BS: Livin below a leaky dam

Subject: BS: Livin below a leaky dam
From: Donuel
Date: 28 Jun 06 - 09:57 AM

National news has mentioned the Needwood earthen dam is in jeopardy.
Thousands have been evacuated but so far we have had no alert.
At the end of Oriental St. in Aspen Hill the dam channel is about 200 yards away and 45 ft lower than our house.

Thing is, the dam is 80 feet tall and 2.5 miles away. There is still no information on my immediate area and have had no evacuation orders.

I'm wondering if a GPS unit would give me clear elevation data?

Subject: RE: BS: Livin below a leaky dam
From: Donuel
Date: 28 Jun 06 - 10:01 AM

http://www.msnbc.msn.com/id/13584487/

Subject: RE: BS: Livin below a leaky dam
From: Bunnahabhain
Date: 28 Jun 06 - 10:24 AM

If evacuations have been ordered, then it is safe to assume the calulations are about right. After New Orleans, disaster management officials will get their way on flooding risks for a few years, without too much political interference.

Shutting the stable door after the horse has bolted may not stop the first one, but after that, it's useful.

RE GPS. Depends waht kind. Most units designed for hiking should give you an elevation. I doubt any designed for marine navigation, or in-car sat-nav types would. HOWEVER, without a good topographical map of your area, the GPS data alone is of very little use. If your house is higher than the current water level in the dam, it is definitly safe. Beyond that, you need to look at the gradient and profile of the channel, but it's not an easy job.

If you're seriously worried, look at the area close to your house- within 1/4 of a mile or so. If there are people being evacuated who live 3 feet below you, then you could rightly feel that maybe you're too close for comfort. If the nearest people being evacuated are 30 foot below you, then you can see you're safe.

But seriously, trust the professionals on this one. I've approched channel capacity calulations from both the engineering and geological angles, and I wouldn't go near anything but the simple, idealised cases. Working with (presumably) an irregular channel, and a non-constant flow is going to be a right pain, and the saftet margins thrown in as a result will be big.

Subject: RE: BS: Livin below a leaky dam
From: CarolC
Date: 28 Jun 06 - 11:33 AM

Here's a topographic map of your area, Donuel...

http://www.topozone.com/map.asp?lat=39.088525&lon=-77.080267&s=200&size=m&layer=DRG100&datum=nad83

You can zoom in and out by changing the scale, and you can change the view area by clicking on the little green triangles located around the edge of the map area. Good luck.

Subject: RE: BS: Livin below a leaky dam
From: Bill D
Date: 28 Jun 06 - 11:58 AM

well, I live S.E. of that area a few miles.....not close enough that Lake Needwood would get me, but I shop in the Aspen Hill area.....I'd just as soon nothing happened there. It's damp enough now.

carpet drying in the driveway as I type....small pieces, that is: ...the big pile is lost and will be hauled off in coming weeks.

Subject: RE: BS: Livin below a leaky dam
From: Rapparee
Date: 28 Jun 06 - 12:06 PM

Google Earth will give you the elevation, I believe.

My wife returned from BWI last night -- her flight was delayed at takeoff for over three hours because of the rain.

Subject: RE: BS: Livin below a leaky dam
From: artbrooks
Date: 28 Jun 06 - 01:53 PM

My daughter was in NO at the librarians' convention...took her 30 hours to get home.

Subject: RE: BS: Livin below a leaky dam
From: Donuel
Date: 28 Jun 06 - 02:03 PM

Good advice all.

It seems that that some roads here could be under 8 ft of water but our house may have a good 20 ft buffer.

now I need to study Carol's link...

Subject: RE: BS: Livin below a leaky dam
From: JohnInKansas
Date: 28 Jun 06 - 06:24 PM

Donuel -

I don't have a high speed connection so Google maps won't let me connect to their maps and I don't know what topographical info they show. The map that Carol linked has the information, but at the enlargement offered it's pretty hard to read the details.

Any decent sporting goods store, esp one dealing with hunting/fishing stuff in your area should have topographical maps that are clear, accurate, and easy to read. There are several regional producers and if all else fails the DeLorme "Gazateer and Topographical" series is pretty good.¹ The DeLormes probably run around $20 by now - my old one was a bit cheaper. Your area, I believe, has an abundance of hiking trails, and regional hiking (sometimes called mountaineering) clubs may have websites with excellent maps of the trail areas that likely would show what you need, although not all clubs post more than "trail guides" that may have less info. Put a trail name into search.

If there's a chance you might need to move, a top map in your pocket might be a good idea, and of course you should have a good topo for your emergency kit - for the future(?).

¹ "Easy to read" is relative, since in some parts of Kansas you may have to flip across several pages to find the next 20 foot elevation line, but I don't think that's a problem in your area.

John

Subject: RE: BS: Livin below a leaky dam
From: Severn
Date: 28 Jun 06 - 06:32 PM

My daughter and ex-wife still live where I used to in Aspen Hill with the yard bordering Sycamore creek. I work with the Postal Service in Rockville. You can bet I'm following the story closely.

Subject: RE: BS: Livin below a leaky dam
From: Barry Finn
Date: 28 Jun 06 - 07:32 PM

Good luck Donuel, I'd rather have you here & posting & putting up your comics than to sing a really good unfunny song about "Living Under A Leaky Dam".
All the best
Barry

Subject: RE: BS: Livin below a leaky dam
From: The Fooles Troupe
Date: 28 Jun 06 - 07:32 PM

"Working with (presumably) an irregular channel, and a non-constant flow is going to be a right pain," etc...

Yeah, the way it will surge around and spill over and splash up in a 'natural channel bed', it may even apparently flow uphill (for short distances) in places where it gets up a good 'head of steam' once she starts flowing... that's what 'safety margins' are for...

Also will depend whether you get a 'big burst' failure, or a slow 'catastrophic leak to destruction' too - and my crystal ball is currently out for repair... :-)

No need to panic, but sensible precautions are always useful for those not completely precisely informed...

Subject: RE: BS: Livin below a leaky dam
From: frogprince
Date: 28 Jun 06 - 08:06 PM

"Why can't I fall in love, 'til I don't give a dam..."

I'll get my hat, and a couple of sandbags...

But really, hope you and your neighbors don't get subjected to a grievous and dangerous mess.

Subject: RE: BS: Livin below a leaky dam
From: M.Ted
Date: 28 Jun 06 - 09:48 PM

I thought about you, the very first thing, when I heard that the dam was in peril on the radio--we've got a couple of inches of water in the garage and the lights have been flickering perilously all evening. As the old song goes, Higher Ground--

Subject: RE: BS: Livin below a leaky dam
From: Scoville
Date: 29 Jun 06 - 09:28 AM

Johnstown

Subject: RE: BS: Livin below a leaky dam
From: beardedbruce
Date: 29 Jun 06 - 09:48 AM

Reports today that Lake Needwood crested at 25 feet above normal- but the dam ( while leaking) is still holding.