RANDOM BOULDER FIELDS {RBF} (For bank protection) 2 EXAMPLES.

RANDOM BOULDER

FIELDS {RBF} (For bank protection)

2 EXAMPLES

Typically a Random Native Boulder Field is built in-channel adjacent to the bank of concern

to strengthen that area, increase hydraulic roughness, increase turbulence, partially block flow, decrease flow velocities, dissipate energy,

& shift velocities & the thalweg toward the center of the stream. RBF increase habitat

diversity, & can increase aeration & dissolved oxygen. Aesthetics can be anywhere from

natural appearing to soothing & stupendous!!

Taking the classic concept of making the bank of concern

hydraulically rougher & tougher, & the opposite bank smoother & weaker, the RBF

also increases the bed roughness near the bank of

concern!!!

POPLAR RIVER, LUTSEN, MN.

SEPARATING THE MEGA-SLIDE FROM

THE RIVER (AND MORE)

By the stream dream team

Stream stabilization/restoration: Conceptually we will separate the stream from the 90+ ft tall hill, & in the channel we will make the inside of the bend smoother & the outer section of the bend & bank hydraulically rougher & tougher.

PRE-PROJECT PHOTOSby Dave Derrick

AUGUST 13, 2007

(Lowest flow in almost 30 years)

Derrick-8-13-2007-lowest flow in 30 yrs

From top of mega slump looking US.

In some sections the

outer section of the

channel was smooth &

inner section boulder

strewn, that will be

reversed!!!

THE PLAN

Stream Project Functions:

Bendway Weirs move scour & the thalweg away from attacked bank, with velocities reduced within weir field & on bank. Randomly placed native boulder field increases roughness, increases turbulence & complexity, & decreases flow velocities. Vegetation roughness reduces near-bank flow velocities. Roots strengthen bank & bind soil. Mini-swale captures colluvium.

Not shown on the next slide, but a Random Boulder Field (RBF)

will be installed within the Bendway Weir

field.

Mega- Slump Stream Project

Planform

Mega Slump

Bridge

Bendway Weir

Keys

Pre-dug Scour Holes

Boulder Revetment

Mini SwaleTransplanted Veg

A couple pebbles to be used for the keys & Bendway Weirs. Boulder specifications: D-100: max 54 inches, min 40 inches; D-50: max 38

inches, min 32 inches; D-35: max. 28 inches, min 22 inches.

CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

CONSTRUCTION PHOTOS

by Dave Derrick and Jay Michels

AUGUST 5-8, 2008

Looking DS @ constructed mini-weir & Bendway Weir #1. Note constructed boulder field & pool riffle-pool complex on right side of channel


CONSTRUCTION PIX OF RANDOM

SCATTERING OF BOULDERS TO CREATE THE

BOULDER FIELDS BETWEEN THE

BENDWAY WEIRS

Looking DS @ boulder flying though air


Looking DS @ the big boulder splash


Looking DS @ 2 more boulders flying though air


Looking US @ completed boulder field & Bendway Weir & stone toe & Jay. Does it look natural???? I would say so… Smooth on inside of bend


Stream Project Functions::::::::• Longitudinal toe stone provides scour protection• Toe stone protection completely separates stream from Mega Slump• Willow poles provide vegetative roughness, increase height of “soft

protection”, shades stone & water, & has many wildlife functions {everything from carbon input to structure cover to insect production, beneficial to pollinators, etc.}

• Mini-Swale provides a storage area for colluvium from Mega Slump• Bendway Weirs increase stream roughness, reduce toe scour,

provide diversity & complexity of depth, velocity (horizontal & vertical) & substrate, plus they move the thalweg away from the toe of the eroding bank.

• The dug pools at the ends of the Bendway Weirs provide mini pool-riffle-pool sequences throughout the bend.

• Boulder fields provide additional roughness, plus a “natural” look

CONSTRUCTION COMPLETE

(going from upstream to downstream)

Photos by Dave Derrick AUGUST 8, 2008

Looking DS. Boulder field to left, dug pools & riffles on right

CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

Looking DS @ constructed mini-weir & Bendway Weir #1. Note constructed boulder field & pool riffle-pool complex on right side of channel



Looking DS @ toe stone & Bendway Weirs 2 - 4.

