Nearly 200 million acre-feet (MAF) of rainfall pours over Pakistan annually. The volume is nearly equal to the entire flow of the Indus River system, but 90 per cent of it is lost through runoff, evaporation and a lack of local storage infrastructure. Our main reservoirs — Tarbela, Mangla and Chashma — store only 15MAF at a time, and groundwater is being extracted at an unsustainable 50-55MAF annually, which is rapidly depleting the aquifers. Of the roughly 350MAF available annually from rainfall, rivers and aquifers, only around 160MAF is put to effective use.
The systemic inefficiencies result not only in economic loss, but also in irreversible ecological damage. Due to inadequate upstream conservation and flow regulation, the Indus Delta has become a silent victim as it is denied the freshwater it needs to survive.
Climate change has made rainfall more erratic and intense, but this deluge could be transformed from a threat into a solution. The potential is clear. According to the Pakistan Council of Research in Water Resources (PCRWR), the Tharparkar region alone receives sufficient rainfall to meet local needs if just 0.25pc of the rainfall gets harvested. Far less is currently stored.
In Nagarparkar, small rain-fed dams already support Rs1-4 billion worth of crop output annually. Islamabad could meet 60pc of its groundwater recharge needs through rooftop rainwater harvesting. Such steps should be scaled nationally.
While the Indus Basin recharge zones have been fairly studied, we urgently need to map and determine the recharge potential of Pakistan’s vast arid zones — especially in Balochistan, western Sindh and parts of southern Punjab — using advanced hydrogeological technology. To do this, Pakistan needs a dedicated body with legal and financial backing.
ASHOK SUTHAR
THARPARKAR
