Looking at the Google map, the river has a dam in it, right at this location. I’m not sure what that means for the flow rate. I actually can’t find any TVA information near there...but the USGS shows alot more flow than that in some of the smaller streams tributary to the TN River.
Anyway, 1,000 cfs seems low. The river is around 1,500 feet wide where it is narrow at the bottom of the dam...I don’t know the depth, but there are locks...so I assume at least 7 feet for barges. Using a rectangular channel, that’s 10,500 sf cross section...so to attain 1,000 cfs, the river would be moving at 0.1 fps...or less than 0.1 mph.
And think about it - you propose a 20 ft diameter pipe....flowing at 2 miles per hour. Certainly the river flows at least 2 miles per hour....and it is orders of magnitude bigger than a 20 ft dia pipe.
So, I’d say it would take more than a few pumps to drain the TN River. But its ok. Atlanta uses 440 million gallons a day...or 680 cfs, so the river can certainly supply Atlanta.
But intuitively, if the hydro-electric dam harnesses the full flow of the river in a 50 ft drop...and the water has to be pumped a hundred miles and be lifted 400 feet....it would take a couple of these power plants just to lift the water. Assuming you supply all of Atlanta with water from the TN River, a quick back of the envelope calculation is 74,000 kwh...at around $0.15, that’s $11,100 a day (totally ignoring friction losses btw) or over four million dollars a year in electrical costs. If you only supply Atlanta with 25% of its water, its $1 million...etc.
Anyway, Atlanta must be in dire straights, if pumping water from the river is being considered.
About the dam: It looks like a hydro-electric dam...what I find curious is that the TVA seems to have very deliberately set the dam height such that the river did not back up into Georgia. That’s probably because the TVA only owned or controlled property on the TN side...I bet Georgians wish there had been a little bit of negotiation when that happened.
They said A pipeline’s flow of water would not and could not ever make a smidgen’s worth of difference in the flow and water level of the Tennessee River.
...Whatever water is needed by all the users along the Tennessee River won’t be affected at all by another pipe drawing off a little of it, even it it was a 20’ diameter pipe. NY City pipes water a long distance through huge underground tunnels from somewhere upstate, maybe it’s the Finger Lakes, and they don’t go dry.
BUT the flow number I cited was NOT correct. My mistake, sorry. I looked at the wrong station pin based on the TVA map view, and it was just a tributary.
The Tennessee River at Chattanooga is flowing about 18,500 ft^3/min.
http://www.lawrencevilleweather.com/wx.php?forecast=riversobs&gauge=CHAT1
So with this, everything else is moot, except...
The fact that Georgia IS looking to get access to the river means that the cost of pumping would be tolerable.
About the dam: It looks like a hydro-electric dam...what I find curious is that the TVA seems to have very deliberately set the dam height such that the river did not back up into Georgia. That’s probably because the TVA only owned or controlled property on the TN side...I bet Georgians wish there had been a little bit of negotiation when that happened.
I bet you are 100% right on that. Almost certainly done to NOT get Georgia involved.
But there would need to be a fair difference in elevation. It looks like you would need at least six feet or so higher (based on the elevations in the drainage on Google Earth), and that cove on Nickajake Lake would cross Huckabee Lane and be in Georgia.
Making a dam six or more feet taller would not have been a trivial extra expense. AND maybe there were other elevation issues elsewhere that made the choice cut and dried.. It's be interesting to find out the story behind the dam height design.
Of course, if Georgia did get water rights, excavating a canal from the cove to an empoundment and water pumping station in Georgia would be no big deal at all.
By the way, the new underground water tunnel they are making for NYC has a largest diameter of 24' in certain sections.
http://en.wikipedia.org/wiki/New_York_City_Water_Tunnel_No._3
Just checked.
Atlanta used 320 million gallons per day in 1990, and 420M gallons per day in 2000. They are projected to go to 700M gallons per day by 2020.
700M gallons = 93,576,389 ft^3 / day = 1083 ft^3/sec. About what that one stream was flowing, and about 6% of what the Tennessee river was flowing per that CHAT1 gauge.
AND of course they are already getting by at 400 million, so they only need 300M more incrementally.
So maybe a 8’ to 12’ pipeline would do. Still have some lifting to do to get over the ridges though.
:-)
From wikipedia,
At various points since the early 19th century, Georgia has disputed its northern border with Tennessee. In 1796, when Tennessee was admitted to the Union, the border was originally defined by United States Congress as located on the 35th parallel, thereby ensuring that at least a portion of the river would be located within Georgia. As a result of an erroneously conducted survey in 1818 (ratified by the Tennessee legislature, but not Georgia), however, the actual border line was set on the ground approximately one mile south, thus placing the disputed portion of the river entirely in Tennessee.
Also, according to this article:
http://www.ajc.com/news/ap/environment/georgia-lawmakers-eye-tennessee-water/nWLfQ/ "But for Georgians, it's a matter of honor. The current boundary does not reflect the line agreed upon in 1818 when Georgia handed over the territory to the federal government [for the creation of the TVA], a line which would have given Georgia rights to the river.
"There's no question that the grant from the state of Georgia to the U.S. government was clearly stated as the 35th parallel," said Georgia state Sen. Charlie Bethel, R-Dalton, "and there's no question that what is currently identified as the state line is not the 35th parallel."