STONES IN COMPRESSION –

BOTH NATURALLY & MACHINE PLACED

by Dave Derrick

COMPRESS: To press

or squeeze (something) so that it is smaller or fills less space.

COMPRESSION: The act, process, or result of compressing

From: The Meriam-Webster on-line dictionary

In river engineering, we are talking about stones with a sloped side facing upstream so that flow (water pressure) pushes against the sloped face & pushes the stone down into the bed of

the stream (in compression).

Several river folk performed literature searches to see if anyone had analyzed

how much more stable a stone in compression is compared to a similar stone that was not in compression, but

no one has done that research !!! Sounds like an important thesis to me.

STONES, & OTHER OBJECTS,

NATUALLY IN COMPRESSION

Stones naturally in compression

With “slabby” stones, “B” axis

of stone is almost always parallel

to flow. “A” axis (longest side) of

stone is perpendicular to flow. Big Piney

Creek, AR.

Stones are imbricated (overlaying each other) like shingles on a roof.

A Hydraulic Cover Stone (HCS) dug into the streambed substrate for stability. Upstream sloped face of HCS is in

compression & forces the HCS into the bed. The downstream wake (surface modulation) is the “Hydraulic Cover”.

Flow

HCSFlow force Force

NATURAL-Looking across. Hard to believe the stream moved these stones. Bedload !! High flow compresses stones into the bed of the stream

NATURAL-RILEY COUNTY, KS. - PIX BY DERRICK 7-19-2012

Flow force

Force

NATURAL-Looking US @ rocks in compression. High flow hitting top stone pushes it down into the bottom (footer) stone & into the bed.

NATURAL-RILEY COUNTY, KS. - PIX BY DERRICK 7-19-2012

FLOOD IN PARK-Looking DS @ picnic table in compression.

FLOOD IN PARK AREA-CATFISH CR. PIX DAVE DERRICK-8-5-2011

Flow

FLOOD IN PARK-Accelerated flow velocities around vehicle results in a scour hole. Water was several ft deep across entire floodplain.

Sloped angle of car into flow resulted in the car being pushed into the ground instead of being carried DS during the flood.

FLOOD IN PARK-CATFISH CR. PIX BY REBECCA KAUTEN-8-4-2011

FLOOD IN PARK-Looking US. Auto blocked & split flow. Note “shadow” deposition DS of car.

FLOOD IN PARK-CATFISH CR. PIX BY REBECCA KAUTEN-8-4-2011

GOAL & FUNCTION-BASED DESIGN FOR RIPARIAN & STREAM SYSTEMS

THE EIGHTEENMILE CREEK PROJECT

PHASE II CONSTRUCTED JUNE 18-20, 2007

by Dave Derrick

Vic with a sloped face stone that will be perfect for placing into compression when the sloped side is facing upstream.

Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick

Vic with a sloped face stone that will be perfect for placing into compression when the sloped side is facing upstream.

Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick

Flow force

Force

Looking DS @ a group of several HCS. US stone in compression

Construction-18 Mile Creek, Phase II-June 2007, Pix-Vic DiGialomo

Looking US @ same group of 5 Hydraulic Cover Stones

Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick

THE EIGHTEENMILE CREEK PROJECT

A LINE OF STONES IN COMPRESSION THAT WILL PROTECT THE

FISHERMAN’S WALKING PATH

Flow from left, looking @ stones in compression.

Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick

See the footer stone?

Attack Flow

Close-up of fisherman’s path stones in compression. Flow hits angled upstream face of stone, which pushes that stone into the footer stone, which is then pushed down

into the bed of the stream (compression), resulting in a very stable structure.

Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick

See the footer stone?

Attack Flow

It’s all about the fishing!!!!

Construction-18 Mile Creek, Phase II-Fall 2007

This PowerPoint presentation was developed & built by Dave Derrick.

Any questions or comments, call my personal cell @ 601-218-7717, or email @ d_derrick@r2d-eng.com

Enjoy the information!!

KAYLYN LOUISE DERRICK, AGE ½.