This lecture is always more easily understood if it takes place in 3dimensions, like in a parking lo

1
This lecture is always more easily understood if
it takes place in 3-dimensions, like in a parking
lot (pile of rock), or on a point bar of a stream.
Redirective methods
2
LECTURE OBJECTIVES

• With this lecture the student will be able to
• Determine when, and when not, to use selected
  redirective bank protection methods
• Visualize, analyze for applicability, and
  articulate how the method of choice will affect
  the hydraulic flow, both near and far field

3
What to Use, Continuous, or Discontinuous
(Intermittent) Bank Protection?Or do areas lost
to the stream need to be recovered?

• If the resource the project is being designed to
  protect (pipeline, levee, house, road, bridge,
  bat habitat, etc.) is in close physical proximity
  to the top of the streambank, then a continuous
  bank protection method needs to be used, or
  possibly a method that will gain back some of the
  area that has been recently lost to bank
  migration (false bankline with backfilled area).
• If intermittent protection methods (hard points,
  Rock Vanes, J-Hooks, Bendway Weirs, spur dikes,
  etc.) are used, then allowances must be made for
  some erosion, bank scalloping, and a resultant
  uneven bankline between hard structures.
• Properly positioned continuous bank protection
  should result in a smoothed bank alignment.

4
Continuous or Discontinuous ??
5
Do you have the luxury of Space??
Clear Creek, Arcade, NY. Pix from Chuck Godfrey,
TU.
6
(No Transcript)
7
BENDWAY WEIRS ARE ENERGY MANAGEMENT
THALWEG MANAGEMENT TOOLS, THEY DO NOT
PROVIDE TOTAL BANK STABILIZATION !! BY
THEMSELVES, NONE OF THE REDIRECTIVE RIVER
TRAINING STRUCTURES PROVIDE TOTAL BANK
STABILIZATION. DURING EXTREME, LONG
DURATION, HIGH ENERGY FLOW EVENTS SOME
BANK SCALLOPING CAN OCCUR.
8
Luxuries We Like To Have

• The Luxury of Space
• The Luxury of Time (nature strengthens the
  project over time)
• The Luxury of Monitoring
• The Luxury of Adaptive Management
• NOTE Think conceptually regarding functions,
  use Derricks LAW OF EXTREMES to understand how
  things work.

9
Adaptive Management

• Considering that a perfect knowledge
  of ecological processes within a non-equilibrium
  system is currently unavailable, and innovative
  technical solutions are in a cycle of rapid
  development (in many cases without thoroughly
  tested and verified design guidance), the
  Adaptive Management strategy can help achieve
  maximum function and benefits from a specific
  project.
• Adaptive Management allows for minor
  adjustments and changes to be made to the project
  design after the initial construction phase.
  These changes are based on data gathered and
  analyzed from project monitoring. This "learning
  by doing" results in optimum performance,
  function, and benefits from the project, and can
  provide valuable design and monitoring data for
  future decisions within an ecosystem.

10
Lets talk habitat
11
Bank Protection Techniques and Associated Habitat

• Intermittent (discontinuous) bank
  protection usually provides the most diversity.
  Structures, whether wood, stone, or vegetation,
  can increase backwater areas, increase edge or
  shoreline length, and result in diversity and
  complexity of depth, velocity (both vertical and
  horizontal), substrate, and flow patterns.
• A properly engineered structure,
  located correctly, can lead to changes in the
  energy patterns and bathymetry in at least the
  near-field, (and sometimes the far-field).
• Changes attributable to a structure
  are rarely going to be "all good", or "all bad".
  Rating the habitat value of the resulting changes
  will depend on what ecological goals were
  initially set (either species specific, or
  ecosystem based goals).

