INNOVATIVE POLICY INTERVENTIONS TO INCREASE DOMESTIC RAIN WATER HARVESTING IN URBAN AREAS ABSTRACT URBAN WATER CRISIS IN INDIA

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1 INNOVATIVE POLICY INTERVENTIONS TO INCREASE DOMESTIC RAIN WATER HARVESTING IN URBAN AREAS Tejwant Singh Brar, Research Scholar, Architecture and Planning Department, IITR, Roorkee, R.K. Jain, Associate Professor and Former Head, Architecture and Planning Department, IITR, Roorkee and Deepak Khare, Associate Professor, Department of WRDM, IITR, Roorkee. ABSTRACT In the context of the burgeoning water crisis in urban India, the technology of Rain Water Harvesting holds great promise in some of the water deficit cities of India. The technology is simple, cost effective and sustainable. An integrated system of rainwater harvesting can be designed for a city, in which RWH at the domestic and neighbourhood level can be combined with other rain water harvesting techniques at the city level for recharging the aquifer which will augment the net availability of fresh water for consumption. This paper draws attention to the need to change building bye-laws to augment artificial Recharge of ground water based on roof top rainwater harvesting The paper also suggests that an appropriate regulatory and incentive mechanism can be developed by the city governments to operationalise the technology. Key words: Domestic Rooftop Rain Water Harvesting (DRRWH), Recharge of ground water, Building bye laws. URBAN WATER CRISIS IN INDIA India is one of the less urbanised among the developing countries, with less than 30% of its population living in urban areas, but in absolute terms it has more than 300 million people living in towns and cities. This is almost twice the combined urban population of France, Germany and United Kingdom. The Urban India is growing more than 3.5% per annum, and it is projected that by the year 2041, urban population shall swell to 800 million, which is larger than the total population of the whole of Europe. India has 23 metropolitan (million plus) and 3 mega (ten million plus) cities and it is estimated that by the year 2021 the number of metropolis shall go up to 75 and that of mega cities to 6, when India will have probably the largest concentration of mega cities anywhere in the world (Singh, K and Steinberg, F, 1996). Already many of the Indian cities are facing acute shortage of potable water. Exploitation of surface water resources have reached a saturation point and excessive extraction of ground water and limited open area for recharge in some of the cities have resulted in sharp decline in the ground water table, which is manifested in failure in of tube wells, deterioration in ground water quality, saline water ingress etc (TERI, 2000). Many people are forced to access water from unsafe sources, leading to widespread waterborne diseases like diarrhoea, hepatitis, roundworm, with a telling effect on public health and hygiene. A recent study has indicated that about 30.5 million Disability Adjusted Life Years (DALY) are lost each year due to the poor quality of drinking water and absence of sanitation facilities. The financial loss in terms of productivity has been quantified at Rs. 360 billion (US $ 9 billion) annually (MUD, 2000). Water crisis in urban India is

2 assuming a cause of very serious concern of the planners, engineers, scientist, administrators and policy makers (Dhar Chakrabarti, 2000). RAIN WATER HARVESTING India receives on an average 1100 mm of annual precipitation, which is the highest in any part of the world. Although its distribution in space and time is highly variable, most of it is allowed to go waste as run off water into the sea through the river system. In the urban areas there is very little recharge to the sub-surface since most of the surface is impervious (either occupied by buildings or roads). Therefore, even if a part of the rainwater can be harvested, this may recharge the depleting ground water level and significantly contribute to the net availability of water for drinking and other purposes in the urban areas, particularly in the deficient areas (CGWB 1999). Roof water or rainwater harvesting techniques had traditionally been practiced by the urban communities in different parts of the country. Ranging from a purely domestic based system such as collection of falling water in containers or storage tanks to a community or even town level systems such as ponds, percolation tanks, dams or dykes had been in existence in many towns. Over the years, the introduction of pipe water supply on the one hand and gradual replacement of the community by the Government and Municipalities for the management of water supply in the cities on the other, has led to the abandonment of the ancient wisdoms (Agarwal, A. and Narain, S. 1997). The deepening urban water crisis has off late revived the interest on water harvesting structures. RAIN WATER HARVESTING STRUCTURES IN URBAN ENVIRONMENT Storage Tanks For harvesting the roof top rain water, the storage tanks may be used. These tanks may be constructed on the surface as well as under ground by utilising local material. The size of tank depends upon availability of runoff & water demand. After proper chlorination, the stored water may be used for