50072
Two major types of hydrologic models can be distinguished : Recent research in hydrologic modelling tries to have a more global approach to the understanding of the behaviour of hydrologic systems to make better predictions and to face the major challenges in water resources management Groundwater modelling Groundwater models are computer models of groundwater flow systems , and are used by hydrogeologist s. Groundwater models are employed to simulate and predict aquifer conditions .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities:  
Answer:
 None