.5% of Earth's water is fresh water out of which 68.9% is of Glaciers and Ice caps, 30.8% is locked up in ground. Only 0.3% is surface water which serves most of life needs [1]. Water is a primary requirement for our daily activities, Safe and readily available water is required for public health, food production, recreational use, drinking and domestic use. Water management is directly relatable to the economic growth of the country, Water availability is one of the primary criteria for setting up of industries which are associated with local and foreign investments. Majorly many parts of North Karnataka are facing water crisis which is also an indirect reason for poor generation of employment opportunities hence many youths are heading towards metropolitan cities like Bengaluru resulted in rapid increase of population failure of typical water supply system to meet the requirement.
According to Composite Water Management Index, August 2019 released by NITI Aayog 5 out of 20 world largest cities are under water stress are in India, Indian urban population is expected to reach 600 million by 2030 with expected demand supply gap of 50Bcm [2].
In recent years India has experienced weak monsoons resulted in drought conditions at many places. Ground water table is reducing day by day in many parts of the country, Punjab which produces 10% of India's paddy utilizes 80% ground water for paddy irrigation depleting its own ground water resource, 70% of India's thermal power faces water stress by 2030 which contributes 83% of India's energy power generation in 2016, Presently 40% of India's thermal power plants are in water scare regions, 14 of them faced shutdown in 2013-16 due to water scarcity [2].
Recently Indian government introduced ministry of jalshakthi, which launched programs like Jalshakthi abhiyan to encourage and promote water conservation, Rain water harvesting, renovation and rejuvenation of water bodies, bore well structures. Once a drought village Jakhni of Bunderkhand district, Uttar Pradesh is emerged as self-water reliable village by adopting methods like collection and storage of rain water, Restoration of ponds, Grey water usage with no external funding. Sustainable water management has to be incorporated in private and public buildings to overcome the water demand. Decentralized approach has to be adopted in order to achieve this state. Rain water harvesting by roof top water collection and ground water improvement by simple techniques are the easy, suitable and sustainable solutions for the problems associated with water requirement and its management.
Rain water is the ultimate and primary source of fresh water. Lakes, ponds, Rivers, Ground water are the secondary sources. Rain water has highest potential to meet the demand of people if public are involved in conservation of rain water in their houses, public building's, Institutions. Rain water harvesting has been carried out from decades from simple harvesting techniques like collection of water through small drums by using normal cloth as a filter medium to modern techniques. Rain water harvesting is defined as collection of rain water from the surface where it falls, either it may be roof top harvesting or open space harvesting. Rain water harvesting potential depends on catchment area, intensity of rainfall. Rain water collected is stored and utilized or the water from open source can be utilized for ground water recharging. Year 2021
( D D D D ) CRain water is collected from roof tops and is filtered to remove dry leaves, waste materials, dirt present on the roof top, the water is taken to storage tank which can be overhead tank, surface tank and overhead tank by using down take pipes. The stored water can be treated and can be used as potable water or can be used for non-potable purposes like irrigation, gardening etc. The stored water can also be used for recharging of ground water by different methods such as recharging through establishment of recharge pits or trenches, constructing artificial recharge wells or by using abandoned or existing bore wells. average annual rainfall of 877.8 mm [3]. Satellite view of RVCE campus is shown in figure 1 below. The main motto of the institution to achieve sustainability in terms of water, energy and waste management, in road to achieve this the institution has setup rain water harvesting units in three phases across the campus which has collection capacity of 3.6 lakh liters in total, two bore wells are also established for the purpose of ground water recharging, Campus also has Reverse osmosis water treatment and softening plant of 22000 liters capacity and Sewage treatment plant of 50 kld output [4].
Present study aims at estimating potential of rain water and runoff which can be collected annually from different roof top area of different buildings located at RVCE.
V.
Methodology By harvesting rain water from different buildings of RVCE we can collect 21492572 liters of water annually making RVCE campus self-reliable and self-sustainable in water usage. Collected water can be utilized for flushing, gardening purposes, since the daily requirement of the institution is high adopting RWH techniques is found to be simple and sustainable technique which can be implanted in the campus.
Runoff is defined as the ratio of precipitation that makes its way towards rivers or oceans as surface or subsurface flow to the precipitation received. After undergoing infiltration and other loses from the rainfall, to determine potential runoff water that can be collected from different catchment surfaces like playgrounds, parks, pavements etc. present at RVCE campus, figure 4 and figure 5 shown below gives satellite image of cricket ground and site respectively. area of the catchment surfaces are determined using Google earth and represented in table 3, runoff coefficients of different surfaces were collected and annual water yield from runoff is obtained by knowing area and average annual rainfall of the catchment. Annual water yield, Q is obtained by using the formula Q = R x A x C Where, R is the average annual precipitation A is the catchment area C is the runoff coefficient Runoff coefficient of pavements = 0.7-0.95, parks = 0.1-0.25, unimproved areas = 0.1-0.3, tiles = 0.8-0.9, playgrounds = 0.2-0.35 [5]. The runoff water which can be collected from different surfaces such as pavements, parks, sites, playgrounds located at RVCE campus is 32725384.29 liters which can be utilized for recharging of ground water by adopting recharge structures.
