Sandi Formica, Executive Director, Watershed Conservation

Transcription

Reducing Sediment and Nutrient Loadings
through Stream Restoration and Streambank Stabilization in the
Beaver Lake and Illinois River Watersheds
Sandi J. Formica and Matt Van Eps, Watershed Conservation Resource Center
Restoration of Our Rivers, October 4-5, 2012
Bentonville, AR
Severe Streambank Erosion
Source of Sediment and Nutrients to Rivers
Bankfull Flow Event on the White River
• 400 square mile watershed area
• On the State 303 (d) list
124 square mile area located in
Beaver Lake watershed NWA drinking water
West Fork White River Watershed Assessment (ADEQ 2004)
• State 303 (d) listed stream since 1998
• aquatic life use not supported - high turbidity & excessive silt
• Estimated Annual Sediment Load is 36,000 tons per year
• 66% from accelerated streambank erosion
Blossom Way Branch Watershed Assessment (WCRC 2009)
• Urban watershed within the City of Rogers
• 7 square mile area located in the Osage Creek watershed
• Estimated Annual Sediment Load is 1,700 tons per year
• 11% from accelerated streambank erosion
Annual Sediment Load
Urban
(without construction)
413 tons (25%)
Construction
822 tons (49%)
Blossom Way Branch
Pasture
129 tons (8%)
Streambank Erosion
187 tons (11%)
Other Sources - Total
108 tons (7%)
Sediment Evaluation
Comparison between West Fork White River and
Blossom Way Branch Watersheds
Blossom Way Branch
4,660 ac
55%
West Fork White River
79,360 ac
12%
Agriculture
29%
29%
Forest Land
5%
58%
Barren Land
8%
1%
Water
1%
0.1%
Blossom Way Branch
% Total Load
% Total Load
(1,658 ton/yr)
(35,759 ton/yr)
Pasture
8%
5%
Streambank Erosion
11%
66%
Urban
25%
3%
Construction
49%
8%
Unpaved Roads
N/A
13%
Paved Roads
2%
1%
Forest
1%
1%
Other
5%
3%
Land Use
Urban
Land Use
Benefits of River and Streambank Restoration
using Natural Channel Design Principles
1. Restoring unstable sections of streams reduces sediment, phosphorus,
and nitrogen loadings within watershed
Other Benefits:
2. Improves the local ecology through aquatic and terrestrial habitat
restoration
White River Streambank Restoration
Six Months
After Restoration
Before Restoration
3,600 tons/yr sediment
3,500 lbs/yr T phosphorus
3. Reduces land loss
4. Protects infrastructure and
addresses safety concerns
WFWR: Ave. Loss – 20 ft/yr
2004 Flood – Over 100 ft
20 ft/yr
Cut bank at Gulley
Park near trail
After Restoration
Exposed High Pressure
Water Line on Niokaska Creek
at Sweetbrier Park
5. Creates environmental education
and recreation opportunities
6. Promotes conservation and good
stewardship
Fly Fishing at White River Streambank Restoration
Planting Native Vegetation at
the White River Streambank
Restoration Site
Implementing River and Streambank Restoration
in the Beaver Lake and Illinois River Watersheds
Beaver Lake Watershed Projects
• West Fork White River at Brentwood
• White River Streambank at Noland Treatment Plant
• Mullins Branch Stream at University of Arkansas*
Illinois River Watershed Projects
• Niokaska Creek at Gulley Park*
• Niokaska Creek at Sweetbriar Park*
Funding Sources
• Federally funded grants
• Local funding from municipalities
• Private Foundations
• In-kind services
• state government
• watershed groups & volunteers
• water districts
*Urban Area
Implementing River and Streambank Restoration
in the Beaver Lake and Illinois River Watersheds
Project Partners
• Project partners are a critical component of successful projects
• Each Project has a minimum of four partners
• Arkansas Natural Resource Commission – 319 program grants
• US Environmental Protection Agency – 319 & wetland programs
grants
•
•
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•
•
•
•
•
•
•
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City of Fayetteville
University of Arkansas
Private Foundations
Beaver Water District
Arkansas Game & Fish Commission
CH2M Hill
West Fork Environmental Protection Assoc.
Illinois River Watershed Partnership
Beaver Watershed Alliance
Washington County Cooperative Ext. Serv.
Northwest Arkansas Land Trust
Evaluation of Streambank Erosion and
Estimating Sediment and Nutrient loadings
 Projects include a streambank
monitoring component
 Measure erosion rates before
and after restoration
 Sample bank materials
 Quantifying the amount
sediment & nutrients unstable
streambanks contribute
provides information:
 Urban & watershed planning
• Prioritize sites for restoration
