 |
| Historic Photographs posted On this day (March 1st 1936) the Hoover dam was finally completed becoming the largest concrete arch dam. https://rarehistoricalphotos.com/building-hoover-dam/ DeWayne Ruggles: If I remember correctly they pumped cold water throughout pipes that went up and down the length of the dam to get the concrete to set. Then after the mass of the concrete had set they filled the pipes with concrete.. |
 |
| Today USA posted The Hoover Dam before it was filled with water in 1936. |
 |
| Historic Photographs posted A Turbine in the Hoover Dam, 1933. https://rarehistoricalphotos.com/building-hoover-dam/ Brett Wanamaker shared Josh Hansen: One of our customers has their business located in the Allis Chalmers hall that has the reinforced test room used to test the ones they made at AC. Huge! |
 |
| Explore USA posted The Hoover Dam at Lake Mead and The Mike O'Callaghan–Pat Tillman Memorial Bridge arch bridge crossing the Colorado River from Nevada on the left to Arizona on the right. |
 |
| My America posted Spectacular photo of the Hoover Dam 📸: [instagram.com/danglasvegas] |
 |
| safe_image for 7 Things You Might Not Know About the Hoover Dam |
 |
| Facebook sponsered ad |
 |
| HighestBridges, West turbine room. Image by Eric Sakowski / HighestBridges.com |
 |
| John Punter commented on a post |
 |
| Dave Gunderson posted Hoover Dam Control Room 1948. This room was located in the ‘Central Power House’ on the 8th floor. At this time, the Dam was not yet fully functional as the last generator was installed in the 60’s. I first saw this control room in 1992 and it looked very close to this photo (down to the lime green walls). The Control Room was completely redesigned in the early 90’s with modern controls and instrumentation. Interesting enough, we had to replace the original cabling that was fifty years old. The old wiring using rubber insulation that had gotten brittle over time. For a year and a half we were crawling all over the plant removing miles of cables in ancient conduits. The new control system was referred to as a Supervisory Control And Data Acquisition SCADA System. All run by Computers. Hoover Dam was an interesting place to work at. Daniel H. Nelson: In the 1990s before 9-11 I was lucky enough to have a retired engineer for a tour guide who took us clear down to the generators and they had one of the armatures out on a cradle as they were replacing the bearings for the first time since it was built it was huge with the shaft where the bearings went was 36 inches in diameter. It said built by Allis Chalmers Co.Dave Gunderson: Daniel H. Nelson the best comment of the thread 👍. The Units (Generator/Turbine) had personalities from one unit to another unit. This depended on available ‘Head’ for generation. Very complex. But explainable. Bobby Rockwell: I think they still take core samples to check on the curing. Richard Struve: After 911, all public power generation plants were required to sever any and all physical connections from their control systems to the Internet. This included their administrative connections. It is also normal to disallow any outside laptop or similar device from connecting to the control net. Company laptops which are weekly scanned, are the only programming device allowed to connect. The SCADA terminals, being part of the control net, are not allowed external access. To clarify a bit, the SCADA computers are only the operator interface and data collection part. Programmable Logic Controllers, and/or Distributable Control Systems do the actual control. Typically, the systems will work without the SCADA computers. Richard T. Alamo: In the event of a power failure gates called stoplogs are automatically tripped to close and stop the flow of water through the generators, it's a pretty simple system, as long as gravity still works no worries. Djoko Soewarno: Sounds cool, so the generator itself how long it usually last? Before replace it with the new one? Dave Gunderson: Djoko Soewarno nothing lasts forever. We ALL have a life cycle. That includes turbines, valves, bearings and Generators. We went through an uprating process in the case of Hoover: 1.Generators were uprated (rewound) during the 90’s. 2.Wicket Gates in the Scroll Cages were replaced, allowing more water in. 3.Francis Turbines were redesigned and replaced for efficiency. This WAS the main enhancement. 4.SCADA was improved… |
 |
| This is one of several photos that are available in the comments. Given the "plates" on the left side, I wonder if they are working on the thrust bearing. [Update: Nope. They are rewinding the rotor and those are the metal sheets that are stacked up to build the armature.] |
