Aquatic RestorationRivers
Unit 6, Module 25 July 2003
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s2
Objectives
Students will be able to: describe current statistics regarding the physical degradation,
water quantity, and water quality of streams. identify goals and considerations of stream restoration. evaluate the factors that influence the dynamic equilibrium of
streams. provide examples of potential causes of bank erosion. describe restoration techniques used to alter accelerated bank
erosion. identify potential causes and restoration measures for altered
width/depth ratios in streams. identify potential causes and restoration measures for altered
sinuosity in streams. identify potential causes and restoration measures for altered flow
in streams. identify potential causes and restoration measures for altered
temperatures and dissolved oxygen levels in streams.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s3
Overview
Introduction Lake Restoration Stream Restoration Wetland Restoration
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s4
Restoration philosophy
“Process of returning a river or watershed to a condition that relaxes human constraints on the development of natural patterns of diversity.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s5
Restoration philosophy
Restoration does not create a single, stable state, but enables the system to express a range of conditions dictated by the biological and physical characteristics of the watershed and its natural disturbance regime” (Frissell and Ralph 1998)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s6
State of the Streams
Approximately 3.2 million miles (5.15 km) of streams in the U.S. Only about 2% of streams remain in relatively
undisturbed, natural conditions Less than 1/3 of 1% preserved as national and
scenic rivers
(Echeverria 1989)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s7
Physical Degradation
40% U.S. perennial streams affected by siltation
Miles PercentSiltation 265,000 39.8Bank erosion 152,000 22.8Channel modifications 143,500 21.5Migratory blockages 9,700 6.0Bank encroachment 9,000 1.4
(Modified from Judy et al. 1984)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s8
Water Quantity Issues
40% U.S. perennial streams affected by low flows
Miles PercentDiversions
Agricultural 105,000 15.8Municipal 10,700 1.6Industrial 3,290 0.5
DamsWater supply 30,800 4.6Flood control 26,900 4.0Power 24,800 3.7
(Modified from Judy et al. 1984)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s9
Water quantity issues
Over 2.5 million dams in the U.S. (Johnston Associates 1989)
Only about 75,000 dams more than 6 feet tall (USACE 2002)
600,000 stream miles are under reservoirs (Echeverria 1989)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s10
Water Quality Issues
Over 41% of nation’s streams impacted by turbidity
Miles Percent
Turbidity 277,000 41.6
Elevated temperature 215,000 32.3
Excess nutrients144,000 21.6
Toxic substances 90,900 13.6
Dissolved oxygen 75,400 11.3
pH 26,000 3.9
Salinity 14,600 2.2
Gas supersaturation 5,500 0.8
(Modified from Judy et al. 1984)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s11
Stream restoration goal
To alter biophysical processes and structures to promote a dynamic equilibrium with diverse abundant aquatic species and channel stability
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s12
Other stream restoration considerations
In addition to in-stream habitat, current restoration projects should consider:
Geomorphology at a watershed scale Inclusion of physical scientists (interdisciplinary) Fluvial geomorphology, sediment transport,
channel hydraulics, hydrology Historical information to document the evolution of
the channel How processes have been altered by human
activities in the watershed
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s13
Stream channel stability
“Morphologically defined as the ability of the stream to maintain, over time, its dimension, pattern, and profile in such a manner that it is neither aggrading nor degrading and is able to transport without adverse consequences the flows and detritus of its watershed” (Rosgen 1996)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s14
Dimension: (cross section)
Width/depth ratio at bankfull stage Entrenchment ratio
Width of flood prone area/bankfull width Dominant channel materials
sizes or types
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s15
Pattern (plan view)
Sinuosity stream
length/valley length
Meander width ratio (secondary measurement) meander belt
width/bankfull width
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s16
Profile (longitudinal)
Slope difference in elevation/stream length
Bed features (secondary measurement) Description of characteristics such as
riffle/pools
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s17
Dynamic equilibrium
Qs . D50 in balance with Qw . SQs = sediment load Qw = stream dischargeD50 = sediment size S = stream slope
(Lane 1955)•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s18
Dynamic equilibrium
Qualitatively…variables are in balance at channel equilibrium. If one factor changes, the other variables change to reach a new equilibrium.
