IATI pilot project 'Submarine Groundwater Discharge: Adaption of an autonomous aquatic vehicle for robotic measurements, sampling and monitoring' (IATI-SGD)

The IATI-SGD pilot project is a joint project between the two Helmholtz centres GEOMAR and UFZ.

The flow of terrestrial groundwater into the sea, usually called “submarine groundwater discharge” (SGD), is a global phenomenon that has been observed and demonstrated in near- shore environments and shelves of all continents. While the slow seepage of groundwater that flows out along most of the world's shorelines is more important volumetrically, discrete outflow via submarine springs is an exotic form of SGD that attracts considerable attention because of the springs' unique physical appearance and properties. Some of them are large enough to provide freshwater for human needs, hence they are considered to be of potential economic importance. We are proposing an integrated onshore-offshore IATI pilot project to study this phenomenon in the Salalah coastal plain and shallow offshore waters.
Within the marine component we are proposing to develop a „smart“ robotic vehicle with sensor systems for marine environmental monitoring purposes. To this end we will be acquiring an off- the-shelf wave glider by Liquid Robotics Inc. (LRI) that is capable of self-navigating preset courses without direct human interference, operating entirely with wave-generated and solar power. The wave glider will be retrofit with sensors for a suite of chemical and biological measurements tailored to identifying submarine groundwater discharge phenomena. In contrast to standard sensor input we will not only store or transmit the collected data but develop robotic capabilities beyond simple acquisition. The wave glider will be able to use the sensor input to navigate the area under investigation, e.g. by detecting gradients in sensor data the glider will decide to change detection resolution or adapt its course to improve data quality. The combined sensor input will be utilized for autonomous event-based decision making, such as alerting a shore-based station, changing its navigation pattern, autonomously adapting its sampling strategy and so forth. This will be accomplished using a set of user-defined rules. The key challenges will be to build and integrate robust sensors (for temperature, salinity, pH, density, fluorescence, Radon isotope decay activity, etc.) as well as strong robotic capabilities for long- term offshore operations.
Submarine groundwater discharge (SGD) originates from aquifer systems that are located in coastal regions or large continental aquifer systems. In order to assess and quantify SGD fluxes, groundwater flow pathways within the different aquifer systems have to be investigated onshore.
The onshore part of the pilot project aims at the identification and quantification of groundwater flow from the coastal plain to the ocean (see Fig. 1).

Figure 1: Schematic view of the Salalah coastal aquifer plain and its predominant water fluxes.

Water resources in the shallow and the deep coastal aquifers will be assessed and quantified. Exploration, analysis, monitoring and modeling will start from the foothill of the Dhofar Mountains and will continue to the Arabian Sea. The focus will be on water sources, groundwater residence times, the connectivity of the different aquifer systems and the potential of the coastal aquifers for natural loss of groundwater through SGD. In order to link fluxes detected by the wave glider system and the onshore activities a groundwater flow model of the coastal and deeper aquifers will be built. Monitoring sensors and hydrochemical analyses will be developed in close cooperation with the wave glider team in order to trace groundwater flows from the aquifer systems to the discharge locations offshore. This combined monitoring and modeling approach will then allow to detect and to quantify SGD fluxes for large coastal regions.


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Dr. Jan Friesen (UFZ)


phone: +49 341 235 1082