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Originally Posted by tuxnharley
(Post 1586166151)
That certainly looks like a man made feature, given the even grading of the side slopes and the rock lined spillway for the runoff to flow over and into the basin.
If that was an original sink hole that was modified to be a retention basin, it was an incredibly poor choice given that the runoff would then exacerbate any underground erosion. My experience with retention basins is that they are intentionally designed and created with impermeable liners such as a barrier fabric or a clay seal layer so as to prevent any ground water intrusion. They then discharge out to surrounding water courses through a small pipe that is designed and sized so as to meter out the accumulated runoff slowly. This prevents any increased risk of down stream flooding from the increased volume of runoff generated from the newly paved impermeable surfaces, as compared to the before construction condition. First, the retention area adjacent to the Sky Dome is definitely a sinkhole provided by nature. We always dress up the slopes and seed the grass for erosion control. The gravel trenches are added to channel the runoff, also for erosion control. A sinkhole in our area is almost always used to get the water into the underground cave system. Although we have some creeks and streams that feed into other above ground rivers, etc., there is more runoff that goes underground. Similar to a large city that uses a man-made storm sewer, ours is created by nature. We don't see the use of a sinkhole as "exacerbating" the erosion, but rather providing an access to an underground system. The rock below surface is no more than a few feet under, so erosion is usually not a problem. A man-made retention area, on the other hand, is designed to hold the total "additional" runoff created by developing a parcel of land. For instance, a three acre lot that was improved with a one acre parking lot, would require a retention area that would hold the additional water created from the asphalt. Of course the volume would be the difference between the absorption rate of the umimproved area vs. the 100% runoff from the parking lot. The required volume of the retention area is equal to the 100 year flood plain, or the amount of runoff created during the largest rainfall within the last 100 years. When a retention area is built, one of the goals is actually to hit a crevice (a cave) which empties into the cave system. This would prevent standing (stagnant) water in the retention area. In fact, many times we drill a "dry well" in the bottom of the retention area in order to find a crevice. Thus, a man-made sinkhole. Unfortunately, the retention area must be sized as if there were no cave system, because there is no reliable way to calculate how much water the cave will hold, or when it might get stopped up. In this region, we use sinkholes, whether made by nature or man, as tools to manage stormwater. Mammoth Cave is the largest underground cave system in the world. There is over 400 miles of caves mapped, and it is estimated to be only 10% of the total. The towns and caves in the region also include Cave City, Horse Cave, Park City, Silver Cave, State Trooper Cave and Lost River Cave. It is believed that all of these are connected underground. BTW, in the 90s I developed a large subdivision and was required to build a very large retention area. I then drilled two dry wells 135' deep through solid rock and never hit a crevice or cave. I then called a geology professor from Western Kentucky University. He brought out an "anti-gravity" device, and within a few hours found a cave entrance less than five feet below the surface! I learned that day that sometimes a little bit of science is much better than a big drill! Hope this helps. :cheers: |
Originally Posted by misteroman
(Post 1586168276)
The wife and I had a nice talk yesterday about this. I have my paperwork in to transfer to the assembly plant and took a tour of the area in July.
The one house we almost bought ahead of time and were just going to rent out had about 50' sinkhole about 300' feet from the house. realtor said theyre very common and that one was probably 100 yrs old. Another house we looked at had a similar one and just talked to the owner a few weeks ago(hes from my area originally) and he had a fresh 5' one a few months back a couple hundred feet back and said its really no big deal. Now with this happening were wondering if its God trying to tell us something. There are a few hundred thousand structures and tens of thousands of miles of roads in the region, with no problems. I have lived in BG for over 40 years, and I guarantee that any sinkhole that affects an improved lot or building is big news. I have knowledge of one large sinkhole on a new road (Dishman Ln.), one small sinkhole on a new parking lot (Staples), and a handful of smaller ones. On the farms, I have seen thousands. The biggest danger is probably to the cows. The Corvette Museum sinkhole is the only one I have heard of that was "inside" a building. The odds are probably about the same as getting hit by a meteor. :cheers: |
Originally Posted by C6BOB
(Post 1586159742)
Behind the Museum is a "drain pond" or "storm drain". I never got a good answer for what it was. I always thought it looked like a sink hole.
http://file.walagata.com/w/mazdabob/domeback.jpg Will be interesting to learn as time goes on if anyone may be at-fault. Just tragic. |
Originally Posted by NVR2L8
(Post 1586168900)
I am not an engineer by profession, but I have done several developments in the area, and understand the local karst region and stormwater management policies.
