Water Management in Deccan International School

Deccan International School is located in Padmanabhanagar in the south of Bengaluru. The overall area of the school complex is 10 acres. There is a contour drop of 10 m within the campus.

The school campus is situated in a low-lying area near the dry Chikka Kalasandra lake. Hence, during heavy rain, many areas on the school campus get flooded. At the same time, the school regularly faced water scarcity issues during the summer months.

The school needs water for drinking, handwashing, gardening and flushing. A significant amount of water is also needed for the swimming pools in the aquatic centre. The water demand based on a survey conducted was found to be 35 KL/day.

This story focuses on how the school has solved this paradoxical problem of water scarcity and abundance using 11 recharge wells that direct a large part of the 13801 KL/annum (13.8 million litres) rainwater runoff into the ground.

Area of school campus and its proximity to the Chikka Kallasandra Lake

The main sources of water for this campus are:

1. Four borewells (BW1 near the main block, BW2 near the Junior school block, BW3 near the swimming pool, BW4 near the Ashram school). BW1 had silt accumulation due to badly designed direct borewell recharge. It is working fine after casing replacement and recharge well filter media cleanup. Apart from BW2, all the borewells would go dry in the summer. After recharge wells were dug, they have been yielding throughout the year.
2. Water tankers. The school had to buy 12 KL of tanker water per day in the summer (2 tankers of 6 KL each), mainly for the swimming pools.
3. Cauvery water: The school gets Cauvery water from BWSSB – about 2 KL per day. This is mainly used for drinking purposes after filtration.

Flooding problem and solution

The primary issue the school faced was flooding during heavy rains.  The areas that were most prone to flooding have been listed below. The solution for each of these areas was tailored slightly differently.

• Flooding area 1 – the parking lot
• Flooding area 2 – Junior school courtyard
• Flooding area 3 – Open area behind Ashram school (previously called grape garden area)

Flooding area 1 – The parking lot

Water enters the school through this area from a large catchment beyond that includes the Telecom layout. Two recharge wells of dimensions 5ft x 30ft were dug here, with the overflow of one directed to the other. The overflow from RW2 has been directed into a chamber from which all the water is directed into the main SWD of the school. Multiple recharge wells are present in this SWD. This line of recharge wells in the internal SWD lies upstream of BW1 and BW2, and the consequent recharge could be a significant contributor to the revival of these borewells.

Since the volume of water coming into this area has been observed to be high in the last 2 years, the school is now also considering diverting a part of the runoff towards the open well near the Ashram school.

One of  the RWs in the SWD

Open well near Ashram block (12 ½ ft dia, 55 ft deep)

Placement of recharge wells for flood management in flooding area 1 (the blue arrows show the direction of water flow)

Flooding area 2 – the Junior School courtyard ( runoff volume: 199 KL /annum)

The Junior School courtyard used to flood when water overflowed from the stormwater drain and also from the runoff from the elevated play area to the southeast. However, since the recharge wells in the SWD were dug, this flooding has reduced significantly. A cattle trap drain has also been made downstream of the courtyard to take any excess water from this area to an 80 KL rainwater tank.

Junior school courtyard (left: the school side, right: opp the school with cattle trap drain)

Flooding area 3: the grape garden area (runoff volume: 47 KL)

This area directly receives the runoff from the Telecom Layout and extension roads, the parking area, the path next to the playground, the Ashram school rooftops and ground, through a large culvert that opens out into the grape garden area. After the two recharge wells were dug, the school didn’t see any flooding in this area. A basketball court has now been constructed in this area and has not faced any water-logging to date.

Next steps

After successfully arresting flooding and water scarcity issues, the school is not now looking into water security and environmental sustainability. The following steps are being planned in this regard.

Open well: An old open well near the ashram block that had run dry has now started to hold water after the heavy rains of 2021 and 2022. Motivated by this, the school plans to direct the rooftop rainwater from the Ashram School building into this well and also some of the water from the parking lot in its direction to keep the shallow aquifer here active.

Rooftop rainwater harvesting: Rooftop rainwater harvesting is being planned for the rest of the buildings as well. This water is planned to be used to supplement their domestic needs and further reduce the pumping of borewell water. 

Rainwater harvesting tank: A rainwater tank of 80 KL capacity exists near the junior block that is currently taking in a lot of silty water that is picked up from the playground through which it flows. The school plans to rectify this issue and use the harvested rainwater for gardening purposes.

Map with important areas marked