Groundwater pumping threatens world’s rivers and streams: study

A dry riverbed winds through agricultural land

2019 October — Researchers from UVic, Germany and the Netherlands have collaborated on a study that provides an alarming glimpse into the future of the world’s rivers and streams – if humans keep pumping groundwater at the current rate.

According to the study, which includes a global-scale hydrological model, almost 20 per cent of the catchment areas where groundwater is pumped suffer from a flow of streams and rivers that is too low to sustain their freshwater ecosystems. That number is expected to increase to 50 per cent by 2050.

“With the model, I am able to calculate the flow of groundwater to rivers all over the world and to study how a reduction of this groundwater flow, when groundwater is pumped, impacts river flow,” writes Inge de Graaf, lead author and Assistant Professor at the University of Freiburg in Germany. Other contributors include Tom Gleeson, of UVic’s Civil Engineering Department and author of the Water Underground blog.

Although the results of the study are “shocking,” Graaf says she is still optimistic about the future and believes that by raising awareness and taking protective measures, the situation can be corrected.

Featured in Nature, the international journal of science, the study is a collaboration of Utrecht University, the Deltares water institute, the University of Freiburg, and UVic.

Over the last 50 years, population growth and economic development have led to a large increase in freshwater demand, especially for the irrigation of food crops. In fact, about half the water used for irrigation is pumped from groundwater. In many dry regions around the world, as more groundwater is pumped than is recovered from rain, water levels drop. When water levels drop, the flow of groundwater to rivers and streams decreases. As a consequence, river flows will decline or even completely dry up and water temperatures will rise, forming a major threat to fish and water plants.

Read the study.

2019Oct02 AT