Global groundwater resources

MOOSDORF, N. (Leibniz-Centre for Tropical Marine Research (ZMT), Bremen): Global scale groundwater analyses

The Earth System has been researched for decades with perspectives on global biogeochemical cycles, climate change, planetary boundaries or similar topics. While terrestrial surface water is acknowledged as important reservoir and transport pathway, groundwater is often neglected in by analyses of the Earth System. This may in part be because of the high complexity of groundwater systems or because of limited global data availability. Nonetheless, new globally available datasets and methods allow to increasingly include groundwater into Earth System Models. Here, I will present results highlighting the implications of groundwater in the Earth System and the limitations of global scale analyses.

Fig. 1: Top) Simulated average water table depths (averaged for the period 1960–2010) in meters below the land surface on the upper aquifer under natural conditions (without human water withdrawal) for the maximum confining scenario and the best parameter set. Bottom) head different; heads in bottom minus top layer. For water under pressure in the confined aquifer (bottom layer) a positive value is shown. When heads in the confining layer are higher, negative values are shown Quelle: de Graaf et al., 2017

TANIGUCHI, M. (Research Institute for Humanity and Nature (RIHN), Kyoto, Japan): Overview of submarine groundwater discharge from physical, chemical, ecological and economical points of view

Submarine groundwater discharge (SGD) is one of the important water and dissolved material pathways from land to the ocean. Recent SGD studies will be reviewed from physical, chemical, ecological and economical points of view. SGD will be also discussed with different scales such as point, coast, bay, basin, and global scales. Other SGD related issues will be referred including numerical simulations of SGD changes due to sea level rise, impacts of underground dam on the coastal ecosystem, 100 years evaluations of underground water exchange (saltwater intrusion and SGD) between land and ocean in Asian mega cities depending on the development stage of the urbanization.

Fig. 2: Schematic depiction (no scale) of processes associated with SGD. Arrows indicate fluid movement Quelle: Taniguchi et al., 2002