HomeMy WebLinkAboutWPO201300072 Review Comments WPO VSMP 2014-08-04�pF A
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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:
Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer:
Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins -en ing eering com]
Owner or rep.:
Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date:
15 April 2014 [WPO], 16 April 2014 [Road]
(Rev. 1)
12 June 2014 [Road], 16 June 2014 [WPO /SWM &ESC]
(Rev. 2)
22 July 2014 [Road], 24 July 2014 [WPO /SWM &ESC]
Date of comments:
22 May 2014
(Rev. 1)
15 July 2014
(Rev. 2)
4 August 2014
Reviewer:
John Anderson
Please contact reviewer to schedule a meeting to discuss comments, if helpful.
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT. (Rev. 1) TIA lends question: Briarwood
Commercial Development TIA (Table 4.2 –ITE Trip Generation) by Davenport (Project # 13 -338,
11/20/13, rev. 3/7/14) shows 24 -hr two -way volume trip generation for Areas A -B -C as 10,896.
Sheet 6 displays this data (Elm Tree Court) using a double -end arrow and label: 5,448 VPD. TIA
shows 24 -hour two -way volume trip generation for Areas D -E -F as 11,324. Sheet 6 displays this
data (Road `A') as 5,662 VPD. Revise labels to show that 10,896 and 11,324 VPD are TIA 2 -way
estimates. The figures 5,448 and 5.662 may be mistaken as total 2 -way estimates, which they are
not. (Rev. 2) Comment addressed.
2. Remove entrances from the road plans. These must be approved with site plans. (Rev. 1)
Comment addressed.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
(Rev. 1) Comment addressed. [Jun -]1 letter: "Existing grading easement allows for disturbance
10' into the existing lot. No lot disturbance occurs outside of this area. "]
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan. (Rev. 1) Comment addressed —Bonds will need to be signed by the owners of all
properties on which construction takes place, or legal easements will be needed [ref – Albemarle
County Design Standards Manual [ ACDSM], 8. Grading; C. Off -site work]. [Jun -]1 letter:
"Townhouse grading approved under SDP - 2010 -84 and is an existing condition for this road plan.
Proposed grading ties into the approved grading as shown on Sheet 4 "].
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6). (Rev. 1)
Ref. Planning Division comments dated July 3, 2014, comment #4—"A waiver request [for 3'
wide planting strips] shall be taken to the Planning Commission for consideration."
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger. (Rev. 1)
Comment not addressed. [See ACDSM 8.B.2.b. /c.] Please provide specific, geotechnical
Engineering Review Comments
Page 2 of 7
engineering details for all retaining walls, including Redi -rock Ledgestone gravity wall system.
Revise handrail /fence post detail, sheet 5: show a zero (0 %) slope extending at least 24" behind
wall (railing post may not coincide with drainage swale low- point); show drainage swale in every
view of Wall #3 —D, E, F, G, H, I. Consider, show, and detail sub - surface drainage features.
Label and dimension aggregate prism installed immediately behind SRW blocks in handrail /fence
post detail. Specify drainage at foundation (or higher levels) as necessary to ensure areas
immediately behind each wall have adequate drainage. Do not show unbroken 2:1 slope behind
wall #3, but in each section view (D -I), break slope with drainage swale located at least 24" behind
wall. Furnish qualified Engineer's report that life cycles and surcharge of plantings shown in
schematic and table views on sheet 5 and 15, and on sheet 2 of (SDP201300035) Briarwood Site
Plan Amendment #2, Briarwood Phases IA -A, IB -1, 4 -8, received 23 -June 14, will not
compromise integrity of walls or geogrid, if geogrid is used. Avoid planting within drip -line
distance of walls. A 314 sf canopy tree, for example, should not be planted within 10 -ft of walls.
Explanatory note that "final structure wall design to be submitted with final structural engineering
plans " does not meet review requirements. Retaining wall design is a precondition to approval of
road plan, mitigation plan [SDP201300035], and site plan [SDP201400047] since integral to
infrastructure of the site (Road `A'). (Rev. 2) Partially addressed – discussed these items with
Scott Collins, Jul -31, or Adam Long, Aug -1. With submittal of Redi -rock Retaining Wall design
on 7/21 (d. 7/14/14): i) revise handrail consistent with location in top - course of Redi -rock wall; ii)
landscaping between Walls 1 and 2 should prevent trespass between walls: no objection if
eliminate lower wall (Wall 2) handrail if required to meet ARB /other departmental requirements;
iii) restore backslope grade shown in Wall 3 profile views (D,E,F,G,H,I) of earlier submittal
(Geotechnical design engineer, M. Circeo, maintains drainage swale unnecessary); iv) revise
proposed tree locations, Wall 3, to ensure min setback – requirement/formula outlined as item #3,
7/23/14 correspondence, Margaret Maliszewski, ACCD, to Miller Cupp Associates Architects,
P.C. / Collins Engineering; and, v) transfer all information from Circeo design titled Redirock
Retaining Walls, Briarwood Commercial, Albemarle County, Virginia, to road plans (2 -3 new
sheets). Transfer without revision, addition, or deletion, except by or through Michael R. Circeo.
7. Delete Notes 1 and 2, sheet 5. These notes are invalid. (Rev. 1) Comment partially addressed;
sheet 5 segmented retaining wall (SRW) and geogrid reinforcement details removed. New sheet
5 Wall Cross - sections and Details are inadequate. Ref. ACDSM, 8.B.2.c (Rev. 2) Comment
addressed –see 6, above.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient. (Rev. 1) Comment partially addressed. Handrail shown for Wall #3, only (see
sections D -I, sheet 5). No railing shown for sections of Wall #1 or 2 (sections A, B, C, sheet 5).
Furnish safety railing for all proposed wall sections 4' or higher. (Rev. 2) Comment addressed.
Also, see comment #6, above.
9. Show managed slopes on Wall Number 3 detail –sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly. (Rev. 1)
Comment addressed.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown). (Rev. 1) Comment addressed.
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive –sheet 3. (Rev. 1)
Comment addressed.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3' R, Minimum. (Rev. 1) Comment addressed.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %. (Rev. 1)
Comment addressed.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
Engineering Review Comments
Page 3 of 7
turn- around, see plans for details.' Furnish design details for temporary turn- around. (Rev. 1)
Comment addressed.
15. Sheet 6 — Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
(Rev. 1) Comment addressed.
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
(Rev. 1) Comment addressed.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details. (Rev. 1) Comment addressed.
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable. (Rev. 1) Comment addressed.
19. Str -8 (type, DI -7) — the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12). (Rev. 1) Comment partially addressed; 10 -yr design storm
table, sheet 14, lacks column headings - please provide column headings. (Rev. 2) Comment
addressed.
20. Str -24 (type, DI -7) — Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate. (Rev. 1)
Comment addressed.
21. VDOT approval is required. Comments are attached. (Rev. 1) Acknowledged.
22. For Road `A', Road `B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 7 1. (Rev. 1) Acknowledged.
NEW
23. Increase radius of curve at NE corner of Road `A' -Road `B' intersection to 30 -ft, Min, to allow
longer vehicles to clear opposing traffic when turning [Ref. AASHTO/Minimum Turning Paths of
Design Vehicles —link: http: / /design transportation.org/ Documents /TumRadii,GreenBook2004.pdf ]
(Rev. 2) Comment addressed.
24. Provide stationing for Briarwood Drive to aide design, review, bond estimate, bond reduction,
inspection, and maintenance: begin with station 10 +00 at CL intersection Briarwood Drive and
Elm Tree Court. In addition, furnish: CL profile for Briarwood Drive; typical cross sections at
these points: tip of median near Rte. 29; widest and narrowest widths east of Road `A'; and
between Road `A' and Elm Tree Court. Indicate drainage patterns. Show symmetrical transition
of pavement at intersection with existing street (Rte. 29) [18- 32.6.2.f]. (Rev. 2) Comment
addressed.
25. Provide storm drain inlets to capture uncollected runoff from Briarwood Drive; these inlets should
be located as close to Rte. 29 as possible, included with median design. To this end, furnish inlets
along each side of the proposed median on Briarwood Drive, just prior to Rte. 29. Propose
structures within the median structure, on each side. V4" per ft. crown for the 3 lanes into the
subdivision and the 4 lanes out should transition smoothly to U.S. Rte 29, existing EP. (Rev. 2)
Comment addressed.
26. Inlet structures Ex -38 and Ex -37, sheet 4: One or the other will be relocated; please indicate which.
(Rev. 2) Comment addressed.
27. Sheet 5: for Wall sections A,B,C,D,E,F,G,H,I, show road station that corresponds with each
section ( Briarwood Drive, or Road `A'). There is no clear reference to locate these sections.
