Accession Number:

ADA327050

Title:

Monongahela Dam 4 Spillway, Pennsylvania Hydraulic Model Investigation.

Descriptive Note:

Technical rept.,

Corporate Author:

ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS COASTAL HYDRAULICS LA B

Personal Author(s):

Report Date:

1997-05-01

Pagination or Media Count:

141.0

Abstract:

Monongahela Dam 4 is located on the Monongahela River 34.1 km 21.2 miles upstream of the confluence of the Ohio, Allegheny, and Monongahela Rivers, in the city of Charleroi, PA. The existing dam maintains the navigation pool between the Dam 4 and Dam 5 locks and dams. Normal upper pool elevation for the Monongahela 4 is presently at el 743.5 all elevations cited herein are in feet referred to the National Geodetic Vertical Datum. The existing spillway section of Dam 4 consists of a gated crest el 724.0 located within the main channel of the waterway. Energy is dissipated on a horizontal apron with baffle blocks terminated by an end sill. The U.S. Army Engineer District, Pittsburgh,, developed a plan for renovating locks and dams on the lower Monongahela River that would save the cost of having to reconstruct LD 3 and reduce transportation costs by eliminating bottlenecks caused by the small locks at LDs 3 and 4 and by reducing one lockage cycle. The plan calls for building a new gated dam at the current LD 2, eliminating LD 3, and replacing the locks at LD 4 with new, larger locks. The change would also mean Pool 2 would be raised by about 1.5 m 5 ft and the current Pool 3 would be lowered by about 1.0 m 3.2 ft lowering the tailwater for LD 4 by 1.0 m 3.2 ft. The dam consists of a navigable gated structure with three radial tainter gates and two piggyback gates. The original derrick stone placed below the structure has experienced significant scour. The future lower tailwater may result in more severe scour unless the condition is remedied. Additionally, a scour hole has developed in the streambed upstream of the dam.

Subject Categories:

  • Civil Engineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE