Mile Run and Sussman's Park

Preliminary Feasibility Analysis
for
Stream Restoration/Enhancement
at
Mile Run at Sussman's Park
and
North Buffalo Creek at Starmount Park
Greensboro, North Carolina
State of North Carolina
Department of Transportation
Planning and Environmental Branch
Prepared by KCI Associates of North Carolina
June, 1997
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Mile Creek at Sussman's Park
Location and Watershed Condition
The section of Mile Creek being considered for restoration/enhancement is located in Sussman's Park,
north of Oak Grove and west of South Elm Street in south Greensboro. The contributing watershed to
Sussman's Park is predominantly urban with apparently significant drainage from closed storm systems.
The section of the channel within the Park is approximately 1,000 linear feet.
Physical Assessment of Channel
The channel was evaluated from the double box culverts at Ashe Street downstream limits to double box
culverts at O'Conner Road. Beginning at the downstream end and working upstream the channel slope is
fairly low (approximately 0.5 percent) for a distance of approximately 600 feet, at this point the slope
increases with localized sections approaching 1-2 percent . In relatively undisturbed sections, the channel
bankfull geometry is represented by widths of 10-12 feet with depths of 3-4 feet. A wide (up to 60 feet),
low, floodplain is attached to the south side of the channel in the central portion of the park. This
floodplain region, though fully vegetated, appears to be an active fluvial surface. The entire flood prone
area is vegetated with herbaceous species. Channel substrate is variable, with frequently exposed sections
of bedrock (felsic intrusive complex) , regolith and areas of sand and gravel. The combination of the
large, residual cobbles and finer sediments produces a bi-modal distribution of sediment typical to an urban
park system. However, the cobble areas in the steeper channel sections appeared to be well flushed and
provided good habitat for macroinvertebrates, which were observed attached to the substrate.
Identified Channel/System Deficiencies
As typical of park systems, there is minimal woody plant material along the channel banks and floodplain
encroachment by filling has occurred , particularly on the north side. The lack of bank vegetation ,
encroachment and the "flashy" urban drainage has caused areas of bank erosion and bank sloughing. Near
the middle of the Park, a particularly high eroded bank (approximately 10 feet in height) has developed
(Photo A, B). Numerous storm drain inputs, including a 36 inch RCP (Photo D) discharge directly into the
channel creating additional stresses on the channel bed and banks. Channel bed degradation has caused the
exposure (Photo C) of a 24 inch sanitary sewer line approximately 200 feet downstream of Ashe Street.
RestorationlEnhancement Feasibility
This section of stream offers numerous opportunities for restoration/enhancement. In general, the channel
within the project area is responding to the urban drainage characteristics by developing primarily stable,
low floodplains adjacent to the channel and along toe sections of sloughed banks (Photo E). Several
actions can be undertaken to assist the stream in establishing a stable system and enhancing the existing
aquatic environment. 11) provide outfall basins at storm drain outfalls to enhance water quality
2) revegetate and create a riparian buffer along both sides of channel ' CC?I? J
3) adjust plan form of channel away (slightly) from eroding high bank and revegetate ?0
4) stabilize eroded bank areas with brush layering, willows etc. ! `fj?Ilr?
5) establish a stable geometry for low and high flows
The potential for successfully establishing a stable system at this location is high based on the following
system attributes.
1) watershed hydrology has stabilized due to minimal new development
2) exposed bedrock substrate indicates bed lowering has ceased
3) stable sections are developing
4) adjacent soils are supporting vigorous vegetation growth
Mile Run at Sussman's Park
Photo A - View Upstream 10' High Bank on Left
Photo B - 10" High Section in Central Portion of Park
Photo D - 36" RCP Storm Drain on Right Bank
Photo E - Stable reach below Ashe Street
North Buffalo Creek at Starmount Park
Location and Watershed Condition
The section of stream under consideration for restoration/enhancement is a tributary to North Buffalo
Creek in Starmount Park between Holden Road and the North Buffalo Creek, west of Greensboro. The
contributing watershed is predominantly sub-urban with significant drainage from the golf and country
club upstream of the site. The total channel length under consideration is approximately 5,100 linear feet.
Channel Description
Two (2) channel sections, divided by West Market Street, were investigated. The upstream section is
approximately 2,300 linear feet from Holden Road to West Market Street. The downstream section is
approximately 2,800 linear feet from West Market Street to the confluence with North Buffalo Creek.
Channel slope through the study area is fairly consistent (approximately 0.5 percent) with localized
changes typical due to bedrock outcrops, sewer crossings, and culverts. In the upstream segment, at
relatively stable reaches, the channel geometry is represented by a nested channel with a low flow channel
inside a higher floodflow channel. The low flow channel width is 3-5 feet with depths of 1.5 feet; the high
flow channel is approximately 25-30 feet wide with depths of 0.5-1.5 feet. Bank erosion in the upstream
section is prevalent along sections of the right bank (south side) with bank heights averaging 4-6 feet
(Photo C, D). The downstream section below West Market Street is characterized by isolated reaches of
bank erosion, with the most significant section (approximately 500 linear feet) occurring along the right
bank and park pedestrian trail system (Photo G). Though less pronounced, this downstream section also
exhibits a nested channel with low flow (3-4 feet wide 1-2 feet deep) and high flow (15-20 feet wide by 1-3
feet deep) surfaces. These floodplain areas, though fully vegetated, appear to be very active fluvial
surface. Channel substrate is variable, with frequently exposed sections of bedrock (felsic intrusive
complex) and regolith as well as areas of sand and gravel (Photo F). The combination of the large, residual
cobbles and finer sediments produces a typical bi-modal distribution of sediment through the system. In
some of the reaches, particularly upstream, large deep pools with sand and fine gravel have established
near the outcrops and are currently used by sunfish for spawning beds.
Identified Channel/System Deficiencies
As typical of park systems, there is minimal woody plant material along the channel banks and some
floodplain encroachment by filling has occurred. The lack of bank vegetation , encroachment and the
"flashy" urban drainage has caused areas of bank erosion and bank sloughing. Numerous storm drain
inputs (on the north side in the upstream reach and south side in the downstream reach) discharge directly
into the channel. Most of these do not appear to be causing excessive erosion problems. Channel bed
degradation has caused the exposure of a number of sanitary sewers in both sections. Widening of the
channel has been undertaken in the upper section of the channel prompting deposition of sediment load and
reduced flows (Photo A). However, this activity has also created a viable warm water fishery and
numerous sunfish and black bass were observed spawning in this zone.
RestoratiomEnhancement Feasibility
In general, the channel within the project area appears to be making adjustments to accommodate urban
drainage through the development of stable, nested channels and low floodplains adjacent to the channel.
However, active eroding reaches in both sections will require work to prevent further degradation and
assistance in establishing a vegetative riparian buffer. The following list some potential
restoration/enhancement options for this system:
1) provide outfall basins at storm drain outfalls to enhance water quality and reduce localized erosion
2) revegetate and create a riparian buffer along both sides of channel
3) move channel away (slightly) from high bank regions and revegetate
4) stabilize eroded bank areas with brush layering, willows etc.
5) establish a stable geometry for low and high flows
6) modify cross section in widened areas to promote sediment transport (dependent of fishery goals)
The potential for successfully establishing a stable system at this location is high based on the following
system attributes:
1) waterhshed hydrology has stabilized due to minimal new development
2) exposed bedrock substrate indicates bed lowering has ceased in most sections
3) stable sections are developing
4) adjacent soils are supporting vigorous vegetation growth
5) adjacent forest areas add to habitat value
North Buffalo Creek at Starmount Park
Photo A - over widened section upstream of Market Street
Photo B - "Nested Channel" downstream of Holden Road
Photo C - Eroded Bank on south side downstream of Holden Road

