Hydrologic modeling is the process of simulating or estimating the behavior of the water cycle components (such as evapotranspiration, infiltration, runoff) and their impact on surface and groundwater resources over a specified area and time. It involves the use of mathematical equations and computer models to simulate the various components of the hydrological system. This specialized skill requires knowledge of hydrology, engineering, and numerical methods as well as proficiency in hydrologic modeling software. The results of hydrologic modeling can be used for a wide range of applications, such as flood forecasting, water resource management, water quality assessment, and climate change impact assessment.