The night of Nov. 11, 1957, the largest and most expensive sewer collapse in the U.S. to that date occurred at Ravenna Boulevard between 16th and 17th Avenues NE. The hole was 60 feet deep but the sewer trunk in question is 145 feet below the street. Repairs took two years to complete, including first a sewer bypass through Ravenna Park, then stabilizing the broken trunk with a newly devised grout material and re-boring the tunnel.
These photos are from the Seattle Municipal Archives website. They have been downsized and contrast adjusted for detail and impact.
Historical accounts:
www.historylink.org/index.cfm?DisplayPag e=output.cfm&…
www.sewerhistory.org/grfx/misc/disaster. htm
Original web photos (search “ravenna sewer):
clerk.ci.seattle.wa.us/~public/phot1.htm
It amazes me that there’s this big tunnel down there that almost no one knows about.
I recently learned that in 1976, another house in the same area experienced a sudden 5-foot slump in the basement floor.
Steve Forbes
Via E-Mail
8/7/2009
These photos are from the Seattle Municipal Archives website. They have been downsized and contrast adjusted for detail and impact.
Historical accounts:
www.historylink.org/index.cfm?DisplayPag e=output.cfm&…
www.sewerhistory.org/grfx/misc/disaster. htm
Original web photos (search “ravenna sewer):
clerk.ci.seattle.wa.us/~public/phot1.htm
It amazes me that there’s this big tunnel down there that almost no one knows about.
I recently learned that in 1976, another house in the same area experienced a sudden 5-foot slump in the basement floor.
Steve Forbes
Via E-Mail
8/7/2009
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| Washout and Sinkhole. 16th Ave. NE and Ravenna Blvd. (North Trunk Sewer Break) Nov. 12, 1957. Photograph courtesy Seattle Municipal Archives. Contrast corrected by Steve Forbes. |
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| Washout and Sinkhole. 16th Ave. NE and Ravenna Blvd. (North Trunk Sewer Break) Nov. 12, 1957. Photograph courtesy Seattle Municipal Archives. Contrast corrected by Steve Forbes. |
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| Washout and Sinkhole. 16th Ave. NE and Ravenna Blvd. (North Trunk Sewer Break) Nov. 12, 1957. Photograph courtesy Seattle Municipal Archives. Contrast corrected by Steve Forbes. |
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| Washout and Sinkhole. 16th Ave. NE and Ravenna Blvd. (North Trunk Sewer Break) Nov. 12, 1957. Photograph courtesy Seattle Municipal Archives. Contrast corrected by Steve Forbes. |
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| New York Times news article. November 15, 1957. |
Of course I had to look at the modern-day view on Google maps. With the exception of no enormous gaping hole and a few more trees, it looks exactly the same. I wonder if the current homeowners are aware of this exciting bit of history!
My freshman year at the U – I do remember when this happened but wasn’t very concerned about it. Could dig out notes I took in classes but doubt I had anything to say about real world news.
I also returned to the U in 1985 and remember coming across 520 on the bus, looking at the new spactator stand being erected at Husky Stadium, and when I returned to the eastside later in the day it was gone! Does anyone have pictures of its collapse?
Steve- Do you have any more information about the house that sank 5 feet in ’76? Maybe the address or cross street?
Thanks for the info on this. I live a block away and had no idea…
http://www.washington.edu/alumni/columns/dec96/back_pages1296.html
We drive through there very often. I’ve seen these photos before and I’ve always been curious about where all the earth went. Was it slowly sifting into the trunk and creating a cavern over time, whose roof fell in that night? Or was it that the trunk broke and all that soil just got flushed through the system? That’s a lot of earth!
I went back to newspapers I could find on microfilm about this. Your first statement is closer to correct, it seems. A huge cavern gradually opened above the broken sewer trunk as the sand was slowly washed away, and the roof of the cavern suddenly caved in. No one seems clear about how long the process took. There was some mention of settling of the street some time beforehand, but that didn’t cause much alarm, apparently. The entire hill, at least at the north end towards Ravenna Park, is a big sand dune. The tunnel is big enough for a person to walk through, hunched over a bit. Originally it was dug by hand and lined with brick. For the repair, it was lined with steel. It needs to slope downhill from near Cowan Park Grocery to near the Ravenna Park ball field, so it’s something like 145 feet below grade at the top of the ridge where the collapse occurred.