(Rev. 2) Comment addressed.
28. Add County `General Construction Notes for Streets' to plans —ref. ACDSM. (Rev. 2) Comment
addressed.
29. Supplement Retaining Wall Notes, to include, at a minimum: i) The Owner shall engage inspection
and testing services (quality control) during construction to ensure project design requirements are
Engineering Review Comments
Page 4 of 7
met; the lack of quality control by the owner does not relieve the contractor of these requirements;
ii) quality control shall include but not be limited to: foundation soil inspection, verification of
geotechnical design parameters, and verification that construction is in general compliance with the
design drawings; iii) only qualified and experienced technicians shall perform testing and
inspections services. (Rev. 2) Comment addressed.
30. VDOT approval is required for improvements to Briarwood Drive and the new intersection design
and location. (Rev. 2) Comment acknowledged.
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change. (Rev. 1) Comment addressed.
2. Treatment must be provided for all improvements (see also WP0201400030). (Rev. 1) VDOT
restrictions on use of Filterra units within public RW set practical limits on extent of water quality
treatment. Nevertheless, collection, rather than release of runoff from expanded width of
Briarwood Drive is possible with storm inlets positioned within new proposed median close to
U.S. 29 ( #25, above). (Rev. 2) Comment addressed.
3. Sheet 2 and 3 existing (pre - development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4). (Rev. 1)
Comment addressed.
4. Do not show the proposed three line SWM underground detention system as pre - development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
(Rev. 1) Comment withdrawn.
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn. (Rev. 1) Comment addressed.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length. (Rev. 1) Comment addressed.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. — 427.74'. Please
show 10 -year W.S.E. below spillway crest. (Rev. 1) Comment addressed.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b). (Rev. 1) Request for anti - vortex device withdrawn — detained 2- /10 -yr storm elevations
are below crest of extended detention facility #3, 30" riser; sheet 4.
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
WQV required = 2,583 cf. Also, WQV provided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Engineering Review Comments
Page 5 of 7
Please re -check calculations and compare against extended detention SWM facility design. (Rev.
1) Comment addressed.
10. All details on sheet 5 should be to scale. (Rev. 1) Comment addressed.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road. (Rev. 1) Comment withdrawn.
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition. (Rev. 1) Comment addressed.
NEW
13. Remove image of extended detention facility from pre - development window, sheet 3. (Rev. 2)
Comment addressed.
14. Label schematic of development feature (second gasoline station ?) on post - development window,
sheet 3. This detail is new, not shown on corresponding Apr -15 plans; it requires a label that
describes what it is (and reason for showing it). Future development north of Briarwood Drive
does not appear on plans under review. Please confirm and specify future impervious area
calculated to be included with revised underground detention system design (WP0201400030);
area is believed to be 29,500 SF. Currently, proposals for widening Briarwood Drive, constructing
new private roads, and site development south of Briarwood Drive (gas station) are under review.
No assurance is made with respect to review or approval of site or WPO design features tied to
future development. (Rev. 2) Comment addressed via plan revision d. 7/31, submitted 8/1/14.
15. Label L/W of floor of main basin and forebay of extended detention SWM facility #3 detail, sheet
4, since storage at elevation 432' has increased. (Rev. 2) Comment addressed.
16. New -With respect to SWPPP dated 7/20/14 prepared by Collins Engineering for construction
activities at Briarwood Commercial Lots, received 7/24/14:
Registration Statement (General VPDES Permit) latitude /longitude do not match SWPP project
coordinates; please reconcile.
- Estimate start- finish / installation - removal dates throughout the SWPPP.
Revise inspection schedule (p. 26). Inspections are required at least once every 10 business days (plus
additional requirements). [Ref. 9VAC25- 880 -70, Part 77, Stormwater Pollution Prevention Plan, F.,
Inspections, 2., Inspection Schedule]
- SWPPP, p. 26, identifies one individual responsible for inspection. Confirm that this individual accepts
sole responsibility for scheduled inspections, reporting, recordkeeping, notification, and for directing
corrective response relating to SWPPP proposed to cover all Briarwood Commercial projects.
EXHIBIT TO SHOW CONCRETE WASH OUT, PORTA - JOHNS, AND FUELING AREA (7/21/14): Show concrete wash
out area (not shown). Concrete wash out area/s may not drain to storm inlets. Propose treatment for concrete
wash waters. [§ 17- 404.B.]
- Show on -site dumpster. Provide treatment (or detention) of dumpster drain water. Dumpster runoff may
contain contaminants that may not discharge freely downslope, to a storm inlet, or to any stream. Provide silt
fence or earthen berm at porta johns as containment in event of spill. Furnish impermeable containment, a
barrier to infiltration designed to hold the entire volume of stored fuel in event of spill, with freeboard measure
of safety, for each fueling tank shown in the SWPP exhibit.
- 17- 404.B. l .a. Wash waters — "Minimize the discharge of pollutants from equipment and vehicle washing,
wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative
control that provides equivalent or better treatment prior to discharge." Propose treatment for wash water.
Construction entrance with wash rack to the north does not drain to a sediment basin; propose treatment.
Engineering Review Comments
Page 6 of 7
Label construction entrance on plan sheets as Paved CE, with wash rack [ref. WP0201300072, E &S
Sequence of Construction Note 3]. Provide detail found at p. 27 of ACDSM —link:
http: / /www. albemarle. oriz/department. asp ?department= cdd &relpaae =4447
Transfer SWPPP best management practices to project plan sheets: practices or narrative listed/shown in
SWPPP and on WPO plans should mirror each other.
Revise SWPPP, SWPPP plan sheets, and corresponding WPO plan sheets.
17. New - Furnish letter of coverage, VDEQ General VPDES Permit.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7). (Rev. 1) Comment partially
addressed. With revised ESC, furnish sediment traps at low end of each diversion dike that ends at inlet
(DI) of pipe beneath Briarwood Drive. IP alone is insufficient. [See also WP0201400059, ESC plan
comments, 7/14/14, items #4.] (Rev. 2) Comment addressed.
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29. (Rev. 1) Comment addressed, but please see #1,
above.
3. Show SAF on plans. (Rev. 1) Comment partially addressed. Show SAF along south edge of Briarwood
Drive. Provide SF, this location, as well. (Rev. 2) Comment addressed.
4. Relocate stone weir outfall, ST 1. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal). (Rev. 1) Comment addressed.
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing) [Rev. 1— Addressed]; check DA, SB
#1 against DA, sheet 7 [Addressed]; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1
[Addressed]; correct t,,, SB #1 [Revise t, to 9.0 min; delete Min. 1.0' dimension label on sediment basin
profiles (emergency spillways are not proposed for either basin) [Review error, comment withdrawn].
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066. (Rev. 1) In combining ESC for
amended underground detention system (WP0201400030) with road plan's two -phase ESC plan, it is
evident that the sequence of construction is problematic. It appears unlikely any downslope controls can be
installed near Wall #3, given space limitations for road, sidewalk, etc. This means there is nothing shown in
Phase 2 design to limit off -site sediment transport, other than IP on new or existing storm drains. Rather,
Phase 1 of the ESC plan shows limited grading for the private road and construction of a portion of the
retaining wall. Without considering the question of whether the wall can be built to design in two
horizontal sections, sheets 6 (phase 1) and 7 (phase 2) as well as sequence of construction notes (sheet 5),
show that sediment basin #1 will serve as perimeter control for grading shown in phase 1 only. Sediment
basin #1 (or alternative, effective ESC measures) must remain in place until grading and improvements,
including widening Briarwood Drive, are complete. Sediment basin #1 must remain in place until upslope
areas are stabilized (graded sections near wall, wall construction complete, private road [to extent shown]
complete, Briarwood Drive widening complete). Installing the 3 -line underground system is only possible
after upslope disturbed areas are stabilized (Sequence Note 12), and should be delayed until such time as
they are. Please revise sheets 5 (sequence of construction; please call to discuss), 6 (ESC -Phase 1), and 7
(ESC -Phase 2). Please re- evaluate sequence and revise to provide adequate ESC measures for all stages of
Engineering Review Comments
Page 7 of 7
road, slope, and wall construction, and during installation of the amended (3 -line) underground detention
system. ESC measures shown for installation of the underground detention system on WP0201400030
(Apr -15) plans did not transfer to these plans. Notably, a sediment trap shown between the system and U.S.
Rte 29 is eliminated, and no ESC measures take its place. There is no apparent provision for ESC during
installation of the underground detention system north of Briarwood Drive. Please provide ESC for this
phase of work. [Ref. 5/22/14 Underground Detention ESC plan review comments, #3, specifically] (Rev.
