In addition to the general requirements of Article IV, the requirements of this section apply to all development proposed in special flood hazard areas (Zones A, AE, AH and AO).
In areas of shallow flooding (Zone AO), the lowest floor (including
basement) shall be elevated at least as high above the highest adjacent
grade as the depth number specified in feet on the Flood Insurance
Rate Map, or at least two feet if a depth number is not specified;
adequate drainage paths shall be provided to guide floodwaters around
and away from the structure.
Enclosures below the lowest floor shall be constructed using flood-damage-resistant
materials. See FEMA Technical Bulletin #2, Flood Damage-Resistant
Materials Requirements, as may be amended.
Enclosures below the lowest floor (including crawlspaces) shall be
provided with flood openings which shall meet the following criteria
(see FEMA Technical Bulletin #1, Openings in Foundation Walls and
Walls of Enclosures, as may be amended):
There shall be a minimum of two openings on different sides
of each enclosed area; if a building has more than one enclosed area
below the design flood elevation, each area shall have openings on
exterior walls.
The total net area of all openings shall be at least one square
inch for each square foot of enclosed area, or the openings shall
be designed and certified by a engineer registered in the State of
Delaware or architect licensed in the State of Delaware to provide
for equalization of hydrostatic flood forces on exterior walls by
allowing for the automatic entry and exit of floodwaters.
Where installed in doors and windows, openings that meet requirements of § 107-27B(3)(a) through (d) above are acceptable; however, doors and windows without installed openings do not meet the requirements of this section.
Crawlspaces shall have the finished interior ground level equal to
or higher than the outside finished ground level on at least one entire
side of the foundation wall.
Be elevated on a permanent, reinforced foundation that raises the lowest floor to or above the base flood elevation and is otherwise in accordance with § 107-27A.
Be installed in accordance with the anchor and tie-down requirements
of the Building Code or the manufacturer's written installation
instructions and specifications.
For the purpose of this requirement, the lowest floor of a manufactured
home is the bottom of the lowest horizontal supporting member of the
lowest floor.
The lowest floor (including basement) shall be elevated to or above the base flood elevation, or the structure shall be dry floodproofed in accordance with § 107-28B.
In areas of shallow flooding (Zone AO), if not dry floodproofed,
the lowest floor (including basement) shall be elevated at least as
high above the highest adjacent grade as the depth number specified
in feet on the Flood Insurance Rate Map, or at least two feet if a
depth number is not specified; adequate drainage paths shall be provided
to guide floodwaters around and away from the structure.
Be designed to be dry floodproofed such that the structure is watertight
with walls and floors substantially impermeable to the passage of
water to the level of the base flood elevation. In areas of shallow
flooding (Zone AO), the structure shall be dry floodproofed at least
as high above the highest adjacent grade as the depth number specified
in feet on the Flood Insurance Rate Map, or at least two feet if a
depth number is not specified.
Be certified by a professional engineer registered in the State of
Delaware, or a professional architect licensed in the State of Delaware
with a floodproofing certificate, that the design and methods of construction
meet the requirements of this section. Refer to FEMA Technical Bulletin
#3, Non-Residential Floodproofing - Requirements and Certification,
as may be amended, for guidance.
Accessory structures shall meet the requirements of these regulations.
Accessory structures that have a footprint of no more than 200 square
feet may be allowed without requiring elevation or floodproofing,
provided such structures meet all of the following requirements:
Within any floodway area designated on the Flood Insurance Rate Map,
no encroachments, including fill, new construction, substantial improvements,
or other development, shall be permitted unless it has been demonstrated
through hydrologic and hydraulic engineering analysis that the proposed
encroachment would not result in any increase in flood levels within
the community during the occurrence of the base flood discharge. Such
technical data shall be submitted to the Floodplain Administrator
and to FEMA. The analyses shall be prepared by a professional engineer
registered in the State of Delaware in a format required by FEMA for
a conditional letter of map revision or letter of map revision. Submittal
requirements and processing fees shall be the responsibility of the
applicant.
Analyses demonstrating that the activity will result in an increase
in the base flood elevation, provided a conditional letter of map
revision has been issued by FEMA and the applicant completes all of
the following:
Documentation that individual legal notices have been delivered
to all impacted property owners to explain the impact of the proposed
action on their properties;
Documentation that the applicant has notified the Delaware Department
of Natural Resources and Environmental Control (Division of Watershed
Stewardship).
For development activities in a special flood hazard area with base
flood elevations but no designated floodways, the applicant shall
develop hydrologic and hydraulic engineering analyses and technical
data reflecting the proposed activity and shall submit such analyses
and data to the Floodplain Administrator and to FEMA. The analyses
shall be prepared by a professional engineer registered in the State
of Delaware in a format required by FEMA for a conditional letter
of map revision or letter of map revision. Submittal requirements
and processing fees shall be the responsibility of the applicant.
The proposed development activity may be permitted if the analyses
demonstrate that the cumulative effect of the proposed development
activity, when combined with all other existing and potential special
flood hazard area encroachments, will not increase the base flood
elevation more than one foot at any point.
For the purpose of these regulations, a watercourse is deliberately
altered when a person causes a change to occur within its banks. Deliberate
changes to a watercourse include, but are not limited to: widening,
deepening or relocating of the channel; installation of culverts;
construction of bridges, and excavation or filling of the channel
or watercourse banks.
For any proposed deliberate alteration of a watercourse, the applicant
shall develop hydrologic and hydraulic engineering analyses and technical
data reflecting such changes and submit such technical data to the
Floodplain Administrator and to FEMA. The analyses shall be prepared
by a licensed professional engineer in a format required by FEMA for
a conditional letter of map revision or letter of map revision. Submittal
requirements and processing fees shall be the responsibility of the
applicant.
Documentation of compliance with § 107-30A if the alteration is in a floodway or § 107-30B if the alteration is in a watercourse with base flood elevations but no floodway.
A certification by a professional engineer registered in the
State of Delaware that the bankful flood-carrying capacity of the
watercourse will not be diminished.
Evidence that adjacent communities, the U.S. Army Corps of Engineers,
and the Delaware Department of Natural Resources and Environmental
Control (Division of Watershed Stewardship) have been notified of
the proposal and evidence that such notifications have been submitted
to the Federal Emergency Management Agency.
Evidence that the applicant shall be responsible for providing
the necessary maintenance for the altered or relocated portion of
the watercourse so that the flood-carrying capacity will not be diminished.
The Floodplain Administrator may require the permit holder to enter
into an agreement with the Town of Georgetown or Sussex County specifying
the maintenance responsibilities; if an agreement is required, the
permit shall be conditioned to require that the agreement be recorded
on the deed of the property, which shall be binding on future owners.