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SECTON 6 – MITIGATION FOR SECONDARY AND CUMULATIVE IMPACTS
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there can be no encroachments within 20 feet of the top of stream bank or within a distance
of 3 times the stream width, if no base flood elevation or floodway information is available,
unless a professional engineer certifies that encroachment will not result in increase in base
flood level. These regulations are summarized in Section 5.6 of the UDO, Floodplain
Management.
The Town’s zoning ordinance includes a Floodplain Overlay District, which supersedes
standards applied by the underlying district, to keep development out of the floodplain.
Within the Floodplain Overlay District, no structure shall be located, extended, converted,
or altered, and no development activity shall occur, in any way except after approval of a
Floodplain Development Permit, detailed in Section 2.5.9 of the Town’s UDO. Although
there are provisions in the UDO, floodplain development has not occurred in recent years.
The Town also has established a conservation zoning district, which includes parks,
greenways, and open space. The zoning map is included in Appendix D; it shows that
Crabtree Creek and its floodplain is effectively protected with a wide riparian buffer
through these zoning districts.
FIRMs for the Neuse River basin and Cape Fear River basin in Wake County, currently
dated April 2007, are in the process of being updated and are expected to be available for
public review in 2014.
6.2.4
Erosion and Sediment Control
Wake County implements the Town’s Erosion and Sediment Control Program. The
County’s program requires a plan when 1 acre or more of land is disturbed. The Town
proactively inspects erosion and sediment control measures to verify that measures are in
compliance, and provides non-compliance reports to the County. The County’s program is
described in more detail in Appendix B.
The Town has various policies for controlling sedimentation and erosion. The Town’s
sediment and erosion control practices support an overall stream protection plan by limiting
in-stream suspended sediment and sediment deposition. Policies in place include
performance guarantee requirements, and maintenance guarantee requirements. These
policies help the Town to ensure that soils are controlled on development sites and that sites
are stabilized with vegetative cover as rapidly as possible.
General performance guarantees must be 150 percent of all required public improvements
on a site plan, including: roads, sidewalks, and greenways; site grading; erosion control
measures; seeding and stabilization; water mains, valves, hydrants, and other infrastructure
related to water service; sanitary sewers and related infrastructure; storm sewers and
stormwater management facilities; retaining walls; landscaping, such as buffer vegetation
and street trees; and traffic control devices.
Another sediment and erosion control strategy used by the Town is to ensure the timely
restoration of disturbed soils. The NPDES Stormwater General Permit (NCG 010000) for
construction activities requires that stabilization occurs within 7 calendar days of the last
land-disturbing activity for slopes steeper than 3 horizontal to 1 vertical (3: 1) and within 14
calendar days for non-slopes.