A.
Alteration or relocation of watercourse.
(1)
No encroachment, alteration, or improvement of any kind shall
be made to any watercourse until all adjacent municipalities which
may be affected by such action have been notified by the municipality,
and until all required permits or approvals have first been obtained
from the Department of Environmental Protection's regional office.
(2)
No encroachment, alteration, or improvement of any kind shall
be made to any watercourse unless it can be shown that the activity
will not reduce or impede the flood-carrying capacity of the watercourse
in any way.
(3)
In addition, FEMA and the Pennsylvania Department of Community
and Economic Development shall be notified prior to any alteration
or relocation of any watercourse.
B.
When Downingtown Borough proposes to permit the following encroachments:
any development that causes a rise in the base flood elevations within
the floodway; or any development occurring in Zones A1-30 and Zone
AE without a designated floodway, which will cause a rise of more
than one foot in the base flood elevation; or alteration or relocation
of a stream (including, but not limited to, installing culverts and
bridges), the applicant shall (as per 44 CFR 65.12):
(1)
Apply to FEMA for conditional approval of such action prior
to permitting the encroachments to occur.
(2)
Upon receipt of the FEMA Administrator's conditional approval
of map change and prior to approving the proposed encroachments, a
community shall provide evidence to FEMA of the adoption of floodplain
management ordinances incorporating the increased base flood elevations
and/or revised floodway reflecting the post-project condition.
(3)
Upon completion of the proposed encroachments, the applicant
shall provide as-built certifications. FEMA will initiate a final
map revision upon receipt of such certifications in accordance with
44 CFR Part 67.
C.
Any new construction, development, uses or activities allowed within
any identified floodplain area shall be undertaken in strict compliance
with the provisions contained in this chapter and any other applicable
codes, ordinances and regulations.
[Amended 4-3-2024 by Ord. No. 2024-02]
Within any identified floodplain area, any new construction, except storage sheds and decks constructed in compliance with Subsection E and F below, shall be prohibited. If a variance is obtained for new construction or substantial improvements in the identified floodplain area in accordance with the criteria in Article IX, then the following provisions apply:
A.
Residential structures.
(1)
In AE, A1-30, and AH Zones, any new construction or substantial
improvement shall have the lowest floor (including basement) elevated
up to, or above, the regulatory flood elevation.
(2)
In A Zones, where there are no base flood elevations specified on the FIRM, any new construction or substantial improvement shall have the lowest floor (including the basement) elevated up to, or above, the regulatory flood elevation determined in accordance with § 150-5.02C of this chapter.
(3)
In AO Zones, any new construction or substantial improvement
shall have the lowest floor (including the basement) at or above the
highest adjacent grade at least as high as the depth number specified
on the FIRM.
(4)
The design and construction standards and specifications contained
in the current edition of the International Building Code (IBC) and
International Residential Code (IRC), or the latest edition thereof
adopted by the Commonwealth of Pennsylvania, and ASCE 24 and 34 Pa.
Code (Chapters 401-405, as amended) shall be utilized, where they
are more restrictive.
B.
Nonresidential structures.
(1)
In AE, A1-30 and AH Zones, any new construction or substantial
improvement of a nonresidential structure shall have the lowest floor
(including the basement) elevated up to, or above, the regulatory
flood elevation, or be designed and constructed so that the space
enclosed below the regulatory flood elevation:
(2)
In A Zones, where no base flood elevations are specified on the FIRM, any new construction or substantial improvement shall have the lowest floor (including the basement) elevated or completely floodproofed up to, or above, the regulatory flood elevation determined in accordance with § 150-5.02C of this chapter.
(3)
In AO Zones, any new construction or substantial improvement
shall have its lowest floor elevated or completely floodproofed above
the highest adjacent grade to at least as high as the depth number
specified on the FIRM.
