Introduction Ingraham Hwy & Homestead Canal Construction Culverts Airborne Resistivity Tables References PDF Version

Ingraham Highway and Homestead Canal

The Ingraham Highway was constructed between 1915 and 1919 (Fig. 2). This highway provided an overland route between Royal Palm State Park and Flamingo, a settlement on the shore of Florida Bay with access to the backcountry of the Everglades. The road was built using fill from a borrow ditch, known as the Homestead canal, which followed the western edge of the road from Flamingo northward. The road, which on average was one foot above the surrounding ground elevation ([ 2 ]), frequently overtopped during the wet season, making it impassable. This highway had no culverts and effectively prevented flow except during the wet season. After the road turned eastward at the concrete bridge (Fig. 2), near the present location of the Flamingo water supply wells, the borrow ditch was located on the northside of the road. The borrow canal was open to Florida Bay. During the early decades of this century, when the drainage of the Everglades accelerated, the southern glades frequently dried out, reversing the hydraulic gradient and allowing the Homestead Canal to become a conduit for the inland flow of salt water. In addition to the free exchange of salt water through the outlet near Flamingo, saline water also entered the canal at Whiskey Creek.

Since the water level was near or above the ground surface, the road was constructed by dredging (excavating the rock by detonating dynamite in bore holes to fracture the limestone). The rock was thrown to one side and graded to make a roadbed. During the last week of December 1917, the dredge was about four and a half to five miles from Royal Palm, making slow progress towards Cape Sable, when during blasting a subaqueous cavern was uncovered ([ 16 ]). The thirty foot boom was let down and swung around, but it did not encounter any obstruction. Broken pieces of stalactites, to over four feet diameter were retrieved. It is likely the dredge crossed a geologic reef remnant. Rock reef ridges exist in ENP which may serve as conduits thus altering flow patterns in the area. Upon completion of the Homestead canal and road to Flamingo, an extension of the canal was cut to Lake Ingraham in an attempt to drain the Cape Sable prairie.

During the period 1946 to 1956, water samples were collected from the canal along Ingraham Highway southwest from Royal Palm. D.B. Bogart ([ 14 ]) recognized that the canal acted as an avenue for salt-water intrusion from the estuary to the area between Whitewater Bay and Homestead. His findings were based on the chloride analysis of the samples. He concluded that in dry periods, salty water moved upstream toward ranger station at Royal Palm Park. One of the higher values collected had a chloride content of 21,000 ppm collected at Nine-mile bend on July 20, 1948. Several dams were installed in the Homestead canal in an attempt to slow salt water encroachment by regulating what had been uncontrolled flow.

The first dam was installed at station 19 (Nine-Mile Bend) in June 1950. In June 1951 a second barrier was installed in the canal at station 16, 3 miles north of station 19. A year later a third barrier was added in the canal at station 15, 1 mile north of station 16. The canal water remained relatively fresh in the reach above station 16 until the drought of 1955-56 ([ 11 ]). Data collected in May of 1956 show values of 9,420 ppm below the dam at station 16 and 4,900 ppm above the dam. Values of 82 ppm were also recorded from the old concrete bridge 2 miles north of station 15. Klein and Hartwell studied chloride levels from these stations and nearby wells. They concluded that although the general freshening of water at these sites in the 1950's may have been the result of the installation of salt-water barriers in the Homestead Canal, it was more likely due to relative higher seasonal water levels since the 1943 survey of the area around the Flamingo supply wells was made.

Construction of the new road began in 1956 and the Homestead canal was filled in from Flamingo north to the wellfield (located near culvert 76). Today, remnants of the road and canal still exist. A 10 mile section south of Royal Palm can still be traveled by service vehicles. In this section the road and canal continue to form an effective barrier for overland flow to the south. During high water the road is overtopped in several low spots as water flows south from the canal to the wetlands. A 3.4-mile section from the wellfield to the east was totally removed and can only be noticed as a slight depression. The removal of the section occured shortly after completion of S.R. 9336, to limit access to the area east of the road to help reduce poaching. The road to Royal Palm was left in place as it provided access to private property. The borrow canal north of the road is overgrown and contains a lot of organic deposit but still allows flow to occur from east to west during the wet season.