2) Comment addressed.
7. All basin and trap profiles on sheet 9 should be to scale. (Rev. 1) Comment addressed.
8. Identify any off -site borrow or waste sites. (Rev. 1) Comment not addressed. (Rev. 2) Comment
addressed.
9. (New) Sheet 7 proposes grading affecting 30 -ft of vertical contours, near Wall #3. Provide ESC measures
and sequence of construction that prevent sediment -laden runoff from reaching Briarwood Drive or off -site
receiving streams or entering 3 -line amended underground detention system during all phases of grading.
(Rev. 2) Comment addressed.
10. Minor, new, sheet 8 — revise crest of stone weir elevation in sediment trap #1 profile to read 427.00'; revise
30" DIA riser top elevation (sediment basin #2 profile) to read = 428.96'. (Rev. 2) Comment addressed.
11. (New) SEE ESC comment #1, WP0201400059, 7- 14 -14: MS -19: photos indicate erosion down slope of
pipe outfalls beneath U.S. Rte. 29, an indication that receiving channels are inadequate. The computations
should reflect this, and appropriate measures should be specified to correct the problem. The computations
(roughness and velocities) appear to indicate conditions of adequacy that do not exist. (Rev. 2) Comment
addressed.
D. Final Plat
1. Must match road plan.
File: WP0201300072, SUB201400066- briarwood- 080414rev -2
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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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins -en ing eering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
(Rev. 1) 12 June 2014 [Road], 16 June 2014 [WPO /SWM &ESC]
Date of comments: 22 May 2014
(Rev. 1) 15 July 2014
Reviewer: John Anderson
Please contact reviewer to schedule a meeting to discuss comments, if helpful.
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT. (Rev. 1) TIA lends question: Briarwood
Commercial Development TIA (Table 4.2 ITE Trip Generation) by Davenport (Project # 13 -338,
11/20/13, rev. 3/7/14) shows 24 -hr two -way volume trip generation for Areas A -B -C as 10,896.
Sheet 6 displays this data (Elm Tree Court) using a double -end arrow and label: 5,448 VPD. TIA
shows 24 -hour two -way volume trip generation for Areas D -E -F as 11,324. Sheet 6 displays this
data (Road `A') as 5,662 VPD. Revise labels to show that 10,896 and 11,324 VPD are TIA 2 -way
estimates. The figures 5,448 and 5.662 may be mistaken as total 2 -way estimates, which they are
not.
2. Remove entrances from the road plans. These must be approved with site plans. (Rev. 1)
Comment addressed.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
(Rev. 1) Comment addressed. [Jun -]1 letter: "Existing grading easement allows for disturbance
10' into the existing lot. No lot disturbance occurs outside of this area. ",
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan. (Rev. 1) Comment addressed —Bonds will need to be signed by the owners of all
properties on which construction takes place, or legal easements will be needed [ref – Albemarle
County Design Standards Manual [ ACDSM], 8. Grading; C. Off -site work]. [Jun -11 letter:
"Townhouse grading approved under SDP - 2010 -84 and is an existing condition for this road plan.
Proposed grading ties into the approved grading as shown on Sheet 4 "].
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6). (Rev. 1)
Ref, Planning Division comments dated July 3, 2014, comment 44 — "A waiver request [for 3'
wide planting strips] shall be taken to the Planning Commission for consideration."
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger. (Rev. 1)
Comment not addressed. [See ACDSM 8.B.2.b. /c.] Please provide specific, geotechnical
engineering details for all retaining walls, including Redi -rock Ledgestone gravity wall system.
Revise handrail /fence post detail, sheet 5: show a zero (0 %) slope extending at least 24" behind
Engineering Review Comments
Page 2 of 6
wall (railing post may not coincide with drainage swale low- point); show drainage swale in every
view of Wall #3 —D, E, F, G, H, I. Consider, show, and detail sub - surface drainage features.
Label and dimension aggregate prism installed immediately behind SRW blocks in handrail /fence
post detail. Specify drainage at foundation (or higher levels) as necessary to ensure areas
immediately behind each wall have adequate drainage. Do not show unbroken 2:1 slope behind
wall #3, but in each section view (D -I), break slope with drainage swale located at least 24" behind
wall. Furnish qualified Engineer's report that life cycles and surcharge of plantings shown in
schematic and table views on sheet 5 and 15, and on sheet 2 of (SDP201300035) Briarwood Site
Plan Amendment #2, Briarwood Phases IA -A, IB -1, 4 -8, received 23 -June 14, will not
compromise integrity of walls or geogrid, if geogrid is used. Avoid planting within drip -line
distance of walls. A 314 sf canopy tree, for example, should not be planted within 10 -ft of walls.
Explanatory note that "final structure wall design to be submitted with final structural engineering
plans" does not meet review requirements. Retaining wall design is a precondition to approval of
road plan, mitigation plan [SDP201300035], and site plan [SDP201400047] since integral to
infrastructure of the site (Road `A').
7. Delete Notes 1 and 2, sheet 5. These notes are invalid. (Rev. 1) Comment partially addressed;
sheet 5 segmented retaining wall (SRW) and geogrid reinforcement details removed. New sheet
5 Wall Cross - sections and Details are inadequate. Ref. ACDSM, 8.B.2.c.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient. (Rev. 1) Comment partially addressed. Handrail shown for Wall #3, only (see
sections D -I, sheet 5). No railing shown for sections of Wall #1 or 2 (sections A, B, C, sheet 5).
Furnish safety railing for all proposed wall sections 4' or higher. Also, see comment #6, above.
9. Show managed slopes on Wall Number 3 detail –sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly. (Rev. 1)
Comment addressed.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown). (Rev. 1) Comment addressed.
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive –sheet 3. (Rev. l )
Comment addressed.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3' R, Minimum. (Rev. 1) Comment addressed.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %. (Rev. 1)
Comment addressed.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around. (Rev. 1)
Comment addressed.
15. Sheet 6 – Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
(Rev. 1) Comment addressed.
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
(Rev. 1) Comment addressed.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT detail:, (Rev. 1) Comment addressed.
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable. (Rev. 1) Comment addressed.
19. Str -8 (type, DI -7) – the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12). (Rev. 1) Comment partially addressed; 10 -yr design storm
table, sheet 14, lacks column headings- please provide column headings.
20. Str -24 (type, DI -7) – Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
Engineering Review Comments
Page 3 of 6
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate. (Rev. 1)
Comment addressed.
21. VDOT approval is required. Comments are attached. (Rev. 1) Acknowledged.
22. For Road `A', Road B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71. (Rev. 1) Acknowledged.
NEW
23. Increase radius of curve at NE corner of Road `A' -Road `B' intersection to 30 -ft, Min, to allow
longer vehicles to clear opposing traffic when turning [Ref. AASHTO /Minimum Turning Paths of
Design Vehicles —link: http: / /design transportation.orw Documents /TumRadii,GreenBook2004.12df ]
24. Provide stationing for Briarwood Drive to aide design, review, bond estimate, bond reduction,
inspection, and maintenance: begin with station 10 +00 at CL intersection Briarwood Drive and
Elm Tree Court. In addition, furnish: CL profile for Briarwood Drive; typical cross sections at
these points: tip of median near Rte. 29; widest and narrowest widths east of Road `A'; and
between Road `A' and Elm Tree Court. Indicate drainage patterns. Show symmetrical transition
of pavement at intersection with existing street (Rte. 29) [18- 32.6.2.f].
25. Provide storm drain inlets to capture uncollected runoff from Briarwood Drive; these inlets should
be located as close to Rte. 29 as possible, included with median design. To this end, furnish inlets
along each side of the proposed median on Briarwood Drive, just prior to Rte. 29. Propose
structures within the median structure, on each side. ' /a" per ft. crown for the 3 lanes into the
subdivision and the 4 lanes out should transition smoothly to U.S. Rte 29, existing EP.
26. Inlet structures Ex -38 and Ex -37, sheet 4: One or the other will be relocated; please indicate which.
27. Sheet 5: for Wall sections A,B,C,D,E,F,G,H,I, show road station that corresponds with each
section ( Briarwood Drive, or Road `A'). There is no clear reference to locate these sections.
28. Add County `General Construction Notes for Streets' to plans —ref. ACDSM.
29. Supplement Retaining Wall Notes, to include, at a minimum: i) The Owner shall engage inspection
and testing services (quality control) during construction to ensure project design requirements are
met; the lack of quality control by the owner does not relieve the contractor of these requirements;
ii) quality control shall include but not be limited to: foundation soil inspection, verification of
geotechnical design parameters, and verification that construction is in general compliance with the
design drawings; iii) only qualified and experienced technicians shall perform testing and
inspections services.