12
Downstream angled four inch high gabion vane
13
flow
14
Downstream angled rock vanes
15
Downstream angled rock vanes
16
UPSTREAM ANGLED ROCK VANES
Looking downstream
Phil Balch design, Little Blue River Elva
Hynek property near Marysville, KS July 2003
17
Site 8 E. Hynek
Rock Vanes
Rising Limb 40,000 cfs flood
18
From www.E-senss.com
Deposition is brown, scour is blue
Pool
from John McCullahs Salix Applied Earthcare
Pool
Typical upstream angled rock vane
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
Looking DS at ice around a rock vane, Marion Cr.
Alaska
23
Looking DS at a rock vane on the sag
river, near prudhoe bay, alaska
24
30 degrees
Flow
From Phil Balch, Cottonwood River, Kansas
25
Vegging the key, note dead water upstream of
rockless vane
26
Rock Vanes with bioengineering, urban setting,
Charlotte, NC
Irwin Creek (1998)
Purloined from Andrew Burg, note dead water
between Rock Vanes
Looking upstream
27
Looking US at damaged weir, one large stone
Displaced, no redundancy
28
J-HOOK VANES

• A Dave Rosgen invention, named due to the overall
  plan view shape of the structure
• The J section is a semi-circular flow
  concentrator designed to provide a plunge-scour
  pool for habitat for salmonids, has nothing to do
  with bank protection.
• Plunging flow into pool dissipates energy,
  entrains air, provides hydraulic cover (surface
  disturbance)

29
Neil Young, no John McCullah
30
Creek Stones naturally in compression
flow
31
(No Transcript)
32
Looking US
J-Hook on Marion Creek, AK
33
Differences between Bendway Weirs Rock
Vanes
34
Differences between Rock Vanes Bendway Weirs
here are Rock Vanes
Photo by Wayne Kinney
Mini case study 1 of 6
35
Here are Bendway Weirs on the same river, now
lets look at those same Rock Vanes again
Photo by Wayne Kinney
Mini case study 2 of 6
36
DIFFERENCES BETWEENBENDWAY WEIRS ROCK
VANES

• LEVEL-CRESTED (flat)
• ANGLED-upstream 20 degrees from perpendicular (70
  degrees from the bank)
• LENGTH-determined by how much river flow needs to
  be controlled by future thalweg location
• HEIGHT- lower than any flow that can erode the
  bank, usually /- 1 ft of the base flow (typical
  low-flow) water surface elevation

• SLOPED- Best at 10 to 1
• ANGLED- 30 degrees from a line tangent to the
  bank
• LENGTH-determined by height at bank end, vane
  slope angle, and bathymetry at river end
• HEIGHT- varies by designer, anywhere from 1/3
  bank full stage to bank full stage

Mini case study 3 of 6
37
Rock Vanes (again)
Photo by Wayne Kinney
Mini case study 4 of 6
38
Looking DS _at_ Rock Vanes on the Pembina River,
Canadian Rockies. Note dead water upstream of RV
thalweg trace heading toward end of second Rock
Vane
Photo by John McCullah
Mini case study 5 of 6
39
Looking DS _at_ Rock Vanes on the Pembina River,
Canadian Rockies. Low flow. Note deposition US
of Rock Vane
Photo by John McCullah
Mini case study 6 of 6
40
Got it????
41
Flow over the top of the weir is slowed due to
roughness, redirected perpendicular to the
longitudinal axis of the weir
42
Bendway Weirs were invented by Tom Pokrefke
for use on large navigable rivers.
43
Looking DS at a partially drained movable-bed
coal model of the Middle Mississippi River
(Dogtooth Bend). Note new location of thalweg
off the stream ends of the weirs.
44
1.
2.
UNREVETTED BEND
REVETTED BEND Newly installed bendway weir
effects of bendway weir
3.
4.
From Rob Davinroy, St. Louis Corps
45
Movable-bed coal model. Looking DS, no Bendway
Weirs, time lapse photography with confetti on
surface of water (white streaks). Note high
velocity flow against outer bank, flow crossing
toward outer bank
46
Movable-bed Model. Looking DS, Bendway Weirs
installed. Currents are more evenly distributed.
Note flows do not cross over to outside of bend.
47
How Do Bendway Weirs Work?

• Water flowing over the weir is redirected at an
  angle perpendicular to the longitudinal axis of
  the weir.
• With weirs angled upstream the erosive flow
  (energy) is directed away from the outer bank and
  toward the inner part of the bend.
• Strong secondary currents (helical flow) in bend
  are broken up.
• A set of weirs are designed to act as a system to
  capture, control, and redirect current directions
  and velocities through the bend and into the
  downstream crossing.
• Last weir in system can aim flow (and channel
  thalweg) where you need it.

