The Town Manager of Christiansburg was heard to say that he had been told by the National Weather Service that Christiansburg recently suffered what was more than a 1000 year flood. 1000 year event classification per National Weather Service is 4 1/4″ in 3 hours is 1000 year storm; 6 1/2″ in 3 hours. First off, try to find any reference to a “thousand year flood”. You will find a few but these are floods where hundreds of acers are flooded. You will not find it a definition of this ‘concept’ anywhere online. A phone call to the National Weather Service will yield that there is no such set standard for inches of rainfall in a specific timeframe to determine flood events.
Wikipedia does have informtion on the 100 year flood: A one-hundred-year flood is calculated to be the level of flood water expected to be equaled or exceeded every 100 years on average. The 100-year flood is more accurately referred to as the 1% flood, since it is a flood that has a 1% chance of being equaled or exceeded in any single year. Based on the expected flood water level, a predicted area of inundation can be mapped out. This floodplain map figures very importantly in building permits, environmental regulations, and flood insurance.
First, let me point out a few little details that the Town Manager may want to check out:
1. the National Flood Insurance Program has copies of current flood plain maps available online. More of that nasty Freedom of Information, Empowering Citizens junk:) Just looking at the section in Cambria, if this most recent rainfall would have met the criteria for a 100 year (much less than a 1000 year flood) businesses on both sides of Crab Creek along Cambria and Depot Streets would have been flooded, including some of those on the far side of Depot. The railroad tracks would have been underwater. All of those areas on the opposite side of the track from the Depot would have been underwater.
2.A Public Information Statement from the National Weather Service in Blacksburg VA notes unofficial precipitation totals for a 15 hour period ending at 8 AM Friday and shows the Christiansburg level at 2.37″. Having been in the Cambria area, I would argue that it was closer to a 4″ rainfall there, and there was one report of over six inches there from a source who had positioned a personal rainguage in a location where the level was compromised by flow from a roof.
3. A local Storm Report from National Weather Service Blacksburg, VA notes that there was a flash flood on North Franklin Street at Spradlin Farms that closed the road due to high water reaching a depth of 3 feet. Road was re-oped around 4:00 AM (What creeks are there in Spradlin Farm area? Shouldn’t that be high and dry if storm water management is adequate?)
4. At 2:40 AM the National Weather Service Blacksburg, VA released a flash flood advisory reporting flash flooding all across the town. (Flooding should be the result of water having no place to go. If there is more water trying to go into the same location, a phenomenon that occurs when you significantly increase the amount of impervious surface without upgrading stormwater management features to accomodate that flow.)
5. Also at 2:40 AM several basements reported flooded in various locations across town.
I spent part of today out taking more photos of damage in Cambria and in other areas. Those photos will be loaded on online in the next few days. They are currently enroute to storage. Those photos clearly show that the elevation of the railroad track is higher than either the Cambria Emporium or the Depot and the buildings on the other side of Crab Creek.
It should further be noted that the large grassy areas which are at a lower elevation that the Cambria Emporium or the Depot but are on the opposite side of the track are untouched by water flow or debris. In full investigative mode, I wandered down the track looking and taking photos on both sides. No evidence of flooding was found on the Creek side of the railroad tracks. However, there is extensive evidence to indicate that water running downhill from properties on the otherside of the track pushed debris up to the very edge of the track. A lot of debris flowed down a channel along side the track headed straight for….yep you guessed the Cambria Depot and Emporium, which ironically (NOT) did get flooded.
I’ll be loading the audio of today’s PC meeting in a bit but I was in another meeting with the camera so I only have partial videos of that meeting. The audio fortunately caught something I would have missed. A citizen asking for a rezoning to allow a used carlot, uphill from the depot and the train track, which will include a newly paved area for the cars to be parked upon.
The owner of the property noted that he had some problems with water running off of Depot St. onto his property but that the town had a drain there and that took care of it, pretty much. But, in the past 2 years he did add two drains of his own to keep his buildings from flooding. Those drains run downhill and drop off the slope at the tracks……(at about the same place I found where part of the slope had been washed away, several large limbs had been washed down, oh, and a large black cable that runs between two large wooden poles has been pulled down and is now tangled in the debris. Wanna bet the next good rain takes out that power line?
Walking down the track shows a clear path of water running down the track headed to Cambria Street. Debris is pushed up onto the track, maybe a train derailment in the future?
What in the heck is it going to take for these guys to get a clue and realize that it is stormwater management that is the issue? The Town needs to have professionals come in to look at these. (I have a nightvision feature on my camera and I can’t wait to see what the shots from the grates down inside those drains show:)
Back to processing audio and video recordings:) Got some more photo albums to put together on stormwater. Keep checking at http://myvaresources.com for updates of existing and new photo albums.
Mr. Terpenny, you might want to get those comments from ‘specialists’ in writing to present to Town Council. It is probably just that you accidentally mispoke again, but that is so common, you really should take steps to help keep those mistakes from happening. If you come up with a document I can verify, I will be happy to post it on my website.