30. VDOT approval is required for improvements to Briarwood Drive and the new intersection design
and location.
Engineering Review Comments
Page 4 of 6
B. Stormwater Management Plan -Road plan WPO (WPO201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change. (Rev. 1) Comment addressed.
2. Treatment must be provided for all improvements (see also WPO201400030). (Rev. 1) VDOT
restrictions on use of Filterra units within public RW set practical limits on extent of water quality
treatment. Nevertheless, collection, rather than release of runoff from expanded width of
Briarwood Drive is possible with storm inlets positioned within new proposed median close to
U.S. 29 ( #25, above).
3. Sheet 2 and 3 existing (pre - development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4). (Rev. 1)
Comment addressed.
4. Do not show the proposed three line SWM underground detention system as pre - development;
WPO201300018 approved a two -line system which was never constructed while WPO201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
(Rev. 1) Comment withdrawn.
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WPO201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn. (Rev. 1) Comment addressed.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length. (Rev. 1) Comment addressed.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest. (Rev. 1) Comment addressed.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b). (Rev. 1) Request for anti - vortex device withdrawn — detained 2- /10 -yr storm elevations
are below crest of extended detention facility #3, 30" riser; sheet 4.
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
WQV required = 2,583 cf. Also, WQV provided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design. (Rev.
1) Comment addressed.
10. All details on sheet 5 should be to scale. (Rev. 1) Comment addressed.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road. (Rev. 1) Comment withdrawn.
Engineering Review Comments
Page 5 of 6
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition. (Rev. 1) Comment addressed.
NEW
13. Remove image of extended detention facility from pre - development window, sheet 3.
14. Label schematic of development feature (second gasoline station ?) on post - development window,
sheet 3. This detail is new, not shown on corresponding Apr -15 plans; it requires a label that
describes what it is (and reason for showing it). Future development north of Briarwood Drive
does not appear on plans under review. Please confirm and specify future impervious area
calculated to be included with revised underground detention system design (WP0201400030);
area is believed to be 29,500 SF. Currently, proposals for widening Briarwood Drive, constructing
new private roads, and site development south of Briarwood Drive (gas station) are under review.
No assurance is made with respect to review or approval of site or WPO design features tied to
future development.
15. Label L/W of floor of main basin and forebay of extended detention SWM facility #3 detail, sheet
4, since storage at elevation 432' has increased.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST 1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7). (Rev. 1) Comment partially
addressed. With revised ESC, furnish sediment traps at low end of each diversion dike that ends at inlet
(DI) of pipe beneath Briarwood Drive. IP alone is insufficient. [See also WP0201400059, ESC plan
comments, 7/14/14, items #4.]
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29. (Rev. 1) Comment addressed, but please see #1,
above.
3. Show SAF on plans. (Rev. 1) Comment partially addressed. Show SAF along south edge of Briarwood
Drive. Provide SF, this location, as well.
4. Relocate stone weir outfall, ST I. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal). (Rev. 1) Comment addressed.
5. Sheet 9 Revise Existing Sediment Trap #1 detail title (not existing) [Rev. 1— Addressed]; check DA, SB
#1 against DA, sheet 7 [Addressed]; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1
[Addressed]; correct t,,, SB #1 [Revise t, to 9.0 min; delete Min. 1.0' dimension label on sediment basin
profiles (emergency spillways are not proposed for either basin) [Review error, comment withdrawn].
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066. (Rev. 1) In combining ESC for
amended underground detention system (WP0201400030) with road plan's two -phase ESC plan, it is
evident that the sequence of construction is problematic. It appears unlikely any downslope controls can be
installed near Wall #3, given space limitations for road, sidewalk, etc. This means there is nothing shown in
Phase 2 design to limit off -site sediment transport, other than IP on new or existing storm drains. Rather,
Phase 1 of the ESC plan shows limited grading for the private road and construction of a portion of the
retaining wall. Without considering the question of whether the wall can be built to design in two
horizontal sections, sheets 6 (phase 1) and 7 (phase 2) as well as sequence of construction notes (sheet 5),
Engineering Review Comments
Page 6 of 6
show that sediment basin #1 will serve as perimeter control for grading shown in phase I only. Sediment
basin # 1 (or alternative, effective ESC measures) must remain in place until grading and improvements,
including widening Briarwood Drive, are complete. Sediment basin #1 must remain in place until upslope
areas are stabilized (graded sections near wall, wall construction complete, private road [to extent shown]
complete, Briarwood Drive widening complete). Installing the 3 -line underground system is only possible
after upslope disturbed areas are stabilized (Sequence Note 12), and should be delayed until such time as
they are. Please revise sheets 5 (sequence of construction; please call to discuss), 6 (ESC -Phase 1), and 7
(ESC -Phase 2). Please re- evaluate sequence and revise to provide adequate ESC measures for all stages of
road, slope, and wall construction, and during installation of the amended (3 -line) underground detention
system. ESC measures shown for installation of the underground detention system on WPO201400030
(Apr -15) plans did not transfer to these plans. Notably, a sediment trap shown between the system and U.S.
Rte 29 is eliminated, and no ESC measures take its place. There is no apparent provision for ESC during
installation of the underground detention system north of Briarwood Drive. Please provide ESC for this
phase of work. [Ref. 5/22/14 Underground Detention ESC plan review comments, #3, specifically]
7. All basin and trap profiles on sheet 9 should be to scale. (Rev. 1) Comment addressed.
8. Identify any off -site borrow or waste sites. (Rev. 1) Comment not addressed.
9. (New) Sheet 7 proposes grading affecting 30 -ft of vertical contours, near Wall #3. Provide ESC measures
and sequence of construction that prevent sediment -laden runoff from reaching Briarwood Drive or off -site
receiving streams or entering 3 -line amended underground detention system during all phases of grading.
10. Minor, new, sheet 8 — revise crest of stone weir elevation in sediment trap #1 profile to read 427.00'; revise
30" DIA riser top elevation (sediment basin #2 profile) to read = 428.96'.
11. (New) SEE ESC comment #1, WPO201400059, 7- 14 -14: MS -19: photos indicate erosion down slope of
pipe outfalls beneath U.S. Rte. 29, an indication that receiving channels are inadequate. The computations
should reflect this, and appropriate measures should be specified to correct the problem. The computations
(roughness and velocities) appear to indicate conditions of adequacy that do not exist.
D. Final Plat
1. Must match road plan.
File: WPO201300072, SUB201400066- briarwood- 071514rev -1
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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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins -en ing eering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embarqmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
Date of comments: 22 May 2014
Reviewer: John Anderson
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT.
2. Remove entrances from the road plans. These must be approved with site plans.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan.
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6).
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger.
7. Delete Notes 1 and 2, sheet 5. These notes are invalid.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient.
9. Show managed slopes on Wall Number 3 detail —sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown).
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive —sheet 3.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have Y R, Minimum.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around.
15. Sheet 6 — Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details.
Engineering Review Comments
Page 2 of 3
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable.
19. Str -8 (type, DI -7) - the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12).
20. Str -24 (type, DI -7) - Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate.
21. VDOT approval is required. Comments are attached.
22. For Road `A', Road `B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change.
2. Treatment must be provided for all improvements (see also WP0201400030).
3. Sheet 2 and 3 existing (pre- development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4).
4. Do not show the proposed three line SWM underground detention system as pre - development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -11.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b).
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
Engineering Review Comments
Page 3 of 3
WQV required = 2,583 cf. Also, WQV provided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design.
10. All details on sheet 5 should be to scale.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road.
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST 1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7).
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29.
3. Show SAF on plans.
4. Relocate stone weir outfall, ST 1. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal).
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing); check DA, SB #1 against DA, sheet
7; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1; correct t,, SB #1; delete Min. 1.0'
dimension label on sediment basin profiles (emergency spillways are not proposed for either basin).
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066.
7. All basin and trap profiles on sheet 9 should be to scale.
8. Identify any off -site borrow or waste sites.
D. Final Plat
1. Must match road plan.
File: WP0201300072, SUB201400066- briarwood- 052214
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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;
Date of comments:
Reviewer:
Briarwood Commercial Lots
Collins Engineering [293 -3719]
Woodbriar Associates
22 Nov 2013
19 Dec 2013
Michelle Roberge
The application cannot be approved per 32.4.2.8, Effect of Approval of Initial Site Plan on Other
Future and Pending Approvals. The ordinance states, "b. Erosion and sediment control plan and grading
permit; conventional zoning districts. On any site within a conventional zoning district, including any
conventional zoning district also within an entrance corridor overlay district, an approved initial site plan
is an "approved site plan " within the meaning of section 17- 204(E). As such, an erosion and sediment
control plan and corresponding grading permit may be approved under chapter 17, provided that the
developer has satisfied the conditions of approval identified by the agent in the letter required by section
32.4.2.5(c)."
