Read on Twitter
#Thread on: How does Pune's groundwater move?
Here's a picture showing most of the city, with its two main rivers Mula-Mutha. The groundwater from surrounding areas is slowly seeping towards the rivers.
Everything from an awesome report on Pune's aquifers by ACWADAM (2019).
Here's a picture showing most of the city, with its two main rivers Mula-Mutha. The groundwater from surrounding areas is slowly seeping towards the rivers.
Everything from an awesome report on Pune's aquifers by ACWADAM (2019).
60 million years ago, lava from the earth's mantle was spurted over most of Maharashtra, as MANY LAYERS of Deccan Trap Basalt.
Two important types:
Compact Basalt (CB) = Hard & without much water.
Vesicular Amygdaloidal Basalt (VAB) = Lots of pores for water = "aquifer rock"
Two important types:
Compact Basalt (CB) = Hard & without much water.
Vesicular Amygdaloidal Basalt (VAB) = Lots of pores for water = "aquifer rock"
ACWADAM has mapped 33 such layers in Pune!
VAB = Pink = Aquifer
CB = Green = Impermeable layer
Water has eroded away much of this layered cake over millions of years. The lowest point is the current river.
To relate the two maps: @VetalTekdi ~ Ward 20. Hanuman Tekdi ~ Ward 27.
VAB = Pink = Aquifer
CB = Green = Impermeable layer
Water has eroded away much of this layered cake over millions of years. The lowest point is the current river.
To relate the two maps: @VetalTekdi ~ Ward 20. Hanuman Tekdi ~ Ward 27.
A generalized aquifer map was prepared by ACWADAM shows the 5 aquifer layers that are exposed/unconfined.
Aquifer 5 has the highest elevation and has all other aquifers underneath. Layers are generally 5-10 meters thick.
As shown in first pic, water moves towards the rivers.
Aquifer 5 has the highest elevation and has all other aquifers underneath. Layers are generally 5-10 meters thick.
As shown in first pic, water moves towards the rivers.
Areas where an aquifer overlying an impermeable layer is sharply eroded, springs may appear in the region.
While PMC supplies ~10 Trillion Cubic Meters (TMC), additional ~5 TMC of groundwater is used by residents.
This implies ~70% of Pune's rainfall has to be put in the ground to sustain present levels! Current maybe around 25%.
This is where the land-use changes need to happen.
This implies ~70% of Pune's rainfall has to be put in the ground to sustain present levels! Current maybe around 25%.
This is where the land-use changes need to happen.
The aquifer layering in Pune is just a small part of the larger connected layered aquifer system.
Just as the Mula-Mutha gain waters from Pune's 5 Aquifer layers, others in Bhima Basin do the same, as aquifers are offering an arghya into the rivers.
Just as the Mula-Mutha gain waters from Pune's 5 Aquifer layers, others in Bhima Basin do the same, as aquifers are offering an arghya into the rivers.
It is amazing how different this groundwater regime is, compared to the simpler Indus-Ganga Plains Aquifer, and that the junta does not actively know it. #Retweet