BW#2

BW#3

BW#4

Looking DS @ Bendway Weirs # 4 & 5. Diversity & complexity of flow


Looking at constructed natural appearing random boulder field (foreground) & random chaotic stone toe


Looking US @ pool & colorful boulder assemblage.


Watching the river flow, looking US @ Bendway Weir #5 & boulder field


Watching the river flow, looking US @ BW #5 & boulder field, fantastic diversity of depth, velocity, turbulence, substrate, holding water (refugia)


Looking US @ placed boulders dissipating stream energy


Looking DS @ stone toe, boulder field, & Bendway Weirs 7 & 8.


Looking US @ Bendway Weir #7 & stone toe, smooth on inside of bend, rough on outside of bend.


Looking DS @ Key #8 (with veg) & BW #8. Note pools & flow at end of weir


Looking DS @ stone toe, boulder field, & Bendway Weirs 7 & 8.


SITE 4: MINIMAL BANK STABILIZATION TO REDUCE THE

SEDIMENT LOAD INTO DINGMANS CREEK FROM THE SMALL SLIDE

DELAWARE WATER GAP NATIONAL RECREATION AREA,

NATIONAL PARK SERVICE PROJECT CONSTRUCTED

SEPTEMBER 24, 2009

PROBLEMS• For approximately 200 ft Dingmans Creek is

flowing against & eroding the left valley wall (estimated height 35 ft). The amount of fine sediment delivered to the stream is significant. This entire colluvium slide is very unstable. If erosion progresses at this site it may kick the stream back toward the park road downstream and create a threat to road stability (Johnny B. Mountain Road).

• The point bar (right side) of the channel is very rough with a number of boulders increasing the hydraulic roughness & impeding flow.

• 35 Vegetated Traffic Control Stones (TCS)

• Every 4th TCS is keyed 10 ft into the bank (perpendicular) with rooted Black Willow whips & other live poles planted at a rate of 3 plants per ft.

• Every 4th TCS has a Single Stone Bendway Weir (SSBW) to move the thalweg away from the left bank & toward the center of the channel approximately 5-8 ft.

• The space between & behind the TCS is heavily vegetated with a variety of species of rooted-stock trees & shrubs.

• The loose eroding talus slope slide was heavily planted with several species of rooted-stock shrubs & trees

• Native boulders from the point bar were placed as a random boulder field streamward of the TCS & SSBW.

METHODS EMPLOYED

PRE-PROJECT PHOTOSby

Dave Derrick (HIGH WATER)

HIGH WATER-Looking DS @ fast water (smoother bed) near bank.

PRE-PROJECT DINGMANS CR-SITE 4 PIX BY DERRICK 7-24-2008

HIGH WATER-Looking DS @ smoother bed near bank, rougher toward inside of bend!!


HIGH WATER-Looking US @ project bank. Erosion of bank is contributing significant sediment to the system. Bed is rough

on the inside of the bend, but smooth near eroding bank


HIGH WATER-Looking DS toward DS end of project, smoother bed near bank, rougher toward inside of bend!!


SOLUTIONS (THE PLAN)• This project is designed to stabilize 200 ft of the bank at the

present location by increasing roughness of the entire bank with 3 gallon container rooted-stock trees & shrubs.

• Hard protection is limited to the toe & includes 35 vegetated Traffic Control Stones (TCS). TCS were typically 3 ft by 3 ft by 4 ft & spaced 3 to 6 ft apart. Every 4th TCS was keyed 8 to 10’ into the bank & had a Single-Stone Bendway Weir (SSBW) placed at the stream end. Live poles were placed in the key trench before stone was placed. Eight SSBW were built.

• A random natural bedload boulder field was placed around & in front of the SSBW & TCS’s.

Courtesy of Ecological Restoration, Inc

Courtesy of Ecological

Restoration, Inc.

Correction: There should be 3 Traffic Control Stones between each Single Stone

Bendway Weir, not 2.

Courtesy of Ecological Restoration, Inc.

SSBWTCS

Key

Two healthy Single Stone Bendway Weir (SSBW) stones.

