Prof. Adar’s main research activities are associated with quantitative assessment of groundwater flow systems and sources of recharge in complex arid basins with puzzling geology and scarce hydrological information.

Adar has developed the novel transient Mixing Cell Model (MCM_tr) approach utilizing hydrochemistry and environmental isotopes coupled with a non steady flow model.

Among other research activities, are the initiation and/or involvement in the investigation of:
(1) the role of water reservoirs and shallow groundwater on top-soil salinization in the Jezreel Valley;
(2) the effects of forestation over sand-dune terrain on local groundwater reservoirs;
(3) the dynamics of flow and pollutant transport in a fractured chalk aquitard (low permeable yet fractured formation) in the vicinity of the Ramat Hovav Industrial Park; (4) identification and quantification of pollutant sources into ephemeral rivers from various basins with different anthropogenic activities;
(5) the effect of industrial effluents on the hydraulic properties of a fractured chalk aquitard;
(6) identification of irregular salinization processes in the Coastal Aquifer of Israel;
(7) salinization and deterioration of topsoil water quality due to anthropogenic activities;
(8) soil and groundwater contamination in the coastal aquifer of Israel (Ramat Hasharon area) by organic industrial pollutants and
(9) hydrological aspects of management and policy associated with transboundary water resources in Israel and the Middle East.