Ravenna AKA Great Pit Of Carkoon
August 31st, 2009 @ 12:00 am by Cliffe | Sorted Photo Exposure
Vintage Seattle reader Steve Forbes writes in with this fascinating set of 1957 shots as a section of Ravenna Boulevard was nearly swallowed up. I was not aware of this — thanks for bringing it to my attention, Steve. He writes:
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. |
August 31st, 2009 @ 8:12 am
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!
August 31st, 2009 @ 8:59 am
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?
August 31st, 2009 @ 9:54 am
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…
August 31st, 2009 @ 10:36 am
http://www.washington.edu/alumni/columns/dec96/back_pages1296.html
August 31st, 2009 @ 1:08 pm
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!
August 31st, 2009 @ 6:36 pm
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.
September 25th, 2009 @ 7:46 pm
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.
September 25th, 2009 @ 7:56 pm
Hello LS once again.
Dang! Correction! I misread my city map. The steep street in question is NE 56th St.
October 5th, 2009 @ 2:24 pm
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.
October 7th, 2009 @ 9:32 pm
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.