BANK EROSION PINS By Dave Derrick, Potomologist & VP, River Research & Design, Inc.
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BANK EROSION PINS By Dave Derrick, Potomologist & VP, River Research & Design, Inc.
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Transcript of BANK EROSION PINS By Dave Derrick, Potomologist & VP, River Research & Design, Inc.
BANK EROSION PINS
By Dave Derrick, Potomologist & VP,
River Research & Design, Inc.
BANK EROSION PINSA simple, inexpensive & accurate way to precisely
measure bank erosion rates. Five ft long sections of ½ inch diameter rebar are driven horizontally into
the toe, middle, & upper sections of an eroding bank until the river end of the rebar is flush with
the face of the bank. Over time the length of rebar exposed shows the amount of erosion!! Wooden
stakes are usually labeled (5 ft, 10 ft, etc) & driven at 5 ft intervals (5 stakes) on top bank above the
rebar in case the rebar is washed away.
Phil Balch in KS installing
bank pins
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The rebar is driven into the bank until the
end is flush with the face of
the bank.
Thalweg trace
Bank Erosion Rate Measurement
5 ft long sections of ½ inch diameter rebar is driven into the toe, middle, & upper bank until the rebar is flush with the face of the bank.
5 ft long rebar bank erosion pins
Distance varies, 40
to 200 ft typical
On shorter banks only two erosion pins would be needed, not three
Thalweg trace
Bank Erosion Rate Measurement
Mark stakes with distance from edge of bank (5 ft, 10 ft, 15 ft, etc.), then measure back from edge of bank & drive stakes into ground at 5 ft intervals
20 ft
5 ft long sections of ½ inch diameter rebar is driven into the toe, middle, & upper bank until the rebar is flush with the face of the bank.
5 ft long rebar
Stakes Distance varies, 40
to 200 ft typical
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Bank erosion pins
Pins were originally installed with river ends flush with streambank
surface
Measure exposed length of rebar to determine amount of erosion, then divide by time since rebar was installed to determine the erosion rate. Convert this number to the erosion rate in feet per year.
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21 ft of lateral migration in one month!
Travelute Site, Little Blue River, KS.
Stake was placed 25
ft from breaking edge of
top bank one month
ago
This PowerPoint presentation was developed & built by Dave Derrick. Any questions or
comments, call my personal cell @ 601-218-7717, or email @ [email protected]
For questions involving erosion pin installation, call or email Phil Balch, [email protected]
Wildhorse Riverworks, Inc., 11821 NW 13th St. Topeka, Kansas 66615 Mobile 785-213-3778;
Office 785-478-4886
CLEOPHUS SPEED ELVIS DERRICK, WITH FRIENDS
