Geosynthetics June/July 2019 - 33

CASE STUDY

Streambank restoration
using engineered
bank stabilization
By Jeffery T. Hoilman and Stanley M. Miller

ountain Creek flows through the community of Red Bank near Chattanooga,
Tenn., to the Tennessee River. Mountain Creek has been identified by the
Tennessee Department of Environment and Conservation (TDEC 2018) as a
303(d)-listed stream, meaning that its pollution exceeds the state's standards for
one or more water quality criteria. Habitat alteration has been identified as the
main source of pollutants and is due in part to channel erosion caused by urban
development and increased stormwater runoff. A previous study (Schorr et al.
2001) conducted on the Mountain Creek watershed indicated that erosion of the
stream channel is estimated to be between 66% and 81%. A project was proposed to
reinforce approximately 105 linear feet (32 meters) of creek bank that was located
along a meander bend, stabilize the slope leading from an elementary school's
access road to the creek, improve water quality in the watershed and protect the
school's outdoor nature classroom (Figure 1).
This restoration project was spearheaded by TenneSEA (Tennessee Student
Environmental Alliance), a Chattanooga organization that collaborates with
communities to teach children about their connection to nature. TenneSEA
reached out to local Red Bank Elementary alumni who are involved in floodplain management, stormwater, and the erosion prevention and sediment
control (EPSC) industry. A collaborative team of local businesses, nonprofit
organizations, the school and government agencies donated their time and
resources to tackle the project. Students at Red Bank Elementary also played a
part by participating in the "Stream Team" (Figure 2 on page 34). The program
teaches students about the natural world around them by solving real-world
problems while developing sustainable solutions. Students learned about the
Mountain Creek watershed, flooding, EPSC and water quality. They were also
involved in the engineering design and construction oversight. After evaluating several engineering and geotechnical options to restore the streambank,
stabilize it to resist future erosion and provide a sustainable solution, engineers

PROJECT HIGHLIGHTS
MOUNTAIN CREEK
STREAMBANK RESTORATION
OWNER

Red Bank Elementary School/
Hamilton County Department
of Education
LOCATION

Chattanooga, Tenn.
GENERAL CONTRACTOR

Wright Brothers Construction
DESIGN ENGINEER

Propex and Chattanooga
Engineering Group
GEOSYNTHETIC PRODUCTS

ARMORMAX 75
SCOURLOK
GEOTEX 601 Nonwoven
GEOSYNTHETIC MANUFACTURER

Propex

Jeffery T. Hoilman, P.E., CPESC, CPSWQ,
CESSWI, is market development
manager for Propex Operating
Company LLC.
Stanley M. Miller, Ph.D., P.E., is professor
emeritus in the Department of Civil
Engineering at the University of Idaho
and an engineering consultant.
All photographs, illustrations and tables
courtesy of the authors.

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Geosynthetics June/July 2019

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