau, the houses of the Diola-people are

frequently equipped with homebrew rainwater harvesters made from local, organic materials.

In the Irrawaddy Delta of Myanmar, the groundwater is saline and communities rely on mud-lined rainwater ponds to meet their drinking water needs throughout the dry season. Some of these ponds are centuries old and are treated with great reverence and respect.

Until 2009 in Colorado, water rights laws almost completely restricted rainwater harvesting; a property owner who captured rainwater was deemed to be stealing it from those who have rights to take water from the watershed. Now, residential well owners that meet certain criteria may obtain a permit to install a rooftop precipitation collection system(SB 09-080). Up to 10 large scale pilot studies may also be permitted (HB 09-1129).

In India, rain water harvesting was first introduced by Andhra

Pradesh ex-Chief Minister N. Chandrababu Naidu. He made a rule that every house which is going to built in cities of that state must have a percolation pit/rainwater harvesting system. This rule increased the ground water level in good phase. After his term as Chief Minister, the next leaders neglected this system.

In the state of Tamil Nadu, rainwater harvesting was made compulsory for every building to avoid ground water depletion. It proved excellent results within five years, and every other state took it as role model. Since its implementation, Chennai saw a 50 percent rise in water level in five years and the water quality significantly improved.

In Rajasthan, rainwater harvesting has traditionally been practiced by the people of the Thar Desert. There are many ancient water harvesting systems in Rajasthan, which have now been revived

Lanka rainwater harvesting forum is leading the Sri Lanka's initiative.

Traditional methods of rain water harvesting Pits :- Recharge pits are constructed for recharging the shallow aquifer. These are constructed 1 to 2 m, wide and to 3 m. deep which are back filled with boulders, gravels, coarse sand.

Trenches:- These are constructed when the permeable stram is available at shallow depth. Trench may be 0.5 to 1 m. wide, 1 to 1.5m. deep and 10 to 20 m. long depending up availability of water. These are back filled with filter. materials.

Dug wells:- Existing dug wells may be utilised as recharge structure and water should pass through filter media before putting into dug well.

Hand pumps :- The existing hand pumps may be used for recharging the shallow/deep aquifers, if the availability of water is limited. Water should pass through filter media before diverting it into hand pumps.

Recharge wells :- Recharge wells of 100 to 300 mm. diameter are generally constructed for recharging the deeper aquifers and water is passed through filter media to avoid choking of recharge wells.

Recharge Shafts :- For recharging the shallow aquifer which are located below clayey surface, recharge shafts of 0.5 to 3 m. diameter and 10 to 15 m. deep are constructed and back filled with boulders, gravels & coarse sand

8.Observation & Finding

Principle #1: Begin with long and thoughtful observation.

Principle #2: Start harvesting rain at the top of your watershed, then work your way down.

Principle #3: Always plan an overflow route, and manage overflow as a resource.

4. Start with small and simple strategies that harvest the rain as close as possible to where it falls.

5. Spread, slow and infiltrate the flow of water into the soil.

6. Maximize living and organic groundcover.

7. Maximize beneficial relationships and efficiency by “stacking functions.”

9.Conclusion

It is a very useful process during rainy season and during the scarcity of water.by doing this process we can safe water for domestic purpose,drinking purpose and for future needs.it is a very simple and affordable process.with the decreasing availability of water, rain water harvesting is the best option.

Appropriate Project funds were used to build a small water harvesting system for the school garden and a drip irrigation system for the reforestation in an area designated for the newly constructed Visitor´s Center for the local forest reserve, Bosque de Zárate, a nationally declared protected area.

10. Suggestion The system now functions with very little water, and serves as an example to community members as well as visitors to the reserve of appropriate irrigation and water management techniques. As the trees grow older and need less assistance, it is agreed that the community will locate the tank under the roof of the Visitor´s Center, harvesting rains that fall upon the large surface.

11. Bibliography

Coombes PJ (2007). Energy and economic impacts of rainwater tanks on the operation of regional water systems. Australian Journal of Water Resources 11 (2) 177 – 191.

Ferguson M (2012) a 12-month rainwater tank water savings and energy use study for 52 real life installations. Ozwater12 COnference, Sydney, Australia: May 2012.

Frasier, Gary, and Lloyd Myers. Handbook of Water Harvesting. Washington D.C.: U.S. Dept. of Agriculture, Agricultural Research Service, 1983

Geerts, S., Raes, D. (2009). Deficit irrigation as an on-farm strategy to maximize crop water productivity in dry areas. Agric. Water Manage 96, 1275–1284

Gould, John, and Erik Nissen-Peterson. Rainwater Catchment Systems. UK: Intermediate Technology Publications, 1999.

Hemenway, Toby. Gaia’s Garden: A Guide to Home-Scale Permaculture. Vermont: Chelsea Green Publishing Company, 2000.

Lowes, P. (1987). "The Water Decade: Half Time". In in John Pickford (ed.). Developing World Water. London: Grosvenor Press International. pp. 16–17. ISBN 0-946027-29-3.

http://www.tn.gov.in/dtp/rainwater.htm http://mastec.nic.in/MASTEC/Report%20Rain%20Water%20Harvesting.

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