Sediment load
Sediment size Stream dischargeStream slope
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s19
How would the stream respond. . .
if stream discharge (Qw) increased? Width, Depth (Dimension) Meander wavelength (Pattern) Slope (Profile)
if sediment load (Qs) increased? Width, Depth (Dimension) Meander wavelength? (Pattern) Slope (Profile)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s20
How would the stream respond. . .
if stream discharge (Qw) increased and sediment load (Qs) decreased? Width, Depth (Dimension) Sinuosity, Meander wavelength (Pattern) Slope (Profile)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s21
Potential causes of bank erosion
Vegetative clearing Channelization Streambed disturbance Dams Levees Soil exposure or
compaction Overgrazing Dredging for mineral
extraction Woody debris removal Piped discharge Water withdrawal
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s22
Measuring bank erosion potential
Measure the following variables then rate from very low to extreme Bank height/bankfull
height Root depth/bank
height % root density Bank angle (degrees) % Surface protection Soil stratification Particle size
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s23
Restoration Techniques for Accelerated Bank Erosion
Bank shaping Fascines Live Staking Root wads
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s24
Bank shaping
Purpose• Alter the bank angle so that bank angle (degrees) that it
is stableEfficacy• Usually necessary before vegetation can be added to the
bank
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s25
Fascines
Live shrubs (willow) bundled together with rope Purpose: Vegetate eroded banks providing
stabilization and habitat (root density and soil surface protection)
Image: Ontario's Stream Rehabilitation Manual.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s26
Fascines
Efficacy• Simple and works
immediately because shrubs grow rapidly to hold soil in place
• Higher success if allowed to grow for one year before water rerouted
• Works well by itself for small streams
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s27
Live staking
Purpose: Vegetate eroded banks providing stabilization and habitat (root density and soil surface protection)
Efficacy•Effective with small erosion problems or in combination with brush mattresses, fascines, or erosion control blankets•Best if allowed to grow for one year before water rerouted
Image: Ontario's Stream Rehabilitation Manual.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s28
Live staking
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s29
Root wads
• Purpose• Deflects current away from unstable banks• Provides complex instream cover for fish and substrate
for aquatic macroinvertebrates• Efficacy
• Effective with larger erosion problems
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s30
Stream restoration case study #1
Vermilion River, Minnesota Impact - bank erosion
Over 220 feet in length, 8 feet above water level in one spot
Receded over 6 feet in 1 year
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s31
Vermilion River restoration
Goals of 1997-2000 Restorations Reduce the sediment load to improve
downstream water quality Create more productive fish habitat Protect the adjacent property Provide a demonstration project for other
erosion problems on the Vermillion River
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s32
Vermilion River: Methods
Fascines Rootwads
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s33
Vermilion River: Methods
Bank shaping Boulder vanes
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s34
Live Staking
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s35
Vermilion River restoration
Evaluation Property is protected Valuable as demonstration projects Clear objectives
But, were objectives based on stream morphology or just chosen because the techniques are new?
Unknown if fish habitat and sediment loads have been measured
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s36
Altered width/depth ratio
Potential causes: Vegetative clearing Water withdrawal Channelization Streambank
armoring Streambed
disturbance Dams Levees Hard surfacing
Roads and railroads Overgrazing Reduction of
floodplain Dredging for mineral
extraction Bridges Woody debris
removal Piped discharge
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s37
Altered width/depth ratio: restoration
Wing deflectors:
Purpose• Reduces the width to
depth ratio• Forms scour pools and
increases velocity and depth providing habitat
• Single wing deflectors can direct current away from eroding banks
Image: Ontario's Stream Rehabilitation Manual.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s38
Wing Deflectors
Efficacy• Effective, but require monitoring and maintenance
Image: Ontario's Stream Rehabilitation Manual.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s39
Potential causes of altered sinuosity
Channelization Streambank armoring Streambed disturbance Dams Levees Hard surfacing Reduction of floodplain Land grading Woody debris removal Piped discharge
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s40
Sinuosity: restoration
• Carbon Copy Technique• Restore stream to the pattern before
disturbance• Use historical aerial photographs• May not be stable with current conditions
• Empirical relationships• Measure bankfull width and discharge then
calculate meander length and sinuosity• Use if soil conditions have remained the same
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s41
Sinuosity: restoration
• Systems approach• Analyze meanders on
a watershed scale• Evaluate
geomorphology• Compare to find
dominant meander wavelength
(Fourier analysis)
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s42
Potential causes of altered flow
Vegetative Clearing Channelization Streambank
armoring Water withdrawal Dams Levees Soil exposure or
compaction
Irrigation or drainage
Hard surfacing Overgrazing Roads and
railroads Reduction of