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Photo E - Exposed Sanatary Sewer

Photo G - Eroded Bank adjacent to pedestrian pathway

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Table of Contents
1.0 Introduction
2.0 Project Goals
3.0 Existing Conditions
3.1 Watershed
3.2 Site Description
3.3 Channel Description
3.3.1 Channel Banks and Riparian zones
3.3.2 Riffle-Pool Complexes
3.4 Hydrology
4.0 Conc ept Plan
4.1 Planform
4.2 Cross Section
4.3 Bank Stabilization
4.4 Riparian Buffer
4.5 Water Quality Features
List of Figures
Figure 1 Restoration Concept Plan
List of Photos
Photo A - Stable reach below Ashe Road.
Photo B - Eroded section central portion of Sussman's Park.
Photo C - Eroded bank in lower section of Sussmans's Park.
Photo D - 36" RCP stormdrain on right bank.

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1.0 INTRODUCTION
KCI Associates of North Carolina, under contract to the North Carolina Department of
Transportation, has prepared this Conceptual Stream Restoration Plan for Mile Run
Creek in Sussman's Park in Greensboro, Guilford County, North Carolina. This plan
serves as a working document, outlining the proposed stream restoration/enhancement
improvements as progress is made toward a final design that will ultimately fulfill the
project goals and specifications. The preliminary stream restoration feasibility analysis
conducted on this project identified sufficient deficiencies on this reach to warrant
restoration. These deficiencies included: 1. presence of bank erosion and sloughing due
to a lack of bank vegetation, encroachment, and disturbances caused by "flashy" urban
drainage, 2. stresses on the channel bed and banks from numerous storm drain inputs and
3. the need for improved water quality and aquatic habitat. The potential to correct these
deficiencies was viewed as favorable due to several existing conditions: stable watershed
hydrology (due to minimal new development), bed lowering has ceased in most sections,
stable cross sections are developing, and adjacent soils are supporting vigorous vegetation
growth.
2.0 PROJECT GOALS
With an initial consensus that the subject tributary has both degraded functions and good
potential for restoration, the following set of goals and objectives were established to
guide the development of the conceptual restoration plan.
• Establish a stable channel geometry for low and high flows.
• Enhance water quality and reduce localized erosion.
• Stabilize eroded banks.
• Enhance warm water fisheries habitat.
• Maintain and promote efficient sediment transport.
3.0 EXISTING CONDITIONS
' 3.1 Watershed
The subject watershed is located in the Piedmont physiographic region of central North
Carolina and drains approximately 307 hectares (760 acres) to form Mile Run Creek.
The watershed is predominantly urban with significant drainage inputs from closed storm
systems to the site. The topographic relief of the watershed is 32 meters (108 feet)
ranging from 261 meters (858 feet) above mean sea level (MSL) in the northwest portion
of the watershed to 229 meters (750 feet) above MSL in Sussman's Park. The landuses
in the watershed are a combination of residential, commercial/industrial, institutional, and
' recreational. The residential areas in the immediate vicinity of the project site are high
density residences, while single family homes comprise the majority of the remaining

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' residential uses. Commercial and institutional zones are less prominent in the watershed,
however, a commercial/industrial facility (warehouse) is situated east of Sussman's Park.
The influence of urbanization is most notable in its effect on the hydrologic and water
' quality characteristics of the site.
' 3.2 Site Description

