Using ApRES to enhance groundwater management in arid and semi-arid regions

Groundwater provides 50 percent of the world’s drinking water and supplies 38 percent of global irrigated land. It is often the primary source of freshwater in arid countries, many of which are in the developing world. Consequently, groundwater is the most heavily extracted of all raw materials worldwide. With an estimated withdrawal rate of 1000 km3 per year, it makes up 26 percent of all freshwater abstraction globally.[1]

Industrial and agricultural development has created additional need for groundwater in recent years, the extraction of which has been facilitated by advances in drilling and pumping technology. This has created increased pressure on groundwater reserves – in a number of places groundwater is being extracted faster than it is being replenished through rainfall. The result is sinking water tables, empty wells, higher pumping costs and, in coastal areas, the intrusion of saltwater from the sea which degrades the groundwater. However, the true extent of this exploitation is difficult to measure, which makes it challenging to regulate and control ground water use.

ApRES (Autonomous phase-sensitive Radio Echo Sounder) is a downward-looking radar that has been developed in collaboration between the British Antarctic Survey (BAS) and University College London to monitor very precisely an ice shelf’s changing thickness. By precisely measuring the change in the thickness of the ice, it’s possible to see how fast the ice shelf is being melted by the ocean. The instrument is relatively low cost, and is capable of being left to monitor the ice shelf over a period of a year or more, surviving the harsh Antarctic winter with low power requirements. From the point of view of radar, the surface of the water table has many properties similar to the transition between ice and water at the bottom of an ice shelf.

ApRES can be automated, which means that it can be used in contexts where high levels of technical input are unavailable. An ApRES network is able to monitor the discharge and recharge of aquifers in arid and semi-arid regions, making the management of groundwater in water scarce regions practically possible.

The role of the Development i-Team will be to help identify the best places in the developing world to trial the introduction of an ApRES groundwater monitoring system. In order to identify the best adoption contexts, and barriers to adoption, the i-Team is investigating the following questions:

  • Which developing countries are water-poor and have significant arid areas reliant on underground water, making the ability to continuously monitor the water table most transformative?
  • Which of these countries also have economic, political, social and regulatory environments that would enable the implementation and effective use of water-table monitoring systems?
  • Is water-table monitoring presently carried out in these countries, and if so, how?
  • Who might be the main end-users: government or other regulatory agencies, commercial and/or subsistence farmers, mining and other industries, and/or domestic water users, for instance?
  • How might potential end users be identified?
  • What contextual issues might enable or reduce use by particular stakeholder groups of end-users?

Having determined which countries could best benefit from an ApRES groundwater monitoring system, the i-Team will propose an initial set of technical targets for its optimisation in these specific country contexts. This might include instrument cost thresholds, the threshold for ease/difficulty of use, the preferred data format and delivery method.

[1] Water abstraction refers to freshwater taken from ground or surface water sources, either permanently or temporarily, and moved to the place of use.

i-Teams website link: 

Using ApRES to enhance groundwater management in arid and semi-arid regions