drinking purpose (CGWB 1999). Recharge pits Recharge pits are constructed for recharging the shallow aquifers. These are constructed 1 to 2 m. Wide and 2 to 3 m. Deep which are back filled with boulders, gravels & coarse sand. The size of filter material is generally taken as below: - Coarse sand: mm - Gravels: 5-10 mm - Boulders: 5-20 cm The filter material should be filled in graded form. Boulders at the bottom, gravels in between & coarse sand at the top so that the silt content that will come with runoff will be deposited on the top of the coarse sand layer and can easily be removed. If clay layer encountered at shallow depth, it should be punctured with auger hole and that auger hole should be refilled with fine gravel of 3 to 6 mm size (CGWB 1999). Trenches These are constructed when the permeable strata is available at shallow depths. Trench may be 0.5 to 1 m. Wide, 1 to 1.5 m. Deep and 10 to 20 m. Long depending upon availability of water. These are back filled with filter materials. In case of clay layer encountered at shallow depth, the number of auger holes may be constructed & back filled with fine gravels (CGWB 1999). Abandoned dug wells Existing abandoned dug wells may be utilised as recharge structure after cleaning and desilting the same. For removing the silt contents, the runoff water should pass either through a desilting chamber or filter chamber (CGWB 1999). Abandoned hand pumps The existing abandoned 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 (CGWB 1999).

3 Abandoned tube well Abandoned tubewell may be used for recharging the shallow / deep aquifers. These tube wells should be redeveloped before use as recharge structure. Water should pass through filter media before diverting it into recharge tube well (CGWB 1999). Recharge wells Recharge wells of 100 to 300 mm. Diameter are generally constructed for recharging the deeper aquifers and roof top rain water is diverted to recharge well for recharge to ground water. The runoff water may be passed through filter media to avoid choking of recharge wells (CGWB 1999). Vertical recharge shafts For recharging the shallow aquifers which are located below clayey surface at a depth of about 10 to 15 m, recharge shafts of 0.5 to 3 m. Diameter and 10 to 15 m. Deep are constructed depending upon availability of runoff. These are back filled with boulders, gravels & coarse sand. For lesser diameter shafts, the reverse / direct rotary rigs are used with larger diameter shafts. In upper portion of 1 or 2 m depth, the brick masonry work is carried out for the stability of the structure (CGWB 1999). Shaft with recharge well If the aquifer is available at greater depth say 20 or 30 m, in that case a shallow shaft of 2 to 5 m diameter and 5 to 6 m deep may be constructed depending upon availability of runoff. Inside the shaft, a recharge well of 100 to 300 mm diameter is constructed for recharging the available water to deeper aquifer. At the bottom of the shaft a filter media is provided to avoid choking of the recharge well (CGWB 1999). Lateral trench with bore wells For recharging the upper as well as deeper aquifers, lateral trench of 1.5 to 3 m. Wide & 10 to 30 m. long depending upon availability of water with one or more bore wells may be constructed. The lateral trench is back filled with boulders, gravels & coarse sand (CGWB 1999). DOMESTIC ROOF TOP RAIN WATER HARVESTING Of all the techniques of rainwater harvesting, Domestic Rooftop Rain Water Harvesting (DRRWH) is very simple and inexpensive and can be adopted on a decentralised scale at the domestic level without much of additional investment. What are required are simply a catchment surface, an inflow conduit, a storage structure and a filtration system, if the collected water is to be used for drinking purposes (CGWB 2000). This method is particularly suitable for large buildings having the roof area of more than 1000 sqm. For a smaller building having the roof area up to 150 sqm. water can be diverted from the rooftop to the hand pump through the pipe of 50 to 100 mm diameter. Various studies on DRRWH, based on different types of roofing materials and storage systems have established that generally a loss up to 20% may take place due to evaporation and inefficiencies in collection processes. Thus only 80% of rainfall can be harnessed through rooftop. Therefore the following formula can be adopted to determine the total quantity of rainwater that can be reused: Total quantity of water collected (cum.) = Rooftop Area (Sqm.) x Average Monson Rainfall (m) x 0.8 From the above formula, four-fifth of the annual rainfall should be harvested or recycled for domestic use, but in reality that does not happen. No organized and authentic data regarding domestic rooftop rain water harvesting in any Indian city is available, but as things stand today, not even a small fraction of the total rainfall is harvested in the urban areas, barring possibly one or two cities, although the possibilities are enormous. The reasons are the following: All the urban areas are already covered by a centralized pipe water system, which is highly subsidized. Although the system is deficient and does not cater to the full requirement of the residents, there is not much incentive for the residents to invest on an additional system at the domestic level. Only those who own an independent and large roof area and have sufficient open space for the installation of storage tanks can afford to set up such a system, but such categories of people are usually well off to purchase water from alternate sources rather than invest on RRWH. Even if they invest on such a system, it is usually for garden or lawn irrigation rather than for drinking purposes. The occupancy pattern and ownership system of urban property is such that a very small part of the total roof area is owned individually and often the density of population living under a

