Habitat Collapsed!

[ethanb]

We visited the Habitat (off Picnic Point in Lake Mendota; Madison) on Thursday and were somewhat surprised to find that it had tipped over.  It appears the base framework failed and the upright cylindrical section collapsed on its the side.  It's hard to tell exactly what happened though, since everything is so covered with dead weeds. 

Ethan

[stevenq99]

thats too bad I really wanted to dive it this summer.  How was the vis?

[FreediveWI]

Vis was decent on it and the water is around 54 degrees right now so your good all day in a wetsuit. 

We also had some luck spearing yesterday- but not by the habitiat, we had to go elsewhere for that.

jon

[gfmayhew]

Reposted from my dive logs, but I thought some folks might be interested. Comments, as always, are appreciated. My interpretation of events from one dive is hardly accurate.  :-\ Thanks for the pics Jon!
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Well, I finally got out on the Habitat this Spring, something the weather has been determined I would not be able to do!

John Smith, our friend Isaac, and myself took Isaac’s boat from the Monona launch on Wednesday last week (5/24/2006). There had been intermittent thunderstorms all day, but it was all sunshine and light breezes when we left the launch at ~4:30PM. The ride out was pleasant, and we geared up in the boat, commenting that the drysuits were probably unnecessary.

We hit the water around 5PM, dropped down the anchor line to 20 feet and reset it on a rock. The visibility was great for Mendota: around 25 feet. The first thermocline was around 30 feet, and I was glad I did have my drysuit on. We found the upside down truck almost immediately, and followed the lines around to the Habitat, itself.

The Habitat was an old diving research bell, originally sunk in Mendota in the 1970s. It served for ten years, housing researchers from various departments of the UW, who would study things like human physiology under pressure, or the movements of fish in the water column. It was decommissioned in the 80’s and flooded to keep it from becoming a torpedo, should the supports fail. Maintenance of it was ceded to Kosmic Divers, 4Lakes Scuba, and Hoofer Scuba. For the last twenty years, it has served as a diving hotspot for Lake Mendota. The 4Lakes Scuba guide has a nice write-up of the Habitat, and Koz of Kosmic Divers has a pile of photos.

Sadly, the Habitat fell on its side sometime over the winter. The cause is uncertain, but from our observations, the main candidate is simply age. The Habitat was never designed to weather 30 years of submersion, and it lasted in its upright state a lot longer than anyone expected. Inspection of the supports over the years showed increasing pitting due to rust.

The bell lies on its side in ~40-45ffw, partially propped up by the support base. The entryway (old “bottom”) is overhanging the base, and the bell slopes at about 30 degrees down to the “top”, which rests on the lake floor. One set of angle-iron supports collapsed into the center of the support base, which caused the bell to slide off onto its side. It looks like the other supports leaned in towards the middle of the support base, most likely pulled over by the fall of the bell. This collapse could have taken hours, or days, to begin, but once it started, the whole thing just fell over. I did not notice if there was an impact trough in the silt.

There are some new hazards to consider when diving on the Habitat now. First and foremost, the iron grate that once served as the entryway “door” is now closed. But it is not sealed and can be opened by a diver with some effort. It’s a heavy grate, and should a diver penetrate the confines of the Habitat through this door, it is very likely they will become trapped when the grate closes. If diving in a squad of three or more buddies, this danger is somewhat less. Another major hazard is the instability of the angle-iron that served as the support structure. These are propped somewhat precariously, and at least one beam is loose and could topple, trapping a diver beneath it. Also, there is plenty of silt on, in, and around the bell now, and trying to penetrate it will cause a serious silt-out, multiplying the dangers of the other hazards. But the structure is still interesting, and is more visible than it used to be, since it no longer spans the height of the water column.

We finished out our dive by heading down to the speedboat, which was covered in so much sunken milfoil that it looked like a miniature version of the Rouse Simmons. After a short buzz around that, we returned to the Habitat for one last look around, and then moved back up the slope to our anchor line. We ascended slowly, and I noticed the huge amount of big, fat, copepods feeding above fifteen feet. To me, this means the diatoms are still present, so I would guess we have about three weeks before we get the algae blooms that blow the visibility.

We exited the water by the difficult scramble up the propeller for the inboard motor on Isaac’s boat. The sky was getting black and the wind had really picked up. We took off what gear we could and raced for the launch. We got the boat out of the water, and made it back around to Diversions and got unloaded before the rain really cut loose. It was so windy that the rain was coming in horizontally. Then, I noticed I had locked my keys in the car…but that’s another story.

Peace!
George