a reply to: new_here
the connectivity and interactions of the rivers & lakes in SC, so what can you tell me about the Columbia situation? Is it because they couldn't
regulate/release water from, say, Broad River ahead of time to prepare for this, or just what? I mean, I understand what you're saying about Lake
Wateree, but Mom has gotten about as much rain as Columbia, but her neck of the woods is not as affected.
Thank you and yes I do know more than the avg bear about SC riverbasins - BA in Env Studies =lots of papers written!!
I think the biggest contrib factor in Columbia was
- The sheer volume of rain training over the same area over and over
- catastrophic cascading series of earthen dam failures- more on this in a sec
- I don't think that the Broad River has any or little dam controls
- Saluda has some dam controls, but not as much as say the Catawba
If I remember right, DHEC has been fussing with the Home Owner Assoc (HOA) in the Arkadia Lakes area over who's responsible for dam maintenance of
those earthen dams that collapsed. It was kinda in limbo - ergo no one was really maintaining them. I'll have to find the article for you later.
Reason I know was b/c we had a similar problem with an upstream dam that was threatening some of our property and DHEC closed the road b/c of eminent
failure threat. Believe you me I did a lot of research on earthen dam failures in SC. Turns out the ppl that own the pond lived in TX; 80+ yo &
suffered from Alzheimers and the kids were bickering over who was to maintain the dam - & no one was doing it. In which case DHEC stepped in, either
fix it or drain it yourself or we will and send you the bill!!
One thing I learned from that episode was 1) absolutely no trees should be on a dam - wind blows- soft ground- tree topples and takes a chunk of dam
with it=catastrophic failure. Also - no driving on dam - compacts the soil and weakens it. So it could of been any of those things, or the spill way
clogged or jammed with debris, in which case dam would be topped ie over flow, eroding the top of the dam.
I'm sure there will be a megga finger pointing session amongst the PTB once the water has receded, but watch the language they will use in the press -
I've noticed it all ready today --said dam did not fail,
it was topped
Failed=mega liability vs topped = implies act of God -ie megga rain =not so much liability.
It's also where she is on the ridge line. The closer/higher you live on a ridge line the less water you have to deal with (you just have to deal with
mudslides like in the Mts !!) Every one in line below you will have more water & more ponds to deal with.
I live on a ridge line --if look at all the creeks on my side of the hwy they all flow into the Lynches River basin and on into the PeeDee on to
Just across the road, they all flow into the Catawba River basin, which is not that far -10 miles? on into Wateree which goes into the Congagree
Swamp into which also the Saluda and Broad rivers flow, of which all goes into the Santee Lakes -Lake Marion & Lake Moultrie.
Camden is the start of the fall line - north of Camden you start going up in elevation--ever been on hwy 97 to Great Falls? Very hilly; go south of
Camden to hwy 521 to Sumter - very flat.
Yes there is a diff btwn fall line and ridge line - fall line is geologic feature that runs thru the middle of SC from GA on to Va I think - google
images it and you'll get a feel for it; ridge line is what defines into what river basins the creeks will flow; there are several in SC
What I saw this AM was for the most part a catastrophic cascade of pond failures - the top one went, then the next one, then the next one and
depending on the depth and cubic sq ft of load determines how much of a wall of water was coming down the pike. Shallow lake - not so much---Lake
Murray --better make you peace with God my friend!!!
I think these guys were in between the two.
I hope this makes sense?? and that I didn't bore you to death!!Got any more questions-happy to answ if I can
edit on 4-10-2015 by SCGrits because: (no reason given)