RAIN WATER MANAGEMENT SYSTEMPratul T.Patil

NICMAR, HyderabadE-mail:pratulptl39@gmail.com

Abstract- Rain water management system important type of system due to shortage of water. It’s also help in reducing the demand secondary water. In paper we discuss various old and new techniques to management the rain water system. I also discuss my case study which on the Rain water harvesting system in MHADA Building, Bandra.

I. INTRODUCTION:Water is essential to all life – human, animal and vegetation. It is therefore important that adequate supplies of water be developed to sustain such life. Development of water supplies should, however, be undertaken in such a way as to preserve the hydrological balance and the biological functions of all Ecosystems. The application of innovative technologies and the improvement of indigenous ones should therefore include management of the water sources to ensure sustainability and to safeguard the sources against pollution. As land pressure rises, more and more marginal areas in the world are being used for agriculture. Much of this land is located in the arid or semi-arid belts where rainfall is irregular and much of the precious water is soon lost as surface runoff. Rain water was, is and will be the only source of water in most of the part of India. Annual rainfall of India is nearly 150% of world’s average rainfall but the spatial and temporal distribution is erratic. We receive most of the rainfall during monsoon season and nearly seven to eight months are without any rainfall. During monsoon, there are some high intensity rainfalls, these rainfalls cannot be absorbed fully by the soil and it runs off. The runoff water can cause erosion, thus deteriorating the cultivable land and due to less infiltration, can lead to poor replenishment of ground water.

The source of almost all fresh water is precipitation from the atmosphere, in the form of mist, rain and snow. Fresh water falling as mist, rain or snow contains materials dissolved from the atmosphere and material from the sea and land over which the rain bearing clouds have traveled. In industrialized areas rain is typically acidic because of dissolved oxides of sulfur and nitrogen formed from burning of fossil fuels in cars, factories, trains and aircraft and from the atmospheric emissions of industry. In some cases this acid rain results in pollution of lakes and rivers.

In coastal areas fresh water may contain significant concentrations of salts derived from the sea if windy conditions have lifted drops of seawater into the rain-bearing clouds. This can give rise to elevated concentrations of sodium, chloride, magnesium and sulfate as well as many other compounds in smaller concentrations.

In desert areas, or areas with impoverished or dusty soils, rain-bearing winds can pick up sand and dust and this can be deposited elsewhere in precipitation and causing the freshwater flow to be measurably contaminated both by insoluble solids but also by the soluble components of those soils. Significant quantities of iron may be transported in this way including the well-documented transfer of iron-rich rainfall falling in Brazil derived from sand-storms in the Sahara in north Africa.

Out of all the water on Earth, salt water in oceans, seas and saline groundwater make up about 97% of it. Only 2.5–2.75% is fresh water, including 1.75–2% frozen in glaciers, ice and snow, 0.7–0.8% as fresh groundwater and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers. Freshwater lakes contain about 87% of this fresh surface water, including 29% in the African Great Lakes, 20% in Lake Baikal in Russia, 21% in the North American Great Lakes, and 14% in other lakes. Swamps have most

of the balance with only a small amount in rivers, most notably the Amazon River. The atmosphere contains 0.04% water. In areas with no fresh water on the ground surface, fresh water derived from precipitation may, because of its lower density, overlie saline ground water in lenses or layers. Most of the world's fresh water is frozen in ice sheets. Many areas suffer from lack of distribution of fresh water, such as deserts.

FIGURE I. FRESH WATER PERCENTAGE IN WORLD

TABLE I. AVERAGE RAINFALL DATA IN INDIA

SR.NO. STATE RAINFALL IN MM

1 Andaman and Nicobar Islands 29672 ArunachalPradesh 27823 Assam 28184 Meghalaya 28185 Nagaland 18816 Manipur 18817 Mizoram 18818 Tripura 18819 West Bengal 273910 Sikkim 273911 Orissa 148912 Bihar 132613 Uttar Pradesh 102514 Haryana 61715 Delhi 61716 Chandigarh 61717 Punjab 64918 Himachal Pradesh 125119 Jammu and Kashmir 101120 Rajasthan 31321 Madhya Pradesh 101722 Gujarat 110723 Goa 300524 Maharashtra 300525 Andhra Pradesh 109426 Telengana 961