First, the retention area adjacent to the Sky Dome is definitely a sinkhole provided by nature. We always dress up the slopes and seed the grass for erosion control. The gravel trenches are added to channel the runoff, also for erosion control. A sinkhole in our area is almost always used to get the water into the underground cave system. Although we have some creeks and streams that feed into other above ground rivers, etc., there is more runoff that goes underground. Similar to a large city that uses a man-made storm sewer, ours is created by nature. We don't see the use of a sinkhole as "exacerbating" the erosion, but rather providing an access to an underground system. The rock below surface is no more than a few feet under, so erosion is usually not a problem..... Retention ponds are used as much as a settling bed for the trash and oils that come off of large parking areas as they are for storm water control. Simply dumping them down nature's drain hole is not good environmental practice. How does this larger than natural infusion of surface water NOT 'exacerbate' the underground erosion problem? It's like flushing the toilet more than nature intended. All of the earth infill in the karst formations gets washed away causing more sinkholes and collapses. Sure this will happen naturally over a longer period of time, but this building was built right NEXT to a large sinkhole and additional, concentrated storm water runoff was intentionally directed into it....what did people THINK was going to be the result?!?! To me it's like being surprised that your house on the beach gets blown away by a hurricane......odds are.... |
unless you know this area and have worked in this area you just don't understand. I am reasonably sure that nvr2l8 knows what he is talking about. not just theoretical college professor babble, but real world experience in dealing with this issue.
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Originally Posted by hifi875
(Post 1586171133)
unless you know this area and have worked in this area you just don't understand. I am reasonably sure that nvr2l8 knows what he is talking about. not just theoretical college professor babble, but real world experience in dealing with this issue.
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Driving the beautiful back roads east of the Interstate there by the museum, I marveled at all the small "farm pond" like looking water holes. Those are mostly water filled sink holes then?
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Originally Posted by Doug Harden
(Post 1586170858)
I'm sorry, but I am an architect by day and I truly do not understand "trying" to get unfiltered, polluted surface water runoff into the underground system as a good thing??
Retention ponds are used as much as a settling bed for the trash and oils that come off of large parking areas as they are for storm water control. Simply dumping them down nature's drain hole is not good environmental practice. How does this larger than natural infusion of surface water NOT 'exacerbate' the underground erosion problem? It's like flushing the toilet more than nature intended. All of the earth infill in the karst formations gets washed away causing more sinkholes and collapses. Sure this will happen naturally over a longer period of time, but this building was built right NEXT to a large sinkhole and additional, concentrated storm water runoff was intentionally directed into it....what did people THINK was going to be the result?!?! To me it's like being surprised that your house on the beach gets blown away by a hurricane......odds are.... As you point out, sending polluted water into the underground aquifer is by definition a bad thing, although it has been done since this region was populated in the 1700s. A couple of decades ago, stormwater management regulations were put into place that required a specific design of sinkhole use incorporating gravel filtration at the bottom. In the last several years, a completely new and comprehensive stormwater management law was put into place, and a much more strict procedures are required. Developers in the area have learned the requirements in order to get their projects approved. The underground system is a natural treatment system, although the pollution issue is still a concern. You can imagine a stream with clean water, having been "treated" by the flow over the rock bed. I know this is over simplifying for you, but this may help others understand. The "exacerbating" concern is also important. Bowling Green receives an average annual rainfall of about 45 inches. All of this water will either be absorbed by the land, evaporated into the air, flow into the creeks, streams, etc., or flow into the underground system. All of these were taking place long before the first person settled in the area. Nothing has changed that much except we now have to manage the process and try to control the pollution. The underground karst system is virtually 100% rock, mainly irregular layers of limestone and a few others. Some of it is hard, some soft. The erosion is definitely a factor, but it is not like sand or dirt be eroded. The erosion has been taking place naturally for millions of years. Bottom line, the water has to go somewhere, and this system is what nature provided for us. The thousands of natural sinkholes that appear on farms were developed by nature, with no intervention of man. Doug, I realize that your credentials are probably much stronger than mine, and I am only trying to add a little context to the discussion. :cheers: |
Originally Posted by NVR2L8
(Post 1586172105)
Doug - You are making good points and asking the right questions, and I respect you for that. As a layman, I will respond the best way that I can.