(4)
Any nonresidential structure, or part thereof, made watertight
below the regulatory flood elevation shall be floodproofed in accordance
with the W1 or W2 space classification standards contained in the
publication entitled "Flood-Proofing Regulations" published by the
United States Army Corps of Engineers (June 1972, as amended March
1992) or with some other equivalent standard. All plans and specifications
for such floodproofing shall be accompanied by a statement certified
by a registered professional engineer or architect which states that
the proposed design and methods of construction are in conformance
with the above-referenced standards. There should be a statement submitted
with the permit application and a statement submitted with the as-built
floodproofing certificate prior to the issuance of the certificate
of occupancy.
(5)
Any nonresidential structure that will be floodproofed must
submit the following to the Floodplain Administrator along with the
nonresidential floodproofing certificate and prior to the issuance
of the certificate of occupancy:
(a)
An inspection and maintenance plan detailing the annual maintenance
of floodproofed components ensuring that all components will operate
properly under flood conditions. Components that must be inspected
include, at a minimum:
(b)
Flood emergency operation plan detailing the procedures to be
followed during a flooding event, and must include information pertaining
to how all components will operate properly under all conditions,
including power failures. The design professional must produce the
plan. An adequate plan must include the following:
[1]
An established chain of command and responsibility
with leadership responsibilities clearly defined for all aspects of
the plan.
[2]
A procedure for notification of necessary parties
when flooding threatens and flood warnings are issued. Personnel required
to be at the building should have a planned and safe means of ingress
and should have no other emergency response duties during a flood
event. Alternates should be assigned in the event that the primary
persons responsible are unable to complete their assigned duties under
the plan.
[3]
A list of specific duties assigned to ensure that
all responsibilities are addressed expeditiously. The locations of
materials necessary to properly install all floodproofing components
must be included in the list.
[4]
An evacuation plan for all personnel or occupants;
those without duties for the flood emergency as well as those with
duties for implementing the plan. All possible ingress and egress
routes must be identified.
[5]
A periodic training and exercise program to keep
personnel and occupants aware of their duties and responsibilities.
Training drills should be held at least once a year and should be
coordinated with community officials.
(6)
The design and construction standards and specifications contained
in the 2009 International Building Code (IBC) and in the 2009 International
Residential Code (IRC), or the latest revision thereof as adopted
by the Commonwealth of Pennsylvania, and ASCE 24 and 34 Pa. Code (Chapters
401-405, as amended) shall be utilized, where they are more restrictive.
C.
Space below the lowest floor.
(1)
Fully enclosed space below the lowest floor (excluding basements)
which will be used solely for the parking of a vehicle, building access,
or incidental storage in an area other than a basement, shall be designed
and constructed to allow for the automatic entry and exit of floodwaters
for the purpose of equalizing hydrostatic forces on exterior walls.
The term "fully enclosed space" also includes crawl spaces.
(2)
Designs for meeting this requirement must either be certified
by a registered professional engineer or architect, or meet or exceed
the following minimum criteria:
(a)
A minimum of two openings having a net total area of not less
than one square inch for every square foot of enclosed space installed
on two separate walls.
(b)
The bottom of all openings shall be no higher than one foot
above grade.
(c)
Openings may be equipped with screens, louvers, or other coverings
or devices provided that they permit the automatic entry and exit
of floodwaters.
D.
Historic structures. Historic structures undergoing repair or rehabilitation
that would constitute a substantial improvement, as defined in this
chapter, must comply with all chapter requirements that do not preclude
the structure's continued designation as an historic structure. Documentation
that a specific ordinance requirement will cause removal of the structure
from the National Register of Historic Places or the State Inventory
of Historic Places must be obtained from the Secretary of the Interior
or the State Historic Preservation Officer. Any exemption from chapter
requirements will be the minimum necessary to preserve the historic
character and design of the structure.
E.
Accessory structures. Structures accessory to a principal building,
including a storage shed, need not be elevated or floodproofed to
remain dry, but shall comply, at a minimum, with the following requirements:
(1)
The structure shall not be designed or used for human habitation,
but shall be limited to the parking of vehicles, or to the storage
of tools, material, and equipment related to the principal use or
activity.