27 Pondicherry 99828 Karnataka 345629 Kerala 305530 Tamil Nadu 99831 Lakshadweep 1515

[3]

A. History Of Rain Water Management:

Water management like many techniques in use today is not new, it was practiced from ancient times in India. We can get references in our ancient religious text, which give good insight into the water storage and conservation system. Evidences of water system for irrigation and drinking water supply can be seen in Indus valley civilization (3000 BC to 1500 BC) at Dholavira, Mohenjo-Daro, Harappa and Lothal. Various rulers like The Satvahans, the Gupta, and The Pallavas expanded irrigation systems during their periods from 1st century BC to 7th century AD. The cholas (985 to 1205 AD) introduced the concept of chain tanks, i.e. no. of tanks connected by channels, which help in flexibility in water distribution.

During the Mughal rule, Abdul Rahim khan built the unique water supply system of Burhanpur town, by constructing long lines of underground tunnels with vertical airshafts to tap the ground water flow from Satpuda hill ranges to Tapi River.

Under the Nizamshahi kings (1490 to 1635 AD) 15 channels were built to supply water to the city of Ahmednagar from deep wells at the foot of nearby hills. Hence, rain water harvesting is as old as civilization and practiced continuously in different ways for different purposes in India.

B. Aims Of Rainwater Management: To collect rain water for secondary purposes so that the

load on municipal water for drinking purpose is reduced. To control depletion of ground water level. To increase ground water table and its availability. Rehabilitate the existing traditional water harvesting

structure like village ponds, percolation tanks etc. To control the flow of sea water within the ground. For agricultural, industrial, and other non-drinking

purpose. Improve physical and chemical quality of ground water. Reduce storm water runoff and soil erosion.

One of the biggest challenges of the 21st century is to overcome the growing water shortage. Rainwater Management has thus regained its importance as a valuable alternative or supplementary water resource, along with more conventional water supply technologies. 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. 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. 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.

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. During the past decade, RAIN WATER MANAGEMENT has been actively reintroduced by local organizations as an option for increasing access to water in currently Underserved areas (rural or urban). But 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 RAIN WATER MANAGEMENT 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 RAIN WATER MANAGEMENT can also be introduced as the sole water source for communities or households.

C. Need For Rain Water Management:

Prior to industrialization and successive increased rate of urbanization, the natural filter for rain was ground. This filter allows the penetration and hence the ground water was at substantial level. Continuous pumping of water for industrial and domestic use lead to drop of level. Also in urban area especially concrete pavements, footpath, parking area etc. were responsible for less filtration and more surface runoff leading finally towards sea. Less deposition of water in this water bank below and more withdrawal for many activities are the key factors for this depletion of water. Hence, it is the responsibility of mankind to increase this level. In this regard the rain water harvesting is a very natural and cost effective solution which will improve the depleted water level. 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. India has 16% of the total population of the world. But the country has only 4% of the water resources present on the earth. Though India is one of the wettest region in the world with an annual average rainfall of 117 cubic m of rain over the plains water scarcity contains to hunt various parts in India with varying intensity. As it is, India’s rainfall is characterized by its diversity, both by the geographical division and season of the year. There is also very large variation in each geographical region from one year to another, resulting in flood in some areas and drought in others. Municipal water supply in most Indian Cities is unreliable. Many villages in India do not have potable water supply. Hence Rainwater Management has been proposed as an ideal sustainable solution in India too,

D. Benefits Of Rain Water Management: It provides a source of water at the point where it is

needed It provides an essential reserve in times of emergency and

breakdown of public water supply systems It helps to conserve and enhance the storage of ground

water aquifers thereby improving the ground water table Harvested rain water can provide good irrigation source

for agriculture In coastal areas, over extraction of ground water leads to

saline water intrusion. Recharging of ground water aquifer helps to arrest the invasion of saline water

The construction is simple and of low cost, running cost is low and the technology is not labour intensive

It helps to achieve LEED (leadership in energy and environment design) green building rating credit

E. Contribution Of Rain Water Management To A Sustainable Water Strategy: self-sufficiency in water supply decentralized approach restoring the hydrological cycle

II. TRADITIONAL METHODS OF RAIN WATER MANAGE MENT

A. Trans-Himalayan Region:The Trans-Himalayan region of India consists of the cold deserts of Ladakh and Kargil in Jammu and Kashmir, and the Lahaul and Spiti valleys of Himachal Pradesh. Traditional recharge structure practiced here is the Zing (fig 2).