%20At%20The%20Controls%20_%20The%20first%20Generator%20to%20be%20placed%20into%20operation%20at%20Hoover.png) |
| Comments on a post |
 |
| Someone commented on Dave's post that they would like a photo of the modern control room. This was his reply Ray Vaughan: When this went down, was there a back up system with actual meters and controls elsewhere? Dave Gunderson: Ray Vaughan there were secondary protocols in place using the primary instruments. I also designed a secondary system to monitor the flow and levels of the water. Thanks for asking. Alan Chris Heasley: Dave Gunderson who's SCADA software was used? What was used as the control platform? Just retired after 50 years in Automation and Process Control. Love picts like this... Dave Gunderson: Alan Chris Heasley the original SCADA system software was PC based and written in-house. The development software was done in VB6. We did use a commercial HMI for the operator screens (at the time it was called an MMI). Of course, the hardware lifecycle was met and it was redesigned with new hardware. Other improvements included smart relaying.The other improvements was going from copper RS-485 to fiber optic IP based comm. You understand. Good stuff… |
 |
| Dave Gunderson posted The first Generator to be placed into operation at Hoover Dam happened in October 1936. This photo was taken to celebrate the occasion. If you look closely and have visited the Dam, you will recognize the area. It was taken in the Nevada Powerhouse. The spectators in the upper left deck is where the modern day tourists get to view the Generators. You probably looked down at this generator and didn’t know its importance. About the photo. The generator and it’s turbine are the round half wheels on the bottom of the photo. This generator is known as a ‘House Unit’ and provides power exclusively for the Dam’s use. The official designation of the generator is ‘N0’ Nevada Unit Zero. There is another unit in the Arizona Powerhouse called ‘A0’ that has the same functionality. It was probably the second generator installed at Hoover due to the significance of its mission. The other special attributes of these units are the turbines used to power them. They use a Pelton Turbine. The other generators at Hoover use Francis Turbines. Dave Gunderson: The primary concrete mix was perfected by Reclamation Engineer A.O. Patch and was called a ‘no fines mix’. The virtue of the mix being its resistance to shrinking as it dried. A modern expert on the subject was Dr David Moore who had spent time at the dam and was a subject matter expert on concrete.https://www.romanconcrete.com/docs/hooverdam/hooverdam.htm Bob Lieblein: The large shaft in the background is part of a Francis . Michael Lessick: Was that the Westinghouse side or the General Electric side ? If memory serves me right, that was how the contract was split up. |
3 of 44 photos posted by Linda Dougherty of the power plant tour. It includes a few photos of the tumble bay.
 |
| a |
 |
| b |
 |
| c |
 |
| Erik Nordberg updated This week's cover image celebrates the Boulder Dam, later called Hoover Dam, which began generating power on October 9, 1936. Photo from the Library of Congress |
I first encountered the term "Tumble Bay" in a comment by DanielG concerning the Croton Dam in Michigan. Some research has indicated two distinct uses of the term. One use is as a "splash bay" for the outfall from a Tainter gate. Another use is as the tapered receiving channel at the bottom of a long weir.
 |
| Vintage Las Vegas posted Hoover Dam's south spillway, August 1941. When Lake Mead first reached capacity, the 100 X 16-foot drum gates atop the Arizona-side spillway were partially lowered, beginning a testing of the spillway tunnels. The spillways on both sides of the dam were used again during the flooding of summer 1983. Here's the part of the dam we're seeing in this photo: https://imgur.com/dA0Wudf.jpg Photo from Southern California Edison Collection, Huntington Library. |
 |
| Vintage Las Vegas commented on Chris' comment I've seen the phrases "opening the spillway" which is totally incorrect, and "lowering the spillway" which is partially incorrect. The spillway is a fixed thing, it doesn't move. There are steel gates at the top of the spillway which can be moved. Here are two photos, with the gates up in the 90s, and down today. |
A Google search showed only one dam outside of Michigan that used this design: Elkhart Hydro Dam. And that is close to Michigan and has the same geology of a deeply buried bedrock by sand, silt and clay.