(2)
Floor area shall not exceed 200 square feet.
(3)
The structure will have a low damage potential.
(4)
The structure will be located on the site so as to cause the
least obstruction to the flow of floodwaters and must be located outside
the floodway. The structure may be erected in the floodplain, provided
the structure cannot be erected in a location outside of the floodplain
in the property's rear or side yard area that would otherwise comply
with all other applicable provisions of the Downingtown Borough Code.
(5)
Power lines, wiring, and outlets will be elevated to the regulatory
flood elevation.
(6)
Permanently affixed utility equipment and appliances such as
furnaces, heaters, washers, dryers, etc., are prohibited.
(7)
Sanitary facilities are prohibited.
(8)
The structure shall be adequately anchored to prevent flotation,
collapse, and lateral movement and shall be designed to automatically
provide for the entry and exit of floodwater for the purpose of equalizing
hydrostatic forces on the walls. Designs for meeting this requirement
must either be certified by a registered professional engineer or
architect, or meet or exceed the following minimum criteria:
(a)
A minimum of two openings having a net total area of not less
than one square inch for every square foot of enclosed space.
(b)
The bottom of all openings shall be no higher than one foot
above grade.
(c)
Openings may be equipped with screens, louvers, etc., or other
coverings or devices, provided that they permit the automatic entry
and exit of floodwaters.
(9)
If a variance is required and granted, a signed declaration
of land restriction (nonconversion agreement) shall be recorded on
the property deed prior to issuance of the certificate of occupancy.
(10)
Prohibit the storage of hazardous materials, in excess of five
gallons, in accessory structures.
F.
Decks.
(1)
A deck may be erected in the floodplain, provided there is no covered
area above the deck. No deck may be erected in the floodway.
(2)
If there is any area between the deck and the grade below, that area
must remain open and unobstructed.
(3)
No deck located in the floodplain may have an area greater than 200
square feet.
The following minimum standards shall apply for all construction
and development proposed within any identified floodplain area:
A.
Fill. Within any identified floodplain area, the use of fill shall be prohibited. If a variance is obtained in accordance with the criteria in Article IX, then the following provisions apply:
(1)
If fill is used, it shall:
(a)
Extend laterally at least 15 feet beyond the building line from
all points;
(b)
Consist of soil or small rock materials only; sanitary landfills
shall not be permitted;
(c)
Be compacted to provide the necessary permeability and resistance
to erosion, scouring, or settling;
(d)
Be no steeper than one vertical to two horizontal feet unless
substantiated data justifying steeper slopes are submitted to, and
approved by, the Floodplain Administrator; and
(e)
Be used to the extent to which it does not adversely affect
adjacent properties.
B.
Drainage facilities. Storm drainage facilities shall be designed
to convey the flow of stormwater runoff in a safe and efficient manner.
The system shall ensure proper drainage along streets, and provide
positive drainage away from buildings. The system shall also be designed
to prevent the discharge of excess runoff onto adjacent properties.
C.
Water and sanitary sewer facilities and systems.
(1)
All new or replacement water supply and sanitary sewer facilities
and systems shall be located, designed and constructed to minimize
or eliminate flood damages and the infiltration of floodwaters.
(2)
Sanitary sewer facilities and systems shall be designed to prevent
the discharge of untreated sewage into floodwaters.
(3)
No part of any on-site waste disposal system shall be located
within any identified floodplain area except in strict compliance
with all state and local regulations for such systems. If any such
system is permitted, it shall be located so as to avoid impairment
to it, or contamination from it, during a flood.
(4)
The design and construction provisions of the UCC and FEMA No.
348, "Protecting Building Utility Systems from Flood Damage" and the
"International Private Sewage Disposal Code" shall be utilized.
D.
Other utilities. All other utilities such as gas lines, electrical
and telephone systems shall be located, elevated (where possible)
and constructed to minimize the chance of impairment during a flood.
E.
Streets. The finished elevation of all new streets shall be no more
than one foot below the regulatory flood elevation.
F.
