HomeMy WebLinkAboutSDP202000011 Review Comments Initial Site Plan 2020-03-03Phone (434) 296-5832
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SDP2020-00011
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Site Plan review
Boys and Girls Club, Northside — Initial Site Plan *
Craig Kotarski, PE, Timmons Group — 608 Preston Ave, Suite 200,
Charlottesville, VA 22903 [craig.kotarski(iDtimmons.com ]
Boys and Girls Club, 1000 Cherry Ave., Charlottesville, VA 22903
[ jpierceLbeclubva.org ]
31 Jan 2020
3 Mar 2020
John Anderson
Christopher Perez
Fax (434) 972-4126
* Engineering deems Initial Site Plan detail adequate for approval of the ISP. For Final Site Plan Approval:
1. VSMP /WPO plan approval is required prior to Final Site Plan approval. WP0202000005 is under review.
Note: Applicant made critical slopes waiver request; based on information submitted, including Applicant
email, 2/27/2020 4:05 PM, Engineering supports critical slopes waiver request.
2. Stream buffers exist on parcel. Requirements listed at Ch. 17, Article VI, Stream Buffers, apply.
CIA
3. Flush curb detail indicates —10" base. Please confirm depth of base and identify base material (asphalt,
asphalt type; stone, stone type).
4. Similarly, VDOT Std. CG-3 /CG-2 details indicate —10" base, each typ. section. Identify base material and
depth of each layer if base is a mixed stone /asphalt composite.
5. C1.2: Include VDOT SL-1 detail (safety slab).
6. C2.0: Show and label stream buffers.
C4.0:
7. This plan sheet appears twice; please label 2nd occurrence C4.3.
8. Revise CG-2 to CG-6 along south side of heavy-duty asphalt access, S side of building. Gutter is required
to convey drive aisle /access /parking area storm runoff. Curb alone is insufficient. (18-4.12.15.g.)
9. Label Jouett MS main building, to orient project.
10. Label Ivy Creek School main building.
C4.1
11. Since proposed 8' (Max. ht.) retaining wall N of main parking area supports infrastructure (parking), sealed
geotechnical retaining wall plans are required prior to FSP approval. Please ref. retaining wall checklist for
plan reviewers (Attached).
12. Label typical narrowest width dimension of 19 proposed curvilinear parking spaces.
13. Provide bollard at double -doors opening to 5' sidewalk and flush mount curb on south side of building to
protect occupants exiting blindly to sidewalk without visibility east, of approaching vehicles. Place left of
door, on exiting. Recommend bollards both right and left. At a minimum, provide bollard to left on exiting.
14. Provide evidence of coordination and approval from ACSA concerning design approval of sanitary sewer
pump station connecting via 6" new force main to Ex. pump station alongside Jouett Middle School.
Engineering Review Comments
Page 2 of 6
15. Consider sequence and pedestrian safety needed during force main construction. Provide narrative and
details to protect visitors to Jouett MS (parents, teachers, students, etc.).
16. (C4.1, C5.0, C5.2): Label proposed storm lines downstream of 70-1f and 700-1f x 96" DIA CMP
underground detention systems public drainage easements. Provide easement plat, showing SWM facility,
facility access, and public drainage easements. Public drainage easement must extend to a natural drainage
feature, or to the property line.
17. For both detention systems, provide overland relief to protect improvements against flooding, and critical
slopes against erosion in event of weir plate obstruction. Design overland relief to convey 10-yr event.
Assume complete bypass of systems, should one or both become non -operational.
18. C4.1, C5.0, C5.1: Revise CG-2 to CG-6 at all locations where storm runoff collects against a curb. CG-2
alone is insufficient. (18-4.12.15.g.)
19. Recommend revise parking drive aisle grade slightly, provide DI at pipe 209 intersection with CG-6 (rev.
CG-2) in front of N side of building. Proposed grade requires exact construction to bend drive aisle runoff
between contours 543 and Str. 206. A more reliable design (a recommendation) is to direct runoff to a new
DI at pipe 209 (rev. CG-2 to CG-6 between Str. 234 and new DI, then CG-2 after new DI); then, after new
DI, provide grade directing runoff to Str. 206. Water flowing across a paved surface tends to travel
straight. A likely better long-term drainage design that more nearly meets expectations for pavement
/drainage performance is to collect runoff traveling west at a new DI, then collect runoff traveling north in
parking aisle /areas N of the building. Collection of concentrated flow at main entrance to facility avoids
ice which is likely consequence of sheet flow over this distance, west then north, if proposed pavement
grade is constructed. At entrance to the building, pipe 209 is immediately below, and for slight expense, a
DI may greatly reduce risk to patrons, including children unaware of risk or hazard of black ice in winter.
C4.1, C4.2
20. Label underground detention systems. If Mfr. system, include name of Mfr. in plan or profile view. (If
Mfr. system, for VSMP/WPO plan, include recommended installation guidelines, maintenance, and
periodic inspection guidelines.)
21. For VSMP and final site plan, ensure manway entries to underground facilities permit visual check of weirs
without entry. Manways should provide check of SWM facility operation, especially weirs. Do not place
SWM facility manways in a designated parking or loading space.
22. Add FM (force main) size descriptor (6" DIA).
23. Ensure Nyloplast ® pipes and risers are identified and labeled. Provide Nyloplast typical construction
installation and periodic maintenance and inspection guidelines.
