HomeMy WebLinkAboutWPO201200084 Review Comments Stormwater Management Plan 2013-03-01i"
,. `IRGINZP
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project:
Plan preparer:
Owner or rep.:
Plan received date:
(Revl)
(Rev2)
Date of comments:
(Rev])
(Rev2)
Reviewer:
Morey Creek Professional Center
Timmons Group
U.Va. Physicians Group
2 October 2012
3 December 2012
11 February 2013
30 October 2012
7 January 2013
1 March 2013
Michael Koslow
Review coordinator: Megan Yaniglos
SDP201200060, WP0201200084
[fax 29583171
500 Ray C. Hunt Drive
Charlottesville, Va. 22903
The 3rd Site plan and Water Protection Ordinance plans submitted 5 February 2013 have received
Engineering Review and do not appear to meet Albemarle County minimum checklist items for
approval. Please adequately address the following comments for final approval:
A) Final Site Development Plans (SDP201200060)
1) VDOT approval is required. Comments will be forwarded by review coordinator when received.
[DM905]
(Rev]) Comment has been acknowledged.
2) Could not find the 100 year flood plain line on the plan set. Please show the 100 year flood plain
labeled on the plan sheets and confirm no flood plain impacts are proposed with this project.
(Rev]) Comment has been addressed.
3) Please specify low maintenance ground cover for slopes steeper than 3:1 including area near the
north corner of the site.
(Rev]) Comment has been addressed.
4) Please include a typical retaining wall detail or VDOT wall type designation. Please extend
proposed guardrail to all wall areas adjacent to parking or travel ways where wall is > 4' in height.
(Rev]) Comment has been addressed.
5) Please provide parking garage entrance profiles to ensure grade breaks and slopes are safe. Please
submit parking garage layout and circulation plan for review [18- 32.7.2.A].
(Rev]) Comment has been addressed.
6) Please specify inlet shaping for all proposed drainage structures > 4' in height on plans as
indicated in drainage calculations.
(Rev]) Comment has been addressed.
7) Please revise drainage calculations to remove references to WCBR Vista Room (in SWM
Narrative).
(Rev]) Comment remains (see 11412013 email to Nick DuBose).
(Rev2) Comment has been addressed.
Engineering Review Comments
Page 2 of 3
B) Stormwater Management and Mitigation Plan (WPO201200084)
1) Please submit a Mitigation plan, application, and fee for proposed work in the 100 ft stream buffer.
(Revl) Please revise mitigation plan as follows:
a. Clearly indicate on a standalone plan sheet the proposed stream buffer
disturbance area
b. Provide a calculation for the required mitigation planting area (see
Design Standards Manual - generally 2:1 ratio)
c. Provide a planting list which includes a minimum of 85% native plants
as described in Piedmont Virginia native plant database:
www. albemarle. oraW ativeplants
(Rev2) a. Please shade or otherwise clearly indicate the proposed stream buffer
disturbance area. Sheet Ll.I shows part of the area, but plan view near
Fontaine Ave. might need to shift up to indicate the entire stream
buffer disturbance area.
b. Please indicate the disturbance area. Table on sheet L1.3 only
indicates a distribution of mitigation plantings (i.e. if 14,890 sft of
stream buffer disturbance is proposed, please include this number with
the calculation to indicate why 29,780 sft of buffer replantings were
needed).
c. Proposed plant schedule is appropriate for area and species indicated.
d. Please include an easement around proposed mitigation planting area.
2) The County of Albemarle cannot endorse any single product or company. Please state on the plans
the SWM structure is "ADS Bayfilter" or equivalent filtering design structure.
(Rev]) Comment has been addressed.
3) Please include Albemarle County General Construction Notes for Stormwater Management Plans.
(Rev]) Comment has been addressed.
C) Erosion Control Plan (WPO201200084)
1) Please add the Albemarle County Temporary Paved Construction Entrance to the E &SC portion of
the plan.
(Revl) Comment has been addressed.
2) Sediment catchment area #2 appears to be around 2.5 acres of drainage area upon initial grading
prior to installation of any drainage structures. Please show adequate sediment control structures
for the actual drainage areas prior to commencement of the grading operation.
(Revl) Please shift or reduce scale of Erosion and Sediment Control Plan — Phase I (C3.1) to
indicate the entire drainage areas for SBI and SB2 (including off -site drainage areas). Also,
calculated dewatering orifice diameters for SBI and SB2 are 3.20" and 3.62" respectively.
