Savidge - Lowell Mill and Carbonton Dam Removals

8/6/2019 Savidge - Lowell Mill and Carbonton Dam Removals

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ASSESSING AQUATIC FAUNAL

RESPONSE TO DAM REMOVAL:TWO CASE STUDIES IN NCTimothy W. Savidge, The Catena Group Inc.


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DAM REMOVAL AS STREAM

MITIGATION IN NC NC Dam Removal Task

Force (NCDRTF)

recommends large scale damremoval as an appropriateand desirable form of

compensatory streammitigation.

In 2002 NCDRTF prioritized11 dams in NC that would

provide the highestecological benefit by beingremoved

Removal of # 1 Lowell MillDam and # 4 Carbonton Damby Restoration Systems, LLC


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Monitoring Protocol

Generate baseline data (Habitat conditions,

faunal composition and distribution etc.) withinand outside area of dam influence

Identify success metrics Design five-year monitoring that will allow for

documentation of success criteria


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LOWELL MILL DAM REMOVAL LITTLE

RIVER: GOALS Restoration of appropriate aquatic

community in 34,990 linear feet of

river and stream channel fromlentic to lotic conditions

Known Barrier for American Shad:potential restoration of 497,800

linear feet for anadromous fishpassage

Restoration of Rare, Endangeredand Threatened Aquatic Species:11 rare mussel, 6 rare fish, and 1rare salamander species knownfrom basin, including two federallyendangered species


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Pre-removal aquatic surveys

14 sites within Little River (3upstream, 7 in reservoir pool,

4 downstream Reservoir pool dominated by

lentic-adapted species

Higher mussel diversity andrelative abundance (CPUE)in un-impounded sitescompared to impounded sites

Decreasing diversity andabundance withinimpoundment towards dam


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Post Removal Monitoring

Re-sample the monitoringsites, at various times duringmonitoring period, dependingon metric (i.e. musselrecruitment surveys not until

Year-4) Sample upstream of former

impoundment at next barrier

to anadromous fish passage


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Anadromous Fish Sampling


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Restored Anadromous Fish Passage

Spawning American shadcaptured upstream of formerdam, at Atkinson Mill Dam onLittle River during Year-1 andYear-2 Monitoring and in

lower portions of BuffaloCreek

Young of Year found within

former impoundment duringYear-5 Monitoring


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Young Of Year American Shad in

Former Impoundment


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Measures of Success: Appropriate

Aquatic Community Establishment of a suite of lotic-adapted fish

species within former impoundment. Increases of relative abundance and species

diversity of lotic freshwater mussel fauna withinformer impoundment

Increases of relative abundance and species

diversity of lotic aquatic snail fauna within formerimpoundment


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Restoration of Lotic Habitat


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Establishment of Appropriate Aquatic

Community: Fish Community

Fish surveys using NC Index of Biotic Integrity (IBI) surveysconducted at 6 stations (> 600 foot wadeable section) during

Year-1, Year-3 and Year-5. Method produces a numeric scorebased on 12 metrics (species richness and composition, trophicguild composition, abundance, health etc.)

Scores ranged from 38-54 (Fair-Excellent) Year-1 (Ave. 46);

42-56 (Good/Fair-Excellent) Year-3 (Ave. 49),

50-56 (Good-Excellent) Year-5 (Ave. 53)


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Establishment of Appropriate Aquatic

Community: Mussels and Snails

Transition from suite of lentic and habitat generalist mussel species, tohabitat generalist and lotic adapted ones, post removal recruitment

Gravel Elimia found at 1 site in very low numbers pre-removal; and at 5sites in high numers post removal

Restoration of Rare Endangered and


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Restoration of Rare, Endangered andThreatened Aquatic Species

11 rare mussel species: 6

rare fish species, 1 raresalamander species

outside of impoundment

area


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Rare, Endangered and Threatened

Aquatic Species 1 rare species within impoundment

pre-removal (Atlantic Pigtoe: 1

individual) 4 rare species within impoundmentpost-removal (Pinewoods Shiner:11 individuals, 4 locations; NeuseRiver Waterdog: 2 individuals, 1location; Creeper: 1 individual, 1location; Tar River Spinymussel: 1individual 1 location

Potential habitat for other rare

mussel species established,number of locations


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Rare, Endangered & Threatened