Zings are water harvesting structures found in Ladakh. They are small tanks, in which collects melted glacier water. Essential to the system is the network of guiding channels that brings the water from the glacier to the tank. As glaciers melt during the day, the channels fill up with a trickle that in the afternoon turns into

flowing water. The water collects towards the evening, and is used the next day. [7]

Fig. 2 Zing methodB. Western Himalayan Region: The western Himalayan region consists of the western half, which stretches from the Kashmir valley to the Uttarakhand region. Traditional recharge structure practiced here are the Kul, Naula, Kuhi and Khatri.Kuls are water channels found in precipitous mountain areas. These channels carry water from glaciers to villages in the Spiti valley of Himachal Pradesh. Where the terrain is muddy, the kul is lined with rocks to keep it from becoming clogged. In the Jammu region too, similar irrigation systems called kuls are found.

Naula is a surface-water harvesting method typical to the hill areas of Uttaranchal. These are small wells or ponds in which water is collected by making a stone wall across a stream. [2]

Fig. 3 Kuhls methodKhatris are structures, about 10 x 12 feet in size and six feet deep carved out in the hard rock mountain. These traditional water harvesting structures are found in Hamirpur, Kangra and Mandi districts of Himachal Pradesh There are two types of khatris: one for animals and washing purposes in which rain water is collected from the roof through pipes, and other used for human consumption in which rainwater is collected by seepage through rocks. Interestingly, the khatris are owned by individual as well as by a community. There are government khatris as well, which are maintained by the panchayat.

Kuhls are a traditional irrigation system in Himachal Pradesh surface channels diverting water from natural flowing streams (khuds). A typical community kuhl services six to 30 farmers, irrigating an area of about 20 ha. The system consists of a temporary headwall (constructed usually with river boulders) across a khud (ravine) for storage and diversion of the flow through a canal to the fields. By modern standards, building Kuhls was simple, with boulders and labour forming the major input. The kuhl was provided with moghas (kuchcha outlets) to draw out water and irrigate nearby terraced fields. The water would flow from field to field and surplus water, if any, would drain back to the khud. The Kuhls as shown in fig. 3 were constructed and maintained by the village community. [2]

C. Eastern Himalaya Region:

Eastern Himalayan region comprises of the states of Sikkim and Arunachal Pradesh and the Darjeeling district of West Bengal. Traditional artificial recharge method practiced here is the Apatani.Apatani is a wet rice cultivation cum fish farming system practiced in elevated regions of about 1600 m and gentle sloping valleys, having an average annual rainfall about 1700 mm and also rich water resources like springs and streams. This system harvests both ground and surface water for irrigation. It is practiced by Apatani tribes of ziro in the lower Subansiri district of Arunachal Pradesh. In Apatani system, valleys are terraced into plots separated by 0.6 meters high earthen dams supported by bamboo frames. All plots have inlet and outlet on opposite sides. The inlet of low lying plot functions as an outlet of the high lying plot. Deeper channels connect the inlet point to outlet point. The terraced plot can be flooded or drained off with water by opening and blocking the inlets and outlets as and when required. The stream water is tapped by constructing a wall of 2-4 m high and 1 m thick near forested hill slopes. This is conveyed to agricultural fields through a channel network. This method is shown in fig 4.

Fig. 4 Apatani methodD. Northeastern Hill Ranges:

Northeastern hill ranges stretches over six state namely, Assam, Nagaland, Manipur, Mizoram, Meghalaya and Tripura in the Indian boundary and over Bangladesh and Myanmar. Traditional artificial recharge practiced here are the Zabo Fig.5.Cheo-oziihi and Bamboo-drip Irrigation. The zabo (the word means 'impounding run-off') system is practiced in Nagaland in north-eastern India. Also known as the ruza system, it combines water conservation with forestry, agriculture and animal care. Villages such as Kikruma, where zabos are found even today, are located on a high ridge. Though drinking water is a major problem, the area receives high rainfall. The rain falls on a patch of protected forest on the hilltop; as the water runs off along the slope, it passes through various terraces. The water is collected in pond-like structures in the middle terraces; below are cattle yards, and towards the foot of the hill are paddy fields, where the run-off ultimately meanders into. [2]

