Grassy Creek Restoration to Provide Hellbender Habitats Greg - - PowerPoint PPT Presentation

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Grassy Creek Restoration to Provide Hellbender Habitats Greg - - PowerPoint PPT Presentation

Aug 30, 2023 467 likes •902 views

Grassy Creek Restoration to Provide Hellbender Habitats Greg Jennings, PhD, PE Jennings Environmental PLLC greg@jenningsenv.com Stream Restoration Adjusting physical, biological, and chemical conditions to set the stream ecosystem on a

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Grassy Creek Restoration to Provide Hellbender Habitats

Greg Jennings, PhD, PE Jennings Environmental PLLC greg@jenningsenv.com

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Stream Restoration

Adjusting physical, biological, and chemical conditions to set the stream ecosystem on a trajectory toward improved ecological functions and services

Beeson Creek, Kernersville, NC

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Stream Restoration Project Components

  • Channel & floodplain morphology (Fluvial Geomorphology)
  • In-stream structures (grade control, bank protection, bedform)
  • Streambank bio-engineering
  • Native riparian buffers
  • Watershed management

UT Sentell Creek Dam Removal, Hendersonville, NC

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Fluvial Geomorphology

  • How are stream channels & floodplains shaped by flowing water?
  • How to restore natural equilibrium to disturbed stream systems?
  • How to manage flood flows and sediment transport?

UT Crabtree Creek, M orrisville, NC

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Grassy Creek, Spruce Pine, NC: 2015

  • Streambank erosion
  • Lack of riparian buffer
  • Incised, straightened channel (plane bed, poor habitats)
  • Stormwater runoff from shopping center
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Grassy Creek, Spruce Pine, NC

  • French Broad River Basin, Blue Ridge Ecoregion 65
  • 3,000 linear feet surrounded by commercial development
  • Drainage area = 9.4 sq mi
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Grassy Creek, Spruce Pine, NC: 2015

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Eastern Hellbender (Cryptobranchus a. alleganiensis)

  • Needs fast flow in order to absorb DO through skin
  • Needs large flat shelter rocks, sand for nesting, deep pools, and

cobble riffles for young

  • Needs food supply of crayfish
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Eastern Hellbender (Cryptobranchus a. alleganiensis)

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Grassy Creek Project Partners

T

  • e River Valley Watch

Blue Ridge RC&D US Fish & Wildlife Service NC Clean Water Management Trust Fund NC Division of Water Resources NC Wildlife Resources Commission Design-Build Team:

  • North State Environmental
  • Jennings Environmental
  • Zink Environmental
  • Stantec
  • Equinox
  • Penrose Environmental
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Project Objectives: 2015-2020

1. Improve water quality by reducing sediment & nutrients 2. Improve aquatic and terrestrial habitats 3. Provide educational opportunities for community 4. Connect Overmountain Victory Trail

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Overmountain Victory Trail

Route of the Overmountain Men march to the Battle of Kings Mountain, October 7, 1780

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Grassy Creek Restoration Timeline

  • Survey, design, permitting in early 2015
  • Construction and planting completed in early 2016
  • Channel realignment, floodplain connection, riparian

planting, in-stream structures, stormwater wetlands

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Grassy Creek Restoration Plan (as-built)

SF SF

SF S F S F

+ 2+00 4+00 6+00 8+00 1 + 1 2 + 14+00 1 6 + 1 8 + 20+00 2 2 + 24+00 2 6 + 28+00 30+00 31+89

EXISTING PIPE IN CONCRETE EXPOSED PIPE CROSSING EXPOSED PIPE CROSSING GRAVEL DRAINAGE DITCH 18'' CPP 18'' CPP 24'' CPP 18'' CPP 24'' CPP 48'' CMP TWO - 48'' CMP STREAM 1 - PERENNIAL 24'' CPP NON-FUNCTIONING STORMWATER BASIN BOULDER WALL ROCK ARMOR ROCK ARMOR STREAM 3 PERENNIAL PIPE CLEANOUT PIPE CLEANOUT LOW HANGING POWER LINE REACH 1: ENHANCE EXISTING BED FEATURES TO PROMOTE STABILITY AND HABITAT DIVERSITY ADD HABITAT ENHANCEMENT FEATURES REACH 2: ENHANCE EXISTING BED FEATURES TO PROMOTE STABILITY AND HABITAT DIVERSITY REACH 3: REALIGN CHANNEL AWAY FROM STEEP AND ERODING BANKS. ADJUST BED PROFILE TO MINIMIZE IMPACTS OF WATER AND SEWER CROSSINGS. INCORPORATE HABITAT ENHANCEMENT FEATURES. REACH 1:CHANNEL BED AND HABITAT ENHANCEMENT REACH 2: CHANNEL BED AND HABITAT ENHANCEMENT REACH 3: CHANNEL REALIGNMENT AND HABITAT ENHANCEMENT HWY 226 C A R T E R S R I D G E R D PRIVATE DRIVEWAY