Storage. All materials that are buoyant, flammable, explosive, or in times of flooding, could be injurious to human, animal, or plant life, and not listed in § 150-6.04, Development which may endanger human life, shall be stored at or above the regulatory flood elevation or floodproofed to the maximum extent possible.
G.
Placement of buildings and structures. All buildings and structures
shall be designed, located, and constructed so as to offer the minimum
obstruction to the flow of water and shall be designed to have a minimum
effect upon the flow and height of floodwater.
H.
Anchoring.
(1)
All buildings and structures shall be firmly anchored in accordance
with accepted engineering practices to prevent flotation, collapse,
or lateral movement.
(2)
All air ducts, large pipes, storage tanks, and other similar
objects or components located below the regulatory flood elevation
shall be securely anchored or affixed to prevent flotation.
I.
Floors, walls and ceilings.
(1)
Wood flooring used at or below the regulatory flood elevation
shall be installed to accommodate a lateral expansion of the flooring,
perpendicular to the flooring grain without causing structural damage
to the building.
(2)
Plywood used at or below the regulatory flood elevation shall
be of a "marine" or "water-resistant" variety.
(3)
Walls and ceilings at or below the regulatory flood elevation
shall be designed and constructed of materials that are "water-resistant"
and will withstand inundation.
(4)
Windows, doors, and other components at or below the regulatory
flood elevation shall be made of metal or other "water-resistant"
material.
J.
Paints and adhesives.
(1)
Paints and other finishes used at or below the regulatory flood
elevation shall be of "marine" or "water-resistant" quality.
(2)
Adhesives used at or below the regulatory flood elevation shall
be of a "marine" or "water-resistant" variety.
(3)
All wooden components (doors, trim, cabinets, etc.) used at
or below the regulatory flood elevation shall be finished with a "marine"
or "water-resistant" paint or other finishing material.
L.
Equipment.
(1)
Water heaters, furnaces, air-conditioning and ventilating units,
and other electrical, mechanical or utility equipment or apparatus
shall not be located below the regulatory flood elevation and shall
be anchored to resist flotation, collapse, and lateral movement.
(2)
Ductwork shall be elevated to or above the regulatory flood
elevation or floodproofed to remain water-resistant.
M.
Fuel supply systems. All gas and oil supply systems shall be designed
to prevent the infiltration of floodwaters into the system and discharges
from the system into floodwaters. Additional provisions shall be made
for the drainage of these systems in the event that floodwater infiltration
occurs.
N.
Uniform Construction Code Coordination. The standards and specifications
contained in 34 Pa. Code (Chapters 401-405), as amended, and not limited
to the following provisions shall apply to the above and other sections
and subsections of this chapter, to the extent that they are more
restrictive and supplement the requirements of this chapter.
(1)
International Building Code (IBC) 2009, or the latest revision
thereof as adopted by the Commonwealth of Pennsylvania: Sections 801,
1202, 1403, 1603, 1605, 1612, 3402, and Appendix G.
(2)
International Residential Building Code (IRC) 2009, or the latest
revision thereof as adopted by the Commonwealth of Pennsylvania: Sections
R104, R105, R109, R322, Appendix E, and Appendix J.
Within any identified floodplain area, any structure of the kind described in Subsection A below shall be prohibited. If a variance is obtained in accordance with the criteria in Article IX, then the following provisions apply: § 150-6.04B, C, and D.
A.
In accordance with the Pennsylvania Flood Plain Management Act,[1] and the regulations adopted by the Department of Community
and Economic Development as required by the Act, any new or substantially
improved structure which will be used for the production or storage
of any of the following dangerous materials or substances; or will
be used for any activity requiring the maintenance of a supply of
more than 550 gallons, or other comparable volume, of any of the following
dangerous materials or substances on the premises; or will involve
the production, storage, or use of any amount of radioactive substances;
shall be subject to the provisions of this Subsection in addition
to all other applicable provisions. The following list of materials
and substances are considered dangerous to human life:
(1)
Acetone.