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Sussman's Park, which is located due north of the community of Oak Grove and east of
the community of Glenwood in the southeast portion of Greensboro and is approximately
10 acres in size. The park is bound by Ashe Street to the northwest, West Florida Street
to the southwest, O'Connor Road to the south and Sussmans St. to the north. The stream
channel traverses the park in a northwest - southeast direction for approximately 305
meters (1000 linear feet) in Sussman's Park before exiting the park under O'Conner
Street. The property exhibits a typical park landscape with maintained turf and
recreational fields/courts.
3.3 Channel Description
The portion of Mile Run Creek which flows through Sussman's Park is categorized as
Class "C", "NSW" (Nutrient Sensitive Waters) according to the Department of
Environment, Health and Natural Resources (DEHNR), Division of Water Quality
(DWQ). The section of the channel within the park is approximately 305 meters (1000
linear feet). Upstream, the channel passes through double box culverts at Ashe Street.
The downstream limits are defined by double box culverts at O'Connor Road. Channel
slope is fairly low (approximately 0.5 percent) to a distance of approximately 183 meters
(600 feet) upstream of O'Connor Road. Slope increases over the last 91.5 meters (300
feet) with localized sections approaching 1 to 2 percent. At relatively stable sections
(Photo A), the channel bankfull geometry is represented by widths of 3.05-3.66 meters
(10-12 feet) and depths of 0.91-1.22 meters (3-4 feet). In the central portion of the park, a
wide (up to 60 feet), low floodplain is present on the south side of the channel. This
floodplain region, though fully vegetated, appears to be an active fluvial surface.
Channel substrate is variable, with frequently exposed sections of bedrock (felsic
intrusive complex) and regolith, as well as areas of sand and gravel. The combination of
the large, residual cobbles and finer sediments produces a typical bi-modal distribution of
sediment through the system. However, the cobble areas in the steeper channel sections
appeared to be well flushed and provided good habitat with numerous macroinvertebrates
observed attached to substrate.
3.3.1 Channel Banks and Riparian Zones
The riparian area of the stream, i.e. those areas in the approximate 2 year floodplain, is
primarily mowed turf. Bank erosion is present at several locations of the reach. Though
not extensive in nature the eroding areas contribute a significant sediment load to the
downstream area. These problems have developed from a combination of increased
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flows in the stream and fill material that modified the floodplain. These factors shifted
flood flows prompting the erosion at pressure points.
The most significant erosion problem exists near the middle of Sussman's Park where a
particularly high eroded bank approximately 3.05 meters (10 feet) has developed (Photo
B & Q. Increased flows and erosive capacity of the stream due to upstream widening
are likely to be contributing to this erosion.
3.3.2 Riffle-Pool Complexes
Riffle-Pool complexes are important features for the development of in-stream aquatic
habitats. Riffle-Pool complexes generally establish (on average) at reoccurrence intervals
approximately six times the bankfull width. The estimated bankfull width (based on
visual observations and preliminary cross-section data) in this project area is
approximately 3-3.5 meters (10-12 feet), therefore, pools and riffles can be expected at
18-21 meters (60-70 feet) intervals. This distribution is noted through most of the stream
reach.
3.4 Site Hydrology
Preliminary existing hydrology for the Sussman's Park site was, established based on a
comparison of the discharge estimates from Standard USGS Regional Regression
Equations for North Carolina (Blue Ridge Piedmont Region) and USGS Urban Regional
Regression Equations. The urban regression equations estimated discharges ranging from
42.84 cubic meters/second (1512.9 cubic feet/second) for the two year storm event to
112.71 cubic meters/second (3980.3 cubic feet/second) for the one hundred year storm.
The standard regression equations estimated 4.61 cubic meters/second (167.8 cubic
feet/second) discharge for the two year event and 22.8 cubic meters/second (805.8 cubic
feet/second) for the one hundred year storm event. Flows for this watershed should fall
somewhere between the estimates generated from these equations. However, this data
differs from field measurements suggesting that more detailed modeling must be
conducted as progress is made toward the final design. This may involve the
implementation of a fully automatic flow monitoring program through the installation of
pressure transducers and data loggers. This specific data will be used to refine the design