Species Habitat


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Habitat


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Former Dam Site


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Lowell Mill Dam


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C BO O O


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CARBONTON DAM REMOVAL

MITIGATION CREDIT CRITERIA Restoration of rare, E, T

species: 8 rare mussel, 4

rare fish species Known fromDeep River, including CapeFear Shiner, Dam recognizedas population barrier

Establishment of AppropriateAquatic Community: Lentic toLotic Faunal AssemblageAfter Removal


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Pre-Removal Sampling

14 sites within reservoirpool

6 un-impoundedreference sites

Developed TargetAquatic Communities(TAC) for various

locations withinimpoundment, based onreference sites


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Formerly Impounded Area Survey Location Map

R t ti f A i t A ti


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Restoration of Appropriate Aquatic

Community

10 of 13 sites in Deep River similar composition to theestablished TAC in Year 1, further developed in following

years; Steady increase in tributaries of lotic adaptedspecies, especially abundance and diversity of darter andshiner species

Gravel elimia found at all sites in former Deep Riverimpoundment post removal (Common to Very Abundant);not found during pre-removal

Rare Endangered and Threatened


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Rare, Endangered and Threatened

Aquatic Species Cape Fear Shiner found at 8

sites (#=41) during Year 2,

collected again during Years3-5

Post Removal Recruitment of

5 Rare Mussel Species inupper 2/3 of impoundment byYear-3; lower 1/3 by Year-5

Yellow Lampmussel,Savannah Liliput, NotchedRainbow*


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C l i C b t D


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Conclusions: Carbonton Dam

CFS located at 11/13 sites within formerimpoundment

Substantial Riffle Habitat Formation withappropriate aquatic community

Post Removal Mussel Recruitment, andincreasing diversity of lotic species

*Former Impoundment Site Sampled by

SCUBA during Pre-removal (14 feet deep)depicted above

Negative Impacts to mussels from dam


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Negative Impacts to mussels from dam

removal? Mussels Stranded in

Former Impoundment(Lentic species)

Mussels Downstream:Release of low DO;Release ofsediment/toxins

Seithi et al. 2004-Wisconsin

Impact from explosives

Mussel Response to Dam Removal


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Mussel Response to Dam Removal

Objectives Determine Mortality to mussels attributed to dam

removal Determine Growth of Mussels below dam

compared to control

Determine changes in mussel density over timeafter dam removal

Mussel Response to Dam Removal:


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Mussel Response to Dam Removal:

Experimental Design Transects across river (10m,

200m,400m, upstream

control) Mussels sampled in sq.m

plots across transects(tagged, measured andreturned)

1 of every 6 plots acrosstransect not sampled (control

for winter handling) Monitored for mortality etc. 3

months, 1 year.5-year

3 M h R l


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3 Month Results

Transect Tagged

Mussels

Recovered/

%mortality

Movement

Control 38 32 (84%)/

0%

3 (9.4%)

10 m 31 14(45%)/ 0%, 4 fd

7 (50%)

200 m 96 57 (59 %)/

1%, 28fd

28 (49%)

400 m 439 353 (80%)/ 0.22%, 25fd

6 (1.7%)


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30m

Transect

200m

Transect

400m

Transect

Control

Transect


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Mussel Groups # of mussels

Original tagged (Group1)3-month tagged (Group 2)

32-month tagged (Group 3)

3124

15

96170

57

438417

112

3835

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Monitoring Interval % recovered

3-month interval

Group 1

Group 2

Group 3

45.2

~

~

59.4

~

~

80.4

~

~

84.2

~

~

15-month interval

Group 1

Group 2

Group 3

3.2

16.7

~

52.6

38.2

~

25.6

21.8

~

76.3

61.8

~

32-month interval

Group 1

Group 2

Group 3

3.2

4.2

~

2.1

11.2

~

3.6

7.7

~

28.9

26.5

~

44-month interval

Group 1

Group 2

0

0

7.3

7.1

3.9

1.7

23.7

29.4


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Implications for success of dam removal

Useful conservation tool torestore aquatic habitat,

rare species habitat,migrating fish habitat Development of monitoring

protocol with quantifiable

success criteria is key Not without adverseimpacts

Careful cost/benefit to

resource analysis neededfor each situation

Incorporate measures tolessen magnitude of

impacts


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Acknowledgements

Restoration Systems:George Howard, Randy

Turner, John Pryor,

Adam Riggsbee

Fritz Rohde-NMFS TCG Staff

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Savidge - Lowell Mill and Carbonton Dam Removals

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