48
Mississippi River model tests-cross-section
comparison shown here
49
Velocities taken on the Mississippi River
50
A system of Bendway Weirs, seen here in a
physical movable-bed model, flow is left to
right. Model is drained, puddles delineate scour
areas.
51
BENDWAY WEIRS ARE ENERGY MANAGEMENT
THALWEG MANAGEMENT TOOLS, THEY DO NOT
PROVIDE TOTAL BANK STABILIZATION !! BY
THEMSELVES, NONE OF THE REDIRECTIVE RIVER
TRAINING STRUCTURES PROVIDE TOTAL BANK
STABILIZATION. DURING EXTREME, LONG
DURATION, HIGH ENERGY FLOW EVENTS SOME
BANK SCALLOPING CAN OCCUR.
52
MODEL STUDY- MISSISSIPPI RIVER AT ST LOUIS
HARBOR Using Bendway Weirs for thalweg
realignment for navigation through 6 bridges
Mini case study 1 of 5
53
Mini case study 2 of 5
Preferred navigation channel location would be
toward the center of the channel, not up against
the left bank
54
Mini case study 3 of 5
Weirs angled 25 degrees upstream redirected flow
too much the navigation channel was lost!!
55
Mini case study 4 of 5
Weirs were re-angled to 6 degrees upstream (from
perpendicular) the navigation channel was much
improved!!
56
Looking DS at lighted floats (9 ft draft for
navigation) on the St. Louis physical movable-bed
coal model. Six bridge spans to navigate through
Mini case study 5 of 5
57
LITTLE BLUE RIVER, MARYSVILLE, KS. Martin -
Jueneman Site
58
Bendway Weirs on the Little Blue River, BWs
working during flood, from Phil Balch of
Wildhorse Riverworks, Inc,
Looking DS with the river on a 40,000 cfs flood.
Note thalweg is streamward of the ends of the
Bendway Weirs
Mini case study 1 of 3 Martin - Jueneman Site
59
Mini case study 2 of 3 Martin - Jueneman Site
Deposition between Weirs from one bankfull flow
6/2002 on the Little Blue River, from Phil Balch
60
Mini case study 3 of 3 Martin - Jueneman Site
Natural Vegetation established on deposition
9/2002
61
Bendway weirs on bear creek, il (as built)
62
Bendway weirs on Bear Creek, il (seen here
after one growing season)
63
Here a combination of Rock Vanes Bendway Weirs
were used to change the radius of the thalweg
around a bend
Rock vane
Thalweg
Flow
Bendway WEIRS
Original bankline
64
The way I like to build Bendway Weirs, note water
surface disturbance
65
CHAUTAUQUA CREEK ICE DAMAGE REDUCTION
PROJECT Near its mouth _at_ Lake Erie

• Severe scour from ice and high flow velocities on
  the right descending bank had resulted in an
  overwidened section of stream.
• Mid-channel sediment bars, mouth of creek _at_ Lake
  Erie clogged
• No holding areas or habitat for steelhead
• A heavily used public fishing section of the
  stream

66
DRILLING PEGGING TOE STONES SINGLE
STONE BENDWAY WEIRS WITH METAL RODS TO
BEDROCK
67
7 ft long, 1 5/8 inch diameter rebar rods for
pegging stone to bedrock.

• Pix by Joe Galati

68
Construction June 2006. Drilling holes for metal
pinning rods

• Pix by Joe Galati

69
Looking upstream at the SINGLE-STONE
BENDWAY WEIRS
70
Aug 31, 2006, looking US at two pegged to bedrock
Single-Stone Bendway Weirs in the stacked stone
wall section.