At this point we can only review a separate WPO application for the proposed gas station since a site plan
has been submitted to the County. Even though application WP0201300072 cannot be approved, I have
reviewed the plan to help with your next submittal. Please see the following comments:
A. Erosion Control Plan & SWM (WP0201300072)
1) It appears the impervious areas for treatment may change as the site plan for each lot becomes
known. This will change the reduction rate calcs and will need to be reflected on a WPO plan. One
thing to be cautious of is the pre and post DA when analyzing MS -19. Use the existing contours
in the GIS system to determine the existing drainage areas to the outfalls. The proposed private
road will change the natural drainage divides and shall be reflected when analyzing MS -19 for
release rates at the outfalls.
2) DA #1 has been approved in WP0201300018. It appears that the impervious area in DA #1 has
changed since the previous approval. For example, the proposed road (as you make a left turn from
Briarwood Drive) is now included in the DA #1. It also appears that this impervious area will now
be treated by the water quality swale that was designed for a portion of Briarwood Drive only.
Please clarify. Also, any changes to the calculations should be amended with the WP0201300018
application.
3) Please provide MS -19 with all WPO applications.
4) All details on sheet 4 should be to scale.
5) The accumulated volume for the Extended Detention Facility #2 at the 408 contour is incorrect.
Engineering Review Comments
Page 2 of 2
6) VDOT will need to review the access roads off of Rte 29 to the Extended Detention Facility #2. I
do not recommend having the access road off of Rte 29. Vdot will also need to review the right
in/right out to Rte 29 and the median on Briarwood Drive. This is the reason a site plan submittal
is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
7) There are items on this plan that will need to be reviewed by the ARB; for example, the extended
detention basins, retaining walls, screening requirements, and etc This is another reason a site plan
submittal is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
8) Provide a profile of entire culvert under Extended Detention Facility #2 to ensure pipe has enough
cover. It does not appear to have enough cover.
9) I recommend changing the side slopes of extended detention ponds to 3:1. 2:1 slopes are too steep.
It poses a safety concern since it is near a residential area.
10) The Extended Detention Facility #1 needs to raise the mid flow orifice slightly to contain the
permanent pool for the 30 hour draw down.
11) On sheet 8, the contour 440 is incorrect for SB #2.
12) On sheet 8, there is a label for Sediment Trap #2, but it is actually Sediment Trap #1. Please revise
label and show location of sediment trap on plan.
13) The reduction rate calc for DA #1 can be removed. Any revisions should amend the
WPO201300018 application.
14) Please clarify the area defined as northern commercial site area and southern commercial area in
the reduction rate calcs for DA #1.
15) On sheet 3, remove all items regarding the underground detention facility #1 since that should be
reviewed as an amendment to WPO201300018.
16) The underground detention facility #2 has a site plan for the gas station. This may be submitted as
a separate WPO application for the corresponding site plan.
17) Clarify how DA #2 will be treated. It is not shown on plans. It will be confusing to propose filterras
on another set of plans. For future reference, please provide reduction rates calcs for treatment,
detention and MS -19 on one WPO for a corresponding site plan.
Sincerely,
Y�N�
Michelle Roberge
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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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins -en ing eering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
(Rev. 1) 12 June 2014 [Road], 16 June 2014 [WPO /SWM &ESC]
Date of comments: 22 May 2014
(Rev. 1) 15 July 2014
Reviewer: John Anderson
Please contact reviewer to schedule a meeting to discuss comments, if helpful.
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT. (Rev. 1) TIA lends question: Briarwood
Commercial Development TIA (Table 4.2 ITE Trip Generation) by Davenport (Project # 13 -338,
11/20/13, rev. 3/7/14) shows 24 -hr two -way volume trip generation for Areas A -B -C as 10,896.
Sheet 6 displays this data (Elm Tree Court) using a double -end arrow and label: 5,448 VPD. TIA
shows 24 -hour two -way volume trip generation for Areas D -E -F as 11,324. Sheet 6 displays this
data (Road `A') as 5,662 VPD. Revise labels to show that 10,896 and 11,324 VPD are TIA 2 -way
estimates. The figures 5,448 and 5.662 may be mistaken as total 2 -way estimates, which they are
not.
2. Remove entrances from the road plans. These must be approved with site plans. (Rev. 1)
Comment addressed.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
(Rev. 1) Comment addressed. [Jun -]1 letter: "Existing grading easement allows for disturbance
10' into the existing lot. No lot disturbance occurs outside of this area. ",
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan. (Rev. 1) Comment addressed —Bonds will need to be signed by the owners of all
properties on which construction takes place, or legal easements will be needed [ref – Albemarle
County Design Standards Manual [ ACDSM], 8. Grading; C. Off -site work]. [Jun -11 letter:
"Townhouse grading approved under SDP - 2010 -84 and is an existing condition for this road plan.
Proposed grading ties into the approved grading as shown on Sheet 4 "].
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6). (Rev. 1)
Ref, Planning Division comments dated July 3, 2014, comment 44 — "A waiver request [for 3'
wide planting strips] shall be taken to the Planning Commission for consideration."
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger. (Rev. 1)
Comment not addressed. [See ACDSM 8.B.2.b. /c.] Please provide specific, geotechnical
engineering details for all retaining walls, including Redi -rock Ledgestone gravity wall system.
Revise handrail /fence post detail, sheet 5: show a zero (0 %) slope extending at least 24" behind
Engineering Review Comments
Page 2 of 6
wall (railing post may not coincide with drainage swale low- point); show drainage swale in every
view of Wall #3 —D, E, F, G, H, I. Consider, show, and detail sub - surface drainage features.
Label and dimension aggregate prism installed immediately behind SRW blocks in handrail /fence
post detail. Specify drainage at foundation (or higher levels) as necessary to ensure areas
immediately behind each wall have adequate drainage. Do not show unbroken 2:1 slope behind
wall #3, but in each section view (D -I), break slope with drainage swale located at least 24" behind
wall. Furnish qualified Engineer's report that life cycles and surcharge of plantings shown in
schematic and table views on sheet 5 and 15, and on sheet 2 of (SDP201300035) Briarwood Site
Plan Amendment #2, Briarwood Phases IA -A, IB -1, 4 -8, received 23 -June 14, will not
compromise integrity of walls or geogrid, if geogrid is used. Avoid planting within drip -line
distance of walls. A 314 sf canopy tree, for example, should not be planted within 10 -ft of walls.
Explanatory note that "final structure wall design to be submitted with final structural engineering
plans" does not meet review requirements. Retaining wall design is a precondition to approval of
road plan, mitigation plan [SDP201300035], and site plan [SDP201400047] since integral to
infrastructure of the site (Road `A').
7. Delete Notes 1 and 2, sheet 5. These notes are invalid. (Rev. 1) Comment partially addressed;
sheet 5 segmented retaining wall (SRW) and geogrid reinforcement details removed. New sheet
5 Wall Cross - sections and Details are inadequate. Ref. ACDSM, 8.B.2.c.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient. (Rev. 1) Comment partially addressed. Handrail shown for Wall #3, only (see
sections D -I, sheet 5). No railing shown for sections of Wall #1 or 2 (sections A, B, C, sheet 5).
Furnish safety railing for all proposed wall sections 4' or higher. Also, see comment #6, above.
9. Show managed slopes on Wall Number 3 detail –sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly. (Rev. 1)
Comment addressed.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown). (Rev. 1) Comment addressed.
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive –sheet 3. (Rev. l )
Comment addressed.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3' R, Minimum. (Rev. 1) Comment addressed.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %. (Rev. 1)
Comment addressed.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around. (Rev. 1)
Comment addressed.
15. Sheet 6 – Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
(Rev. 1) Comment addressed.
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
(Rev. 1) Comment addressed.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT detail:, (Rev. 1) Comment addressed.
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable. (Rev. 1) Comment addressed.
19. Str -8 (type, DI -7) – the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12). (Rev. 1) Comment partially addressed; 10 -yr design storm
table, sheet 14, lacks column headings- please provide column headings.
20. Str -24 (type, DI -7) – Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
Engineering Review Comments
Page 3 of 6
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate. (Rev. 1)
Comment addressed.