Fig.5zabo method

E. Bamboo Drip Irrigation: Meghalaya has an ingenious system of tapping of stream

and spring water by using bamboo pipes to irrigate plantations. About 18-20 liters of water entering the bamboo pipe system per minute gets transported over several hundred meters and finally gets reduced to 20-80 drops per minute at the site of the plant. This 200-year-old system is used by the tribal farmers of Khasi and Jaintia hills to drip-irrigate their black pepper cultivation. Bamboo pipes are used to divert perennial springs on the hilltops to the lower reaches

by gravity. The channel sections, made of bamboo, divert and convey water to the plot site where it is distributed without leakage into branches, again made and laid out with different forms of bamboo pipes. Manipulating the intake pipe positions also controls the flow of water into the lateral pipes. Reduced channel sections and diversion units are used at the last stage of water application. The last channel section enables the water to be dropped near the roots of the plant. Bamboos of varying diameters are used for laying the channels. About four to five stages of distribution are involved from the point of the water diversion to the application point. This method is as shown in fig 6. [2]

Fig.6 Bamboo drip irrigation

F. Thar Deserts:The Thar Desert covers an area of 44.6 million hectare, of

which 27.8 million hectare lies in India and rest in Pakistan. Western Rajasthan, Kutch region of Gujarat, Bhatinda&Ferozepur districts in Punjab and most of Hisar & parts of Mohindergarh districts of Haryana fall under the Thardesert. Many traditional artificial recharge structures have been practiced, they are the Kunds/Kundis, Kuis/Beris, Baoris/bers, Jhararas, Nadi, Tobas, Tankas, Khadins, Vav/VavdiBaoli/Bavadi, Virdas&Paar.

Kund or kundi looks like an upturned cup nestling in a saucer. These structures harvest rainwater for drinking, and dot the sandier tracts of the Thar Desert in western Rajasthan and some areas in Gujarat. Essentially a circular underground well, kunds as shown in fig 7, have a saucer-shaped catchment area that gently slopes towards the centre where the well is situated. A wire mesh across water-inlets prevents debris from falling into the well-pit. The sides of the well-pit are covered with (disinfectant) lime and ash. Most pits have a dome-shaped cover, or at least a lid, to protect the water. If need be, water can be drawn out with a bucket. The depth and diameter of kunds depend on their use. They can be owned by only those with money to invest and land to construct it. Thus for the poor, large public kunds have to be built. [2]

Fig.7Kund methodG. Jhalaras method:

Jhalaras were human-made tanks, found in Rajasthan and Gujarat, essentially meant for community use and for religious rites. Often rectangular in design, jhalaras have steps on three or four sides. Jhalars as shown in fig 8 are ground water bodies which are built to ensure easy & regular supply of water to the surrounding areas. The jhalars are rectangular in shape with steps on three or even on all the four sides of the tank. The steps are built on a series of levels. The jhalaras collect

Subterranean seepage of a talab or a lake located upstream. The water from these jhalaras was not used for drinking but for only community bathing and religious rites. Jodhpur city has eight jhalaras two of which are inside the town & six are found outside the city. The oldest jhalara is the mahamandirjhalara which dates back to 1660 AD.

Nadis are village ponds, found near Jodhpur in Rajasthan. They are used for storing water from an adjoining natural catchment during the rainy season. The site was selected by the villagers based on an available natural catchments and its water yield potential. Water availability from Nadi would range from two months to a year after the rains. In the dunal areas they range from 1.5 to 4.0 meters and those in sandy plains varied from 3 to 12 meters. The location of the Nadi had a strong bearing on its storage capacity due to the related catchment and runoff characteristics. [2]

Fig.8Jhalaras methodH. Khadin method

Khadin, also called a dhora, is an ingenious construction designed to harvest surface runoff water for agriculture. Its main feature is a very long (100-300 m) earthen embankment built across the lower hill slopes lying below gravelly uplands. Sluices and spillways allow excess water to drain off. The khadin system as shown in fig 9 is based on the principle of harvesting rainwater on farmland and subsequent use of this water-saturated land for crop production. First designed by the Paliwal Brahmins of Jaisalmer, western Rajasthan in the 15th century, this system has great similarity with the irrigation methods of the people of Ur (present Iraq) around 4500 BC and later of the Nabateans in the Middle East. A similar system is also reported to have been practiced 4,000 years ago in the Negev desert, and in southwestern Colorado 500 years ago. [2]

