Some 20 year ago, in response to severe water shortages, the South African government passed the National Water Act, which is intended to restrict the amount of water farmers use for irrigation.

However ensuring that farmers only take the water to which they are entitled is tricky.

Maurits Voogt, who works for HydroLogic, a relatively small company based in Amersfoort in the Netherlands, says: “It is a major task to monitor and enforce the legal use of water in places where there are limited qualified personnel available, and the areas that need to be monitored are huge.

“We have developed a smart, satellite-based water auditing service as part of ESA’s programme of Advanced Research in Telecommunications Systems (ARTES). It allows water management authorities to monitor irrigated water use in large areas without actually needing to visit every single farm.

“By doing so, the water auditing application helps them implement regulatory measures effectively, and thereby supports the sustainable use of water resource.”