21. VDOT approval is required. Comments are attached. (Rev. 1) Acknowledged.
22. For Road `A', Road B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71. (Rev. 1) Acknowledged.
NEW
23. Increase radius of curve at NE corner of Road `A' -Road `B' intersection to 30 -ft, Min, to allow
longer vehicles to clear opposing traffic when turning [Ref. AASHTO /Minimum Turning Paths of
Design Vehicles —link: http: / /design transportation.orw Documents /TumRadii,GreenBook2004.12df ]
24. Provide stationing for Briarwood Drive to aide design, review, bond estimate, bond reduction,
inspection, and maintenance: begin with station 10 +00 at CL intersection Briarwood Drive and
Elm Tree Court. In addition, furnish: CL profile for Briarwood Drive; typical cross sections at
these points: tip of median near Rte. 29; widest and narrowest widths east of Road `A'; and
between Road `A' and Elm Tree Court. Indicate drainage patterns. Show symmetrical transition
of pavement at intersection with existing street (Rte. 29) [18- 32.6.2.f].
25. Provide storm drain inlets to capture uncollected runoff from Briarwood Drive; these inlets should
be located as close to Rte. 29 as possible, included with median design. To this end, furnish inlets
along each side of the proposed median on Briarwood Drive, just prior to Rte. 29. Propose
structures within the median structure, on each side. ' /a" per ft. crown for the 3 lanes into the
subdivision and the 4 lanes out should transition smoothly to U.S. Rte 29, existing EP.
26. Inlet structures Ex -38 and Ex -37, sheet 4: One or the other will be relocated; please indicate which.
27. Sheet 5: for Wall sections A,B,C,D,E,F,G,H,I, show road station that corresponds with each
section ( Briarwood Drive, or Road `A'). There is no clear reference to locate these sections.
28. Add County `General Construction Notes for Streets' to plans —ref. ACDSM.
29. Supplement Retaining Wall Notes, to include, at a minimum: i) The Owner shall engage inspection
and testing services (quality control) during construction to ensure project design requirements are
met; the lack of quality control by the owner does not relieve the contractor of these requirements;
ii) quality control shall include but not be limited to: foundation soil inspection, verification of
geotechnical design parameters, and verification that construction is in general compliance with the
design drawings; iii) only qualified and experienced technicians shall perform testing and
inspections services.
30. VDOT approval is required for improvements to Briarwood Drive and the new intersection design
and location.
Engineering Review Comments
Page 4 of 6
B. Stormwater Management Plan -Road plan WPO (WPO201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change. (Rev. 1) Comment addressed.
2. Treatment must be provided for all improvements (see also WPO201400030). (Rev. 1) VDOT
restrictions on use of Filterra units within public RW set practical limits on extent of water quality
treatment. Nevertheless, collection, rather than release of runoff from expanded width of
Briarwood Drive is possible with storm inlets positioned within new proposed median close to
U.S. 29 ( #25, above).
3. Sheet 2 and 3 existing (pre - development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4). (Rev. 1)
Comment addressed.
4. Do not show the proposed three line SWM underground detention system as pre - development;
WPO201300018 approved a two -line system which was never constructed while WPO201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
(Rev. 1) Comment withdrawn.
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WPO201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn. (Rev. 1) Comment addressed.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length. (Rev. 1) Comment addressed.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest. (Rev. 1) Comment addressed.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b). (Rev. 1) Request for anti - vortex device withdrawn — detained 2- /10 -yr storm elevations
are below crest of extended detention facility #3, 30" riser; sheet 4.
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
WQV required = 2,583 cf. Also, WQV provided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design. (Rev.
1) Comment addressed.
10. All details on sheet 5 should be to scale. (Rev. 1) Comment addressed.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road. (Rev. 1) Comment withdrawn.
Engineering Review Comments
Page 5 of 6
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition. (Rev. 1) Comment addressed.
NEW
13. Remove image of extended detention facility from pre - development window, sheet 3.
14. Label schematic of development feature (second gasoline station ?) on post - development window,
sheet 3. This detail is new, not shown on corresponding Apr -15 plans; it requires a label that
describes what it is (and reason for showing it). Future development north of Briarwood Drive
does not appear on plans under review. Please confirm and specify future impervious area
calculated to be included with revised underground detention system design (WP0201400030);
area is believed to be 29,500 SF. Currently, proposals for widening Briarwood Drive, constructing
new private roads, and site development south of Briarwood Drive (gas station) are under review.
No assurance is made with respect to review or approval of site or WPO design features tied to
future development.
15. Label L/W of floor of main basin and forebay of extended detention SWM facility #3 detail, sheet
4, since storage at elevation 432' has increased.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST 1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7). (Rev. 1) Comment partially
addressed. With revised ESC, furnish sediment traps at low end of each diversion dike that ends at inlet
(DI) of pipe beneath Briarwood Drive. IP alone is insufficient. [See also WP0201400059, ESC plan
comments, 7/14/14, items #4.]
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29. (Rev. 1) Comment addressed, but please see #1,
above.
3. Show SAF on plans. (Rev. 1) Comment partially addressed. Show SAF along south edge of Briarwood
Drive. Provide SF, this location, as well.
4. Relocate stone weir outfall, ST I. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal). (Rev. 1) Comment addressed.
5. Sheet 9 Revise Existing Sediment Trap #1 detail title (not existing) [Rev. 1— Addressed]; check DA, SB
#1 against DA, sheet 7 [Addressed]; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1
[Addressed]; correct t,,, SB #1 [Revise t, to 9.0 min; delete Min. 1.0' dimension label on sediment basin
profiles (emergency spillways are not proposed for either basin) [Review error, comment withdrawn].
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066. (Rev. 1) In combining ESC for
amended underground detention system (WP0201400030) with road plan's two -phase ESC plan, it is
evident that the sequence of construction is problematic. It appears unlikely any downslope controls can be
installed near Wall #3, given space limitations for road, sidewalk, etc. This means there is nothing shown in
Phase 2 design to limit off -site sediment transport, other than IP on new or existing storm drains. Rather,
Phase 1 of the ESC plan shows limited grading for the private road and construction of a portion of the
retaining wall. Without considering the question of whether the wall can be built to design in two
horizontal sections, sheets 6 (phase 1) and 7 (phase 2) as well as sequence of construction notes (sheet 5),
Engineering Review Comments
Page 6 of 6
show that sediment basin #1 will serve as perimeter control for grading shown in phase I only. Sediment
basin # 1 (or alternative, effective ESC measures) must remain in place until grading and improvements,
including widening Briarwood Drive, are complete. Sediment basin #1 must remain in place until upslope
areas are stabilized (graded sections near wall, wall construction complete, private road [to extent shown]
complete, Briarwood Drive widening complete). Installing the 3 -line underground system is only possible
after upslope disturbed areas are stabilized (Sequence Note 12), and should be delayed until such time as
they are. Please revise sheets 5 (sequence of construction; please call to discuss), 6 (ESC -Phase 1), and 7
(ESC -Phase 2). Please re- evaluate sequence and revise to provide adequate ESC measures for all stages of
road, slope, and wall construction, and during installation of the amended (3 -line) underground detention
system. ESC measures shown for installation of the underground detention system on WPO201400030
(Apr -15) plans did not transfer to these plans. Notably, a sediment trap shown between the system and U.S.
Rte 29 is eliminated, and no ESC measures take its place. There is no apparent provision for ESC during
installation of the underground detention system north of Briarwood Drive. Please provide ESC for this
phase of work. [Ref. 5/22/14 Underground Detention ESC plan review comments, #3, specifically]
7. All basin and trap profiles on sheet 9 should be to scale. (Rev. 1) Comment addressed.
8. Identify any off -site borrow or waste sites. (Rev. 1) Comment not addressed.
9. (New) Sheet 7 proposes grading affecting 30 -ft of vertical contours, near Wall #3. Provide ESC measures
and sequence of construction that prevent sediment -laden runoff from reaching Briarwood Drive or off -site
receiving streams or entering 3 -line amended underground detention system during all phases of grading.
10. Minor, new, sheet 8 — revise crest of stone weir elevation in sediment trap #1 profile to read 427.00'; revise
30" DIA riser top elevation (sediment basin #2 profile) to read = 428.96'.
11. (New) SEE ESC comment #1, WPO201400059, 7- 14 -14: MS -19: photos indicate erosion down slope of
pipe outfalls beneath U.S. Rte. 29, an indication that receiving channels are inadequate. The computations
should reflect this, and appropriate measures should be specified to correct the problem. The computations
(roughness and velocities) appear to indicate conditions of adequacy that do not exist.
