Determining locations of sublacustrine springs by remote sensing: the Skadar lake case example Montenegro

Locating zones of submarine or sublacustrine groundwater discharge often presents the most important part of a costal hydrogeological research. These zones are most commonly unobservable from the surface, so their determination requires complex research of large areas (the measurement of water temperature and salinity from craft vehicles, diving explorations, etc.). Analyzing of satellite and aerial images represents a more rational way for locating of sublacustrine and submarine springs ( vruljas ). Application of remote sensing for these purposes can include two techniques: determination of temperature anomalies from the thermal infrared satellite images and identification of faults which control groundwater flow. The Landsat 7 ETM+ thermal bands for the area of Skadar Lake are used for the determination of the temperature anomalies, i.e. the locations where colder groundwater outflow below the warmer lake water. For the identification of faults, color composite image (Landsat bands 4, 5, 7) are used, and after a selection of potential zones, detailed aerial images are also analyzed. Considering that the main sublacustrine springs of the southwest cost of Skadar Lake were known by previous complex researches, this area was used as a pilot area for the testing these remote sensing techniques. It has been concluded that the application of remote sensing can be very useful for the focusing the hydrogeological investigations to potential discharge zones which can significantly reduce the cost and time of a research.