The present study concludes that by adopting RWH facility to collect the water from roof tops of all the buildings of RVCE campus, 21.49 Million liters of water can be collected. It is evident that adopting RWH and artificial ground water recharge techniques in all the public buildings can be a solution to water availability and management problems at urban areas.
1. Obtaining roof top area of different buildings at |
RVCE campus using Google earth. |
2. Collection of rainfall data from India Meteorolgical |
Department (IMD) website. |
3. Runoff co-efficient of different materials are obtained |
from |
4. A building is considered and the monthly/annual |
water demand and monthly/annual rain water yield |
from the roof top area is measured and the rain |
water harvesting tank capacity is determined |
according to IS 15979: 2008. |
Month | Average Rainfall (mm) | Monthly yield(l) | Cumulative yield(l) | Monthly demand(l) | Cumulative demand(l) | Volume stored(l) Surplus(l) | |
May | 96 | 161710 | 161710 | 158400 | 158400 | 3310 | 3310 |
June | 85.7 | 144359 | 306069 | 158400 | 316800 | 0 | 0 |
July | 100.3 | 168953 | 475022 | 158400 | 475200 | 0 | 10553 |
August | 117.8 | 198431 | 673453 | 158400 | 633600 | 39853 | 40031 |
September | 194.6 | 327799 | 1001252 | 158400 | 792000 | 209252 | 169399 |
October | 154.5 | 260252 | 1261504 | 158400 | 950400 | 311104 | 101852 |
November | 43.9 | 73948 | 1335452 | 158400 | 1108800 | 226652 | 0 |
December | 15.8 | 26614 | 1362066 | 158400 | 1267200 | 94866 | 0 |
January | 2.3 | 3874 | 1365940 | 158400 | 1425600 | 0 | 0 |
February | 6.4 | 10780 | 1376720 | 158400 | 1584000 | 0 | 0 |
March | 16 | 26951 | 1403671 | 158400 | 1742400 | 0 | 0 |
April | 44.5 | 74959 | 1478630 | 158400 | 1900800 | 0 | 0 |
Total | 877.8 | 1478630 | 1900800 |
D D D D ) |
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Year 2021 | ||||
Sl. No. | Building name | Area | Annual water yield | |
1 | Department of CV | 1535.81 | 862805.77 | |
2 | Department of ME | 1431.69 | 804311.98 | |
3 | Department of CSE | 1063.36 | 597387.14 | |
4 | Department of EC | 1262.1 | 709037.68 | |
( D D D D ) C | 5 6 | Department of EEE Department of AS and ISE | 1773.06 1911.81 | 996090.92 1074039.56 |
7 | Department of BT and EIE | 1050.23 | 590010.81 | |
8 | Department of MCA | 1596.28 | 896777.33 | |
9 | Department of TE | 894.95 | 502775.75 | |
10 | CRC Complex | 803.41 | 451349.31 | |
11 | Department of CE | 1586.42 | 891238.06 | |
12 | Administrative block | 1330.78 | 747621.55 | |
13 | Mechanical PG block | 486.43 | 273272.48 | |
14 | Department of IEM | 925.75 | 520078.94 | |
15 | Old sports complex | 547.44 | 345990.83 | |
16 | New sports complex & Gym center | 1239.1 | 826638.30 | |
17 | Food Court | 1354.09 | 855806.54 | |
18 | Bank and Post office | 153.29 | 86117.09 | |
19 | Aero-space lab | 862.21 | 575204.43 | |
20 | Library building | 873.11 | 490506.21 | |
21 | Hospital Building | 301.61 | 169442.08 | |
22 | Cognitive and Research Block | 863.28 | 484983.78 | |
23 | Workshops | 3213.01 | 2143488.935 | |
24 | Old cauvery hostel | 1251.64 | 703161.33 | |
25 | New cauvery hostel | 2632 | 1478636.54 | |
26 | Sir m v hostel | 2041.95 | 1147151.17 | |
27 | Chamundi hostel | 1159.33 | 651302.31 |
Sl. No. | Type of catchment | Area (m 2 ) | Annual water yield(l) |
1 | Pavements | 27913.06 | 11760975.1 |
2 | Play grounds | 20507.54 | 4950417.62 |
3 | Unimproved areas/ sites | 37633.28 | 8258623.3 |
4 | Parks/greenery | 24187.23 | 4246310.1 |
5 | Brick/tiles/concrete | 4996.95 | 3509058.17 |
Total runoff | 32725384.29 |
D D D D ) C | ( D D D D ) |
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