An interesting Closure order for Henri

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peakbagger

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http://indepthnh.org/2021/08/22/whi...-closures-in-advance-of-tropical-storm-henri/

I recognize most of the areas that they closed and expect that most are related to cars getting stranded due to washouts. The interesting one was closing Lincoln Woods trail to Franconia Falls and East Side Trail. Both of these are not vehicle roads and are for non motorized travel unlike all the other closures. Franconia Falls at high water can be impressive as well as the main channel of the East Branch. While hiking last fall a friend and I ran into a USFS employee quite familiar with the FS activities going on in the Pemi area and she had mentioned that the FS were planning to bring in an engineering crew this summer (2021) to survey the eroded section of the Lincoln Woods trail to plan for future repairs. My guess is that the closure is related to concerns about that eroded location as any significant storm event could scour what is left of the trail down to the underlying bedrock which would, judging by appearances of the exposed ledge on the north side of the trail, leave a near vertical ledge where the trail once existed. When it does erode out the remaining trail could be seriously undermined as what is under there appears to be just a bed of gravel.

There are alternatives for hikers to bypass by just bushwhacking up slope and paralleling the washout. The logical approach would be to mark and rough out this route sooner than later as barring major rework of the river channel and hundreds of tons of stone rip rapping or building a bridge tied to the underlying ledge over this section, its going to wash out sooner than later. One good spring storm with the right debris flow in the river and it becomes a crisis. I think the FS has avoided a relo to date as this is very popular family friendly trail and rerouting it upslope while maintaining a gentle grade would require a fairly major relocation to the level that was done on the west end of East Side trail post Irene.
 
Keeping people off the trail and from getting too close or out of the river.

FWIW, in looking at the CT River gauges for the Shetucket River, in Willimantic where the Willimantic and Natchaug Rivers, meet, current water levels on a Cubic Feet per second are 500 CFPS above their 1955 recording. The flood was 8/19/1955.
 
The WMNF rarely does a closure order for hiker safety as it sets a bad precedent. Lots of other trails with similar or worse hiker risks from high water and they were not closed. The closures of the parking areas along the Kanc were most likely tourist orders as both locations can really crank up.

Is the flooding on the Shetucket River over the one time seasonal high or just the daily high?. Its a moot point anyhow up in the Whties as the gages barely moved up north, It takes a lot of rain in short period to put the rivers over spring meltwater events. It can happen but just rare.
 
Keeping people off the trail and from getting too close or out of the river.

FWIW, in looking at the CT River gauges for the Shetucket River, in Willimantic where the Willimantic and Natchaug Rivers, meet, current water levels on a Cubic Feet per second are 500 CFPS above their 1955 recording. The flood was 8/19/1955.

A lot of that spike had to do with the tornado and storms on THU, not the "hurricane". That merely topped things off. The Quinebaug gauge near my house barely budged from Sunday's rain but is still extremely elevated from THU's action. Central and Northern NH's gauges look totally unaffected as of yet. The East Branch is only measuring about 100 cfs, which is actually below average.
 
The daily value for the past 92 years and four days past what was considered a very bad flooding event. This was 13 years after the Mansfield dam was dedicated. (small rivers, the Fenton, Mt. Hope and the Natchaug go in. The Natchaug comes out and when it meets with the Willimantic River (which gets fed by the Hop River which made the local news for washing out a road) it becomes the Shetucket.

Min
(1949) 25thpercen-tile Median 75th percen-tile Mean Max (1955) Most Recent Instantaneous Value Aug 23
26.0............. 81................ 136.................. 236....... 255.............2970............................. 3540

For Day Trips numbers, the graph shows it went up to this level, then down to about 900 before this event. Also for this year, Ashford got historic rain in July where the Mt. Hop was 10 feet above flood stage. An emergency spill way at the pond at Scout Camp J.N. Webster which had not been utilized in the 55 Event, had several feet of water in it for the first time. Where Route 89 goes between two of the lakes that make up Mansfield Hollow, I got to see the before and after shots as on my way to camp, Lake three has water up along the branches that make up the shore canopy. On my way back, a ring about 10 feet high of mud could be seen on the branches.

Both the Q and Natchaug have dams on them. The French and the Willimantic have few and none that are designed for flood control. We got four inches on Sunday here and it's begun raining again.
 
The daily value for the past 92 years and four days past what was considered a very bad flooding event. This was 13 years after the Mansfield dam was dedicated. (small rivers, the Fenton, Mt. Hope and the Natchaug go in. The Natchaug comes out and when it meets with the Willimantic River (which gets fed by the Hop River which made the local news for washing out a road) it becomes the Shetucket.

Min
(1949) 25thpercen-tile Median 75th percen-tile Mean Max (1955) Most Recent Instantaneous Value Aug 23
26.0............. 81................ 136.................. 236....... 255.............2970............................. 3540

For Day Trips numbers, the graph shows it went up to this level, then down to about 900 before this event. Also for this year, Ashford got historic rain in July where the Mt. Hop was 10 feet above flood stage. An emergency spill way at the pond at Scout Camp J.N. Webster which had not been utilized in the 55 Event, had several feet of water in it for the first time. Where Route 89 goes between two of the lakes that make up Mansfield Hollow, I got to see the before and after shots as on my way to camp, Lake three has water up along the branches that make up the shore canopy. On my way back, a ring about 10 feet high of mud could be seen on the branches.

Both the Q and Natchaug have dams on them. The French and the Willimantic have few and none that are designed for flood control. We got four inches on Sunday here and it's begun raining again.

I kayaked at Mansfield Hollow a couple of times after that rain event and closure. It is crazy how high the water was. I can see why there are gates to close the road on either side because if any idiot ever tried to drive through that it wouldn't end well. I've seen that "brown ring of damage" at a lot of local ponds this year, including Thompson near my house (which is fed by the Quinnebaug).
 
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