4 roof is so high that the per capita availability of recycled rainwater to the occupants of the building is very insignificant and therefore the economics of rainwater harvesting at the domestic level may not work out very favourably. Joint management of roof water not only for the purpose of collection and conservation but also for their extraction and reuse shall also become a difficult proposition because of the complexities of the issues involved, unless these have been planned at the time of construction of houses. A large part of the urban landscape is not roofed, although it may be built up, for example the road space, the lanes and bye lanes etc. Similarly the set backs of the buildings, the open spaces, the parks, gardens, play grounds, city forests etc have no roofs and therefore the run off from such areas can not be pooled under a DRRWH system. Domestic conservation and extraction of ground water through dug well or tube well shall also depend on the depth of the local aquifer. If it is too deep it may not be extracted economically and if it is too shallow it can either pollute ground water or be polluted by other discharges. The buildings of urban India have not been designed with built in provisions for DRRWH system. Although the concept is old and antiquated, its application in the context of modern city life is a very recent phenomenon. Neither the master and zonal plans of the cities nor the building bye laws had any stipulation regarding rooftop rainwater harvesting and therefore gutter, inflow system and storage tanks were not conceived when the buildings were designed and no incentive structure has yet been developed for adding such facilities on the existing buildings. These are formidable constraints, which have hindered any large-scale use of DRRWH system in urban areas. These also underline the inherent limitations on the use and application of the system at a domestic level in modern city life. Possibly a purely domestic based and decentralized rain water harvesting in urban areas do not stand a very great chance of success unless this technique is used as part of an integrated and holistic framework of rain water harvesting in urban areas and unless a proper regulatory and incentive structure is developed to make the system popular and attractive. POLICIES FOR RAINWATER HARVESTING IN URBAN AREAS Planning Process in India is a three tier structure which consists of Central Government, State level and at Urban Local Bodies level (after 74th constitutional amendment). At Central level Planning Commission of India is the main body for allocation of funds for various planning projects. Water being a State subject, the role of Central Ministry of Water Resources is only advisory to the state governments for sustained development of water resources in the country. It is primarily the responsibility of the concerned State Governments to plan, finance and execute schemes for augmenting water resources. Government of India is also promoting rainwater harvesting through Watershed Management Programme, artificial recharge of ground water and roof top rain water harvesting under various schemes. Various measures as initiated by the Central Government for water conservation and augmenting ground water resources are indicated below:- Constitution of Central Ground Water Authority on 14 th January, 1997 under the Environment (Protection) Act, 1986 for regulation and control of ground water management and development. Circulation of a Model Bill to all the States/Union Territories in 1971, 1992 and 1996 to enable them to enact suitable legislation for regulation and control of ground water development. Circulation of Manual on artificial recharge of ground water in 1994 to the States/Union Territories to enable them to formulate area specific artificial recharge schemes to check the declining trend in ground water levels. Implementation of pilot Central Sector Scheme on Studies on Artificial Recharge of Ground Water in the country at an estimated cost of Rs crore. Recharging wells and rain water harvesting are integral part of this scheme. In 10 th Five Year Plan for development of ground water resources and rain water harvesting in major cities Rs Crore have been allocated (MOWR, 2002). State Planning Commissions are main bodies for allocation of funds for various projects at state level. Along with Water, Urban Planning is also a state subject which comes under the Urban development Ministries and the Master plans for the Urban areas are prepared either by the concerned Town & Country Planning departments or the Urban Development Authorities depending on the size of the Urban Areas.

