Pensacola Dam Arches put St. Louis Arch in Shadows
There are more than 5,100 feet of arches on Pensacola Dam, said to be the longest row of arches on any dam in the world. The 51 arches support not only a walkway, but a two lane highway, too. The art deco design is credited to Tulsa native John Duncan Forsyth with W.R. Holway as the chief engineer over the project.
At the west end of Pensacola Dam sits a 120 megawatt, 6-unit powerhouse and on the east end you’ll find 21 spillways. Going east through Disney, there is what locals call “the spillways”. This is where two sister dams come together with 21 more gates. There is a public boat ramp here which is surrounded by numerous public parks.
Pensacola Dam was built with over 500,000 cubic yards of concrete. It took 20 months with crews working 24 hours pouring that concrete, providing many with jobs during the depression era. There are 46,500 acres of water at Grand Lake with a shoreline of 1,300 miles.
This deep lake has a rocky bottom and is 742 feet above sea level. Grand Lake was not built to be a flood control lake. However, it is a contributing part of the Arkansas River watershed. The low fall elevations have been GRDA approved so that migratory waterfowl millet seeding could take place. Environmentalist, federal agencies and property owners have voiced a dislike of that action. Grand Lake is only one of two lakes in Oklahoma, with Lake Hudson being the other, where residents are allowed to build on the waterfront.
Pensacola Dam cost the Cherokee’s over 1,200 acres of land and the Quapaw over 800 acres. The government would condemn the land next to the reservoir and flooded it in 1940. The tribe lost half of its ceremonial grounds in the flooding.
Two more generators were added during the 1950’s and an upgrade was performed to all six generators between 1995 and 2003. That upgrade increased the MW by 20 percent. Every autumn a generator is removed from service for a complete upgrade and put back in place by spring of the following year.