For sites without rock bottom in reach, great care is necessary in defending the channel below from erosion. For such sites the "tumble-bay" dam is best adapted, in which the force of the falling water is dissipated within the confines of the structure. In dams of this type, the sheet of water is given a sheer fall, being well ventilated behind, into the pool or bay which has a depth of 1/2 to 2/3 the height of the fall, and the water escapes from the bay over a breast wall or roll-way with little or no destructive energy. [The Americanna]
 |
| Photo Cooke Hydroelectric Plant, Spillway, Cook Dam Road at Au Sable River, Oscoda, Iosco County, MI |
 |
| Photo Cooke Hydroelectric Plant, Spillway, Cook Dam Road at Au Sable River, Oscoda, Iosco County, MI |
 |
| mi0529data, p6 The tumble bay weir is 20' high and 12.5' thick at the base. p3 |
 |
| Satellite |
I looked at the photos of the dams upstream from this one, but none of them caught water flowing through the spillway. But I noticed the Alcona Dam does not have a spillway. The Mio Dam has a single gate spillway and an emergency spillway.
 |
| Screenshot from the following video [Technically, this is probably a ski-jump spillway rather than a tumble bay. But this teaches me that part of the effectiveness of the ski-jump spillway is that it collects water at the bottom to help absorb the flow's energy.] |
The other use of the term is for the tapered receiving channel along a spillway weir.
 |
| Reservoirs in a Changing World: 12th Conference |
(Update: other example of dams using a tumble bay in their emergency spillway:
)
 |
| USBR-essays |
The depth of the receiving channel is tapered. It starts shallow at the end of the weir away from the discharge and slopes down to the depth of the discharge channel as it receives more water from the weir. (I spent some more time looking for some photos of a normal side-channel spillway for a plain earthen dam, but I still can't find any. I did find some neat photos for the Croton Dam, so those notes have been extensively updated.)
 |
| USBR-essays |
 |
| USBR-essays |
 |
| USBR-tnlfaqs, 1998 |
(new window)
 |
| Photo, Caption Water enters the Arizona spillway (left) during the 1983 floods. Lake Mead water level was 1,225.6 ft (373.6 m) |
 |
| USBR-lakemead |
 |
| 3D Satellite |
 |
| Screenshot "Because water levels are always low, turbines are now being replaced with more efficient ones that have a more favorable blade pitch to take advantage of less water pressure through the tunnels used for power generation." |
 |
| Kathleen's Window, Feb 2014 |
 |
| USlakes |
 |
| Forgotten Railways, Roads, and Places shared Dennis DeBruler http://mead.uslakes.info/level.asp K.a. Hughes Wonder how high the silt comes now? Dennis DeBruler I read that one reason they built the Glen Canyon Dam was to collect the silt so that Lake Mead doesn't fill up with dirt. |
 |
| History Daily posted Columns of the Hoover Dam being filled with concrete, 1934. The concrete was poured around the clock so it would knit together. There is awesome video in the Bell System film "It Couldn't be Done". They aren’t columns, they are blocks all poured separately, otherwise they generate too much heat ‘hydrating’. Concrete doesn’t ‘dry’, it hydrates and generates heat in the process. There are pipes with chilled water running through them to enable the chemical to happen slowly. Dr Carrier company provided the chillers. I wonder if the core has completely cooled yet? Steve Crippe not yetI saw the documentary “DamNation” and I highly recommend it for those of you interested in the daming of America   It is currently low on water https://www.youtube.com/watch?v=ONBeT8j0UIg Armon Nicooneci The current level is at 1083 mean sea level or MSL. Which is good enough. If. it goes down, to 1075 MSL or lower, Arizona and Nevada is in big trouble.Railcars carried the fresh concrete for the dam in 4 by 8 cubic-yard buckets with overhead cableways lowering the concrete to the dam forms. During peak production, concrete buckets were delivered every 78 seconds. [Some comments have a snit over "pour" vs. "place" concrete.] Mike Breski shared Modern engineering has it 10 times over built.  There're 582 miles of one-inch pipe in the dam that carried cooling water for the blocks. After the blocks were cooled, they filled the pipes with concrete. I have heard that there is still concrete drying in the dam. Jim Munding all concrete continues to dry forever at a very slow rate.Historic Photographs posted Richard Barlow: It was built in 5 years 2 years ahead of schedule. In today's dollars it cost $750 million. That's about the same cost as one average Navy ship today. |
 |
This comment was part of the "pour" vs. "place" snit. |
How low can you go. This is when the lake first started filling up.
