ASSESSMENT OF RAINWATER HARVESTING POTENTIAL FOR A PART OF CHANDIGARH

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 9, September 2017, pp , Article ID: IJCIET_08_09_012 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed ASSESSMENT OF RAINWATER HARVESTING POTENTIAL FOR A PART OF CHANDIGARH K. Pavan Kumar and B Sri Muruganandam Associate Professor, School of Civil and Chemical Engineering, VIT University, Vellore ABSTRACT Rainwater harvesting is an important water conservation technique which can be used as a stand-alone method or in conjunction with other water conservation methods. As water scarcity is becoming more pronounced in many urban areas in India, it becomes necessary to conserve water through whatever means available. In India rainwater harvesting is becoming mandatory for many cities and towns. Depending on the volume of rainwater available for harvesting, an appreciable portion of total water demand can be met with rainwater harvesting in many places. In this paper an attempt has been made to assess the total volume of rainfall that can be harvested for meeting part of the domestic water demand. The analysis has been carried out for a part of Chandigarh, which is a joint capital of Haryana and Punjab. As the city has seen quite a few water shortage years in recent past, it is appropriate to suggest a method for conserving water wherever and whenever possible. The analysis as done for four sectors of Chandigarh showed that a large portion of rainwater can be captured through rainwater harvesting, which can be then used for meeting part of the total domestic water demand. Keywords: water resources; water demand; rainwater harvesting Cite this Article: K. Pavan Kumar and B Sri Muruganandam, Assessment of Rainwater Harvesting Potential for a Part of Chandigarh, International Journal of Civil Engineering and Technology, 8(9), 2017, pp INTRODUCTION Water scarcity is one of the most pressing concerns for many urban regions in India. Urbanization is happening at a rapid pace across the country because of which there is a tremendous growth in population both due to internal population growth and due to migrations. One of the immediate effects of increasing population and development is the increasing water demand. Most often the available sources of water like river, lakes, reservoirs or groundwater sources are able to meet the water demand requirements only to certain urban growth levels. However as population increases, there is more stress on these natural water bodies and a stage may come when they are no longer viable as a source of water. In order to avoid such scenarios, there has been a trend among various municipalities to 91 editor@iaeme.com

2 K. Pavan Kumar and B Sri Muruganandam look for methods to conserve water or use water in more judicial ways. Among many water conservation techniques available, rain water harvesting (RWH) is most widely used across the country, especially in urban regions which have well laid out impervious roof tops. A lot of work has been done in India to assess and/or determine the suitability of rainwater harvesting method in different locations. For example, Tripathi et al., (2016) conducted a study on evaluation of site suitability for rainwater harvesting in Vidhyan regions of India. Meter et al., (2014) conducted a detailed study on status and history of rainwater harvesting system for the state of Tamil Nadu, India. They concluded from their study that rainwater harvesting should be best used in conjunction with other water conservation methods rather than as a stand-alone approach. Kumar et al., (2016) conducted an assessment for the performance of small rainwater harvesting structures (farm-ponds) in 5 major rainfed states of India over the period using data from multiple sources and stakeholders. Jha et al., (2014) developed a robust methodology for assessing rainwater harvesting potential and identifying suitable sites/zones for rainwater harvesting structures. Singh et al. (2017) with their detailed study suggested the following points with respect to rainwater harvesting: instead of arbitrary themes for RWH plan zoning, derived themes can be used for reliable results; water demand and groundwater conditions should be considered to prioritize the selected sites; priority zones/sites can be useful to water managers for ensuring sustainable water supply. In the present paper an attempt is being made to determine the rainwater harvesting potential for a sector in Chandigarh city, India. Chandigarh, the dream city of India s first Prime Minister, Shri Jawahar Lal Nehru, was planned by the famous French architect Le Corbusier. Picturesquely located at the foothills of Shivaliks, is also known, as the CITY BEAUTIFUL. The city is divided into 55 dwelling sectors. As per census 2011, total population of the city was 1,054,686 persons having a population density of 9252 persons/sq.km. The altitude of the city ranges from 304 to 365 meters above MSL. The water requirement of the city for drinking, domestic and other purposes is 365 MLD (Million litres per day) water. A major part of water requirement of the city is met by canal water. Canal water supply to the city is approximately 305 MLD. There are 200 deep tube wells in the city, which contribute a total of 91 MLD of water from ground water reserves. Besides there are 39 tube wells, which provide drinking water to rural area also. The main source of irrigation is ground water through 30 deep tube wells installed for the purpose of irrigation by Chandigarh Administration. The projected water requirement at year 2021 would be MLD whereas the total availability would be 310 MLD, so there would be a shortage of 99.5 MLD in future. Every year the rainfall situation of these two states is questionable. Taking 2016 year as an example these two states received scanty monsoon rains this year for the second consecutive year, with deficit standing at 25% each between June and September. Chandigarh, the common capital of the two states, also received poor rains this year, with a deficit of 46%, an official of meteorological department said so to Hindustan Times. These two states are the grain bowls of the country if these states only dry out then agriculture in India would be in a very critical stage. Thus, other methods of utilization of rainwater is essential for these two states. Taking 2016 year as an example Haryana and Punjab states received scanty monsoon rains this year for the second consecutive year, with deficit standing at 25% each between June and September, taking this as a condition statement we intend to find how much water could have been saved if rooftop rainwater harvesting was implemented there as an alternative. 2. RAINFALL PATTERN OF THE CITY: The normal annual rainfall of the city is 1061 mm, which is unevenly distributed over the area in 49 days. The southwest monsoon sets in from last week of June and withdraws in end of September, contributes about 80% of annual rainfall. July and August are the wettest months editor@iaeme.com

