Extractive industries can lead to alteration of the natural groundwater regime, groundwater interaction with surface water and its contribution to environmental water demands by groundwater dependent ecosystems (GDEs) and other groundwater related assets. The assessment of such an impact is challenging, particularly when changes in the natural water regime can be caused by unrelated factors, i.e., climatic variability or other water uses. The remote sensing (RS) historical data can be used to investigate relationships between groundwater levels or fluxes, inundation (or standing waters), vegetation dynamics in the past, prior to any operations.
Significant and valuable information for groundwater systems characterisation can be derived from land surface analysis. Groundwater interacts with the surface through processes such as recharge and discharge. This interaction with the surface influences groundwater balance and defines groundwater environmental functions. Characterisation of groundwater discharge also enables evaluation of hydrogeological pathways (e.g. faults) and discharge mechanisms (e.g. springs or groundwater dependent ecosystems, GDEs).
Remote sensing provides a unique opportunity to understand spatio-temporal dynamics of these processes and to estimate the fluxes. Two particular advantages of RS techniques are the availability of historical data (over 40 years) and the ability to monitor specific surface objects of interest over large areas at low cost. This is particularly valuable in remote and data poor areas.
Remote sensing technologies are best used where their outputs can be validated by on-ground measurements. The results provide important and independent information for hydrogeological analysis, helping to derive a better conceptual groundwater, to define the groundwater fluxes in groundwater discharge zones and to identify the importance of some geological forms (surface expression of faults or stratigraphical boundaries).
A special Groundwater Systems Monitoring Tools (GSMT) has been developed and tested for a number of projects in Pilbara (WA), Namoi (NSW) and Northern Australia.