Fig. 9Khadin methodIII.TECHNIQUES OF RAIN WATER

MANAGEMENTA. Rain Water Harvesting Using Roof Top Area:In this rain is collected from roof of house and with help of Gutters and collecting pipe system. The rain water harvesting system consists of following basic components (Fig.10)(a) Catchment area(b) Coarse mesh / leaf screen(c) Gutter(d) Down spout or conduit(e) First flushing device(f) Filter(g) Storage tank(h) Settlement tank

Fig.10 Components of Rain Water harvesting systemThis Rain water harvesting have two models

a) Rural modelb) Urban model

Fig. 11 Rural Model

Fig. 12 Urban Model

B. Furaat:It is one such offering that has been made by the Furaat Water Harvesting system that has been designed for the Ahmadabad based company by an NID graduate of Product Design, Dinesh Sharma. The company, Furaat Earth Pvt Ltd, was set up by the entrepreneur brothers Habil and Yusuf Attarwala with the intention of reaching action on the ground with a small investment rather than just talking about the need for awareness and local action. In the last two years over 400 installations have been achieved and this year has seen a

growth in both acceptance and in business with over 500 installations being considered, each costing approximately Rs 30,000.

Fig 13 cross section of furaat systemThe Furaat system as shown in fig 5.11 can be used for both kinds of applications, that is, storage type or ground water recharge type of application. In the first case the system on offer can form the first stage of the collection and filtration process while a variety of storage types can be used downstream, and in the second case the modular units can be installed in a variety of capacities to recharge deep ground water reservoirs using deep bore wells as the preferred route for the ground water recharge process. It is a cost effective modular construction technique. Two key components are used in the product – an octagonal horizontal component and a rectangular vertical component – each with a simple locator detail that uses spherical glass beads in a patented configuration to lock the components in place. These are made in high quality concrete castings with precision and durability and in the long run these offer reuse and recycling possibilities in case the location is to be changed in the future due changes in the underground water table characteristics or in new structures on the surface as the site is developed. This is a hidden feature that protects the investment and also significant is the ease with which the well components can be assembled, maintained and cleaned after a few monsoons. All water handling accessories too are made of industrial grade metals of high quality that provides durability, performance and filtration standards that are extremely high and the sand and gravel beds at the first and the last stage too can be cleaned with ease since the design affords easy access as it is like a step-well with the dimensions matched to human proportions for lifting, access and climbing as well as being secure in the quality of filter performance that is guaranteed by the company. The modular construction gives the user and the planner flexibility in making the particular unit to suit the needs of the site condition as well as the available budget since a one level, two level or three level or even a multi-level unit can be made with the same basic components in a very short time. Installation can be completed in less than a day by one or two semi-skilled masons without the use of hoists or cranes to erect the well components. Ground water recharge if done carelessly can be quite damaging for the aquifer since it is easy to use artificial recharge to help introduce contaminants and surface pollution into an aquifer if the filtration process is carelessly handled. Design can play a great role in examining and building imaginative solutions that are economic, appropriate and culturally suitable for the particular location. [5]

C. Crosswave:It is a water holding material for rainfall accumulation installed within underground reservoirs. Underground water space created by Cross-Wave effectively controls flood of river and drainage caused by heavy rain. At the same time it also provides a system through which stored rain water can be used according to necessity. Cross-Wave system is a light-weight, easy to transport and simple to install system. It’s speedy in installation. (1000m3 could be installed in 2 weeks).the different types of cross wave system are as shown in fig. 14, 15, 16. [6]

Fig. 14 Installing cross wave as a retention facility (Earth adjustment type)

Fig 15 Installing cross wave as a osmosis (Permeation type earth adjustment type)

Fig 16 Installing cross wave as rain water harvesting tank (Rainwater use type)Installation Process:

Installation process as shown in fig.17, simply involves digging, spreading the protecting sheet, laying the lining sheets, piling up Cross–Wave, setting spacer and finally covering up with lining sheet & protection sheet. Due to high void ratio of 95 % large amount of space could be utilized. It can easily take 25 ton truck load as well as 45 ton fire tender could easily move over it. The finished surface can be used as parking lot, gardens etc in residential complexes, hospitals, offices etc. The entire operation is time saving as installation can be done manually. No big tools are required. Compared to concrete tanks, in case of Cross wave no curing time is required, which again saves lot of time. Above all, the system is environment–friendly. There is no pollution caused in the process. The material used is polypropylene, which has excellent physical & chemical properties and no pollution is caused to the water stored. The system is easy to maintain, has long life time (50 years) and recyclable too.

