East Powerhouse and Cofferdam

This is the east powerhouse and cofferdam area as it appeared in November of 1937. The Training wall at the end of the powerhouse is approximately 85 feet high; as tall as a six story building.

1937-11-01
2024-11-24

East Powerhouse Penstock Trashracks

Here is shown the first stages of the east powerhouse penstock trashracks. The portal transition forms at the head of the penstocks were the largest forms used on the job; weighing 13 tons and requiring more than 10,000 board feet of lumber....

2024-11-24

Trash Rack Structures

Considerable experimentation was necessary in designing the system for ice prevention on the trash rack structures. To the best of my knowledge compressed air as a means of ice prevention was first installed at Koekuk Dam on the Mississippi...

2024-11-24

Construction Operations

Grand Coulee Dam is of the straight-gravity type, depending entirely upon the weight of the structure to resist the pressure of the water behind it, tending to overturn it or cause it to slide on its base. The river canyon was too wide for a dam...

2024-11-24

Penstock Liners

These completed sections of the penstock liners are awaiting transportation to the dam. The 18-foot diameter tubes, each 292 feet long, were made up of 15 sections of cylinders up to 23 feet long, and weighing up to 39 tons. The 18 liners had a...

2024-11-24

Hemispherical Bulkheads

In the foreground are two finished hemispherical bulkheads, while in the background another set is being prepared for the water-pressure test. These bulkheads were used to close the upper end of the turbine penstocks until the unit coaster gates...

2024-11-24

X-Ray Machine

This is the X-Ray machine used to examine the welds of the steel penstock liners after they were fabricated in the shop of the Western Pipe and Steel Co. at Electric City, Washington, a few miles west of the dam site in the canyon of the Grand...

2024-11-24

Barge Moving Penstock Liners

This barge maneuvered itself between the loading ramp and the right powerhouse by means of cables and a gasoline winch. Upon arriving at the downstream side of the right powerhouse, cranes removed these sections of the main unit penstock liners...

2024-11-24

Barges

Barges of various sizes and purposes have had an important part in the construction of Grand Coulee Dam. The contractors built most of theirs of wood, and used them chiefly as platforms for derricks and cranes. Later, the Bureau constructed...

2024-11-24

Draft Tube Outlet Portal

Three such draft tube outlet portals as seen here permit the spent water to pass from each turbine in the powerhouse into the tailrace. The floor upon which the workman is standing is at elevation 896. To permit dewatering of the turbine pits...

2024-11-24

Penstock Coaster Gate

Here one of the 120 ton main unit penstock coaster gates is being moved from its erection platform in the west crane recess to its position on the dam." On this face (upstream) the endless roller chains are concealed behind the guard covering...

2024-11-24

Cylinder Hoist

It is believed that this installation at Grand Coulee Dam is the first where a cylinder hoist has been used for a gate having the same general functions. Gates of similar design are being installed at Shasta Dam also.' This main unit coaster...

2024-11-24

River at Flood Stage

The river at flood stage in July of 1939 did not pass thru the second tier of outlet tubes, but only thru the slots left in the dam and the lower tubes. When velocities exceed about 10 feet per second falling water begins to entrain air, until at...

2024-11-24

Tandem Ring-Seal Gates

Here is shown the assembly and installation of the tandem ring-seal gates for the outlet tubes before embedding in concrete. Sections of the 8 1/2 foot diameter steel tube liners were set in position and then welded into a continuous tube.

2024-11-24

Hydraulic Lift Cylinders

Here are two of the huge hydraulic lift cylinders for the ring-follower outlet gates located at elevation 950 in the dam. These gates form the upstream pair of the tandem gates, while paradox gates set on the opposite side of the gallery form the...

2024-11-24

Ring Seal Gates

Here is shown a typical arrangement of the ring seal gates previous to final embedding. The pipes rising at the ends of the gate bonnets are the 16 inch diameter air vents for these gates. <br> In the foreground are the gate leaves and...

2024-11-24

Inside Outlet Tubes

This is a view inside one of the outlet tubes, showing the lower part of the gate leaf, and the upper part of the follower ring, which follows the gate leaf up and closes the gap left in the conduit by removal of the gate leaf. In the background...

2024-11-24

Gate Chamber Interior

This is a view in a 950 elevation gate chamber, showing the method of installing and removing the 16 ton crane beams from the ceiling during maintenance operations on the gates. The upper head or ring of the hoist car is raised by hydraulic...

2024-11-24

Girder Framework of Drum Gate

Here may be seen the girder framework of a drum gate in the extreme raised position during erection. Hinges of the gate may be seen at the left end of each horizontal girder. The chamber in which the structure will float, on water admitted from...

2024-11-24

Fitting Skin to Drum Gates

Workmen fitting the lower skin plates in position with pins, previous to bolting and finally riveting. In all the thousands of holes in the various parts of all these gates, less than a dozen holes required reaming in the field or on the job in...

2024-11-24

Placing Steel Pier Plates on Drumgate Piers

Placing the steel pier plates on the sides of the Drumgate piers required very accurate alignment in two planes in order to provide an effectual seal with the floating drum gate.

2024-11-24

Rear Drum Gate

The primary purpose of the drum gates is to permit the raising of the reservoir level by any desired amount from the lowered crest elevation to maximum of 28 feet. It was the fact that, in addition to a considerable increase in storage capacity,...

2024-11-24

Inside Chamber of Drumgate

This is a view inside the chamber beneath the drumgate structure. The hinge system shows along the front edge to the right. Controlled admittance of water into this chamber determines the relative position in which the sealed drumgate will...

2024-11-24

Drumgate Installation

This is a general view of the drumgate erection in December of 1940, with gates 1, 2, and 3 in the extreme raised position." The river flow is now all passing thru the outlet tubes and the turbines in the left powerhouse." Work on the right...

2024-11-24

Copper Cable Web Inside Pier Plates

Here is shown the manner in which the copper cable was laced thru the reinforcing web on the inside of the pier plates. When current is sent thru this cable it will cause the steel plates to become warm by electromagnetic induction, thus...

2024-11-24