3 Assessment of Rainwater Harvesting Potential for a Part of Chandigarh Rest 20% rainfall is received during non-monsoon period in the wake of western disturbances and thunderstorms. The lowest rainfall, which was 49% less than normal, was recorded in 1987 and the highest rainfall, which was 69% more than normal, was recorded in Maximum amount of rain received by the city of Chandigarh during monsoon season is mm in a single day. The rainfall data for the city is as follows: normal annual rainfall mm; normal monsoon rainfall 849 mm; number of rainy days 49. The maximum and minimum temperatures are 39.1 o C and 6.1 o C respectively. The rainfall data for the city of Chandigarh for the last five years are given in Table 1. Table 1 Annual rainfall for Chandigarh for last five years Year Rainfall (mm) Statistically speaking although one-eighth of India is declared as flood prone, there are several thousand villages in India which do not have potable drinking water. A large quantity of water is used for irrigation and there is an urgent need for proper water management in irrigation sector. Over-irrigation through canals has led to water-logging in western Uttar Pradesh, Punjab, Haryana and Hirakud command area. The overdraft by tube-wells has resulted in lowering of water table in a number of villages in Haryana, Punjab and western Uttar Pradesh. 3. METHODOLOGY Monthly rainfall data for Chandigarh for about 20 years was collected from IMD. As shown in Fig. 1, the roof top areas for various sectors were calculated using My MAP Google application. Figure 1 Screenshot of the buildings as taken from Google Maps for which area and perimeter was calculated 93 editor@iaeme.com

4 K. Pavan Kumar and B Sri Muruganandam The area and perimeter of individual buildings as calculated using MyMAP are shown in Table 2 and 3. Table 2 and perimeter for the buildings ( 1 to 75) Table 2 and perimeter for the buildings ( 76 to 153) editor@iaeme.com

5 Assessment of Rainwater Harvesting Potential for a Part of Chandigarh From the roof top areas, the monthly volume of rainfall that can be harvested is calculated using the simple mathematical formula as given below: = (1) Where V m is the volume of rainfall collected for the month m; C is a coefficient which depends on the roof material. The value of C for some of the common impervious surfaces is given in Table 4; A i is the roof top area in m 2 ; and D m is the total rainfall for month m in meters. The monthly potential volume of water for harvesting is shown in Table 5. Table 4 Value of C for some of the common impervious surfaces Type of catchments Coefficients Roof catchment Corrugated metal sheets Ground surfaces Brick pavement Untreated ground catchment slope less than 10% Rocky naturals RESULTS AND DISCUSSION As per a study (2011) a typical person uses 252 lpcd of water every day in this study region. The city houses nuclear family (4 members in one family). We have taken a liberal estimation of 2 families per building. As per the table above, there are 153 buildings. Therefore total population to be served with water will be: Month Table 5 Monthly net water requirements for the region Monthly water demand (m 3 ) Monthly average rainfall (mm) Monthly water available from RWH (m 3 ) Net water requirement (m 3 ) Jan Feb Mar editor@iaeme.com

6 K. Pavan Kumar and B Sri Muruganandam Apr May Jun Jul Aug Sep Oct v Dec Number of people = 153 x (2 families x 4 people each) = 1224 people Hence the total daily water demand will be: Water demand = 252 liter x 1224 = liters The monthly net water requirement for the region is given in Table 5. From the results tabulated in Table 5, it is apparent that there is a surplus of water from rainwater harvesting for the months of January, June, July, August, September and October. Whereas there is a deficit of water during the months of February, March, April, May, vember and December. To meet the water demand during deficit periods, it will be appropriate to construct a storage structure to store water during excess supply and use the stored water during deficit periods. The required storage capacity of the reservoir can be determined using mass curve method. A mass curve is a plot between time (months or years) and cumulative inflow values. After the inflow mass curve has been plotted, the mass curve of demand may also be plotted by accumulating the required outflow. The mass curve of inflow and demand line can be used to determine the required storage capacity. The demand lines drawn tangent to the high points of the mass curve, represent the rate of withdrawal from the reservoir (Garg, 2016). The calculations for the mass curve are shown in Table 6. Table 6 Mass curve calculations for finding reservoir storage capacity Month Inflow (m 3 ) Outflow (m 3 ) Cumulative inflow (m 3 ) Cumulative demand (m 3 ) Cumulative demand (m 3 ) Jan Feb Mar Apr May Jun Jul Aug Sep Oct v Dec The graphical plot for the flow mass curve for different demand patterns is shown in Fig. 2 and 3 respectively editor@iaeme.com