(2)
Ammonia.
(3)
Benzene.
(4)
Calcium carbide.
(5)
Carbon disulfide.
(6)
Celluloid.
(7)
Chlorine.
(8)
Hydrochloric acid.
(9)
Hydrocyanic acid.
(10)
Magnesium.
(11)
Nitric acid and oxides of nitrogen.
(12)
Petroleum products (gasoline, fuel oil, etc.).
(13)
Phosphorus.
(14)
Potassium.
(15)
Sodium.
(16)
Sulphur and sulphur products.
(17)
Pesticides (including insecticides, fungicides, and rodenticides).
(18)
Radioactive substances, insofar as such substances are not otherwise
regulated.
[1]
Editor's Note: See 32 P.S. § 679.101 et seq.
B.
Within any identified floodplain area, any new or substantially improved structure of the kind described in Subsection A above shall be prohibited within the area measured 50 feet landward from the top-of-bank of any watercourse.
C.
Within any Floodway Area, any structure of the kind described in Subsection A above shall be prohibited. Where permitted within any identified floodplain area, any new or substantially improved residential structure of the kind described in § 150-6.04A above shall be elevated to remain completely dry up to at least 1 1/2 feet above base flood elevation and built in accordance with §§ 150-6.01, 150-6.02 and 150-6.03.
D.
Nonresidential structures.
(1)
(2)
Any such structure, or part thereof, that will be built below
the regulatory flood elevation shall be designed and constructed in
accordance with the standards for completely dry floodproofing contained
in the publication "Flood-Proofing Regulations (United States Army
Corps of Engineers, June 1972, as amended March 1992), or with some
other equivalent watertight standard.
All subdivision proposals and development proposals containing
at least 50 lots or at least five acres, whichever is the lesser,
in identified floodplain areas where base flood elevation data are
not available, shall be supported by hydrologic and hydraulic engineering
analyses that determine base flood elevations and floodway information.
The analyses shall be prepared by a licensed professional engineer
in a format required by FEMA for a conditional letter of map revision
(CLOMR) and letter of map revision (LOMR). Submittal requirements
and processing fees shall be the responsibility of the applicant.
A.
Within any identified floodplain area, manufactured homes shall be prohibited. If a variance is obtained in accordance with the criteria in Article IX, then the following provisions apply.
B.
Within any Floodway Area/District, manufactured homes shall be prohibited.
No variance shall be granted.
C.
Within any identified floodplain area, manufactured homes shall be
prohibited within the area measured 50 feet landward from the top-of-bank
of any watercourse. No variance shall be granted.
D.
Where permitted within any identified floodplain area, all manufactured
homes, and any improvements thereto, shall be:
E.
Equipment requirement:
(1)
Water heaters, furnaces, air-conditioning and ventilating units,
and other electrical, mechanical or utility equipment or apparatus
shall not be located below the regulatory flood elevation and shall
be anchored to resist flotation, collapse, and lateral movement.
(2)
Ductwork shall be elevated to or above the regulatory flood
elevation or floodproofed to remain water-resistant.
F.
Installation of manufactured homes shall be done in accordance with
the manufacturers' installation instructions as provided by the manufacturer.
Where the applicant cannot provide the above information, the requirements
of Appendix E of the 2009 "International Residential Building Code"
or the "United States Department of Housing and Urban Development's
Permanent Foundations for Manufactured Housing," 1984 Edition, draft
or latest revision thereto, and 34 Pa. Code Chapter 401-405 shall
apply.
G.
Consideration shall be given to the installation requirements of
the 2009 IBC, and the 2009 IRC, or the latest revision thereto as
adopted by the Commonwealth of Pennsylvania, and 34 Pa. Code, as amended,
where appropriate and/or applicable to units where the manufacturers'
standards for anchoring cannot be provided or were not established
for the proposed unit's(s') installation.
Within any identified floodplain area, recreational vehicles shall be prohibited. If a variance is obtained in accordance with the criteria in Article IX, then the following provisions apply:
