The rain poured several million acre feet (MAF) of water which was way more than the capacity of the Manchhar Lake. In addition, it also created a 100km additional ‘lake’. Experts believe that this water will stay for months as evaporation is our only hope in terms of reclaiming the dry land.
I have studied subsoil data of Rahim Yar Khan in lower Punjab, Daharki in upper Sindh and Port Qasim in Karachi while sinking tube wells up to a depth of 150 feet. The subsoil strata predominantly range between sandy-clay and clayey-sand mixtures, but all three sites had a 10-15 feet thick clay band starting around the 20-30 feet level. Water above it cannot penetrate it and stays put. This impervious clay level if punctured will allow water to seep downwards quickly.
Architect Yasmin Lari on her YouTube channel has defined easy methods to make these wells while utilising minimal tools, stones and gravel. It is great that she has successfully demonstrated them in downtown Karachi. If we make thousands and thousands of these wells across the flooded areas, we will surely be able to avoid inundation and subsequent losses.
S NAYYAR IQBAL RAZA
KARACHI
