Longitudinal, round, perforated pipe edge drains have been used along Kentucky roadways for approximately two decades. Panel (fin) edge drains were first used in Kentucky in 1984. Most of these edge drains were installed on the Interstate and Parkway systems.
Several problems related to the drains have been noted in the last seven years. A number of these problems have been observed to be related to flexible outlet pipes and headwalls.
A recent study was initiated to evaluate headwalls and outlets on I-75 from Lexington, Kentucky to Cincinnati, Ohio (approximately 70 miles) and on I-71 from Louisville, Kentucky to I-75 in Northern Kentucky (approximately 68 miles). This study was initiated as a first phase of a much more intensive study which will evaluate all edge drains and outlets on Interstates and Parkways in Kentucky.
This report documents findings of the investigation of 234 edge drain outlets. Of the 234 outlets investigated, approximately 43 percent of the edge drain outlets inspected were out of service. Approximately 50 percent of the outlet pipes had been damaged during installation. More significant problems were found at the headwall and outlet pipe connection than any other location in the drainage system.
It appears that a maintenance program should be established to clean the troughs of the headwalls and to check the screens for clogging and rust. The metal screens should be replaced with galvanized screens.
Positive flow should also be maintained from the headwalls. The buildup of grass and silt can eventually detour some of the flow. Headwalls located in cuts are more prone to become covered or ponded.
Edge drains and outlets should be inspected after they are installed.
Rigid outlet pipe should be precast into the headwalls. This should help eliminate problems occurring at the headwall connection. Currently, a rigid outlet pipe is connected to an approximately 2-foot long "pigtail" (4-inch flexible pipe) which is precast into the headwall.
Digital Object Identifier
Fleckenstein, L. John; Allen, David L.; and Harison, Jack A., "Evaluation of Headwalls and Outlets for Geocomposite Edge Drains on I-75 and I-71" (1991). Kentucky Transportation Center Research Report. 668.