1.0 Overview and Background
|Satish Dhawan Park
2. Digging an open well
The place for digging the open well was identified next to the pond near the gazebo. Well digger Ramakrishna and team worked on the well. They hit water around 7ft. They continued digging till 15 ft. At this depth they hit soft soil which was collapsing. They had to stop going deeper as there was a scare of the structure collapsing. Jelly and concrete rings were installed to give support and stability to the structure. A 2HP submersible pump was installed to pump the water from the well to use it in the garden.
Here is a video of the soil collapsing at 15 ft.
When all the water from the well was pumped out it was observed that the well required about 8 hours to recuperate ie. time taken by the percolating water to fill the well to a particular level noted.
The well has about 2500L of water. The 2 HP pump requires 20 minutes to pump 2500 litres of water.
Units of electricity used for pumping 2 x .746 x 20/60 = 0.5 units of power.
This pumps out about 2500 litres or 2.5 kl of water.
Cost of power at Rs 5.50 per unit hence cost per kilolitre of water 0.5 x 5.50 / 2.5 = Rs 1.10 per kilolitre.
This water from the well can be pumped to the external storage twice in a day and used in the garden.
Open wells help manage the shallow aquifer by being structures that can both draw water from the shallow aquifer as well as serve as structures that can recharge the ground. Open wells with water are also the source of water with the lowest amount of energy required to source the water. More details about Bangalore and its open wells can be found here http://bengaluru.urbanwaters.in/our-open-well-heritage-510/