[Ord. 621, 2/22/1993, § 301]
The stormwater plan shall be prepared using the general performance and technical standards requirements for plan format contained in the Subdivision and Land Development Ordinance [Chapter 22] and in this Part with the following additions:
A.
Watershed Location. Provide a key map showing the development site's
location within the Borough. Example: use a USGS map with the watershed
and property outlined.
B.
Subwatershed Map. A plan must be submitted showing all the watershed
and subwatersheds for the pre and post development peak runoff calculations.
Example: use the site plan and draw the watersheds and subwatersheds
on it.
C.
Floodplain Boundaries. Identify one-hundred-year floodplains on the
development site (as appropriate) from the use of FEMA maps or the
applicant's determination of the one-hundred-year floodplain
for any watercourse or water body on the development site.
D.
Natural Features. Show all bodies of water (natural and artificial),
watercourses (permanent and intermittent), swales, wetlands and other
natural drainage courses on the development site, or which will be
affected by runoff from the development.
E.
Soils. Provide a map showing soil types and boundaries within the
development site (consult county, SCS, U.S. Geologic Survey for information).
The soils must be defined on the plan. Example: use the site plan
and outline the soils on it.
F.
Contours. Show existing and final contours at intervals of two feet;
in areas with slopes greater than 15%, five-foot contour intervals
may be used.
G.
Stormwater Management Controls. Show any existing stormwater management
and/or drainage structures, such as storm sewers, swales, culverts,
etc., which are located on the development site, or which are located
off site but will be affected by runoff from the development.
[Ord. 621, 2/22/1993, § 302]
The stormwater management plan (including all calculations)
must be prepared and sealed by a registered professional engineer,
or land surveyor with training and expertise in hydrology and hydraulics,
or such other professional persons as are qualified to make certification
under the laws of Pennsylvania. The preparer of the stormwater management
plan must fill out and submit Appendix C with said plan.
[Ord. 621, 2/22/1993, § 303]
Discharge rates for pre and post development conditions must
be calculated by use of the SCS TR55 method or the Rational Method.
All pertinent information (for example - all hydrographs for predevelopment,
post development and inflow into detention facilities) used to generate
the discharge rates must be included with the stormwater management
plan. Also, all calculations for the sizing of the stormwater control
facilities must be submitted with the stormwater management plan.
[Ord. 621, 2/22/1993, § 304]
All inflow hydrographs to detention facilities must be routed
using methodology that analyzes detention storage and outflow simultaneously
with respect to time. The modified-pulse method or approved equal,
as found in Haested Method's Pond 2 or the Army Corps of Engineer's
HEC-1 is recommended.
[Ord. 621, 2/22/1993, § 305]
All proposed stormwater runoff control measures must be shown
on the plan, including methods for collecting, conveying and storing
stormwater runoff on site which are to be used both during and after
construction. Erosion and sedimentation controls must be shown on
a separate plan. The preliminary plan should provide information on
the general type, location, sizing, etc., of all proposed facilities
and their relationship to the existing watershed drainage system.
[Ord. 621, 2/22/1993, § 306]
All existing and proposed easements and rights-of-way for drainage
and/or access to stormwater control facilities shall be shown, and
the proposed owner identified. Show any areas subject to special deed
restrictions relative to or affecting stormwater management on the
development site.
[Ord. 621, 2/22/1993, § 307; as amended by Ord.
685, 5/11/1998]
A list of any approvals/permits relative to stormwater management
that will be required from other governmental agencies (e.g., a water
obstruction permit from PA DEP) and anticipated dates of submission/receipt
should be included with the preliminary plan submission. Copies of
applications may be requested by the Borough.
[Ord. 621, 2/22/1993, § 308]
The preliminary application shall contain a proposed maintenance
plan for all stormwater control facilities, in accordance with the
following:
A.
Identify the proposed ownership entity (e.g., municipality, property
owner, a homeowner's association, other management entity).
B.
If ownership is to be an entity other than the Borough, include a
maintenance program for all facilities, outlining the type of maintenance
activities, probable frequencies, personnel and equipment requirements
and estimated annual maintenance costs.
C.
Identify method of financing continuing operations and maintenance
if facility is to be owned by other than the Borough or other governmental
agency.
