News wire reports only remaining UP ( SP ) culvert is about to collaspe. They are applying to corp of engineers to temporarily fill in the culvert. Several questions.
Any one know the materials that this culvert is built with ?
What are the dimensions ?
Is UP quickly (RE) qualifying crews that are not current to operate Ogden- Salt lake city on UP tracks and the WP track west from Salt Lake city ?
If culvert collaspes how will traffic on the WP be affected ? Especially Amtrak’s Cal Z ?
If UP has to build the cited bridge will the winter weather slow down work ?
All of the alternatives to shutting the GSL causeway down are bad news. Rerouting on the ex-WP Shafter sub with its short sidings and slow Silver Zone Pass will be a dispatchers headache, not to mention the crewing issues. Shifting some SFBA intermodal traffic via Lost Wages and Tehachapi will be expensive in fuel and time, even more so via their Northwest route.
Apparently it is way, Way down. Per the USGS the lake bottom and most nearby terrain is a very thick ‘mud flat’. The tremendous weight of the causeway rocks and ballast causes continual subsidence.
One of the problems that the causeway has presented, which the bridge did not present, is that the flow of water from south to north is restricted to the point that there is a noticeable imbalance between the salinity of the two parts of the lake, which has had some effect on the production of brine shrimp (one of the very few forms of life that can live in the lake). Brine shrimp are exported to Southeast Asia, where they provide food for fish farms. A smaller culvert would make the imbalance worse.
Of course, various minerals also are mined from the lake.
Perhaps the line through Corinne and Promontory Summit could be rebuilt?[:)]
Yes, Mike, a smaller culvert would be better than none.
I erred in my description of the flow of fresh water. The Jordan River, coming from the south brings more fresh water in than the watercourses that come in from the north do, so the imbalance is less salt in the south, and not in the north, and the fresher water inhibits the growth of the brine shrimp. Also, the mineral extraction plants are, I believe on the shore of the south end.
One of the two culverts was closed last year, so the flow between the two parts of the lake has already been reduced considerably. The UP wants to build a 180 foot long bridge in the middle of the causeway, but the Corps of Engineers and state agencies that oversee the lake and its water quality have not studied the UP’s plans so they can give their approval (information from this morning’s Salt Lake Tribune.
There has to be a two-way flow, of both the fresher water and the saltier water.
In the thirty-nine years that I have lived here, I have been in the Great Salt Lake once: once was enough, considering the flying insects at the beach and having to rinse the salt off.
As a point of curiosity, and I’m sure it has been considered,; In the long run, wouldn’t it be more economical to bit the bullet and double track the line south of the lake? It appears to me that the causeway is a major maintenance headache for UP. Partial removal of the causeway would also help return the lake to it’s natural state.
The likelihood of double tracking the ex-WP Shafter sub is almost zero. UP has owned it for 30+ years and hasn’t even lengthened many (any?) sidings - see my map link. There are many other areas around their system that can and will justify upgrading first.
Reportedly SP (and probably UP) had considered building a ‘bypass’ along the west side of the GSL. This would take advantage of the ex-SP Lakeside sub longer sidings and some double tracking. The causeway could be abandoned and the (scenic but slow) Silver Zone Pass bottleneck on the Shafter sub could be bypassed and downgraded, thus saving some major maintenance expenses. Besides construction costs, the ~70 mile (total) longer route is a downside.
The linked SL Tribune articles report that salt and brine shrimp business at the lake runs into $300M plus! I’d think that economic fact would spur the locals to ‘kick in’ a little bypass money …
Isn’t the existance of the shrimp farms and salt flats due to the causeway? The causeway would still need to be maintained as a dam or levee, otherwise if it collapsed the fresher water in the South basin would mix with the north basis heavily-saline water, and it seems that ruin those industries.
Not being a brine shrimp expert, I don’t know the answer to that. [^o)] There is probably a reasonable compromise between maintaining a ‘natural’ salinity level and one more optimized for brine shrimp production. At any rate, the other business owners have to deal with the same environmental issues as the RR does.
Back to the ‘bypass’ speculation, it would probably require a forecast of traffic growth from NorCal - never a sure thing. Third option - a spiral tunnel under Silver Zone Pass [(-D].
I spent a fair bit of time railfanning at Silver Zone pass when I lived in Nevada. I always wondered about the possibility of building a shorter but steeper second track bypassing some of the big loops and use it for eastbound traffic. I figured the tracks would diverge approximately at the summit, with the ‘bypass’ line staying south of I 80.
A good bridge in the middle (deepest part?) would promote both fresh water and salt water circulation. Fresh water will ride over a salt water flow going in the opposite direction riding on density gradients. Of course it will still not be anywhere near as natural as an open lake.
While I don’t know Brine Shrinp from Jumbo Shrip - it sound like the Brine Shrimp ‘farmers’ on the North End of the lake don’t want the lake returned to its ‘natural’ state as that would not have enough salinity to support the Brine Shrimp business.
Or REbuilding…There was a steeper grade used during the construction before the loop (the required 1% route) was complete. Not entirely south of I-80, but basicly followed the same path. You can see it running north of 80 where the current eastern approach crosses.
The fresh water streams enter the lake on the East side. The NW arm of the lake isolated by the fill is essentially an evaporation basin. The remaining culvert would at least provide hydrostatic equilibrium on both sides of the fill. If they plug the last culvert for any length of time, and the lake levels on the opposite sides start to differ, I fear that the fill could fail.