• Demonstrates project
effectiveness
• Determine best use of funding
• Address TMDLs or other water
quality issues
Estimating Sediment and Nutrient Loadings
Streambank erosion rates are measured before and
after stream restoration is implemented
Measured Streambank Profile-Osage 14
8
2006 Profile
2007 Profile
7
6
5
4
3
2
1
Toe Pin
Streambank Material
Water Surface
0
-1
6
5
4
3
2
Horizontal Distance (ft)
1
0
Vertical Distance (ft.)
Erosion Direction
Estimating Sediment and Nutrient Loadings
 Samples collected from
streambank horizons
 Measured
 Bulk Density
 Particle Size Distribution
 Analyzed Samples
 Total Phosphorus
 Total Nitrogen
Streambank Material Sampling Results*
Summary of Average Values
Bulk Density:
71 to 148 lb/ft3
Total Phosphorus: 0.2 – 1.0 lb/ton of sediment
Total Nitrogen: 0.6 – 2.4 lb/ton of sediment
Location
Material Class Bulk Density (lb/ft3)
TP (lb/ton)
TN (lb/ton)
Niokaska - Gulley
Fine
Coarse
80
148
0.6
0.2
2.3
0.6
Niokaska - Sweetbriar
Fine
Coarse
102
135
0.6
0.3
1.6
0.6
White River
Fine
99
1.0
1.9
Mullins Branch
Fine
96
0.4
2.3
Fine
Coarse
93
97
0.6
0.3
2.0
0.6
Osage Creek
Fine
Coarse
71
112
0.9
0.3
2.4
0.6
* Results of the materials analysis is preliminary and under review
Sediment Evaluation
Blossom Way Branch Streambank Erosion
Estimate of Average Annual Load:186 tons/year
Particle Size Distribution
Objectives
• Improve Water Quality and Local
Ecology
• Restore 1,000 feet of streambank and riparian
using natural channel design principles
• Reduce sediment and nutrients loadings from
severe streambank erosion
• Improve aquatic and terrestrial habitats
• Conduct Restoration in Priority
Watershed
• Beaver Lake provides drinking water for over
420,000 people in NWA
• Section of White River on the State 303(d) list
• State NPS priority for reducing nutrients
Project Partners
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Watershed Conservation Resource Center
City of Fayetteville
Arkansas Natural Resources Commission
US Environmental Protection Agency
CH2M Hill
Before Restoration
Project Site
• Bank Height
• 16 ft
• Watershed Area
• 400 mile2
• Bankful Flow
• 11,500 cfs
Pre-Restoration Site Monitoring
 Bank Erosion Monitoring Results
 Ranged from 3.1 to 21.7 feet over
a 7 month period
 Included two major flood
events - April and May 2011
 Air Photo Evaluation of Lateral
Bank Erosion - 2009 - 2011
 Average rate over three years
was 14 ft/year
18
White River Bank Stabilization Project-Bank Profile 5
16
14
Vertical Distance (ft)
12
Measured Erosion: 21.4’
10
8
6
4
2
0
1/19/2011
8/17/2011
-2
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
Horizontal Distance (ft)
Pre-Restoration Site Monitoring
 Results of Bank Material Sampling
Soil Type
Silt Loam
Clay Loam
Bulk Density
(lb/ft3)
104.9
88.0
TP (lb/ton)
TN (lb/ton)
1.0
1.0
1.7
2.3
 Pre-Restoration Estimated Loadings
 Calculated over 7 month monitoring period
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Sediment: 4,800 tons
T Phosphorus: 4,700 lbs
T Nitrogen: 8,700 lbs
 Estimated for average flow year
 Sediment: 3,600 tons/year
 T Phosphorus: 3,500 lbs/year
 T Nitrogen: 6,500 lbs/year
Restoration Design
The primary component of the stabilization design was the construction of a
multi-level bench composed of boulders, trees, and gravel with a layer of topsoil
encapsulated in coconut fiber fabric on top.
Implementation of Restoration
Pre-Construction – 2011 through 2012
 200 trees were salvaged and brought to the site
 City of Fayetteville and CH2M Hill delivered downed trees
 Nabholz Construction donated trees from Highway 265 project
 30 footer logs were compromised tree harvested on site
 900 tons of rock delivered
 Gravel road was constructed across the pasture to handle the
heavy trucks and equipment during wet weather
Heavy Equipment Construction – Feb & Mar 2012
 Inner-berm Bench Construction
 Built out from 16 ft high cutbank
 Widest point 40 feet
 Gravel from point bar on opposite side was removed to
maintain design cross-sectional area
Heavy Equipment Construction – Feb & Mar 2012
 Bankfull Bench Construction
 Built on top of inner-berm bench
 Widest point 20 feet
 Soil Mattresses Constructed
on both Benches
 Coconut fiber erosion control fabric
filled with soil
 Hardwood stakes were used to
secure mattresses
Site Finishing, Re-vegetation, & Irrigation
Mar - Apr 2012
 Seeded with native grasses and wildflowers
 Site was planted with native trees, shrubs, and grasses



