A flow limiting inlet structure is designed to collect water or other fluids in a pool above grade, and to provide improved capture of sediments and surface pollutants such as oils and greases in the pool, while regulating the flow of water or other fluids during discharge into an outlet pipe. In a conventional storm water detention basin a vertical cylindrical discharge structure can be used to regulate the basin water depth and discharge flow rate of storm water out of the detention basin, in conjunction with the use of a specially designed baffle system that prevents the release of any greases or oils floating on the water surface while capturing any floating trash or debris.