National Dam Inspection Program. Green Lane Reservoir Dam (NDI -PA 00618, PA DER 46-250), Delaware River Basin, Perkiomen Creek, Montgomery County, Pennsylvania. Phase I Inspection Report.

摘要

Green Lane Reservoir Dam is a concrete gravity structure approximately 780 feet long, with a maximum height of about 87 feet. A 424 foot upgated spillway (crest Elevation 286.0) is centered along the length of the dam. The non-overflow section (Elevation 297.0) has a top width of 14 feet. Below Elevation 281.0, the upstream slope is battered on a 1 horizontal to 14.55 vertical (1H:14.55V); the downstream slope is 1H:1.35V. Both faces are vertical above Elevation 281.0. A 3-foot high parapet has been constructed on the non-overflow section. The dam is founded on firm bedrock. The foundation rock was mass grouted to depths up to 30 feet to reduce loss of water through seepage. The non-overflow sections are founded in rock on both sides of the stream valley. This rock has also been grouted to reduce seepage. The spillway is a concrete Ogee with a maximum height of approximately 77 feet. A flip bucket type energy dissipator with a 25-foot radius has been constructed at the toe of the spillway. Training walls extend downstream from the dam on both sides of the spillway. The walls are constructed to Elevation 255.0 and retain and protect the channel banks immediately below the dam. A water intake facility is located in the non-overflow section at the north end of the spillway. The intake is separated into two parallel chambers by an internal wall. Flow can be directed between the two chambers by a 36-inch sluice gate positioned in the wall. Openings at four different stages control water entering the intake. Each opening is fitted with a removable screen to prevent debris from entering.