A look under Indus Basin in Pakistan
According to Dawn, the groundwater system underneath Pakistan’s flowing rivers in the Indus plains has at least 400 million acre feet (MAF) of pristine water. This storage is so large that it is equivalent to more than three years of the mean annual flow of the Indus (or 1,000 days of storage, after excluding polluted areas) So even if India blocks Indus water to Pakistan, it can still survive, for three years.