• Pix by derrick

71
Aug 29, 2006 -high water- Looking US, note dead
water near toe thalweg location near arrow, all
due to the Single Stone Bendway Weirs

• Photo by Dave Spann

72
Looking downstream at the SINGLE-STONE
BENDWAY WEIRS HIGH WATER AUG 29, 2006
73
Aug 29, 2006-high water-looking DS
Note rooster tail defining right edge of high
velocity water

• Photo by Dave Spann

74
Aug 29, 2006-high water-Looking DS toward Lake
Erie

• Photo by Dave Spann

75
Mar 14, 2006. Looking DS. Three submerged
Bendway Weirs can be located due to surface
disturbance

• Pix by Joe Galati

76
CASE STUDY- NEOSHO RIVER, SOUTHEAST
KANSASConstructed May-July 2000 Using
Bendway Weirs for thalweg realignment bank
erosion reduction
Mini case study 1 of 5
77
Neosho River Project Specifications

• River is 260 ft wide
• Gravel-sand bed
• Outer bank is 25 ft tall, it eroded 178 ft in 6
  years time
• Bendway Weirs are 65 ft wide, spaced 210 apart,
  11 weirs in all. Constructed of shot rock
• First set of velocities water was 4-5 ft over the
  weirs, second set of velocities water was a
  measured 10 ft over the weirs!!
• Velocities were measured with floating oranges

78
Neosho River, Allen County, Kansas 4-5 ft of
water over weirs (estimated)
Mini case study 1 of 3
79
Looking US at weirs on the Neosho River, KS
Mini case study 2 of 3
80
Neosho River, Allen County, Kansas 10 ft of water
over weirs (measured)
Mini case study 3 of 3
81
Looking DS in project bend, high water on Catt
Creek, 11/4/2004
8.0 ft/sec
Slow water on the outside of the bend??
Thalweg 6.4 ft/sec
Within the weir field 2.6 ft/sec
Mini case study 8 of 12
82
Phil Balch builds Bendway Weirs a little taller
gets great wetlands between weirs. Little Blue
River, Marysville, KS, high suspended-sediment
sand bed river
Pix by Derrick
83
Hydraulic Improvements Due to Bendway Weirs

• Deposition occurs on the outer bank of the bend
• Velocities are reduced near the outer bank
• Flow is generally parallel with the outer bank of
  the bend
• The deepest section of the river (the thalweg) is
  moved away from the outside of the bend toward
  the center of the channel

84
Dr. Doug Shields
85
Stream Features Needed For Habitat Improvement

• (According to Dr. F Douglas Shields, Jr,)
• Occasional deep pools
• Scour holes
• Stable habitat
• Diversity of habitat
• Solid substrate for invertebrates
• Canopy cover
• Woody debris
• Well sorted stone size gradation is best

86
USDA-ARS-National Sedimentation Lab Fish Sampling
on Harland Creek
Deep-water shocking on the MS river found
anywhere from 5 to 13 times as much fish biomass
in bends with Bendway Weirs
87
Functions of Bendway Weirs

• One of the few bank protection methods that
  changes direction of flow and that flow
  redirection can be predicted (even DS of the
  project).
• The reduction in stream forces within the weir
  field usually results in some sediment deposition
  with the weir field.
• The reduction in stream forces immediately
  adjacent to the bank, combined with sediment
  deposited on the outer bank, can benefit
  volunteer or bioengineered vegetation.
• Bank erosion is usually reduced, but not
  completely. Some species will use bare and
  vertical bank surfaces (both aquatic and
  terrestrial). A well-vegetated stable bank is
  not always the natural condition in many stream
  systems.
• Aquatic diversity and complexity is increased
  (depths, substrates, velocities), edge length is
  increased. Dr. Fischenich stated the most
  diverse bathymetry he had ever witnessed from
  man-made structures
• LWD can be naturally recruited (or placed)
  between Bendways, and especially immediately DS
  of the last Bendway Weir in a series
• Costs are competitive or lower than many
  traditional methods.
• Blends well with other bank protection methods.
• Weirs can at times be retrofitted to existing
  projects to reduce concentrated flow.