D. Final Plat
1. Must match road plan.
File: WPO201300072, SUB201400066- briarwood- 071514rev -1
�pF A
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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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(a)collins -en ing eering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embarqmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
Date of comments: 22 May 2014
Reviewer: John Anderson
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT.
2. Remove entrances from the road plans. These must be approved with site plans.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan.
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6).
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger.
7. Delete Notes 1 and 2, sheet 5. These notes are invalid.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient.
9. Show managed slopes on Wall Number 3 detail —sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown).
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive —sheet 3.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have Y R, Minimum.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around.
15. Sheet 6 — Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details.
Engineering Review Comments
Page 2 of 3
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable.
19. Str -8 (type, DI -7) - the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12).
20. Str -24 (type, DI -7) - Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate.
21. VDOT approval is required. Comments are attached.
22. For Road `A', Road `B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change.
2. Treatment must be provided for all improvements (see also WP0201400030).
3. Sheet 2 and 3 existing (pre- development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4).
4. Do not show the proposed three line SWM underground detention system as pre - development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -11.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b).
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
Engineering Review Comments
Page 3 of 3
WQV required = 2,583 cf. Also, WQV provided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design.
10. All details on sheet 5 should be to scale.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road.
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST 1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7).
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29.
3. Show SAF on plans.
4. Relocate stone weir outfall, ST 1. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal).
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing); check DA, SB #1 against DA, sheet
7; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1; correct t,, SB #1; delete Min. 1.0'
dimension label on sediment basin profiles (emergency spillways are not proposed for either basin).
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066.
7. All basin and trap profiles on sheet 9 should be to scale.
8. Identify any off -site borrow or waste sites.
D. Final Plat
1. Must match road plan.
File: WP0201300072, SUB201400066- briarwood- 052214
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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;
Date of comments:
Reviewer:
Briarwood Commercial Lots
Collins Engineering [293 -3719]
Woodbriar Associates
22 Nov 2013
19 Dec 2013
Michelle Roberge
The application cannot be approved per 32.4.2.8, Effect of Approval of Initial Site Plan on Other
Future and Pending Approvals. The ordinance states, "b. Erosion and sediment control plan and grading
permit; conventional zoning districts. On any site within a conventional zoning district, including any
conventional zoning district also within an entrance corridor overlay district, an approved initial site plan
is an "approved site plan " within the meaning of section 17- 204(E). As such, an erosion and sediment
control plan and corresponding grading permit may be approved under chapter 17, provided that the
developer has satisfied the conditions of approval identified by the agent in the letter required by section
32.4.2.5(c)."
At this point we can only review a separate WPO application for the proposed gas station since a site plan
has been submitted to the County. Even though application WP0201300072 cannot be approved, I have
reviewed the plan to help with your next submittal. Please see the following comments:
A. Erosion Control Plan & SWM (WP0201300072)
1) It appears the impervious areas for treatment may change as the site plan for each lot becomes
known. This will change the reduction rate calcs and will need to be reflected on a WPO plan. One
thing to be cautious of is the pre and post DA when analyzing MS -19. Use the existing contours
in the GIS system to determine the existing drainage areas to the outfalls. The proposed private
road will change the natural drainage divides and shall be reflected when analyzing MS -19 for
release rates at the outfalls.
2) DA #1 has been approved in WP0201300018. It appears that the impervious area in DA #1 has
changed since the previous approval. For example, the proposed road (as you make a left turn from
Briarwood Drive) is now included in the DA #1. It also appears that this impervious area will now
be treated by the water quality swale that was designed for a portion of Briarwood Drive only.
Please clarify. Also, any changes to the calculations should be amended with the WP0201300018
application.
3) Please provide MS -19 with all WPO applications.
4) All details on sheet 4 should be to scale.
5) The accumulated volume for the Extended Detention Facility #2 at the 408 contour is incorrect.
Engineering Review Comments
Page 2 of 2
6) VDOT will need to review the access roads off of Rte 29 to the Extended Detention Facility #2. I
do not recommend having the access road off of Rte 29. Vdot will also need to review the right
in/right out to Rte 29 and the median on Briarwood Drive. This is the reason a site plan submittal
is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
7) There are items on this plan that will need to be reviewed by the ARB; for example, the extended
detention basins, retaining walls, screening requirements, and etc This is another reason a site plan
submittal is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
8) Provide a profile of entire culvert under Extended Detention Facility #2 to ensure pipe has enough
cover. It does not appear to have enough cover.
9) I recommend changing the side slopes of extended detention ponds to 3:1. 2:1 slopes are too steep.
It poses a safety concern since it is near a residential area.
10) The Extended Detention Facility #1 needs to raise the mid flow orifice slightly to contain the
permanent pool for the 30 hour draw down.
11) On sheet 8, the contour 440 is incorrect for SB #2.
12) On sheet 8, there is a label for Sediment Trap #2, but it is actually Sediment Trap #1. Please revise
label and show location of sediment trap on plan.
13) The reduction rate calc for DA #1 can be removed. Any revisions should amend the
WPO201300018 application.
14) Please clarify the area defined as northern commercial site area and southern commercial area in
the reduction rate calcs for DA #1.
15) On sheet 3, remove all items regarding the underground detention facility #1 since that should be
reviewed as an amendment to WPO201300018.
16) The underground detention facility #2 has a site plan for the gas station. This may be submitted as
a separate WPO application for the corresponding site plan.
17) Clarify how DA #2 will be treated. It is not shown on plans. It will be confusing to propose filterras
on another set of plans. For future reference, please provide reduction rates calcs for treatment,
detention and MS -19 on one WPO for a corresponding site plan.
Sincerely,
Y�N�
Michelle Roberge
Review Comments
Project Name: Briarwood Commercial Lots Erosion and Sediment Control Plan
Date Completed: Wednesday, September 03, 2014
Reviewer: Ana Kilmer
Department /Division /Agency: CommDev- Central Ops
Reviews
8/25/2014 - swa submitted and forwarded to CAO for approval
8/25/2014 - swa approved by cao
8/28/2014 - swa signed by county executive
9/3/2014 - swa recorded in deed book 4531, page 261
Review Status: Approved
Review Comments
Project Name: Briarwood Commercial Lots Erosion and Sediment Control Plan
Date Completed: Tuesday, August 19, 2014
Reviewer: John Anderson
Department /Division /Agency: Engineering
Reviews
bond estimate complete 8/19/14
Review Status: See Recommendations
�pF A
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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:
Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer:
Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scottAcollins- engineering com]
Owner or rep.:
Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date:
15 April 2014 [WPO], 16 April 2014 [Road]
(Rev. 1)
12 June 2014 [Road], 16 June 2014 [WPO /SWM &ESC]
(Rev. 2)
22 July 2014 [Road], 24 July 2014 [WPO /SWM &ESC]
Date of comments:
22 May 2014
(Rev. 1)
15 July 2014
(Rev. 2)
4 August 2014
Reviewer:
John Anderson
Please contact reviewer to schedule a meeting to discuss comments, if helpful.
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT. (Rev. 1) TIA lends question: Briarwood
Commercial Development TIA (Table 4.2 ITE Trip Generation) by Davenport (Project # 13 -338,
11/20/13, rev. 3/7/14) shows 24 -hr two -way volume trip generation for Areas A -B -C as 10,896.
Sheet 6 displays this data (Elm Tree Court) using a double -end arrow and label: 5,448 VPD. TIA
shows 24 -hour two -way volume trip generation for Areas D -E -F as 11,324. Sheet 6 displays this
data (Road `A') as 5,662 VPD. Revise labels to show that 10,896 and 11,324 VPD are TIA 2 -way
estimates. The figures 5,448 and 5.662 may be mistaken as total 2 -way estimates, which they are
not. (Rev. 2) Comment addressed.
2. Remove entrances from the road plans. These must be approved with site plans. (Rev. 1)
Comment addressed.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
(Rev. 1) Comment addressed. [Jun -]1 letter: "Existing grading easement allows for disturbance
10' into the existing lot. No lot disturbance occurs outside of this area. "]
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan. (Rev. 1) Comment addressed —Bonds will need to be signed by the owners of all
properties on which construction takes place, or legal easements will be needed [ref – Albemarle
County Design Standards Manual [ ACDSM], 8. Grading; C. Off -site work]. [Jun -] 1 letter:
"Townhouse grading approved under SDP - 2010 -84 and is an existing condition for this road plan.
Proposed grading ties into the approved grading as shown on Sheet 4 "].
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6). (Rev. 1)
Ref. Planning Division comments dated July 3, 2014, comment #4 — "A waiver request [for 3'
wide planting strips] shall be taken to the Planning Commission for consideration."
