HomeMy WebLinkAboutComments PWE 9/14/2010
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Memorandum
,
City of Springfield
Date:
To;
From:
Subject:
September 14, 2010
Liz Miller, Urban Planner
Clayton McEachern, Civil Engineer
DRC201O-00020, Blackwell Auto Dealer MDS
I have reviewed the materials provided with the subject application. The recommended
findings and conditions outlined below are provided for your use in preparing the
land-use decision.
STORMWATER MANAGEMENT AND OUALITY
Finding: Section 4.3-11O.B of the SDC requires that the Approval Authority shall grant
development approval only where adequate public and/or private stormwater
management systems provisions have been made as determined by the Public Works
. Director, consistent with the Engineering Design Standards and Procedures Manual
(EDSPM).
Finding: Section 4.3-11 O.D of the SDC requires that run-off from a development shall be
directed to an approved stormwater management system with sufficient capacity to
accept the discharge.
Finding: As required in Section 4.3-11 O.E of the SDC, "a development shall be required
to employ drainage management practices approved by the Public Works Director and
consistent with Metro Plan policies and the Engineering Design Standards and
Procedures Manual."
Finding: Section 3.02 of the City's EDSPM states the Public Works Department will
accept, as interim design standards for stormwater quality, water quality facilities
designed pursuant to the policies and procedures of either the City of Portland (BES), or
the Clean Water Services (CWS).
Finding: Section 3.03.3.B of the City's EDSPM states all public and private development
and redevelopment projects shall employ a system of one or more post-developed BMPs
that in combination are designed to achieve at least a 70 percent reduction in the total
suspended solids in the runoff generated by that development. Section 3.03.4.E of the
manual requires a minimum of 50 percent of the non-building rooftop impervious area on
a site shall be treated for stormwater quality improvement using vegetative methods.
Finding: The vegetation proposed for use in the swales will serve as the primary pollutant
removal mechanism for the stormwater runoff, and will remove suspended solids and
pollutants through the processes of sedimentation and filtration. Satisfactory pollutant
removal will occur only when the vegetation has been fully established. . '.~--f I ~ I, {)
Date Recelved:~
Planner; LM
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Finding: The plans submitted indicate a drainage bio-swale area; however plans have not
been submitted with engineer's analysis, and do not meet suitable criteria for an
infiltration basin.
Condition: Prior to approval of the Final Site Plan, the applicant shall submit an analysis of
the inf1ltration swales using the Simplified approach from the Portland Stormwater
Management Manual prepared and stamped by a licensed engineer. No drainage study'
beyond this is necessary for this development.
Condition: The infiltration basins shall be designed in accordance with the details provided
in the Portland stormwater manual for either an Infiltration planter or Vegetated Infiltration
Swale. No subdrain is necessary as there is not a suitable public stormwater facility to
receive any overflow. Plantings shall consist of native grass and shrubs that are suitable to
these environments. A native seed mix will be deemed suitable if applied correctly and
plants are established to full growth.
Condition: To promote plant health and forthe infiltration basins to work properly the soil
must be suitable for infiltration and protected from compaction during construction. To
. meet this condition the subgrade for the infiltration basins must be decompacted to a
minimum depth of 10" by a suitable method (roto-tilling or scarifying will be deemed
suitable)
FEES AND PERMITS
SYSTEMS DEVELOPMENT CHARGE:
Pay applicable Systems Development Charges when building permits are issued for
developments within the City limits or within the Springfield Urban Growth Boundary.
(The cost relates to the amount of increase in impervious surface area, transportation trip
rates, and plumbing fixture units. Some exceptions apply to Springfield Urban Growth
areas.) [Springfield Code Chapter 11, Article 11]
Systems Development Charges (SDC's) will apply to the construction of buildings and
site improvements within the subject site. The Charges will be based upon the rates in
effect at the time of permit submittal for buildings or site improvements on each portion
or phase of the development. .
OTHER CITY PERMITS:
Land & Drainage Alteration Permits (LDAP). [Contact the Springfield Public Works
Department@ 726-5849 for appropriate applications/requirements]
Date Received:~
Planner: LM