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Dillsboro DamDillsboro Dam
Removed from theRemoved from the
Tuckasegee RiverTuckasegee River
Mark A. CantrellMark A. Cantrell
US Department of InteriorUS Department of Interior
Fish and W ildlife ServiceFish and Wildlife Service
Ashev ille Field OfficeAshev ille Field Office
160 Zil l icoa Street160 Zil l icoa Street
Ashevil le, North Carolina 28801Ashevil le, North Carolina 28801
828/258828/258 --39393939
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FERC relicensing of Duke EnergysNantahala Area Projects
Most expired at about the same timeMost expired at about the same time
Dillsboro was the smallest 225 kWDillsboro was the smallest 225 kW
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Dillsboro Hydroelectric Project
The Dillsboro Project was located in Jackson County,
North Carolina, on the Tuckasegee River nearthe town of Dillsboro.
Constructed in 1913 by C.J. Harris to provideelectricity for Blue Ridge Locust Pin Factory.1. The Project consists of a concrete masonry dam
approximately 12-feet high and 310-feet long,2. a powerhouse containing two generating units with a
total installed capacity of 0.225 MW, related electricpower production components and facilities, and
3. a reservoir approximately 0.9 miles in length. TheProject had limited storage.
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Tuckasegee CooperativeStakeholders Agreement
20052005 -- Many agreements for riverMany agreements for riverenhancementenhancement
Proposed removal of Dillsboro DamProposed removal of Dillsboro Dam FERC approved and Ordered theFERC approved and Ordered thesurrender and demolitionsurrender and demolition
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Potential benefitsPotential benefits
Restore 1 mile of habitatRestore 1 mile of habitat
Reconnect 2 subpopulationsReconnect 2 subpopulations
MusselsMussels
Fish hostsFish hosts
Increase genetic interchangeIncrease genetic interchange
Larger, more stable populationLarger, more stable population
Restore river continuum of allRestore river continuum of allspeciesspecies
Improved river recreationImproved river recreation
Why remove the dam?
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Fish Assemblages
Total number of fish species collected at sampling stations on the Tuckasegee River, upstream ofBarkers Creek, during May 2001, July 2001, September 2001, and March 2002. Stations T-1, T-2, andT-3 were downstream of the Dillsboro Dam. Station DR was a sample site in the Dillsboro
Reservoir. Stations T-4 and T-5 were on the Tuckasegee River, upstream of the Dillsboro Dam andReservoir (Duke Power 2002).
Sample Site T-1 T-2 T-3 DR T-4 T-5
Total Fish Species 32 28 38 11 24 24
Introduced Species 4 3 5 3 5 3
Total Native SpeciesTotal Native Species 2828 2727 3333 88 1919 2121
Assemblage Resistance Ratio 0.88 0.9 0.87 0.73 0.79 0.88
Assemblage Resilience Ratio 0.76 0.73 0.89 0.22 0.51 0.57
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Formal Removal Plans Developed
1. Planning Mussel surveys Mussel Relocation
Bat boxes
2. Dredging in 2009
3. Demolition in January 20104. Post-removal monitoring
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Paperwork
FERC Order USFWS Biological Opinion
Clean Water Act Section NC DWQ 401 Certificate
U.S. Army Corps of Engineers 404
permits
NC DLQ Mining Permit
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Endangered Species
USFWS issued a Biological OpinionProject demolition has the potential to result insedimentation in the Tuckasegee River. Tominimize the potential for sedimentation, Duke
Power has developed specific erosion-controlmeasures, including a detailed constructionsequence, phased drawdown, turbiditymonitoring, and bank stabilization for theProject that are designed to protectenvironmentally sensitive areas. Sedimentinputs from demolition activities should be of
relatively short duration.
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Mussel Relocation
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Monitoring Plans
During demolition Turbidity
Mussel
Long-term Physical response
Vegetation
Fish
Mussel
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Dillsboro Dam timeline2005 Settlement Agreement
2007 FERC Order, then 7 court cases, appeals, etc
2010
Jan 11 15 Asbestos and hazardous materials removal from the powerhouse
January 18-21 Powerhouse removal of superstructure
January 25-29 Shoreline stabilization for sewer line and fiber optic cable January 25-29 Construction of access road for removal of dam debris
Feb 3 Notching of Dillsboro Dam to begin dewatering
February 16 Completion of dam demolition
March 3 Completion of powerhouse removal May 11 Recycled spillway stone to remaining south dam abutment
July 15, 2010 Demolition & Restoration Complete!
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Dillsboro Dam Gone!Currently
Revegetation continues all native species River access area completed in February
Fish, mussel, bat surveys and monitoring continue
for 3 years
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MonitoringVisual/photographic
Sediment
before/after
upstream/downstream
Biological
Fish Macroinvertebrates
Mussels U.S. Fish & Wildlife Service
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Dillsboro Dam Gone!January 2010 July 2010
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Jan 2010
Dec 2010
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Tuckasegee River Again!
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Bat removal Little brown bats readily accepted boxes
U.S. Fish & Wildlife Service
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Example sediment particle sizeD80 from silt to sand/gravel
U.S. Fish & Wildlife Service
0
10
20
30
40
50
60
70
80
90
100
0.010.1110100
PercentFiner(%)
Grain Size (mm)
Particle Size Distribution T-14
Pre-Removal Max Pre-Removal Min 2nd Quarter 2010
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Of note
Appalachian elktoes have alreadyrecolonized the former pond area
Native fishes have recolonized
River recreation has been booming
Angling
Boating
Significant public acceptance
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Sicklefin Redhorse
Great expectations for extension of this Candidate to
an additional 9.5 miles to base of Cullowhee Dam(n)
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Summary FERC hydroelectric project surrender
Detailed planning
Swift removal
Biological response has been swift
Many detailed reports available Duke Energy Carolinas LLC and their
contractors did a great job
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QUESTIONS?
MANY DETAILED REPORTSAVAILABLE
Contact: [email protected]
U.S. Fish & Wildlife Service
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