Effective groundwater system recharge need of the hour

Human activities are severely damaging many lakes, rivers and wetlands, depleting them at a much faster rate. All of Earth’s ecosystems have undergone dramatic changes and biomes have been modified. The current loss of natural habitat and species is much greater than in the historical past and all of Earth’s ecosystems have undergone significant alterations. Since 1950, an increasing amount of land has been converted cultivable. This has changed the dynamics of water on global and regional scales.

The flow in the Gomti river has declined by nearly 50% in the last fifty years. The river has become seasonal at several places. Many of its tributaries have dried up. The river-bed in upper catchments has been severely affected by intensive farming and encroachments. The Gomti is one of the important tributaries of the Ganga river.

Seasonal or intermittent rivers can be found in every country and in many regions, their length can surpass that of perennial rivers. The drying of rivers is due to factors such as climate change, land-use change, rapid urbanisation and excessive water withdrawal. Most rivers in arid and semi-arid regions are now intermittent. In the near future, more frequent droughts are expected leading to a rapid increase in the number of intermittent rivers.

The Ganga basin is the world’s largest hotspot for groundwater exploitation, accounting for one-fourth of global groundwater exploitation alone. Irrigation in South Asia consumes nearly 50% of the world’s groundwater. The rapid abstraction of groundwater, often exceeding natural recharge, is turning many perennial rivers into sluggish and seasonal ones. The flow of perennial rivers is heavily reliant on groundwater systems. In 1984, the post-monsoon groundwater level in 91.45% of the Gomti basin was above 5-metre which dropped to 52.26% in 2006.

Currently, only 42% of the basin has water levels above 5-metre. This decline has caused wetlands to dry up and rivers to flow intermittently.

The value of natural endowment, such as groundwater, is often underestimated when considering the built infrastructure of cities.

A city’s survival depends on uninterrupted supply of water with groundwater being a significant source. Groundwater depletion has rendered multiple deep bore wells, averaging 100 metre in depth, dry and inoperable. Instead of ‘more crop per drop’, we must focus on ‘more crop per watt’ due to the high energy footprint of crop production, including irrigation.

Given the severity of extreme events and the impacts of climate change, it is essential to focus on adaptive management. We need to develop effective water recharge systems during flash floods .

While we have a solid understanding of extracting water from rivers, our knowledge of returning water to them is incomplete. It is crucial to have a comprehensive understanding of the entire watershed system of a river.