5 Urban Planning process is a four tier structure which consists of Perspective or Master plan, Development Plan, Annual plan and Action plans. The Master plan is a long term (20 25 years) written document supported by necessary maps providing the state government goals, policies, strategies and general programmes of urban local authority regarding spatio-economic development of the settlement under its governance while other plans are conceived prepared and implemented according to the vision of the master plan. A Master plan gives the location and area of the various proposed land uses, the density of proposed development and the details of the development controls, such as Building Bye-laws and landuse controls etc., to achieve the proposed development. Development Plans have a time period of 5 Years to synchronize the fund allocation with Five Year Plans. Annual Plans are prepared to synchronize the fund allocation with the annual state budget. Action Plans Give the Projects to be implemented for sustainable development of the urban settlement. Main function of the Urban Local Bodies is to guide the development according to the Master Plan Prepared by the Town & Country Planning Departments and to provide and maintain the services like Water supply, Sanitation and Transportation. The major flaw in this Planning Processes is that the Building Bye-laws, and Development charges do not encourage citizens to adopt Rain Water Harvesting and other measures to conserve the water. Also as water is being supplied at greatly subsidized rates, cost of water is between Rs 8.10 to Rs 6.10 per Kilo-liter at prices while it is supplied at less than Rs 2.00 per Kilo-liter (10 th Five Year Plan, 2004), by the Urban Local Bodies so people are not encouraged to adopt the rain water harvesting which in turn is depleting the precious available water resources resulting in shortage of water in the urban areas. To overcome these problems there is a need to adopt Water Sensitive Development Controls as part of the Building Bye-laws in the Master plan of the Urban Area Itself. While for the landuse development in the city there must be two different set of strategies 1) For the existing Development, 2) For the Proposed development. There is also a need to encourage the role of NGO s and participation from public while preparation of the Master Plan to get greater public cooperation latter during implementation of various projects. The city of Bangalore, South India will be the first city in the country to have a rainwater harvesting policy. With an average rainfall of 900 till 970 mm over 7 months, Bangalore is at an elevation of 900 MSL and water has to be pumped infrom 400 MSL. Thus, the pumping costs are enormous and so are power charges. Water rates are the highest in the country. Without back-up by any legal provisions, 500 to 600 houses have DRWH systems in place now and the number is growing. The Rainwater Club, a local NGO, developed not only very innovative approaches like the rendering of roofs for rainwaterharvesting, but handed in now a draft policy mapping all possible sources for harvesting rainwater (Hartung, H. and Patschull, C., 2005). REGULATORY FRAMEWORK FOR DRRWH In a residential sector, the ground water recharge structures needed for various land uses can be designed according to the run off generated by them. For a residential sector of 150 ha area with maximum rainfall intensity of 20mm/hr the ground water recharge structures are given in Table 1(Brar T.S., 2002). Table No. 1 : Ground Water Harvesting Structures Required In Sector S. No. Landuse % of landuse Area Maximum unmattled area available % of unmatteled area Area Run off with maximum unmattled area % ha % ha m 3 /s Remarks i) Residential 55% mm dia shaft per house and trenches in EWS housing ii) Commercial 3% 5 35% wells*/ trenches** iii) Public-Semi Public 12% 18 35% wells* iv) Circulation 20% 30 35% wells*/ trenches** v) Recreational 10% % wells*/ trenches** Total 100% wells*/trenches**

