Cantrell - Dillsboro Dam Removal

8/6/2019 Cantrell - Dillsboro Dam Removal

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U. S. Fish and W ildlife Serv ice

U.S. Fish & Wildlife Service

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

[email protected][email protected]


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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



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Example sediment particle sizeD80 from silt to sand/gravel


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]



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Documents

Cantrell - Dillsboro Dam Removal