[Amended 7-13-2016 by
Bylaw Amendment 16-763; 2-17-2021 by Bylaw Amendment 21-867]
A. Control of stormwater runoff shall meet all federal and state requirements, including the Massachusetts Stormwater Handbook (as amended), the requirements of the Town of Franklin's Subdivision of Land Stormwater Management Regulations, §
300-11, the most recent Town of Franklin MS4 stormwater permit, and the Town of Franklin's Best Development Practices Guidebook. All assumptions, methodologies and procedures used to design stormwater treatment practices and stormwater management practices shall accompany the design. All activities, project design, stormwater treatment practices and stormwater management practices should aim to minimize stormwater runoff, maximize infiltration and recharge where appropriate, and minimize pollutants in stormwater runoff.
B. In addition
to meeting the requirements of the Massachusetts Stormwater Standards,
as required under the Town of Franklin MS4 stormwater permit, all
stormwater management systems shall meet the following criteria:
(1) For
new development sites, all stormwater management systems shall be
designed to:
(a) Retain the volume of runoff equivalent to, or greater than, 1.0 inch
multiplied by the total post-construction impervious surface area
on the site; and/or
(b) Remove 90% of the average annual load of total suspended solids (TSS)
generated from the total post-construction impervious area on the
site and 60% of the average annual load of total phosphorus (TP) generated
from the total post-construction impervious surface area on the site.
Pollutant removal shall be calculated consistent with EPA Region 1's
BMP Performance Extrapolation Tool or other BMP performance evaluation
tool provided by EPA Region 1, where available. If EPA Region 1 tools
do not address the planned or installed BMP performance, any federally
or state approved BMP design guidance or performance standards (e.g.,
state stormwater handbooks and design guidance manuals) may be used
to calculate BMP performance.
(2) For
redevelopment sites, stormwater management systems shall also improve
existing conditions by being designed to the following criteria:
(a) Retain the volume of runoff equivalent to, or greater than, 0.80
inch multiplied by the total post-construction impervious surface
area on the site; and/or
(b) Remove 80% of the average annual post-construction load of total
suspended solids (TSS) generated from the total post-construction
impervious area on the site and 50% of the average annual load of
total phosphorus (TP) generated from the total post-construction impervious
surface area on the site. Pollutant removal shall be calculated consistent
with EPA Region 1's BMP Performance Extrapolation Tool or other BMP
performance evaluation tool provided by EPA Region 1 where available.
If EPA Region 1 tools do not address the planned or installed BMP
performance, any federally or state approved BMP design guidance or
performance standards (e.g., state stormwater handbooks and design
guidance manuals) may be used to calculate BMP performance.
An operation and maintenance plan (O&M Plan)
is required at the time of application for all projects. The maintenance
plan shall be designed to ensure compliance with the permit in all
seasons and throughout the life of the system. The Director shall
make the final decision of what maintenance option is appropriate
in a given situation. The Director will consider natural features,
proximity of site to water bodies and wetlands, extent of impervious
surfaces, size of the site, the types of stormwater management structures,
and potential need for ongoing maintenance activities when making
this decision. The O&M Plan shall identify and include all required
documents, including, but not limited to, maintenance agreements and
stormwater management easements. All documents shall be submitted
to the Town Attorney for review and must be in a form satisfactory
to the Town Attorney. The operation and maintenance plan shall remain
on file with the Department of Public Works and shall be an ongoing
requirement. The O&M Plan shall include:
A. The name(s) of the owner(s) for all components of
the system.
B. Maintenance agreement(s). The maintenance agreement
shall include:
(1) The names, addresses, and phone numbers of the person(s)
responsible for operation and maintenance.
(2) The person(s) responsible for financing maintenance
and emergency repairs.
(3) A maintenance schedule for all drainage structures,
including swales and ponds, and the estimated life span of the system.
(4) A list of easements with the purpose and location
of each.
(5) The signature(s) of the owner(s).
(6) A provision requiring a documentation submittal to
Department of Public Works confirming when maintenance has been satisfactory
completed.
C. Stormwater management easement(s).
(1) Stormwater management easements shall be provided
by the property owner(s) as necessary for:
(a)
Access for facility inspections and maintenance.
(b)
Preservation of stormwater runoff conveyance,
infiltration, and detention areas and facilities, including flood
routes for the one-hundred-year storm event.
(c)
Direct maintenance access by heavy equipment
to structures requiring regular cleanout.
(2) Stormwater management easements are required for all
areas used for off-site stormwater control, unless the Director grants
a waiver.
(3) Easements shall be recorded with the County Registry
of Deeds or Land Court prior to issuance of a certificate of completion
by the Director.
D. Changes to operation and maintenance plans.
(1) The owner(s) of the stormwater management system must
notify the Director of changes in ownership or assignment of financial
responsibility.
(2) The maintenance schedule in the maintenance agreement
may be amended to achieve the purposes of this bylaw by mutual agreement
of the Director and the responsible parties. Amendments must be in
writing and signed by all responsible parties. Responsible parties
shall include owner(s), persons with financial responsibility, and
persons with operational responsibility.