This ordinance differs from the general NFIP model in a number of ways. Jefferson County prohibits building in the floodway. They define the floodway as the “Local Regulatory Conveyance Zone,” or the area produced when the Local Regulatory Floodplain (traditionally based on the 1 ft. rise in a 100 year flood) is reduced to create a 1/10 of a foot rise. More interestingly, the County prohibits a wide array of activities along the “blue line” streams (USGS defined perennial streams), requires a 25 foot vegetative buffer along all the channels and even requires that native vegetation be replaced if it disturbed by any construction activities in the area. The Floodplain Management Plan and Floodplain Management Ordinance can be obtained at www.msdlouky.org.