National Dam Inspection Program. Saw Mill Dam (NDS ID PA 00324 DER ID 46-261), Delaware River Basin, Saw Mill Creek, Montgomery County, Pennsylvania. Phase I Inspection Report.

摘要

Saw Mill Dam is a zoned earth embankment with an impervious core, an outer previous shell, a cutoff trench and drainage blanket and rock toe. These features are shown on Plate 3, entitled 'Typical Embankment Sections'. The dam is approximately 1,335 feet long and the height, measured from the crest to the principal spillway discharge pipe inlet, is 47 feet. Borrow materials were obtained from the spillway excavation and within the reservoir area. The core of the dam is composed of clayey materials derived from the borrow areas, and the shell is composed of more previous materials selectively excavated from the borrow pits. The 10 foot wide cutoff trench has 1H:1V side slopes and a grout cap at the base of the trench. The foundation was grouted using a single line grout curtain with six foot hole spacings. The average hole depth is 15 feet and the maximum hole depth is 30 feet. The upstream slope is 3H:1V, the lower two-thirds of the slope is protected with 18 inches of riprap over a 12-inch filter blanket and the upper portion is protected with grass. The downstream slope is 2.5H:1V and protected with grass.