88
Little Blue River Project

• 31 Landowners
• 29 Sites
• 8.22 Miles of Streambank
• Acres of Riparian Habitat - 110 (77,000 trees)
• Acres of Continuous CRP - 85
• Over the last 23 years 12.5 million tons
  sediment
• 92,270 NO3
• 839,271 P
• 6,959,856 K

Estimated Project cost (Including construction,
Kansas Buffer Initiative excluding USDA CRP)
541,000.00 or 12.50 / ft (cost of volunteer
help not included.
89
Little Blue River Marysville, KS. Hennerberg Site
Mini case study 1 of 16
90
Hennerberg Site, Little Blue River, pre-project
condition, bank had moved laterally 205 ft
(measured) in 17 months, 5 million cubic feet of
material lost from this bend alone !!!!!
Mini case study 2 of 16
91
Volumes contributed to stream 3/00 to 8/01
231,200 Tons Sediment
1,110 Lbs. NO3
4,162 Lbs. P
13,400 Lbs K
1 - Hennerberg Site
Mini case study 3 of 16
92
Mini case study 4 of 16
93
Site 1 - Hennerberg 1/02
Mini case study 5 of 16
94
Hennerberg Project, Little Blue River, Bendway
Weirs constructed, bank laid back, no plantings
yet, 2001
Mini case study 6 of 16
95
Mini case study 7 of 16
96
Planting 2001
Mini case study 8 of 16
97
Looking DS, Site 1 - Hennerberg 3/02
Mini case study 9 of 16
98
Looking DS, Site 1 - Hennerberg 7/02
Mini case study 10 of 16
99
Looking DS, Site 1 - Hennerberg 9/02
Mini case study 11 of 16
100
Looking DS, Site 1 - Hennerberg 6/24/03
40,000 cfs flood
Mini case study 12 of 16
101
Looking DS, Site 1 - Hennerberg 8/03
Mini case study 13 of 16
102
Bendway Weirs at the Hennerberg Site, Little Blue
River, Looking Downstream after 2 Growing Seasons
Mini case study 14 of 16
103
Looking US. Bendway Weirs providing nice veg
uneven shoreline (increased edge) important
shallow areas. Little Blue River
Pix by Derrick
Mini case study 15 of 16
104
Looking US. 7 years after construction. Full
sized people, big riparian trees!
Pix by phil balch
Mini case study 16 of 16
105
Bendway Weirs are too long angled too far
upstream. They redirected the river into
opposite bank, which then ricochet back across
the river. Not good for a riverboat pilot!
106
Possible Bendway Weir Applications

• Where current sets, and possibly the thalweg,
  must be realigned (typically flow into a bridge
  opening or hydraulic structure).
• The stream needs to be realigned to reduce
  impacts of stream energy on downstream
  objects/bends. Even small "bank sags" or
  "elbows" can be mitigated with short Bendway
  Weirs.
• Where the thalweg needs to be moved from its
  present location (excessive scour at the toe of a
  continuous structure).
• Where the hydraulic width to depth ratio (W/D) of
  a stream needs to be reduced in an economical and
  environmentally compatible manner (to improve
  sediment transport, reduce existing channel
  overwidening).
• Can be retrofitted into an existing project to
  solve specific local problems and/or increase
  overall project performance.

107
Ways To Construct Stone Bendway Weirs

• On Larger Rivers
• From barges (2 methods)
• - Use bottom dump barge (hinged in
  middle)
• - Use bulldozers or dragline to push
  rock off barge and into river
• End dump method (build key, then dump rock off
  key into river forming a wide "road like" weir)
• On Streams and Smaller Rivers
• Machine-built (2 methods)
• - Build road-like key from top
  bank, then working from key, construct
  remainder of weir.
• - Working from point bar, dig key,
  construct key, then weir
• Hand-built - larger key stones placed on axis,
  smaller stones worked into interstices of rock to
  strengthen weir and provide smooth flow over weir

108
Indicators That a System of Bendway Weirs Are
Working

• Failed material is not removed from base of
  eroded bank
• Outer bank between weirs is stable and vegetated
• Sediment is deposited on outer bank after high
  flow events
• "Dogbone" shaped depositional patterns formed
  between midpoints of weirs at the upper end of
  the weir field
• Typically deeper pools are found between weirs at
  the lower end of the bend
• Point bar scoured, and at times a vertical face
  scoured on the point bar (usually from mid-bend
  to downstream end of bend)
• In some cases low-elevation mud flats are
  deposited between bank ends of weirs

