Program 4 is about understanding the relationship between groundwater and vegetation and how this might be affected by climate change and low rainfall.
While scientists have a reasonable understanding of how much water a single tree may draw from the ground, the groundwater needs of vegetation over an entire catchment are largely unexplored. A changing climate has introduced another significant unknown into the mix. Program 4 researchers are studying multiple variables to clarify the relationship between vegetation and groundwater, for example, rainfall frequency and intensity, rates of recharge, evapotranspiration, plant growth and human use.
Scientists are using range of techniques, from sapflow devices that measure tree water use, to remote sensing using satellites and airborne sensors. Researchers are also looking at how sensitive ecosystems are to changes in groundwater levels and chemistry.
Not only are Program 4 researchers considering these issues, they are also establishing robust and efficient tools for quantifying vegetation water use for sustainable groundwater management.
A sample of Program 4 projects can be found in the box to the right.