Sunday, August 17, 2008

Few details on Grand Canyon flooding from dam break

The Redlands Dam, an earthen dam on Cataract Canyon [corrected 9:25 pm, 8-17-08] near the Grand Canyon, failed early this morning after heavy rains the past two days, causing evacuations of hundreds from campgrounds and the town of Supai, on the Havasupai Reservation [right, National Park Service].

Information on Redlands Dam is hard to find because of national security concerns. Links to dam safety web sites are limited to authorized personnel.

Update - by Monday afternoon, Aug 18, authorities reported that the dam breach played a minor role in the flooding. The primary cause was heavy rains over the preceding two days.


  1. The mainstream media coverage is very confusing making people think that the dam is along Grand Canyon floor (i.e. Colorado River). Obviously that's not the case, the breach, best I can tell, is over 2000 feet above, along the tributary running through Supai village. Poor people they have no place to go. Whose owns the land south of the village? That's not part of the park or some wilderness area. Give them some land that's better connected.

  2. The Supai village is their traditional home, and it's fine--the canyon there is quite wide. The people who aren't fine are the campers, who the supai people relegate to a section of canyon that's pretty much flat and less than 100 feet wide. That's why there are still 11 missing hikers/campers and no missing villagers. I'm a bit annoyed that the tribe charges people so much to camp but doesn't have any sort of flash flood warning system, which would be pretty easy to install since the canyon is wide and flat for at least 5 miles, they could just put sensors at the narrows above the village and save everyone some trouble.

  3. To get a sense for the terrain, go on google maps, click the "terrain" option which is next to the satellite option, search for "havasu springs" and then "havasu falls." The village is in the flat area below havasu springs, the campground is below havasu falls in the slot canyon. I couldn't figure out where the dam was by tracing up cataract canyon, which seems to be the main canyon and is marked on google terrain maps.

  4. Anonymous3:02 PM

    I found the Readlands Dam by browing topos. Its near the Readlands Ranch. The drainage can hold alot of water!

    Topo map here:

  5. Anonymous3:04 PM

    Dam Location:

  6. Thanks for the link to the topo map. I put up a new post with the map at two resolutions. It would be useful to put one map up with all the locations discussed in the news to help sort this all out.