 |
| Vintage Las Vegas posted Lake Mead, April 1935. Recreation on the new lake began around this time. Rising water had not yet reached the base of the dam’s intake towers. Union Pacific Photo | Nevada State Museum, Ref: 0006:2019 |
 |
| Vintage Las Vegas commented on their post Feb. 1, 1935 (Photo: Water & Power Associates) |
 |
| Vintage Las Vegas commented on their post Undated, 1935. Hoover Dam close to completion. Water can already be seen at the base of the dam. (Photo: Water & Power Associates) |
 |
| The Hoover Dam posted On July 7, 1930, construction began on the #HooverDam. Built during the Depression, thousands of men and their families came to Black Canyon to build the dam. It took less than five years, in harsh conditions, to build the largest dam of its time. Now, years later, Hoover Dam still stands as a world-renowned structure. The dam is a National Historic Landmark and has been rated by the American Society of Civil Engineers as one of America's Seven Modern Civil Engineering Wonders. |
 |
| Vintage Las Vegas commented on their post The Arizona side spillway was tested in 1941. |
 |
| Historic Photographs posted Officials boldly ride in one of the penstock pipes of the soon-to-be-completed Hoover Dam (1935). Eileen Ilana Strauch: Amazing feat of engineering and construction. 4 billion kilowatt hours of hydroelectric power each year. Nary a whiff of greenhouse gases to boot. Bravo! Marie Hemstrom: These men were relatively safe. The 96 workers who died deserve remembering. Stephen Byrd: Dane Hansen - The modern construction hardhat was created during the Hoover Dam project...Men drilling into the cliff sides for explosives would wear cloth caps hardened with pitch to protect themselves from falling rock... Historic Photographs |
Jim Brown posted three photos with the comment:
The hoist room of the giant 300 ton (now 250 ton) Lidgerwood cableway at the Hoover Dam, which handled lowering all of the heavy powerhouse components down to the river level. The front drum has two sets of haul cable (most had one) that entered the top of the drum, made several wraps, then left the bottom. The top set travels all the way to the tail tower across the canyon, and is turned back on sheaves to the carriage. Turning the drum one way pulls the carriage towards the head tower, reversing pulls it away.
The two monster hoist drums connect to the same main block, and are kept synchronous by having only one layer of cable, requiring diameter and width to accommodate the needed length, always paying out or in at the exact same rate. This same concept is still used on monster shipyard Goliath cranes with multiple main blocks.
David Woll shared
Note the red spray bar on the left. That is probably doing more water than the fire hose.
 |
| 1 |
 |
| 2 |
 |
| 3 |
July 19, 2022:
 |
| safe_image for Explosion at Hoover Dam [Video] "Video circulating on social media, apparently taken by a tourist, showed a small explosion and smoke and fire coming from the base of the dam, the largest in the United States and the source for a 2,080-megawatt hydroelectric plant, enough for about 1.3 million households. Update: Reuters is reporting that it was a transformer. That is good news if it wasn’t terrorism, though there have been no reports about the cause of the explosion yet." |
 |
| Screenshot from video in above linked article Note the red flames at the base of the smoke column. |
 |
| reuters ..Bureau of Reclamation/Handout via REUTERS |
I’m surprised that nobody has made a comment here after all your research. I’m more surprised that I’m making the first one…
ReplyDeleteNo doubt, you have questions. Yes. Worked there for 12 years. The only employee that physically wasn’t there as I was the ‘outside man’.
Worked Telecomm in the beginning. Later in SCADA. Did the remote Jack of all Trades stuff. Later, promoted to collect and distribute Data from the river (yeah, more specialized Telecomm).
About my posts: Boy was I ever shocked at how popular that topic was. Also shocked to see the abundance of experts crawling out of the woodwork.
Hoover was one of my favorite gigs while I worked. The places I got to see that NOBODY usually sees. So full of history too. You actually get to know the structure, the machinery - all having personalities.
You mention somewhere that Hoover was overbuilt. Absolutely true. Do a little research on the St Francis Dam and that will give you an answer. Also research the Engineer Frank Crowe to get a better understanding about Hoover’s construction. Fascinating history. Best, Dave