Purchased potted plants, such as, sycamore, button bush, alders, river birch, witch hazel, wild
hydrangea, indigo bush, blackhaw viburnum, and more
Harvested local river oats, button bush, willow, sycamore, switch grass, river cane, gamma grass
Sod mats of native plants harvested along the fringe of the pasture
 1 acre of riparian that was previously pasture was tilled and planted with
natives
 Leftover rocks were used to create a boundary between the pasture land and
the newly established riparian planted with natives
 Irrigation system was designed and assembled for the site
Site Transformation
TwoMonths
Months
Before
Construction
AfterConstruction
Construction
Immediately
Six
Following
After
Construction
Post Restoration
Irrigating newly established riparian
area planted with native vegetation
during early summer drought
Irrigating upstream terrace
and bankfull bench
Post Restoration
 If you need rain, build a stream restoration
 Two weeks following construction, 13,000 cfs peak flow
(bankfull Q is 11,500 cfs)
White River Post Restoration
Load Reductions
 Expect 95-100% reduction in annual
sediment and nutrient loads from
streambank erosion at this site for an
average flow year:
 3,600 tons/year of sediment
 3,500 lbs/year of total phosphorus
 6,500 lbs/year of total nitrogen
Total Cost - $352,000
 Survey & Design
 Construction and Materials
 Extensive Re-vegetation
 Public Outreach
 Monitoring and grant administration
River and Streambank Restoration
Summary
Project
Area
Square
miles
White River –Beaver
Lake Watershed
*Preliminary Results
400
Length
ft
Age
yr
Cost
1,000
0.5
$352,000
Sediment T. Phos.
Reduced* Reduced*
Ton/yr
Lb/yr
3,600
3,500
Stream Restoration of Niokaska Creek at Gulley Park
Illinois River Watershed
Project Goal: Demonstrate an urban stream restoration
using a natural channel design approach
Niokaska Creek at Gulley Park
Drainage Area 1.25 mi2
Urbanized basin
USGS gage station on site
1,200 ft. section of stream
channel
 Rosgen Stream Classification: B4
 Incised channel
 Six to eight ft. high eroding
streambanks
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Stream Restoration at Gulley Park
2008 – Before Restoration
2012 – After Restoration
Stream Restoration at Gulley Park
Summary
Project
Area
Length
ft
Age
yr
Cost
400
1,000
0.5
$352,000
3,600
3,500
1.25
1,200
4.0
$262,000
53
29
Square
miles
White River –Beaver
Lake Watershed
Niokaska Creek
Gulley Park – Urban
Sediment T. Phos.
Reduced* Reduced*
Ton/yr
Lb/yr
Urban Stream Restoration of Niokaska Creek
Sweetbriar Park
4.8 square miles
1,600 ft project
Before Restoration
Stream Restoration of Niokaska Creek
Sweetbriar Park
Before Restoration
After Restoration
May 2009
One Week
One Year
August 2010
Summary
Project
Area
Length
ft
Age
yr
Cost
400
1000
0.5
$352,000
3,600
3,500
Niokaska Creek
1.25
1200
4.0
$262,000
53
29
Niokaska Creek
Sweetbriar Park – Urban
4.8
1600
1.5
$317,000
600
200
Square
miles
White River
Beaver Lake Watershed
Sediment T. Phos.
Reduced* Reduced*
Ton/yr
Lb/yr
West Fork White River Stream Restoration Project
Watershed Conservation Resource Center, Beaver Water District, Northwest
Arkansas Land Trust, Arkansas Game and Fish, Arkansas Natural Resources
Commission, Environmental Protection Agency
Project Goal
Demonstrate an rural stream restoration using a
natural channel design approach
Restoration Design
West Fork White River Stream Restoration
Summary
Project
Age
yr
Cost
mile2
Length
ft
400
1,000
0.5
$352,000
3,600
3,500
Niokaska Creek
1.25
1,200
4.0
$262,000
53
29
Niokaska Creek
Sweetbriar Park – Urban
4.8
1,600
1.5
$317,000
600
200
18
1,800
3.5
$406,000
1,880
640
White River
Area
Sediment T. Phos.
Reduced* Reduced*
Ton/yr
Lb/yr
Ongoing Inspection, Maintenance
and Flood Repairs
If You Need Rain,
Build a Stream Restoration!
• Inspection following flood events
• Ongoing Maintenance
•
•
Vegetation management
Hand repairs of structures
• Flood Repairs
• Minimum time - five years
•
Niokaska Restoration
Sweetbriar Park
One Month Old
following construction
Cost have been covered:
•
•
•
Original grant
Partners
2011 Flood Disaster – FEMA
• Funding should be established
when project is initiated
Niokaska Restoration
Gulley Park
Three Days Old
Conclusion and Recommendations
 Streambank erosion is a source of sediment and nutrients
 Tons of sediment and nutrients can be reduced annually
through river restoration projects
 Example: White River Project estimated minimum sediment &
total phosphorus reductions over 10 years:
 10X3,600 tons = 36,000 tons sediment
 10X3,500 tons = 35,000 lbs total phosphorus
 Recommend source of funding be developed for ongoing
inspection and maintenance for five years
Reducing Sediment and Nutrient Loadings
through Stream Restoration and Streambank Stabilization in
the Beaver Lake and Illinois River Watersheds
Thank You
Questions?
Just Completed: Mullins Branch at University of Arkansas Campus!
Before
After Restoration – 1 month old

Sandi Formica, Executive Director, Watershed Conservation

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