Secondary and Cumulative Impacts Master Management Plan

Article 3: Zoning Districts

Section 3.8. Overlay Districts

3.8.3. Floodplain Overlay (FO) District

Morrisville, NC

June 2013

Unified Development Ordinance – Public Hearing Draft

Page 3-71

Sound Mitigation

147

New construction, or substantial improvement, of buildings within the Airport Overlay-A

District or Airport Overlay-B District shall be designed to limit interior noise from aircraft to

an average day/night sound level (DNL) of 45 dB in:

(1)

Any habitable room (e.g., excluding hallways, stairwells, closets, bathrooms) of a

dwelling unit;

(2)

Any guest or sleeping room of a congregate living facility, fraternity/sorority house,

rooming house, bed and breakfast, or hotel/motel;

(3)

Any noise-sensitive area (e.g., classrooms, assembly areas, libraries, offices, sleeping

rooms) of noise-sensitive nonresidential structures such as day care centers, places of

worship, public cultural facilities, schools, hospitals, and nursing homes.

Applications for a Building Permit for any building subject to the standards in subsection a

above shall include the written certification by a Professional Engineer or Licensed Architect

experienced and qualified in the field of acoustical testing and engineering that the

proposed new construction will comply with the applicable standards.

Avigation Easement

148

The developer of new development in the Airport Overlay-A District or Airport Overlay-B District

shall grant an avigation easement to the Raleigh-Durham Airport Authority for the subject

property where needed to ensure the safe approach and departure of aircraft to and from the

Raleigh-Durham International Airport. A copy of the recorded avigation easement shall be

provided to the Planning Director before issuance of any Certificate of Compliance/Occupancy

for a building on the property.

3.8.3.

Floodplain Overlay (FO) District

149

Findings and Purpose

The flood prone areas within the jurisdiction of the Town are subject to periodic inundation. The

cumulative effect of obstructions in floodplains cause increases in flood heights and velocities and

147

Part C, Article III, Section 1.5 (Soundproofing) of the current zoning Ordinance essentially delegates to RDU staff the

determination of whether proposed soundproofing techniques are sufficient. The provision does not provide any guidance as to

what is sufficient. Nor is it clear whether the Town can deny a permit for what RDU staff determines to be insufficient. We propose

revising this subsection to set forth a specific standard for noise level reduction, which is target noise level used in the FAA’s noise

insulation grant program, and to apply it to those buildings, or parts of buildings, that the grant program has identified as

needing additional noise insulation. The 45 dB level represents a 20-25 dB noise level reduction (NLR) in nearly all of the AO

District, which is within the 65 -70 LDN contour.

148

NOTE: This current provision raises some issues about the Town’s authority to require avigation easements. North Carolina’s

Model Airport Zoning Act (N.C. Gen. Stat. § 63-30

et seq.

) authorizes local governments to regulate land uses and structure and

tree height so as to avoid obstructions and hazards to safe airport operations. It also authorizes local governments to acquire air

rights to protect airport approaches, but does not expressly authorize requiring avigation easements. A number of communities

across the nation require avigation easements for development near airports (e.g., Orlando, Colorado Springs, Spokane, and a

number of jurisdictions in California). Recent court decisions by the Nevada Supreme Court (McCarran Int’l Airport v. Sisolak, 137

P.3d 1110 (Nev. 2006)) and Oregon’s Land Use Board of Appeals (Barnes v. City of Hillsboro (Or. LUBA 2010), however, have

invalidated the conditioning of development approvals on the grant of avigation easements as unconstitutional takings. North

Carolina courts have not ruled on this issue, and it is not clear whether the Nevada and Oregon court rulings would be adopted by

North Carolina or federal courts.

149

This subsection carries forward those provisions in Chapter 26 (Flood Damage Prevention) of the Code of Ordinances

pertaining to the purpose and establishment of areas subject to floodplain regulations as a new Floodplain Overlay District.

Chapter 26 provisions pertaining to the procedure for floodplain permits is relocated to Section 2.5.9, Floodplain Development

Permit. Chapter 26 standards for development in the FO District are set out in Section 5.6, Floodplain Management. Chapter 26

definitions are located in Section 11.5, Terms and Uses Defined.