A dynamic modular approach was developed in order to quantitatively simulate the groundwater table and discharge under various climate conditions:
1. A toolset was developed to calculate climate zonation from climate parameter grids;
2. Recharge zones (Hydrological Response Units, HRU’s) were delineated based on geology, land-use;
3. Recharge was calculated for various climate conditions for each recharge zone using 1D analytical- empirical hydrological models;
4. Groundwater table and discharge, (ex-filtration) was calculated under various climate conditions using numerical groundwater flow models;
5. Combination of 4 different climate scenarios: eg. two global climate models (CNRM-CERFACS-CNRM-CM5 and ICHEC-EC-EARTH with two radiation set: (the optimistic RCP 4.5, and the high RCP 8.5) and several production scenarios were coupled and calculated for predictive management goals.
The advantage of the above methodology is that in the Hungarian parts of the Pannonian basin.
• It provides a quantitative link between climate and hydrogeological conditions at large regional flow system under the pressures of different drinking, irrigation, thermal and other water abstractions;
• Modular structure provides flexibility and facilitates changes in input data, calculation tools and spatio-temporal resolution at various levels from scale of the local groundwater dependant ecosystems to the basin wide water balance calculations.
Recharge zones (HRU’s) were determined based on surface geology, land-use conditions. The HELP hydrological model was used for the calculation of 1D water balance for hydrological response units. The MODFLOW numerical groundwater modeling code was used for the calculation of the large scale 3D water balance and head patterns under various climate and production conditions.