109
Upstream instability and angle of attack is
important for all redirective methods, example
here with Bendway Weirs
New outer bank alignment
New attack angle
Original attack angle
110
Where Bendway Weir Use Could Prove Problematic

• In cobble or gravel bed streams the redirective
  effects of Bendway Weirs are limited in the
  downstream direction due to the resistance of the
  bed materials not allowing the channel thalweg to
  be relocated by stream energy redirected by the
  weirs (which is a main objective of Bendway Weir
  use).
• In tight radius bends, caution is advised when
  radius to width (R/W) is less than 4 to 1!!!
• In bends with an arc angle greater than 60
  degrees
• In narrow streams (where base-flow water width is
  less than about 50 ft).
• Where point bars are tall and built of cobble or
  gravel
• Bendway Weirs have not been tried in high
  velocity, supercritical flow, or steep-sloped
  stream systems.

111
Some Bendway Weir Design Rules of Thumb

• No impinging flow into the proposed area of the
  weir field.
• A defined channel crossing is usually required
  upstream of the project bend. The upstream bend
  should be stable.
• Must have the Luxury of Space between the
  eroding riverbank and the object to be protected
• Bendway Weir crest height can typically be set
  equal to the water surface elevation at base flow
  (typical low flow) with a tolerance of plus or
  minus one foot
• Need to lay out the thalweg relocation required
  for the project throughout entire project and US
  and DS of the project. This smoothed thalweg
  alignment should be based on project performance
  goals
• Stream ends of Bendway Weirs should be just short
  of the anticipated relocated thalweg alignment

112
COMBINATIONS OF REDIRECTIVE RESISTIVE
TECHNIQUES
113

• Sulphur Creek _at_ Dunnigan Burn Dump
• Yolo County, CA

114
THE PLAN !!
Thalweg Alignment Pre-Project Condition
THALWEG
LPSTP
BENDWAY WEIR
KEY
Footprint of the Dunnigan burn dump
115
THE PLAN !!
Thalweg Management Pre Post-Project
Conditions
THALWEG-Pre-Project
THALWEG-Post Project
LPSTP
BENDWAY WEIR
KEY
Footprint of the Dunnigan burn dump
116

• The Bendway Weirs are designed to reduce
  velocities near the LPSTP, move the thalweg to
  a location off the ends of the Bendway Weirs.
  Weirs also provide protection redundency.

Mini case study 1 of 9
117
DURING CONSTRUCTION-Looking DS _at_ LPSTP 1
Bendway Weir
Mini case study 2 of 9
Pix by John McCullah - October 1998
118
Looking DS. Weirs were not overtopped the first
winter
Mini case study 3 of 9
Pix by John McCullah
119
2 Years-Looking DS _at_ the project bend
Mini case study 4 of 9
Pix by John McCullah - Jan 17, 2001
120
?? Years later-Looking DS _at_
Mini case study 5 of 9
Pix by John McCullah
121
Looking DS, BWs LPSTP separate Dunnigan Burn
Dump from creek erosion, note deposition between
weirs, thalweg trace, and cutbank along pointbar.
Mini case study 6 of 9
Pix by John McCullah
122
3 Years later-Looking DS _at_ scour deposition in
weir field
Mini case study 7 of 9
Pix by John McCullah - January 2002
123
3 Years later-Looking DS _at_
Mini case study 8 of 9
Pix by John McCullah - January 2002
124
9 Years Later-Looking DS _at_ completely filled in
Bendway Weir field
Mini case study 9 of 9
Sulphur Creek _at_ Dunnigan Burn Dump-Pix by
McCullah-Feb 14, 2008
125
LECTURE OBJECTIVES

• With this lecture the student will be able to
• Determine when, and when not, to use selected
  redirective bank protection methods
• Visualize, analyze for applicability, and
  articulate how the method of choice will affect
  the hydraulic flow, both near and far field

126
Does your mind look like this? GOOD, I AM
DONE. QUESTIONS???