- Restoration, retrofit or upgrade an existing stormwater management
feature (inadequate detention pond, for example). - Creation of new stormwater management features, especially green
infrastructure, for a previously unmanaged site - Provide a water-based benefit to the public other than stormwater
management (for example, extend a public sewer to an area not already
served). - Treatment of abandoned mine drainage.
- The proposal for demonstrated equivalency shall be accompanied by
documentation or methodology quantifying the equivalency of the proposed project
to what would have been originally required. Acceptable documentation or
methodology may include use of the Worksheets and Checklist found in PA DEP
NPDES permit application, Appendix D or approved method showing the proposed
equivalency:
- Controls approximately the same amount of runoff volume as what would
originally have been proposed - Improves approximately the same amount of runoff quality as would have
been originally proposed - Is located within an impaired watershed or stream segment which will
benefit from the proposed project. Impairment may include stream
impairment, reduced stream buffer, and pollutant loading. Refer to the
Westmoreland County Integrated Water Resources Plan at
www.westmorelandstormwater.org .
4. The demonstrated equivalent stormwater activity shall:
- Be constructed concurrently with the project for which it is being applied;
- Be constructed according to plans approved by the municipality and the
WCD including any erosion control and stormwater management practices
as applicable; - Obtain all necessary permits;
- Be located on land owned by or controlled by the applicant or by a
cooperating public or private entity(s) (school, church, club, municipality,
etc.); - Be protected by a perpetual easement or deed restriction, or landowner
agreement; - Be located in the same general watershed as the project for which it is
being applied; and - Have an Operation and Maintenance Plan (O&M) specifying who is
responsible for what tasks.
ยง306. Small Project
- When a regulated development activity (refer to Table in Section 302 of this 'ordinance)
creates impervious area between 3,000 and 10,000 square feet, or total earth disturbance
between 5,000 and 20,000 square feet, the stormwater management requirements are as
follows. Refer also to Appendix C. - For new impervious surfaces, the first 1 inch of runoff shall be permanently removed from the runoff flow, and shall not be released to waters of the Commonwealth. Removal options include reuse, evaporation, transpiration and infiltration.
- Facilities, to the greatest extent possible and subject to municipality approval, shall be
designed to drain the permanently removed runoff volume in a period no greater than 72
hours. Runoff volumes in excess of2 inches shall be safely conveyed to a stable vegetated
area, natural watercourse, the curb or gutter line of roadway or existing storm
collection/conveyance/control system as applicable. - This method is exempt from the requirements of Section 402 of this ordinance.
- A Small Project Stormwater Management Plan must be submitted to Bolivar Borough
and the WCD and shall consist of the following items and related support material needed
to determine compliance with Sections 307 to 311 of this ordinance. The applicant can also
use protocols listed in Appendix C. - Narrative: General description of proposed stormwater management techniques,
including calculations, assumptions and criteria used in the design of the
stormwater management facilities and BMPs, and construction specifications of the
materials to be used for stormwater management facilities and BMPs. - Stormwater Management Plan: Showing locations of all stormwater management
facilities and BMPs, especially green infrastructure, limits of disturbance, including
the type and amount of proposed impervious area, structures, roads, paved areas
and buildings; - Small Project Stormwater Management Worksheet;
- Signed agreement page for operation and maintenance of stormwater facilities and
BMPs (Refer to Appendix B); and - Erosion and Sediment Control Plan: including all reviews and letters of adequacy
from the Conservation District.
ยง307. General Standards.
A. Proposed land development must consider avoiding, minimizing, and mitigating impacts
to the site that may increase stormwater runoff from the proposed project. Applied
sequentially, these three low impact development strategies should be an overall guide as a
project is planned and carried out.
- The Westmoreland County Integrated Water Resources Plan provides an online decision
making tool to assist developers, designers, property owners in addressing all water
resources during development and redevelopment and should be consulted. Refer to
www.paiwrp.com and www.westmorelandstormwater.org. - The following provisions shall be considered the overriding performance standards against
which all proposed storm water control measures shall be evaluated and shall apply
throughout Bolivar Borough.
- Any landowner and any person engaged in the alteration or development of land
which may affect stormwater runoff characteristics shall implement such measures
as are reasonably necessary to prevent injury to health, safety or other property. For
alteration or development taking place in stages, the cumulative development must
be used in determining conformance with this ordinance. Such measures shall
include such actions as are required:
- To assure that the maximum rate of stormwater runoff is no greater after
development than prior to development activities for the 100 year storms.
Rainfall data shall be obtained from NOAA Atlas 14 or other source approved
by the municipality. - To manage the water quality, rate and volume and direction of resulting
stormwater runoff in a manner which otherwise adequately protects health
and property from possible injury. - To notify adjacent property owners or owners of affected properties of any
alteration or increase of stormwater flows.
- Runoff treatment BMPs must be employed where necessary to ensure the water
quality, rate and volume requirements are met. - Volume control BMPs shall be used to maintain existing hydrologic conditions for
small storm events by promoting groundwater recharge and/or evapotranspiration.
Runoff volume controls shall be implemented using the P A DEP Stormwater BMP
Manual 2006 or other approved method such as those listed in the following chart:
Acceptable Computation Methodologies for Stormwater Management Plans:
METHOD: DEVELOPED BY: APPLICABILITY:
Win TR-20 (or commercial | USDANRCS | Applicable where use of | ||||||||||||
computer | package | based | full | hydrologic | computer | |||||||||
on TR-20) | model | IS | desirable | or | ||||||||||
necessary. | ||||||||||||||
Win TR-55 (or commercial | USDANRCS | Applicable | for | land | ||||||||||
computer | package | based | development plans within | |||||||||||
on TR-55 ie. VTIPSUHM | limitations | described | III | |||||||||||
TR-55 | ||||||||||||||
HEC-I, HEC-HMS | US | Army | Corps | of | Applicable where use of | |||||||||
Engineers |
|