24. Provide drainage calculations (LD-229, LD-204) for all storm pipes and inlets.
25. Provide, show, label basketball court fencing.
26. C4.3: Label loading area/s, if any.
C5.0
27. Revise proposed contours, consistent with grading required to install Ditch B.
28. C5.0, C5.2, proposed 2:1 slopes on critical slopes do not, for the moment, appear to include reverse slope
benches. Ensure contours and labels guide construction of reverse slope benches.
29. Provide EC-3, pipe or concrete channel section at proposed 90-degree change in direction of runoff
proposed for Ditch D.
30. (C5.0, C5.1, C5.2): Provide guardrail (VDOT GR-1) with typ. details along south side of heavy-duty
asphalt access located on south side of building. Although CG-2 is proposed, proposed grading is an
unrecoverable slope. Guardrail is required.
31. C5.2: Revise aisle grade on south side of building between contour elevations 534 and 516 to concentrate
flow against CG-6 curb (revise CG-2 to CG-6) for reasons of practicality and safety stated elsewhere.
Proposed grade assumes sheet flow over 18-ft vertical interval when effort should be made to eliminate
runoff from this drive aisle (place against curb) rather than design to spread runoff across entire width of
the drive aisle.
32. C5.0, C5.2: Label proposed slopes (3:1, 2:1) south and west of building. Slopes steeper than 2:1 are
impermissible.
Engineering Review Comments
Page 3 of 6
33. Engineering recommendation to approve waiver to impact critical slopes (south and west of building)
requires design incorporate construction standards at 18-30.7.5, including reverse slope benches.
34. Increase separation between pipe 303 and back face of retaining wall, especially at NW end of wall; see
image.
35. Provide and define ditches /channels formed by proposed /existing contours N of playfield, and elsewhere
(blue arrows, images below). Note presence of critical slopes immediately downslope of many locations.
\
\ WEIR PLAT \
07
\
MO FOF 86•CMP'.� \
UNDERGROUND
` - DETENTION \
C5.1, C5.2
36. Provide channel design for ditches formed by existing /proposed grade. Ref, images, below:
t
41
I
37. Show full extent of proposed grade, south of SE corner of basketball court. Grade =?
Engineering Review Comments
Page 4 of 6
UCAAWW.! 07AI
L _ Mu.
d-0. Q1- 1-2f
C5.4
38. 18-4.12.19.b. (Drainage Plan checklist, drainage item 7): Revise contours to prevent storm runoff running
through dumpster enclosure. Recommend direct pad to drain to a surface stone (French) drain to right of
pad, then exit surface drain via curb cut to drive aisle surface. Minimize contamination of stormwater
runoff due to contact with solid waste.
19 ` rC
54f06'
39. Consider highlight section downslope runoff without, in most cases, defined grade to intercept runoff prior
to curb, or sidewalk. Provide capture /conveyance in locations with 7', 10' or 15' vertical interval leading
to sidewalk, curb, basketball court, or heavy-duty concrete.
Engineering Review Comments
Page 5 of 6
40. Provide curb or hardscape edging between earth slopes and heavy-duty concrete east of main building
(image, above).
C7.0, C7.1
41. Recommend plan note emphasize compaction requirements beneath pipes or MHs entirely in fill section;
prior VDOT specification would be appropriate. (Str. 402, 404, 501, RD3, nearly all Str. 412 — SWM2A)
CONTRACTOR SHALL PLACE FILL UNDER INLET(S) AT 95%
COMPACTION & EMBANKMENT MATERIAL SHALL
CONSIST PREDOMINANTLY OF SOIL AND BE PLACED IN
SUCCESSIVE UNIFORM LAYERS NOT MORE THAN 8' IN
THICKNESS BEFORE COMPACTION IN ACCORDANCE
WITH VDOT 2007 ROAD AND BRIDGE SPECIFICATION
303,04, AFTER T VERTICAL PLACEMENT OF FILL,
CONTRACTOR SHALL EXCAVATE RECENTLY LAID FILL
AND INSTALL COMPACTED VDOT STD. 21A STONE IN AN
8'x8' O.C. COMPACTED 21A AREA CENTERED ON THE
INLET(S). CONTRACTOR SHALL REPEAT THIS OPERATION
UNTIL AN 8'x8' O.C. 21A STONE BASE IN INSTALLED
BETWEEN THE EXISTING GROUND AND THE PROPOSED
INLET(S) BASE IN EFFORTS TO REDUCE THE RISK OF
SETTLING, CONTRACTOR SHALL PROVIDE VDOT WITH
COMPACTION RESULTS PRIOR TO ROAD ACCEPTANCE.
42. Include safety slab label in storm profiles for MH ht. >12-ft. Str. 102, 108, for example.
43. Recommend VDOT anchoring of storm pipe that approaches 16% grade. Conservative design, care, and
precautionary measures for storm pipe installed at steep grade on critical slopes are appropriate.
VDOT drainage manual, p. 9-37
9.4.8.7 Maximum Grades
Slopes that incur uniform flow velocities in excess of 10 fps should be avoided because
of the potential for abrasion. Slopes in excess of 16% are not preferred because of the
need for anchor blocks. When anchor blocks are used, they should be installed at
every other pipe joint, as a minimum. (See Special Design Drawing No. A-73 and MA-
73 for Anchor Details for Concrete Pipe)
44. SWM1 — Str 100: Label reverse slope bench.
45. Label SWM1 and SWM2 in plan view (C5.0).
46. Show /label riprap in profile at outfall Str. 100.
Engineering Review Comments
Page 6 of 6
Please feel free to call if any questions: 434.296-5832 -x3069
Thank you
SDP2020-00011 Boys and Girls Club ISP 030320