[Amended 7-13-2021 by Ord. No. 21-1371, § 2]
A. The Floodplain Conservation District is established as those areas of the Township subject to flooding as defined in the following enumerated subsections, with the most extensive of those areas described in the following subsections determining the outermost boundary of the Floodplain Conservation District:
(1)
Area. Those areas of the Township classified as
and subject to inundation by the waters of the
as identified in the
and delineated on the accompanying
for Upper Dublin Township and Montgomery County, Pennsylvania, dated March 2, 2016, prepared by the Federal Emergency Management Agency (FEMA), and all subsequent revisions thereto, including all digital data developed as part of the
. Said
areas shall be comprised of subdistricts as follows:
(a)
(FW). That portion of the Floodplain Conservation District identified as “Floodway” in the AE Zone in the
prepared by FEMA. The
Area shall be those areas identified as
on the FIRM as well as those
areas which have been identified in other available studies or sources of information for those
where no
has been identified in the FIS. The
represents the channel of a
and the adjacent land areas that must be preserved to discharge the
without cumulatively increasing the water surface elevation by more than one foot at any point.
(i) Within any
area, no encroachments, including fill,
,
, or other
shall be permitted unless it has been demonstrated through hydrologic and hydraulic analysis performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in
levels within the community during the occurrence of the
discharge.
(ii) Within any
area, no
or
shall be allowed unless a
is obtained from the Pennsylvania Department of Environmental Protection.
(b)
(FF). Those portions of land within the Floodplain Conservation District subject to inundation by the 100-year
, lying beyond the
in areas where detailed study data and profiles are available.
(c) Approximated Floodplain (FA). Those portions of land within the Floodplain Conservation District subject to inundation by the 100-year
, where a detailed study has not been performed, but where a 100-year
boundary has been approximated. When available, information from other federal, state and other acceptable sources shall be used to determine the 100-year-
elevation, as well as a
area, if possible. When no other information is available, the 100-year elevation shall be determined by using a point on the boundary of the identified
area which is nearest the
site in question.
(2) The AE Area/District without
consists of those areas identified as an AE Zone on the FIRM included in the FIS prepared by FEMA and for which
have been provided in the FIS but no
has been delineated.
(a) In the AE Area/District without
, no
,
,
or activity shall be permitted unless it can be demonstrated that the cumulative effect of all past and projected
will not increase the
by more than one foot.
(b) No
shall be granted for any
,
,
, or activity within any AE Area/District without
unless it is demonstrated that the cumulative effect of the proposed
would not, together with all other existing and anticipated
, increase the BFE more than one foot.
(c) No
or
shall be located within the area measured 50 feet landward from the top-of-bank of any
, unless the appropriate
are obtained from the Pennsylvania Department of Environmental Protection.
(3) The A Area/District shall be the areas identified as an A Zone on the FIRM included in the FIS prepared by FEMA and for which no 1% annual chance
elevations have been provided. For these areas, elevation and
information from other federal, state, or other acceptable source shall be used when available. Where other acceptable information is not available, the elevation shall be determined by using the elevation of a point on the boundary of the Floodplain Conservation District which is nearest the
site.
(4) The Shallow Flooding Area District shall be those areas identified as Zones AO and AH on the FIRM and in the FIS. These areas are subject to inundation by 1%-annual chance of shallow flooding where average depths are between one and three feet. In Zones AO and AH, drainage paths shall be established to guide floodwaters around and away from
on slopes.
(5) Areas containing soils with a frequency of flooding of 1% or greater per year, as determined by the Natural Resources Conservation Service, United States Department of Agriculture Web-Based Soil Survey (available online at http://websoilsurvey.nrcs.usda.gov), including the following soils:
(a) Bowmansville-Knauers (Bo)
(b) Buckingham Silt Loam (BwA)
(c) Cordorus (Ch)
(d) Hatboro (Ha)
(e) Rowland (Rt)
(f) Rowland (RwA)
(g) Rowland (RwB)
(h) Urban Land (UgB)
(6) Areas containing hydric soils as determined by the following Hydric Soil Boundary Short Procedure. A landowner, upon executing an agreement with the Township Board of Commissioners, may submit detailed soil profiles and a report to the Township Engineer for purposes of determining hydric soil classification and the boundary of the Floodplain Conservation District. If the Township Engineer and the landowner agree that the site specific information supplied by the landowner indicates an accurate classification of the soils, then the Township Board of Commissioners will accept the extent of hydric soil as the boundary of the Floodplain Conversation District if not in conflict with the
Area and the Community Identified Flood Hazard Areas.
(7) Community Identified Flood Hazard Areas shall be those areas where Upper Dublin Township has identified local
hazard or ponding areas, as delineated and adopted on a “Local Flood Hazard Map” using best available topographic data and locally derived information such as
of record, historic high water marks, soils or approximate study methodologies.
(8) Areas not reflected above, but which may be subject to inundation. These areas shall be identified by field survey and by hydrologic and hydraulic calculation and shall be subject to the review and approval of the Township Engineer, who shall make the determination as to the outermost boundary. Hydrologic and hydraulic analyses shall be undertaken only by professional engineers or others of demonstrated qualifications, who shall certify that the technical methods used correctly reflect currently accepted technical concepts. Studies, analyses, computations, etc., shall be submitted in sufficient detail to allow a thorough technical review by the Township.
B. The boundaries of the Floodplain Conservation District may be revised or modified by the Board of Commissioners from time to time upon recommendation by the Township Engineer after application and presentation of detailed engineering studies where studies or information provided by a qualified agency or
documents the need for such revision. However, prior to any such change, approval must be obtained from FEMA. Additionally, as soon as practicable, but not later than six months after the date such information becomes available, the Township will notify FEMA of the changes by submitting technical or scientific data.
C. The
used to establish the boundaries of the Floodplain Conservation District and the
will be available in the Township Municipal Building for review and reference.
D. Whenever there is a difference between any map setting forth the Floodplain Conservation District or a portion thereof and the data contained in the studies, the data contained in the studies shall determine the boundary of the Floodplain Conservation District.