XX

STREAM 2 PERENNIAL STREAM 4 INTERMITTENT WETLAND C WETLAND B WETLAND D STORMWATER TREATMENT SWALE

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Upstream Reaches 1 & 2 (1,800 ft)

  • Bank stabilization
  • In-stream habitat structures
  • Grade control at utility crossing
  • Native riparian vegetation
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J

  • Hook Log Vane

STATION 2+00 meander bend streambank protection and scour pool maintenance

Before J anuary, 2016

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August, 2016 August, 2019

J

  • Hook Log Vane

STATION 2+00 meander bend streambank protection and scour pool maintenance

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Bank Grading & Planting

STATION 8+00 to 18+00 streambank sloping with native woody plants

Before December, 2015

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Bank Grading & Planting

STATION 8+00 to 18+00 streambank sloping with native woody plants

August, 2016 August, 2019

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Boulder Cross Vane

STATION 14+00 grade control and streambank protection downstream of water line crossing

Before J anuary, 2016

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Boulder Cross Vane

STATION 14+00 grade control and streambank protection downstream of water line crossing

August, 2016 August, 2019

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Downstream Reach 3 (1,300 ft)

  • Realign 900 ft channel away from parking lot
  • Excavate floodplain to match bankfull elevation
  • In-stream habitat structures
  • Native riparian vegetation
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Channel Relocation

STATION 18+00 to 27+00 meandering stream with habitat enhancements, floodplain, and native plants

Before November, 2015

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Channel Relocation

STATION 18+00 to 27+00 meandering stream with habitat enhancements, floodplain, and native plants

November, 2015

Transferring bed substrate and fish from old channel to new

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Channel Relocation

STATION 18+00 to 27+00 meandering stream with habitat enhancements, floodplain, and native plants

September, 2018 August, 2019

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Toe Wood Revetment

STATION 25+00 streambank protection & meander pool enhancement

November, 2015 J anuary, 2016

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August, 2016 August, 2019

Toe Wood Revetment

STATION 25+00 streambank protection & meander pool enhancement

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Sewer Crossing

STATION 26+00 stream realignment for perpendicular crossing with bank protection

Before J anuary, 2016

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Sewer Crossing

STATION 26+00 stream realignment for perpendicular crossing with bank protection

J uly, 2016 August, 2019

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Habitat Structures

Flat boulders in glides tilted up on downstream end

M ay, 2016 August, 2019

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Habitat Structures

Flat boulders in glides tilted up on downstream end

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Habitat Structures

Log Vanes for bank protection and scour pools August, 2019

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Constructed Stormwater Wetlands (CSWs)

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Constructed Stormwater Wetlands (CSWs)

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Vegetation

Native plants to replace invasives

  • S

eed (temp & perm)

  • trees & shrubs
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Vegetation

Native plants to replace invasives

Live stakes: silky dogwood, silky willow, ninebark, elderberry

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Education

T

  • urs, signs,

Community access

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  • Morphology, Vegetation, Macroinvertebrates
  • Hellbenders

M onitoring

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  • eDNA evidence of Hellbender in Spring, 2017
  • Photographic evidence in Spring, 2017
  • Live specimens in Spring, 2018

Hellbenders?

2018 2017

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Hellbenders in 2018

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  • Urban constraints limit design &

construction

  • Habitat focus (food chain):
  • “Natural” rocks & logs
  • Riffles, pools, glides, steps
  • Fine roots
  • Hyporheic connections
  • Floodplain connection & riparian

vegetation critical

  • Patience required for ecological

recovery

Lessons Learned