As canals and levees were built during the 19th and 20th centuries, agriculture and urban land uses dramatically increased, significantly reducing the spatial extent of the "natural" Everglades system by the mid 1970's.
Starting in the late 1800's and the early 1900's, long stretches of canals were dug in attempts to drain the relatively pristine Everglades for agriculture. Problems such as devastating floods led to Federal authorization (1948) of the Central and South Florida (C&SF) Project, creating an elaborate network of canals, levees, and water control structures to improve regional flood control and water supply.
It was ultimately very effective in managing water for those purposes, accelerating the development of urban and agricultural sectors of the region. Agricultural and urban development has generally continued through the present day, particularly along the corridors east and north of the Everglades. The C&SF Project led to a reduction in spatial extent of the Everglades, and also fragmented the once-continuous Everglades wetlands into a series of large impoundments.
In the current-day Everglades, the existing management infrastructure bisects the area into a series of impoundments, or Water Conservation Areas (WCAs). Everglades National Park is south of these WCAs, while Big Cypress National Preserve is to the west. Agricultural land uses dominate the area just north of the Everglades, while extensive (primarily) urban land uses predominate along the eastern boundary of the Everglades. Lake Okeechobee, historically bounding the northern Everglades marshes, is now connected to those marshes via canals.