6 Source: Urban Planning And Development Strategies With Respect To Water Resources In Patiala, T. S. Brar. * 4 m dia 6 m deep recharging wells with 300 mm dia shafts. ** 1.5 to 3 m wide trenches with borewells To reduce the run off and to recharge the ground water there is a need to change the building bye laws and to design the ground water recharge structures for various categories of houses according to the area of the plot and run off generated by them. For a residential sector of 150 ha area with maximum rainfall intensity of 20mm/hr the ground water recharge structures for various categories of houses are given in Table 2 (Brar T.S., 2002). Table No. 2 : Ground Water Harvesting Structures Required For Residential Development S. No. i) HIG ii) iii) Size of Plots/ Category 418 m 2 to m 2 (1 Kanal to 14 marla) MIG m 2 to m 2 (12 marla to 8 marla) LIG m 2 to 83.61m 2 (6 marla to 4 marla) Total area under one category Max. Coverage Max. unmetalled area Run off with max. unmetalled area ha % ha m 3 /s % to 60.7% % to 65% % to 75% iv) E.W.S. Housing % (of site) Size and type of groundwater recharging structure x10-3 to 300 mm dia 1.2x10-3 shaft/house x10-3 to 7.1 x x10-4 to 3.7 x mm dia shaft/house 300 mm dia shaft/house x10-4 /house 1.5 to 3 m wide Source: Urban Planning And Development Strategies With Respect To Water Resources In Patiala, T. S. Brar. trench with borewells acc. to site CONCLUSIONS AND RECOMMENDATIONS To encourage the increasing use of rain water harvesting at the domestic, neighborhood and institutional levels following innovative policy interventions, incentives and regulations by local urban bodies must be adopted: DRRWH shall be made mandatory for all new development (T.S.Brar, 2002). The Municipal Building Bye Laws must be amended to that effect. No Building Plan of a new construction must be approved by the Municipality unless it has provisions for DRRWH system. This must also been made mandatory for all commercial and institutional complexes. Incentives must be provided by way of rebate in property taxes for installation of such facilities in the existing residential houses, which do not have any system for rooftop water harvesting. Group Housing Societies must also be encouraged to set up injection well at the neighborhood level for conserving the rainwater. The technology is simple, affordable and cost effective and holds a great promise for water deficit cities in the years to come. REFERENCES 1. Agarwal, A. and Narain, S. (1997) Dying Wisdom: Rise, Fall and Potential of India s Traditional Water Harvesting Systems, Centre for Science and Environment, New Delhi. 2. Brar,T.S. (2002), Urban Planning And Development Strategies With Respect To Water Resources In Patiala, Guru Ramdass School of Planning, Guru Nanak Dev University, Amritsar. 3. Central Ground Water Board, (1999). Activities and Achievements of Central Ground Water Board on Rain Water Harvesting and Artificial Recharge, Ministry of Water Resources, Government of India, New Delhi. 4. Dhar Chakrabarti, P.G. (2000) Urban Crisis in India: New Initiatives for Sustainable Cities, Paper presented at the N-Aerus Conference on Sustainable Cities, May, Geneva

7 5. Hartung, H. and Patschull, C. (2005), The inclusion of domestic roofwater harvesting (drwh) in a national water legislation framework, 6. Ministry of Urban Development (2000), Policy Paper on Urban Infrastructure, Government of India, New Delhi. 7. Ministry of Water Resources (2002), Thirty Fourth Report Ministry of Water Resources Demands For Grants Government of India, New Delhi. 8. Planning Commission of India (2004), Tenth Five Year Plan Government of India, New Delhi. 9. Singh, K. and Steinberg, F. (eds.) (1996) Urban India in Crisis, New Delhi. 10. Tata Energy Research Institute (2000), DISHA 2047 (Directions, Innovations, and Strategies for Harnessing Action), Delhi.