Truesdale Lake  

South Salem, New York

Drawdown: Report 2

These are some of the email reports and communications from Scot Evans from Truesdale Lake, James Gorman from Pond & Lake Connection, and others involved with the project. Putting selected parts up here for all to see what some of the discussion and learning is looking like.

September 23, 2019

The target depth was reached at 1 pm yesterday (sept 22) with three feet below spillway and four feet total drawn out by the siphons. As of Sunday 9/22/19 at 1:00 pm, all siphons have naturally shut down. 

Please schedule any day this week where you can lengthen the 6″ siphon to a four of five foot depth below spillway deck, so we can maintain the three foot depth as you recommended. (It needs to be four to five feet below spillway height since the vortex shut it down when it swirled 8″ above the intake.)

Detail of measurement stick with foot markings in red and spillway height in white outlined in red.
Buckling of the fernco fitting and hose clamp due to the enormous and continuous water pressure in the suction pipe.

Here is a photo & video of the EAST siphon breathing air through the collapsing rubber coupling just before it shut down on Friday night.

photo of the WEST intake’s whirlpool
video of the WEST intake’s whirlpool

I have pulled many fish hooks, lures, sinkers and line by cutting the geotextile fabric and dislodging the stone riprap then replacing it, so your crew should have a good suface to install the extra pipe. Here’s a summary of the drawdown progress:

  • The 1st foot of water from summer level to winter level was drawn out by three operating siphons in 60 hours.
  • The 2nd foot of water from spillway height  to -1.0′ on the gauge was drawn out by three operating siphons in 60 hours.
  • The 3rd foot of water from -1.0′ to -2.0′ on the gauge was drawn out by two operating siphons in 70 hours. (6″ siphon shut down 9/16/19)
  • The 4th foot of water from -2.0′ to -3.0′ on the gauge was drawn out by one operating siphon in 100 hours. (east 12″ siphon shut down 9/20/19)
  • The west 12″ siphon shut down at target depth on 9/22/19.

It was entertaining to watch the last of the siphons shut down at the same time that the lake reached exactly three feet below spillway height.

All’s well here and thanks again for the beautiful construction!

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