Author Topic: Mountain Extension Tree Clearing  (Read 2315 times)

John Kokas

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Re: Mountain Extension Tree Clearing
« Reply #30 on: January 11, 2018, 11:21:52 PM »
A lot of people think Mainer's are crazy for venturing out in the winter.  Having lived in Maine and far upstate NY, one understands the real meaning of "cabin fever" and there are times when -10 below is a lot more desirable than another day coop'ed up in the house!

Philip Marshall

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Re: Mountain Extension Tree Clearing
« Reply #31 on: January 11, 2018, 11:27:30 PM »
I agree 100%, Mike. There is a reason loggers prefer to work in the winter months, especially on wet ground or ecologically sensitive sites. It's all about minimizing soil disturbance.
« Last Edit: January 11, 2018, 11:29:50 PM by Philip Marshall »

Paul Uhland

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Re: Mountain Extension Tree Clearing
« Reply #32 on: January 12, 2018, 12:02:18 AM »
Didn't realize there has to be such minimized site disturbance. Also, your time constraint is so tight. Wow.
Go for it.
Paul Uhland

Mike Fox

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Re: Mountain Extension Tree Clearing
« Reply #33 on: January 13, 2018, 07:15:19 PM »
After the warm weather and rain the last 2 days...











Mike
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John Kokas

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Re: Mountain Extension Tree Clearing
« Reply #34 on: January 13, 2018, 08:17:37 PM »
That's a whole lot of water!  Ice jam?

Gordon Cook

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Re: Mountain Extension Tree Clearing
« Reply #35 on: January 13, 2018, 09:38:44 PM »
Looking at the pictures taken today I was wondering how our Trout Brook bridge and site plans match up against the conditions that you observed?
How extreme was this event compared to the worst case that is planned for? 
And did you check the previous work sites to see what they looked like?
Gawdon

Mike Fox

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Re: Mountain Extension Tree Clearing
« Reply #36 on: January 14, 2018, 01:43:48 AM »
While the water level may be high, it is far from the projected flood plain. The estimated floodwater height, according to FEMA, is about a foot below the height of the grade. Look at the included drawing, the FEMA flood plain is the blue line just below the bridge.

Mike
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Bill Baskerville

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Re: Mountain Extension Tree Clearing
« Reply #37 on: January 14, 2018, 03:36:12 AM »
Wow guys, we are going to raise the top of the rails 3 feet 2 inches above the current ground height.  Subtract rail and ties and that is about 2 feet 6 inches to the bottom of the ties.  I had no idea that we would raise the track that much.  Not that I am complaining, that is just a lot of stone and gravel.

Impressive drawings by the way.  Did Ed do all those?
Wascally Wabbit

Jason M Lamontagne

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Re: Mountain Extension Tree Clearing
« Reply #38 on: January 14, 2018, 11:53:15 AM »
The drawings were a combined effort of Christopher Marston of the NPS, Eric Schade and myself.  While Ed wasn’t involved in this one, he helped us greatly with the production of very professional maps and site plans (which is Ed’s cup of tea).

The stream profile seen in the drawing is from an actual profile survey performed by several of us this fall.  Note in particular the “normal high water line” as labeled on the drawing, then note how quickly the banks fair out away from the stream.  The normal high water marks on site, and at any stream which experiences flow like this, are very plain to discern- as their sharply eroded for a short vertical jump in the profile.

As you can see, the volume of water required to get above the high water mark goes very high very quickly.  This is why the high water mark is so eroded- high flows rarely make it above this mark.

I wasn’t on site yesterday but from Mike’s pictures it looks like the water level is right at the high water mark.  It does this regularly. 

The “floodplain” on the drawing is the FEMA 100 year floodplain.  Now you can see why such an event is only expected every 100 years or so.

The bridge piers are required to be 20% wider than the high water marks.  We have achieved 80%.

See ya
Jason
« Last Edit: January 14, 2018, 12:07:43 PM by Jason M Lamontagne »

Jason M Lamontagne

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Re: Mountain Extension Tree Clearing
« Reply #39 on: January 14, 2018, 11:58:07 AM »
The raising of the rail height is to get the bottom of the bridge at least 1’ above floodplain, a requirement.

The raising will be accomplished with the use of retaining wall blocks on each side of the roadbed fill approaching the bridge, as adding that much more fill material right near the stream is frowned upon.  It’s be a lot of fill, and moreover would widen the roadbed fill substantially.

We are currently studying an option which would allow us to lower the track height 18” from that shown, while maintaining our foot of clearance above floodplain.  If we can accomplish this, the retaining wall can be nearly eliminated (some will he needed right at the pile abutments).

See ya
Jason

John Kokas

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Re: Mountain Extension Tree Clearing
« Reply #40 on: January 14, 2018, 01:01:21 PM »
Thanks Jason for the detailed explanation of the bridge situation.  IMHO it will be best to maintain the higher elevation for the following reason.  As we have found in eastern PA, we are having more than average 100+ year floods.  Some is due to storms themselves but much is due to development and associated runoff.  Thus the Army Corps is reevaluating its criteria and expanding the floodplain mapping.  Planning over the long term, one cannot determine how much development may occur in the future and how it will effect stream flows.  In essence, better safe than sorry ................

Mike Fox

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Re: Mountain Extension Tree Clearing
« Reply #41 on: January 14, 2018, 01:35:19 PM »
This was no where near the 100 year high, but was more likely close to the annual high. I was glad to see this on person, because there are other factors in the immediate area that would cause the water to go even higher. The road bridge, for instance, was approximately 2 feet above the water. While on site, I figured our bridge would also have the same clearance.

Mike
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Jason M Lamontagne

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Re: Mountain Extension Tree Clearing
« Reply #42 on: January 14, 2018, 01:52:00 PM »
Ok I see now that yesterday’s water made it above the high water line.  Mikes picture of the highway bridge made me look again.  Makes me wish I’d gone up yesterday afternoon.

Note the bottom of the bridge is roughly level w the current ground level (maybe 4” lower).  That indicates the clearance we’d have. 

See ya
Jason

Wayne Laepple

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Re: Mountain Extension Tree Clearing
« Reply #43 on: January 14, 2018, 02:02:26 PM »
Another, perhaps unanticipated, benefit of raising the track and the bridge would be that the southbound approach, depending on the length of the runoff, would give southbound trains a bit of a boost to get a "run" toward the steep southbound grade.

Mike Fox

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Re: Mountain Extension Tree Clearing
« Reply #44 on: January 14, 2018, 02:08:45 PM »
Looking at the National Weather Service, precipitation total for Wiscasset for this storm was 2.14 inches. This, added to the fact that the brook was covered with ice, led to ice jams and slow water flow.
Mike
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