MODFLOW is a software for groundwater modeling developed by the USGS. The software is capable of representing conditions related to groundwater flow such as evapotranspiration, recharge, drainage, river interaction among others. Its finite different approach gives the capability to calculate the flow regime with exceptional control on water budget discrepancy. With MODFLOW one can rely on that the flow going in the model is the same as the flow going out of it, from the regional scale and on cross sections.

The concept of a groundwater regime is based on the fact that the occurrence and distribution of groundwater is not merely a product of chance, but the result of a combination of climatic, hydrologic, geologic, topographic and soil-forming factors that together form an integrated dynamic system. These factors are interrelated in such a way that each provides some insight into the functioning of the total system and thus serves as an indicator of local conditions of groundwater occurrence and distribution (PAEL, 1993).

MODFLOW-CFP is an efficient tool that helps us to model karstic conduits and learn about their interaction with groundwater flow.