HomeMy WebLinkAboutSDP202000058 Correspondence 2021-02-05 (2)608 Preston Avenue P 434.295.5624
Suite 200 IF434.295.1800
T I M M O N S GROUP
Charlottesville, VA 22903 www.timmons.com
February 5, 2021
County of Albemarle
John Anderson
401 McIntire Rd, Rm. 227
Charlottesville, VA 22902
RE: Crozet ES Addition, Renovation & Site Improvements — Major Site Plan Review —
SDP2020-00058 - Comment Response Letter
Dear Mr. Anderson:
We have reviewed your comments from December 23, 2020 (Rev. 1) and made the necessary
revisions. Please find our responses to the comments below in bold lettering.
S D P2020-00058:
1. C0.0: Revise plan title to include SDP202000058.
Title has been revised to include County number on Sheet C0.0.
2. C0.1, Note 4: Revise FEMA FIRM effective from Feb. 4, 2005 to May 16, 2016, per code
[18-30.3.2].
Note has been revised as requested on Sheet CO. 1.
3. C1.3: Provide VDOT IS-1, P13-1, ST-1 details (inlet shaping, pipe bedding, MH steps).
Details have been provided on Sheet C1.3.
(Rev. 1) Persists; not addressed. Details not shown on C1.3; please direct to sheet # with these
details, if overlooked.
Details were not plotting due to a printing error. Details are now provided on Sheet C1.3.
Sheet C4.0:
4. Show permeable paver underdrain connections with pipes/Dis/LIG detention in C7.0,
C7.1, whichever these occur.
Permeable pavers are no longer being proposed with this project.
(Rev. 1) NA
5. Label narrowest width dimension typical of 7 curvilinear parking spaces.
The narrowest dimension has been labeled; see Sheet C4.0.
6. With project, re-establish buffer with suitable native species (plantings) in areas that are
currently managed turf. See 17-600, 17-604.A. Note: proposed design is an
improvement over existing managed turf, and over earlier versions of design that
showed impervious improvements in the stream buffer. Proposed design proposes only
biofilters, and only within the landward fifty -feet (50') of the stream buffer.
ENGINEERING I DESIGN I TECHNOLOGY
The plan has been further improved to reduce work within the WPO buffer as one of the two
bioretention areas has been removed. The replanting area is mitigation for the work within
the WPO buffer and should have a nexus and proportionality to the impact. It is an undue
burden to this project to request the whole buffer be replanted especially in areas where
there is no impact to the existing WPO buffer.
(Rev. 1) Withdrawn. In withdrawing, please consider:
a) Engineering agrees with Applicant response, partially.
b) Final site plan for Crozet Elementary School, SDP1989-00031, VMDO, 03/28/89,
administratively signed, OS/25/89, shows stream buffer canopy vegetation along Parrott
Branch at approximately the same locations and to same (horizontal) extent as is visible
in 2020, some thirty-one years later.
c) Stream buffer historical (foot) note earliest code ref. date (Sec. 17-600 Extent of Stream
buffers; retention and establishment) appears to be 06-19-91, which is after Crozet
Elementary School Final Site Plan was administratively signed.
d) At no point over the past thirty -plus years have ordinance or modifications to Crozet
Elementary triggered a request for wholesale plantings within defined limits of the
stream buffer (which may not have existed at the time Crozet Elementary School final
site plan was administratively signed).
e) Establishment of buffer vegetation (17-604.C.5) stipulates 2:1 offset plantings within
unvegetated portions of a stream buffer. If intent of ordinance is for any applicant of
any application on any parcel with stream buffer, even sections of buffer unaffected any
or distant from development, to establish plantings throughout the entire unvegetated
reach of buffer, there would be need to calculate a 2:1 offset, or to estimate quantities
of plants required to achieve 2:1 offset plantings. Rather, ordinance would simply state
requirement that mitigation requires buffer plantings throughout the entire
unvegetated extent of an on -site stream buffer. Reviewer comment is inconsistent with
ordinance 2:1 stream buffer mitigation planting requirement. See 17-604.C.5.
f) The WPO stream buffer ordinance appears not to recognize concepts of nexus or undue
burden but recognizes proportionality via 2:1 mitigation planting requirement, which is
the standard typically applied to (virtually) all applications.
g) For these reasons, review comment oversteps and is withdrawn.