Fig 17 Installation process

D. Types Of Groundwater Dam:

1)The Sub-Surface Dam

A sub-surface dam obstructs the flow of an aquifer and reduces the variation of the level of the groundwater table upstream of the dam. It is built entirely under the ground

Fig. 18 A sub-surface dam

2) The sand storage dam-

The sand storage dam is constructed above ground. Sand and soil particles transported during periods of high flow are allowed to deposit behind the dam, and water is stored in these soil deposits. The sand storage dam is constructed in layers to allow sand to be deposited and finer material be washed downstream as shown in fig.18. A groundwater dam can also be a combination of these two types. When constructing a sub-surface dam in a river bed, one can increase the storage volume by letting the dam wall rise over the surface, thus causing additional accumulation of sediments. Similarly, when a sand-storage dam is constructed it is necessary to excavate a trench in the sand bed in order to reach bedrock, which can be used to create a sub-surface dam too. Groundwater dams are built across streams or valleys. A trench is dug across the valley or stream, reaching to the bedrock or other stable layer like clay. An impervious wall is constructed in the trench, which is then refilled with the excavated material. Various materials may be used for the construction of groundwater dams.

Fig 19

Fig 20 Storage dam

Materials should be waterproof, and the dam should be strong enough to withstand the imposed soil and water loads. Dams may vary from 2 to 10 meters high. Materials include compacted clay, concrete, stones and clay, masonry wall or plastic sheets. The reservoir is recharged during the monsoon period and the stored water can be used during the dry season. Excess water flows over the top of the dam to replenish aquifers downstream. Water may be obtained from the underground reservoir either from a well upstream of the dam or from a pipe fig. 20, passing through the dam, and leading to a collection point downstream. Groundwater dams cannot be a universally applicable as these require specific conditions for functioning. The best sites for construction of groundwater dams are where the soil consists of sands and gravel, with rock or a permeable layer at a depth of a few meters. Ideally the dam should be built where rainwater from a large catchment area flows through a narrow passage.

E. Dams:Constructing ponds in hilly areas and constructing dam on is also method of using rain water .Since in hilly rain precipitation more than other so we get more water from there. By constructing dam we can increase making storage of it and use whenever we required. By help of pipe system it can be transfer to any place where ever we required. There many dams dam constructed on the principles.

IV. CASE STUDY RAIN WATER HARVESTING IN CAO BUILDING MHADA

A. Introduction: We went to the Mhadabuliding to study the installation of

rain water harvesting equipment which is situated in Kalanagar, Off. Western Express Highway. Bandra (E) Mumbai on 21/01/2013.We studied rain water harvesting system installed in Mhadabuliding. The climate of Mumbai is tropical wet and dry, Heavy rainfall is only during monsoon season. As Population is increasing day by day so to tackle the problem of water scarcity by reducing the load on municipal water supply and to meet the future demand, govt. has taken a step forward towards judicious use of water by installing

RAIN WATER HARVESTING system in Mhada building. Project was completed by the group of Water Field Technologies PVT. LTD. They have done various survey for the suitability of site and calculated estimated cost for project. We got the idea about the component of rain water harvesting system and their arrangement. It is the cost effective project as that of solar water heated, the payback period is approximate 2 years. Total cost of the Mhada building rain water harvesting project is Rs 17,50,000/-.from our study we came to the conclusion that the system is sustainable, economical and highly reliable.

B. Geography & Hydrology Of Mumbai:Maharashtra state (307,731 km2 in geographical area) is

situated in the western Corner of the Country comprising of 9.84% of the total geographical area Currently there is acute shortage of water in Mumbai, it has been given to understand that now Hon. Vice President & CEO/A has directed for taking the necessary steps towards water management so as to minimize the consumption of municipal water. The state falls in one of the rain fed regions in the country and receives appreciable amount of unevenly distributed precipitation throughout the year with peak rainfall during monsoon period .Acute shortage of drinking water has been a prominent problem being faced by the people during the past few decades.