CONSTRUCTION DINGMANS CR-SITE 4 PIX BY DERRICK 9-19-2009

PLANTS PLANTED

• Gray Birch 50 2 gallon pots • Gray Birch 200 unrooted poles• Buttonbush 25 bare root• Silky Dogwood 200 bare root• Ninebark 175 bare root • Rhododendron 50 3 gallon pots• White Pine 150 3 gallon pots

Common Name # Size

Traffic Control Stones (TCS) sized about 3 ft by 3 ft by 4 ft, dug into the bed & bank, designed to stabilize & roughen the bank, are spaced 3 to 6

ft apart. Every 4th TCS is keyed into the bank & has a Single Stone Bendway Weir attached. 8 SSBW total

Traffic Control Stones (TCS) with Single Stone

Bendway Weirs (SSBW) & vegged keys & pole

plantings

Key

Key

TCS

KeyTCS

SSBW

TCS

TCS

TCS

TCS

TCS

TCSTCS

SSB

W

SSB

W

Key

Key

Key

Thalweg

Key

Scoop a hole into the bed & bank for the Traffic Control Stone (TCS), then place live poles against

bank, push the TCS into position, then backfill. TCS were typically 3 ft by 3 ft by 4 ft & spaced 3 to 6 ft

apart. Every 4th TCS was keyed 8 to 10’ into the bank & had a Single-Stone Bendway Weir (SSBW) placed at the stream end. Live poles were placed in the key trench before stone was placed. A random natural

bedload boulder field was placed around & in front of the SSBW & TCS’s. All bare areas of the slide area were planted with 3 gallon container rooted-stock

trees & shrubs.

Rooted–stock container shrubs & trees added to Traffic Control Stones at toe & all bare

areas of the entire eroding bank

Key

Key

TCS

KeyTCS

SSBW

TCS

TCS

TCS

TCS

TCS

TCSTCS

SSB

W

SSB

W

Key

Key

Key

Thalweg

CONSTRUCTION PHOTOS

by Dave Derrick, September 19-20, 2009

CONSTRUCTING THE VEGETATED KEY,

TRAFFIC CONTROL STONES, & SINGLE STONE BENDWAY

WEIRS # 4 & 5.

Looking across @ stone being placed in the key for Bendway Weir #4. Live poles have already been placed in the key trench.


Close-up of a Single Stone

Bendway Weir (SSBW) &

vegged key & pole plantings

Thalweg

Key

TCS

SSB

W

Key

Key

Looking DS @ many live pole plantings landward of the TCS.


Looking across @ live poles & key stones in BW #5.


Looking across @ Single Stone Bendway Weir #5.


Weir construction complete, looking across @ Bendway Weir #5.


CONSTRUCTION COMPLETE

Photos by Dave Derrick

SEPT. 24, 2009

Construction complete, looking across @ Bendway Weir #3, vegetated key, hillside plantings, TCS US & DS, & Random Boulder Field.

CONSTRUCTION COMPLETE DINGMANS CR-SITE 4 DERRICK 9-24-2009

Construction complete, looking across @ Bendway Weir #7, along with a vegetated key, hillside plantings, TCS, & Random Boulder Field.


Construction complete, looking DS. Left side hydraulically rough (and will become rougher as plantings grow), right side smooth.


Construction complete, looking US @ toe & bank roughness due to TCS, Single Stone Bendway Weirs, Random Boulder Field, many pole plantings & rooted-stock plants provide roughness


Construction complete-Looking US. The secret to bank stabilization: smooth the opposite bank (point bar area), & roughen & toughen the eroding

bank (toe & entire slide area) & bed using a Random Boulder Field.


1 YEAR AFTER PROJECT

COMPLETION Photos by

Dave DerrickSEPT. 12, 2010

1 YEAR LATER-Mid project Bendway Weirs, Traffic Control Stones, vegged floodplain bench, & Random Boulder Field.

1 YEAR LATER-DINGMANS CR.-SITE 4-PIX BY DERRICK 9-12-2010

1 YEAR LATER-Mid-project Bendway Weirs, Traffic Control Stones, vegged floodplain bench, & Random Boulder Field.

1 YEAR LATER-DINGMANS CR.-SITE 4-PIX BY DERRICK 9-12-2010

This PowerPoint presentation was developed & built by Dave Derrick.

Any questions or comments, call my personal cell @ 601-218-7717, or email @ [email protected]

Enjoy the information!!

mailto:[email protected]

Cleophus says “Geaux Saints”

RANDOM BOULDER FIELDS {RBF} (For bank protection) 2 EXAMPLES.

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