7 Assessment of Rainwater Harvesting Potential for a Part of Chandigarh Figure 2 Mass flow curve with a demand line of 9563 m 3 From the above graph for the demand of 9563 m 3, the required reservoir capacity will be m 3. Similarly, for a demand of 9255 m 3, the required reservoir capacity will be: m 3. Figure 3 Mass flow curve with a demand line of 9255 m 3 The larger storage requirement is obtained for a demand of 9563 m 3, which is m 3. Hence the storage capacity of the required reservoir will be about m 3. Assuming a depth of 5 m, the required area for storage reservoir will be 4000 m, and with square shape, the dimensions of the reservoir will be: 64 m 64 m. 5. CONCLUSION An analysis was carried out for determining the volume of water that can be harvested for a sector in the city of Chandigarh. The monthly water balance showed that the inflow and demand patterns are uneven which necessitates the construction of a storage reservoir. Determination of storage reservoir was done using flow mass curve for different demand patterns. The results from flow mass curve indicated that the reservoir storage capacity for a constant demand of 9563 m 3 resulted in greater value. Hence the capacity of storage reservoir would be about m 3. Providing a storage reservoir would mean an uninterrupted supply of water. From MyMap google application, the areas suitable for rainwater harvesting were identified as follows: Roads and roundabouts: Recharge along storm water drains to both recharge rainwater as well as prevent flooding editor@iaeme.com

8 K. Pavan Kumar and B Sri Muruganandam All green areas: Recharge where suitable and store where hydrogeology is not suitable. Stored water can be used for horticulture. Ponds can be constructed to harvest and use rainwater as in Botanical Garden. Institutional areas such as Punjab University, Capitol complex: Recharge where suitable and store where hydrogeology is not suitable. Stored water can be used for horticulture. Commercial areas: Store in underground tanks for non-potable use. Schools, colleges and religious places: Storage and recharge. Stored water can be used for horticulture and other non-potable uses. Industrial areas and airport: Water from rooftop catchments to be stored that can be used for industrial purposes. Overflow of rooftop water can be recharged. Water from rooftops and hangars to be harvested in storage tanks to be used for non-potable purpose REFERENCES [1] Garg, S. K. Hydrology and water resources engineering, Khanna Publishers, [2] Kimberly J. Van Meter, Nandita B. Basu, Eric Tate, and Joseph Wyckoff (2014) Monsoon harvests: The living legacies of rainwater harvesting systems in South India, Environment Science and Technology, 48, pp [3] Laishram Kanta Singh, Madan K Jha, and Chowdary V M (2017) Multicriteria analysis and GIS modelling for identifying prospective water harvesting and artificial recharge sites for sustainable water supply, Journal of Cleaner Production, 142 (1), pp [4] Madan K Jha, Chowdary V M, Kulkarni Y, and Mal B C (2014) Rainwater harvesting planning using geospatial techniques and multicriteria decision analysis Resources, Conservation and Recycling, 83 (2), pp [5] Sandeep Kumar Tripathi, Babloo Sharma, and Raha, P (2016) Evaluation of site suitability and storage capacity of constructed rainwater harvesting structure in Vindhyan region, India, Indian Journal of Ecology, 43 (1), pp [6] Shalander Kumar, Thiagarajah Ramilan, Ramarao C A, Srinivasa Rao Ch., and Anthony Whitbread (2016) Farm level rainwater harvesting across different agro climatic regions of India: Assessing performance and its determinants, Agricultural Water Management, 176 (10), pp [7] Maharam Dakua, Asef Mohammad Redwan, Begum Nazia Jahan, Syed Mohammed Tareq, Saifuddin Ahmed and wroz Farhan or, A Case Study On Management of Rainwater Reservoir In Hilly s of Bangladesh. International Journal of Civil Engineering and Technology, 7(6), 2016, pp [8] Mohammad M J, Sai Charan G, Ravindranath R, Reddy YV and Altaf SK, Design, Construction and Evaluation of Rain Water Harvesting System For SBIT Engineering College, Khammam, Telangana. International Journal of Civil Engineering and Technology, 8(2), 2017, pp [9] Mohammad M J, Ravi Kumar T, Sashidhar Reddy P, Prathyusha P, Ashok P, Kiran T and Varaprasad YKL, Rain Water Harvesting System for Domestic Use in SBIT Engineering College, Khammam, Telangana. International Journal of Civil Engineering and Technology, 8(2), 2017, pp [10] Mohammad M J, Ramyasree G, Swarooparani CH, Krishnaveni T, Deepika P R and Sairam J, Role of Rain Water Harvesting In Artificial Recharge of Ground Water, International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 3, March 2017, pp editor@iaeme.com