As indicated by the arrows on the map, water used to flow from the Allapattah Marsh, through the Barley Barber and into Lake Okeechobee.
This historical drainage pattern of the area has been modified by highways, railroad and drainage projects. In the late 1800s, the flow into Lake Okeechobee from the Barley Barber Swamp was impeded by the construction of railroads and highways. Canals dug alongside the roadbed to extract fill diverted much of the flow, while the bed acted as a dike. High water flow from the Allapattah Marsh had all but disappeared by the 1940s, due to drainage activity throughout the region.
After the 1940s, construction of the L-65 and St. Lucie canals and of U.S. 441 further affected the original drainage pattern of the area. However, in spite of these changes, the swamp is now considered an outstanding example of Florida as it may have appeared more than 100 years ago.