The document discusses the installation of a rainwater harvesting system at the Kasavanahalli Government School in Bangalore. The school faces major water scarcity as it does not have access to piped water and must rely on expensive tanker water. A plan was devised to harvest rainwater from the school's rooftops, which could collect over 10,000 liters in an average rainfall, and store it in the school's sump and tanks to meet non-potable water needs. Funding for the system was provided by students from the University of Washington, who visited the school after installation to see the completed project.

1. Rainwater Harvesting at Kasavanahalli Government School
Central Jail Road is an area where the erstwhile villages (now part of the corporation
limits) and high-rise buildings are cheek by jowl. The villages can be identified by the type
of houses, the small grocery shops and the government schools that cater to the village
students. The village houses both the old residents and the migrants. The heart of the
village is the Kasavanahalli Government school which helps provide an insight into the
community around it.
Kasavanahalli Higher Primary school (HPS) is located off Central Jail Road, near the
Kasavanahalli Village.
The total student strength is ~200 with 4 teachers. The school shares one of the classroom
blocks with the Samriddhi Trust, which runs a bridge school for children of migrant
labourers in the vicinity.
The school faces major water scarcity. It has one 10 KL sump and plumbing connections
given to the overhead tanks (OHTs) for toilets and handwash stations. However, the main
issue is availability of water. This area doesn’t have access to Cauvery water/piped water
supply. The school also doesn’t have a borewell and hence, has to depend on tanker water.
This incurs expenses that the school finds difficult to manage. The toilets are not being used
due to lack of water.

2. The existing infrastructure at the school is as follows:
The issues faced by the school were brought to Biome’s notice by one of the Bhoomi College
students, Ms. Hema Bapat who stays near the school. During her interaction with the
school, the schoolteachers mentioned the water issues and asked for help. Hema, having
known Biome and our work, approached us for suggestions. The discussions led to arriving
at rooftop rainwater harvesting as one of the solutions. The plan was to harvest the rooftop

3. rainwater, collect it and store it in the sump and tanks which could then be used for toilets,
handwash, plate washing and other non-potable uses.
The harvestable potential of the school rooftops is as follows:
Roof area Runoff in
25mm rainfall
Runoff in
30mm rainfall
Runoff in 650mm
annual rainfall
Block A- 125 sqm 2800 litres 3375 litres 73125 litres
Block B- 105 sqm 2350 litres 2835 litres 61100 litres
Block C- 108 sqm 2160 litres 2590 litres 56160 litres
Cooking area-14 sqm 315 litres 375 litres 8190 litres
The school would be able to harvest ~10KL in one average rain which would suffice them
for 3-4 days at least.
Biome with the help of plumber Manjunath co-designed the rainwater harvesting system
for the school. The last hurdle in this was the funds to implement the RWH system. Biome
is a non-profit trust and was not in a position to fund the system. After going back and forth
with the funders and waiting for almost 6 months, help arrived from the students of the
University of Washington. The students are part of the ‘Women in Leadership’ program of
the University of Washington. The students raised close to 2000 USD which they wanted to
donate to a meaningful program. The suggestion to donate it for installing the RWH in this
school appealed to them, and finally the work could be started.
The students came down to India in September 2017 as part of their program and saw the
installed RWH system. They engaged in some volunteering activities such as painting the
water tank, creating a garden bed and a stone path through a flooded patch, etc.
This blogpost has a brief account of their visit along with some photographs.

4. The diagram below shows the layout of the planned rooftop RWH system.

5. Gutters from the sloping rooftop connected into existing storage structure with filter above it
Two separate filters constructed for filtering harvested water from two main rooftops

6. Filtered water is connected to existing sump by underground pipes and water from first rain
collected