N/A. Comment withdrawn.
Sheet C4.1:
7. Jote 1. Ensure Arch/MEP drawings (these are not reviewed by Engineering) provide
temporary external containment (if required by USBC) for temporary above -ground oil
fuel tank during winter months while construction is ongoing to help mitigate any
impact due to accidental loss of oil that, at a school, may go undetected for hours, or
days — relevant during possible extended school closure during winter holiday, or
closure associated with the pandemic.
We have coordinated with the MEP and Architect and the above ground temporary oil fuel
tank will have a containment tray/pan at the base to mitigate any spills and/or leaks. The tank
with the containment tray the MEP specs will look something like this:
(Rev. 1) Addressed.
8. Review/revise plan view label / detail caption. Bioretention facility 2C, 4.1, v. biofilter
#3, C1.2.
Detail has been removed from Sheet C1.2, as the water feature has been removed from the
project.
(Rev. 1) NA
9. (Related), C1.2: Curb cut & biofilter #3 water feature section includes label reading
'exterior stairs without handrail.' Intent seems clear but given C4.1 label/linework that
indicate a galvanized handrail is to be positioned at top of steps (feature), provide
galvanized handrail detail (openings < 4 in.) to prevent children crossing this railing at
the top of biofilter #3. Provide C4.1, plan view ref. label to this handrail detail.
Water feature has been removed from project.
(Rev. 1) NA
Sheet C5.0:
10. Revise structure label for structure between storm pipes 139A and 139E from 139E to
138B.
Structure naming has been revised as requested. See Sheet C5.0.
(Rev .1) Partially addressed. As follow-up: Please avoid duplicate '1396' structure labels. See
image, below.
Duplicate labels have been revised.
11. Pipes 501 / 505 are proposed 18" DIA. An existing pipe between these two pipes at the
central -main entrance is 15" DIA. Revise 15" pipe DIA, if needed, to ensure adequate
pipe capacity at this location. Design typically avoids smaller diameter downstream
conveyance.
Culvert computations have been provided on sheet C7.2 for pipes 501 and 505. Both have
been decreased in size to a 15" which is more than adequate.
(Rev. 1) Addressed.
12. C5.1: Compare plan view of pipes 303, 305 on C5.1 with C7.1, Storm Sewer Profile
(images, below). (Rev.1) Images removed with Rev. 1 comments.
a. Provide sufficient cover for pipe 303 its entire length. Crown of pipe is exposed
in profile view.
Sufficient cover has been provided over pipe 303. See Sheet C7.1.
b. Provide fine grade lines and spot elevations at Str. 304 to ensure runoff capture
at this location.
Fine grade lines and a spot elevation have been provided for Str. 304. However, all
Nyloplasts in the 300 series are solid covers, so runoff capture is not the intention at
this point.
(Rev. 1) Addressed.
c. Show and label 4" solid HDPE that intersects pipe 305, in profile view.
The 4" solid HDPE pipe has been shown on Sheet C7.1.
d. Show fine grade lines and spot elevations at other (grate) inlets to ensure runoff
is captured.
All rims have been labeled as requested on Sheets C5.0 — C5.1.
e. Reposition pipe 303 end section (Str. 302) to align with pipe. ES is not a flow -
redirecting structure.
Structure 302 has been repositioned as requested.
13. Provide runoff capture (DI) prior to CG-12 ramp at approx. contour 692.75' in bus loop
parking, else ramp receives concentrated runoff.
It is not very practical to place a structure at this location on the curve of the curb line and so
close to the sanitary sewer easement. This curb ramp does not serve any accessible parking
spaces and is provided as a convenience for wheeling anything into the rear entrance.
(Rev. 1) Withdrawn. Engineering accepts this position.