C. Priority To Rain Water Harvesting In Mumbai Region:

The Climate of Mumbai is a tropical wet and dry climate. Mumbai's climate can be best described as moderate temperatures with high level of humidity. Its coastal nature and tropical location ensures moderate temperatures throughout the year, average of 27.2 °C and average precipitation of 242.2 cm (95.35 inches). The temperatures average about 30 °C in summer and 18 °C in winter. Mumbai's experiences 4 distinct seasons winter: (December–Feb); summer: (March–May); Monsoon (June–Sep) and Post Monsoon (Oct–Dec).Rainfall occurs mainly in the monsoon period which is from June to September. Rainfall activity intensifies as the month goes on, leading into wettest month, July. In July the city receives the maximum amount of rain. July and August are characterized by almost nonstop rain and weeks of no sunshine. The weather in August is almost identical July. Towards the latter half of the month, rainfall activity tends to lessen. In September the intensity of rainfall decreases. The monsoons officially end in the 3rd week of September.Out of the existing houses of the state, about 85 % of the houses mostly in the urban areas consist of RCC structures & 15% of galvanized corrugated iron slanted roofed sheets.So 85% of the rooftops can be utilized as catchment area.D. Proposed Scheme For Rooftop Rain Water

Harvesting: Name Of Scheme : Rooftop rainwater Harvesting for

MHADA Buildings at Bandra (E)

Location of project: MHADA Building at Bandra(E). Average annual Rainfall of Mumbai: 2500mm Organization involved in project: water field technologies

Pvt. Ltd. Starting Date: 10 May 2010 Total cost of Project: 17, 50,000/-

E. Project Area:MHADA Building, Kalanagar, Off. Western Express Highway. Bandra (E) Mumbai

Fig 21 Plan of Mhada Building

F. Methodology For Project Completion: Preliminary survey-

a) Inspection of building rooftop for catchment area.b) Collect the information regarding climate,

precipitation.c) Geophysical investigation to ascertain water bearing

zones of shallow deep horizons and salinity levels like- Electrical resistivity- Electromagnetic field

Analysis-a) Procurement of plan of the building to calculate the

catchment area.b) Find out the no. of population and amount of water

used per day.c) Estimate the no. of storage tank with reference to

the amount of precipitation in that area.d) Decide the length and diameter of pipe.e) Decide the pumping capacity of motor according to

the height of building.f) Calculation of payback period.

G. Steps Adopted:Stage I -Survey: The consultant carried out the survey of premises of CAO

Building Collected the data required for the proposed project and

analyzed the same Designed the suitable Rain Water Harvesting (RAIN

WATER HARVESTING) system Carried out the geophysical survey & fixed the location of

bore wellStage II-Working-Drawing, Estimates & Tender Documents:

Prepared drawing on AutoCAD Prepared detailed estimate & rate analysis for the

proposed project Modified the plan as per project requirement

Stage III-Periodic Supervision : The program shall be duly approved by consultant,

engineer-in-charge of the board and contractor appointed for execution of work.

Periodically monitor the physical and financial progress of the work as per above.

Stage IV-Execution of project: The chief officer shall supply to the consultant up to date

schedule of the rates of the board and PWD. The authority and the board shall include the name of the

consultant in small print in any printed document published by the authority which describes the design of the project or users photographs or the drawings prepared by the consultant.

The authority shall reimburse the consultant with the actual cost of any model or special presentation like perspectives requested by the authority, which will remain sole property of the authority.

Stage V-Time schedule: the stages for the work ranging from taking

measurements, preparing preliminary layouts, working drawing and supervision of work was discussed and finalized by the Executive engineer, maintenance division, Mumbai housing and area development board asa) Stage I – 5 daysb) Stage II – 7 daysc) Stage III – 8 day

H. Costing Of Equipments And Consultancy Charges:Table no 2: Total cost of project

SR No.

DescriptionAppox. Quantity

Amount/unitAmount in Rs.