Please increase dewatering orifice diameters from 2" to Y.
(Rev2) Comment has been addressed.
3) Silt fence below diversion will be wire - supported due to area draining to silt fence and the silt
fence is the only protection for the stream. The silt fence should be installed along a single
elevation to allow for filtration instead of diversion to lowest spot along fence. Silt fence installed
unevenly creates deep pockets that will fail during a runoff producing rain event.
(Rev]) Comment has been addressed.
4) Please revise erosion & sediment control phase I to indicate site protection measures installation
prior to site clearing, grubbing, or enclosed drainage structure installation.
(Rev]) Comment has been addressed.
Engineering Review Comments
Page 3 of 3
5) Please revise plan labels from "Sediment Basin 12.25 acres" to "Sediment Trap 12.25 acres" (and
same for sediment trap 2) for plan clarity.
(Rev]) Please revise label for Sediment Basin I on detail labeled "Sediment Trap I" on sheet
C3.0. Please revise labels for "STI " and "ST2" on sheet C3.1 to "SBI " and "SB2" for plan
clarity.
(Rev2) Please revise labels for "STI" and "ST2" on sheet C3.1 to "SBI" and "SB2 "for plan
clarity.
6) Please describe adjacent property terrain and land use in Adjacent Property section of ESC
narrative on sheet C3.0.
(Revl) Comment has been addressed.
7) Please indicate proposed contractor parking and staging areas or clarify if these areas will be
contained within proposed limits of disturbance.
(Revl) If the project construction requires parking and /or staging areas which increase the
limits of disturbance proposed for construction, this must be indicated at the plan stage level.
Comment remains.
(Rev2) Comment has been addressed.
8) Please clarify intent of "CWD" symbol on sheet C3.1. It appears there needs to be silt fence for
west - draining sliver near these areas or other erosion protection measures. Non -VaDCR standard
E &SC measures require Program Authority approval for use.
(Rev]) Comment has been addressed.
9) Please provide length:width flow path calculations for sediment trap 1 & 2. It appears baffles may
be required to ensure 2:1 length:width flow path ratio.
(Rev]) Comment has been addressed.
10) (Rev2) Open cut trench across stream for proposed water main as proposed on sheet C4.0 is not
permitted. Due to the drainage area for Morey Creek being greater than 1 square mile, a utility
stream crossing is not practical. Please either revise design to hang the proposed water line
under the adjacent pedestrian bridge or prepare a Stream Diversion to ensure this work is
staged to prevent work in an active stream.
11) Please introduce erosion control measures to protect ground proposed to be disturbed east of
Morey Creek as shown on sheet C4.0 (i.e. the sidewalk loop). It appears that a sediment trap
would be an appropriate perimeter measure.
12) Please clarify work proposed with this project, note "Greenway Easement Connecting Fontaine
Avenue and Parcel 76 -12D trail to be constructed by the county" on sheet C4.0. Trail appears
to have been proffered as Proffer #1 with ZMA2010 -00003 "Pedestrian Path — owner must
construct off -site pedestrian walkway to VDOT standards from SE corner in existing ROW
along Nside of Fontaine Ave to Fontaine Research Park. Prior to CO of office building ".
Once these comments have been addressed, please submit 2 copies (add 1 more copy if VDOT needs to
review, and 1 more if mass - grading that Planning needs to review) of the revised plans, calculations, and
narratives to Current Development Engineering along with the required review fee and transmittal form.
Current Development Engineering is available from 2:30 -4 PM on Thursdays to discuss these review
comments. Please contact Michael Koslow at 434 - 296 -5832 ext. 3297 or email mkoslow @albemarle.org
to schedule an appointment.
[17- 204.f] An application for an erosion and sediment control plan that requires modifications, terms, or conditions to be
included in order for it to be approved shall be deemed to be withdrawn if the owner fails to submit a revised plan addressing the
omitted modifications, terms or conditions within six (6) months after the owner is informed of the omitted information as
provided under paragraph (B).
File: C: \Users \mkoslow\Documents \Current Reviews \SDP201200060 Morey Creek Office Park - Final \CDDE2_sdp,esc,swm,mp_MAK_Morey
Creek Professional Center SDP201200060.doc