14. General (VSMP-related): Recommend Note on Site Plan that bioretention basins may
not be constructed until all contributing drainage areas are stabilized, and that Note also
require bioretention construction in accord with WPO202000039 plan. The VSMP plan
will likely include similar note, requiring contributing drainage area stabilization prior to
biofilter construction.
A note has been provided as recommended on Sheets C4.0 and C4.1.
(Rev. 1) Addressed.
15. C5.3: Provide trench drain or similar for basketball court to minimize risk of ice on
asphalt walk during winter. Court drains NW to SE. This expanse of impervious area
(basketball court) will sheet rain or snowmelt to an asphalt walk. Proposed grade, 0.5%,
is relatively flat. Debris trapped against chain link serves as a dam to drainage. A C1.1
detail to supplement outdoor basketball court layout may eliminate need for trench
drain if 5' chain link fence detail is included and shows -6" gap at the bottom edge to
allow debris to be swept or blown through the gap. Experience with debris dam at chain
link fence at Sutherland MS tennis courts advises this comment.
The grading of the basketball court has been revised to provide more slope (see Sheet C5.1).
Additionally, the chain link fence has been removed. Therefore, we do not believe an
additional trench drain is needed in this location.
(Rev. 1) Addressed.
16. C1.1:
a. Outdoor basketball court layout: Revise court gates, consistent with C4.1 plan
view, where gates open onto asphalt walk.
Gates have been eliminated from the plan.
(Rev. 1) NA
b. Outdoor basketball court layout: Revise label to read 5' sideline to edge of
pavement to read 5' sideline to chain link fence, since asphalt continues beyond
fence, as asphalt walk.
Chain link fence has been removed from the plan; detail has been revised accordingly
on Sheet C3.1.
(Rev.1) NA
c. Recommend light duty asphalt pavement section specify % slope to ensure
adequate drainage from basketball court, across walk.
Basketball court grading has been revised to increase slope and ensure adequate
drainage. Slope labels have been added to Sheet C5.1.
(Rev. 1) Addressed.
17. C5.4:
a. Recommend Note or label to reference WPO202000039.
In the future, this sheet will only be submitted with the WPO submission. Therefore, a
reference to the WPO plan is not necessary.
b. Recommend label each SWM facility'SWM facility'.
Labels have been provided on Sheets C5.0 and C5.1.
Sheet C7.0:
18. Revise structure label for structure between storm pipes 139A and 139E from 139E to
138E in profile captioned UG Detention — Pipe 141 (@Sta. 10+94.99).
Structure has been renamed as requested.
(Rev. 1) Partially addressed. As follow-up: Please avoid duplicate'1396' structure labels in storm
sewer profile. See image, below:
Duplicate labels have been revised.
19. Str- 126 MH-1 with splitter weir: provide small scale plan / profile relevant details,
notes, labels, and elevations for pipe inverts, MH floor, weir elevation/s such that split
flow is discernable, and ladder, weir, pipe entry / exit conflicts are avoided. Likely
submitted with WPO, but also required for site plan.
Due to stormwater changes, this structure is no longer proposed with this project.
(Rev. 1) Addressed.
20. C7.2: Supplement (or replace) storm sewer tables with VDOT LD-204 and LD-229
stormwater inlet and storm sewer design computations (tables). Additional review
comments possible.
Tables on Sheet C7.2 have been replaced with the requested formatting
(Rev. 1) Addressed.
21. Note: WPO plan approval is required prior to Major Site Plan Amendment approval
(WP0202000039 has been submitted, review pending.)
Acknowledged.
(Rev. 1) Comment persists. Please ensure site plan amendment is consistent with WPO plan, and
most -recent 17-Dec 2020 Engineering WPO plan review comments.
WPO and Major Site Plan Amendment plans are coordinated.
We have included PDF copies of the plans and calculations for your review. If you have any
questions or comments, please feel free to give me a call at 434.327.5380 or email me at
bryan.cichocki@timmons.com.
Sincerely,
Bryan ichocki, PE
Project Manager