Hello LS:
Sorry I missed your question. The house that had its basement slump is on NE 55th place between 17th Ave and Ravenna Blvd. It’s one of the steepest streets in town, I suppose. The house is on the north side about half-way up (or down) the hill. I noted the house because I’d been to a garage sale there once but I forget the house number. It could easily be directly above the tunnel, which cuts straight ahead where Ravenna Blvd turns north and down the hill. Be clear that the basement floor slumped but there was no indication that the house shifted or was damaged.
Hello LS once again.
Dang! Correction! I misread my city map. The steep street in question is NE 56th St.
Wasn’t Ravenna Blvd formerly a creek before it dried up when Green Lake was lowered? Bet there were a lot of little creeks that missed getting culverted.
I think the original Green Lake overflow went down the present Ravenna Creek in Ravenna park. Whether it followed the present Boulevard as far as the present Cowan Park, I’m not certain. It seems clear that the Ravenna trunk sewer (the deep-bored part of which collapsed in this episode) amounted to a culvert for the original Ravenna Creek above Cowan Park. Sewers were generally combined storm and waste-water drainage in those days.
The original creek from Green Lake closely followed what is now Ravenna Blvd and turned into Cowen Park at Brooklyn Ave and on into Ravenna Park, just a couple blocks North of where the sink hole occurred. The Ravenna Park ravine was formed by outflow from Green Lake. Before any development, the natives in the area followed a trail next to the creek to reach Green Lake from Lake Washington. The creek was put into a pipe under Ravenna Blvd and used to come out of the pipe at the corner of Cowen Park (at Brooklyn Ave and Ravenna Blvd). The ravine in Cowen Park was filled shortly after the big sink hole occurred and the pipe was extended. Cowen Park is now a large playfield instead of a ravine. The creek now emerges from the extended pipe immediately to the West of the 15th Ave NE Bridge, which is the boundary between Cowen Park and Ravenna Park. In the ’50s the creek was noticeably bigger. Before my time, it was even larger still — I’ve seen pictures of it in Ravenna Park when it was much more formidable. The difference is due to pavement and storm drain construction that routed rain water away from Green Lake and into drains instead. To this day, Green Lake still drains through Ravenna Park, then goes back into a pipe that takes its old path under University Village to Lake Washington. The sink hole was at the highest point on Ravenna Blvd between 16th and 17th Ave NE. The sewer trunk (officially called “The Ravenna Trunk Sewer”) that caused the sink hole never carried outflow from Green Lake. Any contamination from sewage in the creek in Ravenna Park has been a result of sewer leakage, predominately from the North side of the Park. The Ravenna Trunk Sewer was built during 1909 and 1910. The first contractor quit the job because of “quicksand” that was encountered during the tunneling at the location of what would later become the sink hole. The tunnel was brick-lined and was, at the time, obviously assumed to be sufficiently strong. As an 11 year old in 1957, and living not far from the cave-in, the neighbor kids and I visited the sink hole several times. It was a popular attraction, complete with a vendor selling hot dogs and ice cream. My slightly older friends at John Marshall Jr High were let out of school when the basement of Marshall flooded as a result of the collapse blocking the sewer line.
The creek ran on Ravenna blvd from green lake to @ brooklyn ave , then into cowen park ( till green lake was lowered & the outflow was diverted down stone way -) – I came to the park in 1959, there was a huge sewer pipe running down the middle , lower road all the way to the lower baseball field – then up to 55th . that was gone soon after all repairs were made to the sink hole line.
I lived on NE 62nd, across the street from Ravenna Park (the other side of the park from “The Big Hole,” as it was called then), from 1956 through 1964.
Because my Dad, James E. Hawthorn, was a civil engineer working for the City of Seattle at the time, I have in my possession an 8X10 arial photo of the hole. It’s quite a good picture. I’m wondering if I should try to scan it and post it somewhere.
We kids were really dismayed by the huge sewer pipe that traversed the bottom of the entire park, but it was big fun to walk along it. According to my weak memory, it was there for a very long time after the hole was fixed– many years. I think it was still there at the time we moved away, in 1964.
I do my best to take away my rubbish conscientiously however it is sometimes demotivating whenever I take a look at what some nations seem to be doing to our world!