and determine more accurate tractive forces on the proposed bed and bank materials.
4.0 CONCEPT PLAN
The Concept Plan (Figure 1) for the restoration of Mile Run Creek in Sussman's Park
illustrates a general breakdown of proposed changes in planform, cross-section, bank
stabilization, and outfall features (water quality improvements) for the project area. This
proposal attempts to satiate the needs for improvements both to in-stream and riparian
conditions for the system. This plan was prepared with the expectation that watershed
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conditions are relatively static with only insignificant changes anticipated with respect to
watershed hydrology and sediment loading.
4.1 Planform
The majority of the current planform of the Mile Run Creek project area is stable and will
not be adjusted from its present location. Several minor adjustments may be required in
order to relieve pressure from areas were eroding banks area present. But the overall
system depicts a planform within the range for a stream of this type.
4.2 Cross-section
In general, this stream system exhibits a stable cross-section for the existing hydrologic
conditions, however, several minimal adjustments to the cross-section at the farthest
reaches downstream before Mile Run Creek exits the park at O'Connor Road are
proposed. The stable sections of the stream will be used as a guide to effectively modify
undersized or oversized sections. These adjustments serve to reduce the existing steep
channel banks while creating a stable channel geometry that will be suitable for the
accompanying bank stabilization techniques.
4.3 Bank Stabilization
Several areas of bank erosion are present in the stream reach. These areas will be
stabilized utilizing bioengineering techniques. Four types of bank stabilization and
combinations of techniques are proposed to stabilize the banks. The following provides a
brief description for each:
1) Brush layering - Brush layering is a technique where tightly configured rows of live
cuttings often black willow (Salix nigra) are placed perpendicular into the bank with the
growing tips oriented stream-ward. This technique produces a thick zone of vegetation
along the bank and is often used in areas of high potential velocities and tractive forces.
2) Fiber Rolls - Fiber rolls are manufactured rolls of fiber (often coconut) and
impregnated with various seed mixtures. Fiber rolls are generally staked into the channel
banks and are excellent for protecting bank toes in the lower tractive force environments
such as in cross-over reaches.
3) Rock Toe/Joint Planting - This. technique involves the use of a combination of bank
protection using rocks and vegetation. The bank face and bank toe are stabilized with
appropriate sized rock material and selected vegetation (containerized or posts) are
interspersed between the rocks and into the bank substrate. This technique is used
typically along banks receiving potentially high velocities and tractive forces, such as at
sharp stream bends and adjacent to roadway culverts.
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4) Fiber Matting with Rock Toe and Fiber Roll - This technique is a combination
bank protection with fiber matting and toe protection using either a rock toe or fiber roll.
After the bank is graded, fiber matting is fastened down over exposed surfaces and
' planted with stakes, posts, or rooted vegetative material. This technique has wide
applications and can be used in along most re-graded streambanks.
4.4 Riparian Buffer
An intrinsic part of the restoration plan is the establishment of a riparian buffer along the
entire stream reach. Buffers increase the habitat value of the stream and protect the banks
from erosion. The proposed buffer will vary in width from 10 to 30 meters and will be a
combination of woody vegetation, trees and unmowed turf areas. The extent, density and
type of this buffer will be determined when more detailed hydrologic information is
deduced.
' 4.5 Water Quality Features
' The Concept Plan for Mile Run Creek identifies three areas in which small water quality
features will be installed. Shallow (less than 15cm) detention basins will be developed at
each of three storm drain inputs; two drainage swales and one .9m RCP (Photo D). The
' intent of these structures is to provide a pre-treatment of storm water prior to discharge
into the stream system. These ponds will treat urban drainage inputs improving water
quality while reducing localized erosion.

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Mile Run Creek in Sussman's Park

Photo A - Stable reach below Ashe Road.
Photo B - Eroded section central portion of Sussman's Park.
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Photo D - 36" RCP stormdrain on right bank.
Photo C - Eroded bank in lower section of Sussman's Park