One of the key operations in the construction of hydrogeological models is the transformation of continuous physical systems into discrete models while conserving the aimed model performance level and optimizing the available resources. Such operation is called discretization, and it has to be applied to both spatial and temporal domains in hydrogeology. The present paper deals with the temporal domain discretization. A literature review is given first, and then a parametric study (using 1D flow modeling) is conducted to assess the effects induced by boundary conditions (specified head or specified recharge rate), data temporal resolution and model simulation time step on hydrogeological flow model performances. It was found that the effect induced by the dynamic comportment of a recharge rate boundary condition type is more important than that due to a specified head. For the recharge rate, the time step must be smaller or equal to the data resolution when using Modflow. As for a specified head boundary condition type, it was recommended to take a time step satisfying Δt∞1/(K × Δh).
 Ostrowski, M., Bach, M., Gamerith, V. & De Simone, S. (2010). Analysis of the time-step dependency of parameters in conceptual hydrological models. Institut Wasserbau und Wasserwirtschaft, Technische Universität Darmstadt, Germany
 Mitchell, G. & Diaper, C. (2006). Simulating the urban water and contaminant cycle. Environmental Modelling& Software. 21, 129-134. DOI:10.1016/j.envsoft.2005.03.003.
 Mohrlok, U., Wolf, L. & Klinger, J. (2007). Quantification of infiltration processes in urban areas by accounting for spatial parameter variability. Journal of Soils and Sediments. 8(1), 34-42. DOI: 10.1065/jss2007.05.225.
 Downer, C.W. & Ogden, F.L. (2004). Appropriate vertical discretization of Richards’ equation for twodimensional watershed-scale modeling. Hydrological Processes. 18, 1-22. DOI: 10.1002/hyp.1306.
 Tustsumi, A., Jinno, K. & Berndtsson, R. (2004). Surface and subsurface water balance estimation by the groundwater recharge model and a 3-D two-phase flow model. Hydrological Sciences Journal. 49(2), 205-226. DOI: 10.1623/hysj.126.96.36.199837
 Sutanudjaja, E.H., van Beek, L.P.H, Jong, S.M., van Geer, F.C. & Bierkens, M.F.P (2011) Large-scale groundwater modeling using global datasets: a test case for the Rhine-Meuse basin. Hydrol. Earth Syst. Sci. Discuss. 8, 2555-2608. DOI: 10.5194/hessd-8-2555-2011.
 Berendrecht, W.L., Lourens, A., Snepvangers, J.J.J.C. & Minnema, B. (2007). Large-Scale High-Resolution Groundwater Modelling using Grid Computing. Oxley, L. & Kulasiri, D. Eds. MODSIM. International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand.
 Kostiakov, A.N. (1932). On the Dynamics of the Coefficient of Water Percolation in Soils and on the Necessityof Studying it from a Dynamic Point of View for the Purposes of Amelioration. Trans. Com. Int. Soc. Soil Sci. 6th. Moscow.
 Maniak, U. (1997). Hydrologie Und Wasserwirtschaft: Eine Einfuhrung Fur Ingenieure. 4th ed. Springer.
 Harbaugh, A.W., Banta, E.R., Hill, M.C. & McDonald, M.G. (2000). User guide to modularization conceptsand the ground-water flow process. MODFLOW-2000. The U.S. Geological Survey modular ground-water model. Open File Rep. USGS.
 Nash, J.E. & Sutcliffe, J.V. (1970). River flow forecasting through conceptual models: Part 1. A discussion of principles. Journal of Hydrology. 10(3), 282-290. DOI: 10.1016/0022-1694(70)90255-6
 Gupta, H.V., Sorooshian, S. & Yapo, P.O. (1999). Status of automatic calibration for hydrologic models: Comparison with multilevel expert calibration. J. Hydrologic Eng. 4(2), 135-143. DOI: 10.1061/(ASCE)1084-0699(1999)4:2(135)
 Singh, J., Knapp, H.V. & Demissie, M. (2004). Hydrologic modeling of the Iroquois River watershed usingHSPF and SWAT. ISWS CR 2004-08. Champaign, Ill.: Illinois State Water Survey.
 Moriasi, D.N., Arnold, J.G, van Liew, M.W., Bingner, R.L., Harmel, R.D & Veith, T.L. (2007). Model evaluation guidelines for systematic quantification of accuracy in watershed simulations. American Society ofAgricultural and Biological Engineers. 50(3), 885-900.