Certain lands adjacent to Salt Creek, Buffalo Creek including their various branches and tributaries as well as several low-lying areas in the Village of Palatine have been identified as flood hazard areas. In most cases the floodwaters are not very deep outside of the creek banks; however they still can cover yards and streets flooding cars, garages, basements and lower floors. Floodplains along the creeks are divided into two parts. The floodway includes the creek channel and the adjacent area whereas the flood-fringe is further away from the creek. The floodway carries the major volume of the floodwaters and is essential to conveying the floodwaters downstream. Blocking the waters flowing in the floodway can result in significantly higher flood levels upstream. The flood-fringe areas have typically shallower flood depths are not critical for conveying the floodwaters downstream.
There are other areas in the village that are also prone to flooding and are not adjacent to the creeks. These typically are low-lying areas. To identify these other flood-prone areas, the village relies on maps produced by the United States Geological Survey that are based upon actual floods that have occurred in the past. For these low-lying areas to be classified as floodplain, the area that becomes flooded must be ¼ acre or larger. This is to eliminate those small pockets of accumulated water such as in backyards from being regulated as floodplain.