Wastewater management
suitable for continuous ecological monitoring to detect groundwater abstraction impact, if any.
Conclusions and recommendations The main objective of this study was to utilise the NDVI technique as a tool for monitoring groundwater dependent ecosystems using aerial photo imagery. The ground truthing has also shown that the CVA methodology is effective at mapping potential perennial groundwater discharge areas and therefore may be used as a tool to identify groundwater-surface water interaction monitoring sites. Though the results were positive, there is a need for more stringent filters to be applied to ensure that less unneeded information is received during the analysis. The following recommendations were made: As suggested by Thompson et al (2002), there are also various other biomass indicator combinations, which beg investigation, that may be used to more accurately or effectively interpret the data spectrally. For example, the use of hyperspectral imagery,
which provides a wider range of spectral coverage. This will enable a much better filter on the type of vegetation to be analysed. The inclusion of soil type data, containing information on hydric properties of the soil, e.g. permeability of the soil. This would be highly recommended for localised studies. Detailed analysis of vegetation species; this can be provided by the use of hyperspectral imagery to ascertain the occurrence of wetland vegetation. A depth to water table dataset is also useful to ascertain that vegetation sprouts mapped are linked to groundwater. A further development in the time series analysis is to use the area covered by the ecological site instead of a point source. A GPS mapping of the ecological site area must be undertaken to ensure ground truthing is done for the polygon shapes to
be taken out of the remote sensing process. The groundwater exploration study is currently focusing on prioritising the sites picked up by the ground truthing, determining which are suitable for on the ground monitoring, and developing a monitoring methodology. The primary factor to be monitored is water availability to plants and therefore data from piezometers installed at the sites could be used in conjunction with the biomass monitoring method developed for time series change detection. RéSource August 2012 – 69
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