As you point out, sending polluted water into the underground aquifer is by definition a bad thing, although it has been done since this region was populated in the 1700s. A couple of decades ago, stormwater management regulations were put into place that required a specific design of sinkhole use incorporating gravel filtration at the bottom. In the last several years, a completely new and comprehensive stormwater management law was put into place, and a much more strict procedures are required. Developers in the area have learned the requirements in order to get their projects approved. The underground system is a natural treatment system, although the pollution issue is still a concern. You can imagine a stream with clean water, having been "treated" by the flow over the rock bed. I know this is over simplifying for you, but this may help others understand. The "exacerbating" concern is also important. Bowling Green receives an average annual rainfall of about 45 inches. All of this water will either be absorbed by the land, evaporated into the air, flow into the creeks, streams, etc., or flow into the underground system. All of these were taking place long before the first person settled in the area. Nothing has changed that much except we now have to manage the process and try to control the pollution. The underground karst system is virtually 100% rock, mainly irregular layers of limestone and a few others. Some of it is hard, some soft. The erosion is definitely a factor, but it is not like sand or dirt be eroded. The erosion has been taking place naturally for millions of years. Bottom line, the water has to go somewhere, and this system is what nature provided for us. The thousands of natural sinkholes that appear on farms were developed by nature, with no intervention of man. Doug, I realize that your credentials are probably much stronger than mine, and I am only trying to add a little context to the discussion. :cheers: Only point I will end with, is that the images of the hole under the pavilion show quite a bit of earthen fill, obviously something reduced that to a large void and caused the collapse. |
Originally Posted by NVR2L8
(Post 1586168900)
I am not an engineer by profession, but I have done several developments in the area, and understand the local karst region and stormwater management policies.
First, the retention area adjacent to the Sky Dome is definitely a sinkhole provided by nature. We always dress up the slopes and seed the grass for erosion control. The gravel trenches are added to channel the runoff, also for erosion control. A sinkhole in our area is almost always used to get the water into the underground cave system. Although we have some creeks and streams that feed into other above ground rivers, etc., there is more runoff that goes underground. Similar to a large city that uses a man-made storm sewer, ours is created by nature. We don't see the use of a sinkhole as "exacerbating" the erosion, but rather providing an access to an underground system. The rock below surface is no more than a few feet under, so erosion is usually not a problem. A man-made retention area, on the other hand, is designed to hold the total "additional" runoff created by developing a parcel of land. For instance, a three acre lot that was improved with a one acre parking lot, would require a retention area that would hold the additional water created from the asphalt. Of course the volume would be the difference between the absorption rate of the umimproved area vs. the 100% runoff from the parking lot. The required volume of the retention area is equal to the 100 year flood plain, or the amount of runoff created during the largest rainfall within the last 100 years. When a retention area is built, one of the goals is actually to hit a crevice (a cave) which empties into the cave system. This would prevent standing (stagnant) water in the retention area. In fact, many times we drill a "dry well" in the bottom of the retention area in order to find a crevice. Thus, a man-made sinkhole. Unfortunately, the retention area must be sized as if there were no cave system, because there is no reliable way to calculate how much water the cave will hold, or when it might get stopped up. In this region, we use sinkholes, whether made by nature or man, as tools to manage stormwater. Mammoth Cave is the largest underground cave system in the world. There is over 400 miles of caves mapped, and it is estimated to be only 10% of the total. The towns and caves in the region also include Cave City, Horse Cave, Park City, Silver Cave, State Trooper Cave and Lost River Cave. It is believed that all of these are connected underground. BTW, in the 90s I developed a large subdivision and was required to build a very large retention area. I then drilled two dry wells 135' deep through solid rock and never hit a crevice or cave. I then called a geology professor from Western Kentucky University. He brought out an "anti-gravity" device, and within a few hours found a cave entrance less than five feet below the surface! I learned that day that sometimes a little bit of science is much better than a big drill! Hope this helps. :cheers: Thanks! That does help me understand the local practices in your area much better. That said, I still question the continued application of those practices in this day and age. As others have mentioned, storm water quality has become a priority over the past 40 years or so, as well as just volume retention. As an analogy, remember that less than 100 years ago it was deemed acceptable to discharge raw untreated sewage into waterways such as streams and rivers. A close examination of the helicopter videos clearly shows a continuing series of subterranean voids below the level of the collapse. I believe those existed long before the building was constructed and, over time, continued to erode thus carrying away the material between that level and the building foundation - causing the collapse. I believe it is very possible that the addition of the increased storm water into the retention basin/sink hole could have accelerated this erosion of the underlying subterranean structure. Conjecture on my part? Absolutely so. But - with reasonable basis and back ground. Thanks again! :cheers: |
Originally Posted by Doug Harden
(Post 1586171203)
Sorry, but I've been doing "real world" for over 40 years now...it isn't just theory...
