Piedmont Greenway Master Plan - Town of Kernersville

eplenish floodplains with sediments and nutrients. The flooding yields a “pulsed” increase in habitat, which
is essential for invertebrate communities of amphibians and reptiles, and fish spawning. Flooding also replenishes
shallow groundwater and extends stream flows longer into the summer.
Riparian Areas
“Riparian buffers” is a term developed to convey the importance of both aquatic and terrestrial resources
ecologically linked to river systems. No standard definition exists and municipalities have used
various approaches. For the purpose of this study, we will define riparian corridors to include “. . . any
defined stream channels including the area up to the bankfull flow line, as well as all riparian (streamside)
vegetation in contiguous adjacent uplands.” Characteristic woody riparian vegetation species could include
(but are not limited to) willow, alder, box elder, red maple, river birch, sycamore and oaks. Stream channels
include all perennial and intermittent streams shown as a solid or dashed blue line on U.S. Geological
Survey topographic maps. Riparian corridors and associated buffers provide a variety of important benefits
for both wildlife and humans. They can:
• Provide food and habitat for aquatic and some terrestrial organisms.
• Preserve water quality by filtering sediment from runoff before it enters surface water bodies.
• Protect streambanks from erosion.
• Provide a storage area for floodwaters.
• Preserve open space and aesthetic surroundings.
Preserving riparian corridors often competes with other land uses, especially in growing urban areas.
To address this problem, many municipalities have established either numeric or non-numeric development
setbacks. Some numeric setbacks are 100 feet from creek center beds; others are wider -- 100 feet from the
edge of riparian vegetation or the top of stream bank, whichever is wider. Non-numeric setbacks use language
to describe buffers between adjacent land uses and natural creek side areas. At least as important as
the width of riparian corridors is keeping them connected along their lengths, something often overlooked
in setting policies. In highly urbanized areas, corridors are often fragmented, particularly by road crossings
that disrupt habitat and introduce disturbances and pollutants to streams. The proposed I-73 corridor
is an example of a major road that will affect the Reedy Fork Creek corridor in Guilford County. The total
amount of land within riparian corridors in the study area varies by the watershed of each creek.
Areas in need of protection or restoration
Although the relative proportions of land uses within each watershed’s riparian corridors vary, several
patterns exist:
• The Kerners Mill Creek corridor is heavily impacted by subdivisions and other urban uses.
experiencing rapid growth from residential land use.
• The Moore’s Creek watershed contains steep ridge lines and erodible soils that are in need of
riparian and watershed buffers.
The effect of land use on riparian areas is well known. Except for the critical watershed boundary (in
Guilford County) and wetland areas, the creeks and rivers that historically supported relatively wide corridors
of natural vegetation over their floodplains now support narrow bands of vegetation within their banks
or have been modified for flood protection and water supply. Standing water and drainage of stormwater are
significant problems throughout the Reedy Fork Creek watershed. Reedy Fork has large tracts of wetlands
associated with its floodplain as it leaves Lake Brandt and approaches its confluence with Beaver Creek to
the south. A problem that continues to occur in the project area is the encroachment of buildings and other
land-use development into flood-prone areas outside of the critical area boundary.
The purpose of a buffer is to reduce, diffuse and filter pollutants by providing vegetated areas along
perennial and intermittent streams. The buffers reduce stormwater runoff from adjacent development and
allow water and pollutants to infiltrate the soil where natural processes mitigate and slow their rapid movement
in the water body. This is particularly important along the Guilford County portion of the Piedmont
Greenway where streams flow directly into drinking water supply areas.
Most ecological studies have demonstrated how, in studying relationships between land use and aquatic
communities, the scale of investigation influences the findings. They found land use within 50 meters of
tributaries to correlate more closely with the health of biological communities and in-stream structure than
land use measured beyond 50 meters.
In the state of North Carolina, the Department of Water Quality (DWQ) has two types of buffer requirements:
an agricultural buffer and a development buffer. For agricultural practices, the buffer is only
required (as are BMP’s) in the critical watershed area and is measured from the stream bank landward for a
distance of 10 feet. For developments throughout a watershed, buffers are required along all perennial waters
with a minimum width of 30 feet for low-density development and a minimum 100 feet for high-density
development. The buffer is measured perpendicularly from the stream bank and serves as a setback for new
structures such as houses, barns, and other buildings. Property owners are encouraged, but not required, to
maintain at least the first 25 feet of the buffer next to the stream in a naturally vegetated or undisturbed state.
Property owners and land developers are given recommendations to leave the buffer areas in public ownership
and/or to dedicate them as linear greenway or parks.
(Source: NCDENR, Dept. of Water Quality (DWQ).
• The Reedy Fork Creek from the critical watershed boundary to Triad Park is
PIEDMONT GREENWAY
Final Master Plan Report 88