1 Collection system 500m 750/m 375000

2 Bore wells 3 30000 90000

3 Recharge pit 3 100000 300000

4Bore wells submersible pump

3 40000 120000

5Collection tank(5000lit)

3 50000 150000

6Collection tank(1000lit)

2 10000 20000

7Open well submersible pump

3 40000 120000

8 Geophysical survey - - 25000

9 Pressure filter 1 300000 300000

10Consultancy charges

- 150000 150000

11 Contingencies - 100000 100000

Total 1750000

I. Rain Water Harvesting Potential:

Average annual rainfall of Mumbai : 2500 mm

No. of rainy days:80

Potential of rooftop rain water harvesting:A x R x C

i.e. Roof Area X Annual Rainfall X Runoff Coefficient3866m2 x 2.5m x 0.8=7732m3

Total RAIN WATER HARVESTING Potential:7732m3

:7732000lit/yr Average rooftop rainwater availability

during rainy season:96659 lit/day

J. Cost Benefit Analysis:

Source: BMC’s water supply:Average consumption per month

:3307454lit (A)Say secondary water requirement is

:70% of entire water usedconsumption per secondary purpose(0.7 x A)

:231521.182 lit/monthHence daily secondary water consumption

:77174 lit (B)Average rooftop rainwater availability during rainy season

:96650 lit/day (C)Since C>BRooftop Rainwater Will Be Sufficient To Fulfill Secondary Water Requirement During Monsoon Period And Surplus Water Is To Be Diverted To Bore Well For Artificial Recharge Of Ground Water

K. Pay Back Calculation:Total water bill paid per month

:129028rscost of water paid for secondary water consumption

:129028 x 0.7=90320rstotal charges paid for secondary water consumption

:90320 x 12= 1083840rs/yr (D)total cost of proposed project

:1750000rs (E)PayBack period

:ED

=1.61

say payback period:2yrs of rainy seasons

operation & maintenance cost approximately:30000rs per yr

V. ADVANTAGES OF RAIN WATER MANAGEMENT

The water is free: the only cost is for collection and use. Rainwater provides a water source when groundwater is

unacceptable or unavailable or it can augment limited ground water supplies.

Rainwater Management reduces flow to storm water drains and also reduces non-point source pollution in addition to reduction of flooding of roads in cities.

Rainwater harvesting helps utilities reduce the summer demand peak and delay expansion of existing water treatment plants, great energy saving.

It also help in increasing ground water. Reducing use ground water. Rainwater is sodium-free, important for person on low-sodium

diets. Rainwater is superior for landscape irrigation.

VI. CONCLUSION1) From the above project we learned various techniques and methods of the rain water management system, and we came to know that the Rain Water Harvesting system is an ancient method. From the period of 1st century AD. Many known kings who ruled the India were enthusiastic to do the water storage for irrigation, and also encouraged individuals and villages to build tank to suite their requirement. The rainwater harvesting technology is an important today as it was in historical time. While designing, installing and operating the rainwater management system, proper data analysis of whether parameters, correct estimation of requirements and proper distribution system must be ensured to have maximum benefits from the rainwater harvesting.2) We got the knowledge about the traditional methods in Rain Water Harvesting system in India. Every region in India has their own ancient methods of irrigation. Other techniques like furaat, online filter, cross wave and underground water storage are used for filtration and storage purpose.3) Encourage on-site infiltration of water rather than diversion by impervious roads, parking areas, and drainage structures. Diverted

Rainwater alters the natural hydrologic cycle, discourages groundwater recharge, and generates increased runoff and flooding.

4) In the case study we came to know that construction, maintenance of Rain Water Harvesting system is very easy and simple. It can be handle by any person with minimum knowledge. Payback period is very small compare to its reliable period. The catchment area of MHADA building is 3866m2. The total cost of the Rain Water Harvesting system of MHADA building is 1750000Rs. And payback period is two years. Due to this water bill is reduced.

REFERANCES

[1] www.waterfieldindia.com[2] www.rainwaterharvesting.org/Rural/traditional2.htm[3] www.rainwaterharvesting.org/urban/rainfall.htm[4] www.samsamwater.com[5] http://www.furaat.com/[6] www.sekisui-techno-molding.jp/eng/products/cw/index.htm[7]www.rainwaterharvesting.org/People/..%5CRural%5Ctranhimreg_tradi.htm