Same here. :thumbs: :cheers: |
I have really resisted jumping into this discussion, openly acknowledging that I have no experience in the fields of engineering, architecture, geology or construction, but I do ponder this...
I would assume that whatever process caused the void beneath the dome and eroded away the earth is likely still ongoing (probably flowing water through a cave system, from what I gather) and can it be diverted or mitigated? What steps are taken to ensure that the fill that is used to fill the void won't just be washed away over time and the problem not recur? How is it determined...what process is used...without someone actually going down to explore the void (not me, thank you), how far it extends horizontally, possibly under other museum structures? How are the cars going to be lifted out? NOTE: I am NOT questioning anybody's judgement or "calling anybody out". I'm sure there are good answers to these questions. The people in charge there are not ignorant and they know the area and its geology very well. I am just being inquisitive and wish to be informed. |
So are they going to be able to restore the cars?
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Originally Posted by ~Stingray
(Post 1586165203)
Why are some of the cars listed already condemned? From the pictures floating around the internet, it seams like many can still be fished out. Sure, they will be damage, but fixable.
I could see a donation thing going to help get them out. If they can recover a P-38 from under 250ft of ice and restore to flying condition, these Corvettes can be restored. Chappie |
Originally Posted by tuxnharley
(Post 1586160942)
I think it's upside down and almost completely buried. There is one point in the video where you can just see one wheel showing thru the dirt......:eek: :(
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Originally Posted by Chappie
(Post 1586172759)
If they can recover a P-38 from under 250ft of ice and restore to flying condition, these Corvettes can be restored. Like saying "If we sent a man to the moon, we can cure cancer." Different challenges, different risks, different technologies. It is interesting to hear them state affirmatively that these cars will be recovered, implying a plan is in place, and yet not hear any mention of the actual plan. Surely they must have some idea how this will be done. ****EDIT: Just read where Mr. Strode said some of the skin would be removed from the dome and a crane used to retrieve the cars. Makes sense if the crane can be safely positioned on firm ground outside the dome.**** Some may not see a parallel, but in the case of a recent sinkhole in Florida which swallowed up a bedroom and the occupant of the bed, no attempts to recover the body were made ("too dangerous") and the house was bulldozed into the void. (I would only hope that the vacant lot was then converted into a proper grave.) |
Originally Posted by Chappie
(Post 1586172759)
I thought the same thing. I've seen comments about the 'loss' of these Corvettes. They can be recovered and restored/repaired.
If they can recover a P-38 from under 250ft of ice and restore to flying condition, these Corvettes can be restored. Chappie |
Originally Posted by Eagle3sh
(Post 1586172977)
So someone else knows about Glacier Girl. Restored in KY by the way.
Chappie |
Originally Posted by Rad22
(Post 1586172969)
Invalid If-Then statement.
Like saying "If we sent a man to the moon, we can cure cancer." Different challenges, different risks, different technologies. It is interesting to hear them state affirmatively that these cars will be recovered, implying a plan is in place, and yet not hear any mention of the actual plan. Surely they must have some idea how this will be done. Some may not see a parallel, but in the case of a recent sinkhole in Florida which swallowed up a bedroom and the occupant of the bed, no attempts to recover the body were made ("too dangerous") and the house was bulldozed into the void. (I would only hope that the vacant lot was then converted into a proper grave.) Anyone thinking it'll be a slam dunk on the future of retrieving the cars all no sweat, might want to consider the unknowns here. Check the chasms of black holes visible in the collapse pictures. This whole deal is a work in progress, and some are assuming way too much at this point in the recovery and restoration process on the site. |
Originally Posted by Skid Row Joe
(Post 1586173271)
Totally valid comparison.
Anyone thinking it'll be a slam dunk on the future of retrieving the cars all no sweat, might want to consider the unknowns here. Check the chasms of black holes visible in the collapse pictures. This whole deal is a work in progress, and some are assuming way too much at this point in the recovery and restoration process on the site. My experience (30 yrs.+) Under that black car is the cave.Or washout or whatever.All the soil followed in that path.Notice all slopping.How deep is that void?How long?What direction?That void will have to be filled with crushed stone for the water to flow threw or it will keep collapsing.Got to go.Chew on this thought for a while. |
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