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 trajectory toward improved ecological functions and services Beeson Creek, Kernersville, NC
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
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
Grassy Creek, Spruce Pine, NC: 2015 • Streambank erosion • Lack of riparian buffer • Incised, straightened channel (plane bed, poor habitats) • Stormwater runoff from shopping center
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
Grassy Creek, Spruce Pine, NC: 2015
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
Eastern Hellbender ( Cryptobranchus a. alleganiensis )
Grassy Creek Project Partners T oe 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
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
Overmountain Victory Trail Route of the Overmountain Men march to the Battle of Kings Mountain, October 7, 1780
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
Grassy Creek Restoration Plan (as-built) 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 AND HABITAT ENHANCEMENT CROSSINGS. PRIVATE DRIVEWAY INCORPORATE HABITAT ENHANCEMENT FEATURES. REACH 1:CHANNEL BED C A R 0 T 0 E + R 0 S R I D G STORMWATER E R TREATMENT SWALE 24'' CPP D NON-FUNCTIONING 2+00 STORMWATER WETLAND D EXISTING PIPE BASIN STREAM 3 IN CONCRETE PERENNIAL ROCK ARMOR LOW HANGING 4+00 24'' CPP POWER LINE WETLAND B 6+00 8+00 20+00 24+00 14+00 0 0 2 2 + 0 0 1 6 + S F 8 + 0 0 1 1 2 + 0 EXPOSED PIPE 0 0 + 0 0 1 TWO - 48'' CMP CROSSING SF STREAM 1 - PERENNIAL 18'' CPP 0 0 + S 24'' CPP F STREAM 2 WETLAND C 6 48'' CMP 2 18'' CPP PIPE PERENNIAL CLEANOUT REACH 2: CHANNEL BED AND 18'' CPP SF HABITAT ENHANCEMENT GRAVEL DRAINAGE DITCH 28+00 STREAM 4 INTERMITTENT EXPOSED PIPE CROSSING BOULDER WALL 30+00 SF REACH 3: CHANNEL REALIGNMENT PIPE CLEANOUT AND HABITAT ENHANCEMENT 31+89 ROCK ARMOR HWY 226 XX
Upstream Reaches 1 & 2 (1,800 ft) • Bank stabilization • In-stream habitat structures • Grade control at utility crossing • Native riparian vegetation
J -Hook Log Vane STATION 2+00 meander bend streambank protection and scour pool maintenance Before J anuary, 2016
J -Hook Log Vane STATION 2+00 meander bend streambank protection and scour pool maintenance August, 2016 August, 2019
Bank Grading & Planting STATION 8+00 to 18+00 streambank sloping with native woody plants Before December, 2015
Bank Grading & Planting STATION 8+00 to 18+00 streambank sloping with native woody plants August, 2016 August, 2019
Boulder Cross Vane STATION 14+00 grade control and streambank protection downstream of water line crossing Before J anuary, 2016
Boulder Cross Vane STATION 14+00 grade control and streambank protection downstream of water line crossing August, 2016 August, 2019
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
Channel Relocation STATION 18+00 to 27+00 meandering stream with habitat enhancements, floodplain, and native plants Before November, 2015
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
Channel Relocation STATION 18+00 to 27+00 meandering stream with habitat enhancements, floodplain, and native plants September, 2018 August, 2019
Toe Wood Revetment STATION 25+00 streambank protection & meander pool enhancement November, 2015 J anuary, 2016
Toe Wood Revetment STATION 25+00 streambank protection & meander pool enhancement August, 2016 August, 2019
Sewer Crossing STATION 26+00 stream realignment for perpendicular crossing with bank protection Before J anuary, 2016
Sewer Crossing STATION 26+00 stream realignment for perpendicular crossing with bank protection J uly, 2016 August, 2019
Habitat Structures Flat boulders in glides tilted up on downstream end M ay, 2016 August, 2019
Habitat Structures Flat boulders in glides tilted up on downstream end
Habitat Structures Log Vanes for bank protection and scour pools August, 2019
Constructed Stormwater Wetlands (CSWs)
Constructed Stormwater Wetlands (CSWs)
Vegetation Native plants to replace invasives • S eed (temp & perm) • trees & shrubs
Vegetation Native plants to replace invasives Live stakes: silky dogwood, silky willow, ninebark, elderberry
Education T ours, signs, Community access
M onitoring • Morphology, Vegetation, Macroinvertebrates • Hellbenders
Hellbenders? • eDNA evidence of Hellbender in Spring, 2017 • Photographic evidence in Spring, 2017 • Live specimens in Spring, 2018 2018 2017
Hellbenders in 2018
Lessons Learned • 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
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