The assessment of surface water and groundwater resources is the most important component in the long-term planning of an integrated water management scheme, since it provides information on the sustainable average available input on the supply side, its hydro-chemical properties as well as its temporal variability. Generally, two main methodologies are employed to quantitatively determine available water resources. These are:
Forward modeling with process models is a powerful tool for the determination of surface water and groundwater discharge, since, once calibrated and validated, they allow for the prediction of the temporal and spatial variability of the discharge components. However, they require a large amount of detailed spatially distributed data on the catchment, e.g. hydrological soil and vegetation characteristics, relief, etc. that are not readily available.
(Wolf & Hötzl 2011, Klinger et al. 2014, Klinger et al. 2015)