A blog about a first-time house owner learning to maintain his backyard, and thoughts about nature, science, history, and life.

Saturday, October 27, 2012

Concern for the Dock

Storm QPF

By now, pretty much everyone in the US has heard about the ugly weather situation brewing for the Northeast early next week.  Under the influence of a blocking high pressure system in the Atlantic, Hurricane Sandy is forecast to slide to the west - quite rare but not unheard of - and make landfall somewhere between the Delmarva Peninsula and Long Island...it's increasingly looking like southern or central New Jersey.  Merging with a low pressure center approaching from the midwest, the storm will move inland and likely track just to the west of central New York.  The storm will slow down as it moves inland, producing an extended period of heavy rainfall.  Though we won't experience winds as strong as what they see along the coast, it will be windy and rainy, likely for well over 24 hours.  We can expect to see plenty of branches down and plenty of flooding.

I'm concerned about my dock.  I know that the last dock was washed away in April, when we received 2.12" of liquid-equivalent precipitation over a three day period, including 6" of snow.  The combination of snowmelt and rainfall produced widespread flooding across the county.  The current dock is anchored securely into the creek bed and has the added security of a steel cable, which ties the dock to a tree on the creek's bank.

The forecast calls for 1.75-3" of rain from Monday through Tuesday in the Freeville area...so it's likely that the new dock will be tested by similar rainfall to what took out the last dock.  I'm even more concerned, though, because depending on the exact track of the storm and the position of the heavy rainfall bands, rainfall exceeding 4" - roughly twice that from April's storm - is within the realm of possibility.  I've found in my research that 4" of rain in a relatively short period of time pretty much guarantees widespread flash flooding in the Northeast.  Furthermore, the creek is already running high from heavy rains earlier this week, and more rain is forecast for this afternoon through Sunday night, before the rain associated with Sandy gets here.  I'm imagining a wall of rushing water taking aim at the dock and shearing it in half - the rest of it left hanging by a steel cable thread.

When I look at the creek's bank, I see that the dock is in more or less the most vulnerable position along the U-shaped bend in the creek - at the lower right part of the U, right where the water approaching from the straightaway can slam into the dock.  Along the straightaway, the creek bank is low and vegetated, with a shallow incline, but entering into the U, the bank gets much steeper and much less vegetated.  Tree roots hold much of the soil in place to within about a foot of the water's surface, but below the roots, large gouges have been taken out of the bank.  Some of the largest gouges are right around the dock.

It appears that all I can do is wait and hope that the storm tracks farther east or farther west, moves faster, and that the heaviest rain bands miss Freeville and areas upstream.  I can't pull the dock out of the water, and there's nothing else I can do to reinforce it.  I'll have to hope that the nails hold fast and that the steel cable keeps the dock in place.  I knew that a test of the dock's sturdiness would come, but I didn't expect it so soon.  In any event, I'll keep you informed of the progress of the weather scenario and how the dock is (or isn't) holding out over the next few days.

1 comment:

  1. that last photo looks so serene and peaceful. The calm before the storm, indeed.