floodplain Land grading Piped discharge
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s43
Altered Flow: Restoration
Dam Removal • Sediment
• Needs treatment if contaminated• Concentrations of nutrients in sediment probably
high• Hard to predict what will happen when dam
removed• Stream type will evolve after dam removal
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s44
Dam removal
•1. Breaching of dam•2. Temporary coffer-dams built to work behind
•3. Sediment removal •4. Disposal of timbers off-site
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s45
Increased Water Temperatures and Reduced Instream Oxygen Concentrations
Potential Causes Vegetative Clearing Channelization Streambank
armoring Water withdrawal Dams Levees
Hard surfacing Overgrazing Reduction of
floodplain Dredging for mineral
extraction Woody debris
removal Piped discharge
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s46
Altered Temp and DO: Restoration
Revegetation of riparian areasSite preparation:• Possibly re-grade bank• Control existing exotic speciesCheck the soil conditions (lack of nutrients)Tillage and mulching may increase planting success
and decrease weedinessBest management practices such as fencing
livestock
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s47
Revegetation
Method:• Use a reference site
• Determine species diversity, horizontal and vertical structure of canopy, sub-canopy, understory, and ground-layer
• Determine which plants will recolonize site naturally• Small existing plant populations, seed bank, nearby
populations of wind and animal dispersed species a reference site
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s48
Revegetation
• Planting techniques • Final density, multi-stage, dense initial, or
accelerated succession Works well as a community stewardship
project
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s49
Revegetation
Other considerations• Landscape
connectivity to existing habitats
• Increase in woody debris could be positive
• How will nutrient cycles be impacted?
•Image: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by FISRWG.
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s50
Revegetation
Management• Vital to water plants• Continue to control
exotic species• Consider impacts of
herbivores
•Two years after planting
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s51
Stream restoration case study #2
Weminuche River, CO Drains 30 mi2 in
southwestern Colorado
Shows how observation and understanding of stream classification and historical information helped set specific goals to create channel stability based on the stream type
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s52
Weminuche River, Colarado
Impacts of 1978 riparian vegetation removal (government cost-share program increasing grazing areas) caused channel instability
Width/depth ratio increased form 14 to 35 Meander width ratio decreased from 10 to 2 Down valley meander migration rate increased
approximately 8 feet/year Increased sediment supply (erosion) and decreased
transport capacity led to excessive bar deposition (aggradation)
Meander length and radius of curvature increased (sinuosity decreased)
Fish habitat and aesthetic values decreased Poised to cut through banks to create new main channel
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s53
Weminuche River, Colorado
Funded as a mitigation Goal of 1987 restoration
Return stream function and channel stability to benefit brook trout
Techniques Recreated dimension, pattern, profile of a stable
stream type Studied pre-disturbance features, developed
empirical relationships
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s54
Weminuche River, Colorado
Evaluation Channel stability returned
Width/depth returned to 14Slope from 0.01 to 0.005Sinuosity returned to 2.0Meander wavelength established at 10 bankfull widths
Meander radius of curvature at 2.8 bankfull widthsWillow transplanted along streambanks
Great example of considering stream morphology instead of just addressing bank erosion in small sections
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s55
Stream restoration case study #3
Merrimack River,New Hampshire & Massachusetts Drains 5010 mi2 in
NH and MA flowing to the Atlantic Ocean
Demonstrates a watershed approach to stream restoration of point and non-point pollution
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s56
Merrimack River, MA and NH
Impact from human use 1930s contamination from pollutants such as
raw sewage, paper mill waste, tannery sludge Too polluted for domestic water supply uses One of the 10 most polluted streams in nation
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s57
Merrimack River, MA and NH
Passing of the Clean Water Act of 1977 (water quality standards) and formation of the Merrimack Watershed Council brought about restoration actions: 84 wastewater treatment plants constructed Majority (~85%) of industries complying with
federal standards Suspended solids decreased (by 1/3 in one
reach), coliform bacteria and organic loading concentrations reduced, dissolved oxygen levels increased
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s58
Merrimack River, MA and NH
Future goals of the Merrimack Watershed Council Improve the protection of present and future
water supply Improve water quality through…interagency
cooperation on water quality issues Continue work on flow issues Promote growth management within the
Watershed Continue to improve access to the River and the
acquisition of open space
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s59
Merrimack River, MA and NH
Evaluation Good example of a watershed
scale restoration with cooperation between multi-state agencies and organizations
Reminder that some industries still not in compliance with water quality standards set in 1977
Shift from a point pollution focus to non-point and water quantity issues
Developed by: Peichel, Reed Updated: 7/14/03 U6-m25-s60
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