A combination of North American Green’s #erosioncontrol products helped prepare a site for a the housing development in Virginia.

1. Background
Roanoke is one of Virginia’s largest met-
ropolitan regions and offers a diverse
area to work and live. With continuous
growth and ample attractions in beautiful
Roanoke, contractors are continually
constructing new land developments for
housing and business purposes. Before
construction activities begin, Best
Management Practices (BMPs) need to
be in place to eliminate the risk of site
erosion and to stay in compliance with
National Pollution Discharge
Elimination System (NPDES) require-
ments.
Problem
A new housing development in Roanoke
County was experiencing high amounts
of on-site sediment migration. The devel-
opment site with its tree lined lots and
rolling hills was an ideal location for
high-end housing, but in order for the
development to be successful the aesthet-
ics of the area had to be maintained. The
original BMP solutions, straw bales and
silt fences, used to control sediment
migration from the roadside drainage swales and slopes, failed to trap sediment. The extreme-
ly vulnerable soils on the 3:1 and 2:1 slopes experienced excessive sediment migration from
the intense rainfall events which occurred during the tropical storm season. The heavy sedi-
ment loads, eroding from the unprotected slopes were migrating into the adjacent roadside
channels. Once in the channels, the sediment was then being transferred into nearby water-
ways causing additional sediment pollution. In addition to the major environmental concerns
of erosion and sedimentation, the large gullies that were created from sediment migration cre-
ated huge eyesores for future buyers and the site developer. During initial development, the
swales and slopes had been cut to grade and then seeded. Since the housing lots were expect-
ed to be sold and built upon quickly after site construction ended, protecting the entire slopes
with an erosion control product was impractical. Sediment migration would have to be con-
trolled instead. Soon after the swales and slopes had been seeded, silt fence and straw bales
were installed as sediment perimeter barriers and as channel check dams. These systems failed
CASE
STUDY
Volume 10
Number 3
April 2007
14649 Highway 41 North
Evansville, Indiana 47725
812-867-6632
1-800-772-2040
FAX 812-867-0247
www.nagreen.com
SedimentSTOP®
Offers
Protection in Roadside Swales
Composite Design Conquers Erosion and Sediment Migration
FACTS
Straw bales used as a sediment control device in a roadside
drainage swale failed to control erosion and trap sediment (top)
while SedimentSTOP in conjunction with C350 actively filtered
sediment and prevented channel erosion (bottom).

2. to provide the protection needed and acted like a dam by not
allowing water to filtrate through, creating more of a prob-
lem than a solution. Gullies were forming due to the poor
filtration that the straw bales and silt fences provided. The
site developer at Balzer & Associates turned to the Erosion
Solutions Specialists at Landscape Supply, Inc. for a solution
to the problem at hand.
Solution
North American Green Erosion Solutions Specialists rec-
ommended a composite design using a combination of North
American Green’s rolled erosion control products. To elim-
inate sediment migration on the steep slopes SedimentSTOP
was selected. SedimentSTOP provided an environmentally
friendly solution and a safe alternative to rock rip-rap.
SedimentSTOP is comprised of a straw and coconut fiber
matrix that is rolled into a sediment filtration log. The multi-
ple layers of netting eliminate failures if the outer layer is
damaged during construction, providing a high strength fil-
tration device that can be customizable to the project needs.
Unlike the straw bales and silt fences, SedimentSTOP pro-
vided effective sediment filtration by trapping soil particles
while allowing water to pass through. It also acted as an
energy dissipater slowing the water velocities in the channels
eliminating the need for rock riprap check dams.
SedimentSTOP provided a complete green solution for sedi-
ment control. North American Green’s Vmax3®
C350®
Composite Turf Reinforcement Mat (C-TRM) and S150,
a double net straw erosion control blanket (ECB), were used in conjunction with SedimentSTOP to protect the
channels from erosion while providing additional filtration from stormwater runoff. While the SedimentSTOP
slowed water and filtrated sediment out of the moving water, the C350 protected the channel bottom from ero-
sion due to high-flow velocities and also acted as a filtration system by entrapping sediment. The mulching char-
acteristics of C350’s coconut fiber matrix aided in the establishment of vegetation. As the vegetation matured,
the C350 provided permanent stem and root reinforcement needed to handle the high shear stresses in the chan-
nel bottom. For added cost effectiveness, the S150 double net straw blanket was selected to protect the side
slopes of the channel. The double netted blanket offered the channel side slopes enough protection from rain-
fall impact and channel overflow, while creating an ideal environment for seed germination and establishment.
The combination of these three products provided a cost effective, along with an aesthetically pleasing green
solution by controlling erosion and by filtrating stormwater runoff from the unprotected slopes.
Results
Construction of the housing development started in April of 2006. The composite design was put to the test
immediately after installation. Four days after installation the Roanoke area received two inches of rainfall.
Then, only two months later, the partially vegetated site received 11 inches of rain within a three day period.
During these rainfall events, SedimentSTOP dramatically decreased surface sheet erosion from the unprotected
slopes in addition to acting as an energy dissipater in the channel, reducing flow velocities. The C350 and S150
provided channel protection against soil movement and aided in vegetation establishment. The developer could
not believe the protection that North American Green’s RECPs provided during these unexpected rainfall events.
The construction site experienced no sediment migration off of the site, and the channels protected with the S150
and C350 experienced no erosion or under-cutting. The new housing development is still under construction,
but for future buyers the aesthetics of the area look incredible.
A composite design utilizing turf reinforcement mats, erosion
control blankets, and sediment filtration devices protects the
drainage swales form erosion and sediment migration (top). The
mulching characteristics of the erosion control products allowed
for vegetation to establish within only a few months (bottom).