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger. (Rev. 1)
Comment not addressed. [See ACDSM 8.B.2.b. /c.] Please provide specific, geotechnical
Engineering Review Comments
Page 2 of 7
engineering details for all retaining walls, including Redi -rock Ledgestone gravity wall system.
Revise handrail /fence post detail, sheet 5: show a zero (0 %) slope extending at least 24" behind
wall (railing post may not coincide with drainage swale low- point); show drainage swale in every
view of Wall #3 —D, E, F, G, H, I. Consider, show, and detail sub - surface drainage features.
Label and dimension aggregate prism installed immediately behind SRW blocks in handrail /fence
post detail. Specify drainage at foundation (or higher levels) as necessary to ensure areas
immediately behind each wall have adequate drainage. Do not show unbroken 2:1 slope behind
wall #3, but in each section view (D -I), break slope with drainage swale located at least 24" behind
wall. Furnish qualified Engineer's report that life cycles and surcharge of plantings shown in
schematic and table views on sheet 5 and 15, and on sheet 2 of (SDP201300035) Briarwood Site
Plan Amendment #2, Briarwood Phases IA -A, IB -1, 4 -8, received 23 -June 14, will not
compromise integrity of walls or geogrid, if geogrid is used. Avoid planting within drip -line
distance of walls. A 314 sf canopy tree, for example, should not be planted within 10 -ft of walls.
Explanatory note that "final structure wall design to be submitted with final structural engineering
plans " does not meet review requirements. Retaining wall design is a precondition to approval of
road plan, mitigation plan [SDP201300035], and site plan [SDP201400047] since integral to
infrastructure of the site (Road `A'). (Rev. 2) Partially addressed – discussed these items with
Scott Collins, Jul -31, or Adam Long, Aug -1. With submittal of Redi -rock Retaining Wall design
on 7/21 (d. 7/14/14): i) revise handrail consistent with location in top - course of Redi -rock wall; ii)
landscaping between Walls 1 and 2 should prevent trespass between walls: no objection if
eliminate lower wall (Wall 2) handrail if required to meet ARB /other departmental requirements;
iii) restore backslope grade shown in Wall 3 profile views (D,E,F,G,H,I) of earlier submittal
(Geotechnical design engineer, M. Circeo, maintains drainage swale unnecessary); iv) revise
proposed tree locations, Wall 3, to ensure min setback – requirement/formula outlined as item #3,
7/23/14 correspondence, Margaret Maliszewski, ACCD, to Miller Cupp Associates Architects,
P.C. / Collins Engineering; and, v) transfer all information from Circeo design titled Redirock
Retaining Walls, Briarwood Commercial, Albemarle County, Virginia, to road plans (2 -3 new
sheets). Transfer without revision, addition, or deletion, except by or through Michael R. Circeo.
7. Delete Notes 1 and 2, sheet 5. These notes are invalid. (Rev. 1) Comment partially addressed;
sheet 5 segmented retaining wall (SRW) and geogrid reinforcement details removed. New sheet
5 Wall Cross- sections and Details are inadequate. Ref ACDSM, 8.13.2.c. (Rev. 2) Comment
addressed –see 6, above.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient. (Rev. 1) Comment partially addressed. Handrail shown for Wall #3, only (see
sections D -1, sheet 5). No railing shown for sections of Wall #1 or 2 (sections A, B, C, sheet 5).
Furnish safety railing for all proposed wall sections 4' or higher. (Rev. 2) Comment addressed.
Also, see comment #6, above.
9. Show managed slopes on Wall Number 3 detail –sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly. (Rev. 1)
Comment addressed.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown). (Rev. 1) Comment addressed.
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive –sheet 3. (Rev. 1)
Comment addressed.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3' R, Minimum. (Rev. 1) Comment addressed.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %. (Rev. 1)
Comment addressed.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
Engineering Review Comments
Page 3 of 7
turn- around, see plans for details.' Furnish design details for temporary turn- around. (Rev. 1)
Comment addressed.
15. Sheet 6 — Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
(Rev. 1) Comment addressed.
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
(Rev. 1) Comment addressed.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details. (Rev. 1) Comment addressed.
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable. (Rev. 1) Comment addressed.
19. Str -8 (type, DI -7) — the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12). (Rev. 1) Comment partially addressed; 10 -yr design storm
table, sheet 14, lacks column headings - please provide column headings. (Rev. 2) Comment
addressed.
20. Str -24 (type, DI -7) — Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate. (Rev. 1)
Comment addressed.
21. VDOT approval is required. Comments are attached. (Rev. 1) Acknowledged.
22. For Road `A', Road `B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sea. 7 1. (Rev. 1) Acknowledged.
NEW
23. Increase radius of curve at NE corner of Road `A' -Road `B' intersection to 30 -ft, Min, to allow
longer vehicles to clear opposing traffic when turning [Ref. AASHTO /Minimum Turning Paths of
Design Vehicles —link: http: / /design transportation.org/ Documents /TumRadii,GreenBook2004.pdf ]
(Rev. 2) Comment addressed.
24. Provide stationing for Briarwood Drive to aide design, review, bond estimate, bond reduction,
inspection, and maintenance: begin with station 10 +00 at CL intersection Briarwood Drive and
Elm Tree Court. In addition, furnish: CL profile for Briarwood Drive; typical cross sections at
these points: tip of median near Rte. 29; widest and narrowest widths east of Road `A'; and
between Road `A' and Elm Tree Court. Indicate drainage patterns. Show symmetrical transition
of pavement at intersection with existing street (Rte. 29) [18- 32.6.2.f]. (Rev. 2) Comment
addressed.
25. Provide storm drain inlets to capture uncollected runoff from Briarwood Drive; these inlets should
be located as close to Rte. 29 as possible, included with median design. To this end, furnish inlets
along each side of the proposed median on Briarwood Drive, just prior to Rte. 29. Propose
structures within the median structure, on each side. '' /a" per ft. crown for the 3 lanes into the
subdivision and the 4 lanes out should transition smoothly to U.S. Rte 29, existing EP. (Rev. 2)
Comment addressed.
26. Inlet structures Ex -38 and Ex -37, sheet 4: One or the other will be relocated; please indicate which.
(Rev. 2) Comment addressed.
27. Sheet 5: for Wall sections A,B,C,D,E,F,G,H,I, show road station that corresponds with each
section ( Briarwood Drive, or Road `A'). There is no clear reference to locate these sections.
(Rev. 2) Comment addressed.
28. Add County `General Construction Notes for Streets' to plans —ref. ACDSM. (Rev. 2) Comment
addressed.
29. Supplement Retaining Wall Notes, to include, at a minimum: i) The Owner shall engage inspection
and testing services (quality control) during construction to ensure project design requirements are
Engineering Review Comments
Page 4 of 7
met; the lack of quality control by the owner does not relieve the contractor of these requirements;
ii) quality control shall include but not be limited to: foundation soil inspection, verification of
geotechnical design parameters, and verification that construction is in general compliance with the
design drawings; iii) only qualified and experienced technicians shall perform testing and
inspections services. (Rev. 2) Comment addressed.
30. VDOT approval is required for improvements to Briarwood Drive and the new intersection design
and location. (Rev. 2) Comment acknowledged.
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change. (Rev. 1) Comment addressed.
2. Treatment must be provided for all improvements (see also WP0201400030). (Rev. 1) VDOT
restrictions on use of Filterra units within public RW set practical limits on extent of water quality
treatment. Nevertheless, collection, rather than release of runoff from expanded width of
Briarwood Drive is possible with storm inlets positioned within new proposed median close to
U.S. 29 ( #25, above). (Rev. 2) Comment addressed.
3. Sheet 2 and 3 existing (pre - development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4). (Rev. 1)
Comment addressed.
4. Do not show the proposed three line SWM underground detention system as pre- development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
(Rev. 1) Comment withdrawn.
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn. (Rev. 1) Comment addressed.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length. (Rev. 1) Comment addressed.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest. (Rev. 1) Comment addressed.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b). (Rev. 1) Request for anti - vortex device withdrawn — detained 2410 -yr storm elevations
are below crest of extended detention facility #3, 30" riser; sheet 4.
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
WQV required = 2,583 cf. Also, WQVprovided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Engineering Review Comments
Page 5 of 7
Please re -check calculations and compare against extended detention SWM facility design. (Rev.
1) Comment addressed.
10. All details on sheet 5 should be to scale. (Rev. 1) Comment addressed.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road. (Rev. 1) Comment withdrawn.
12. Minor: reverse :S symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition. (Rev. 1) Comment addressed.
NEW
13. Remove image of extended detention facility from pre - development window, sheet 3. (Rev. 2)
Comment addressed.
14. Label schematic of development feature (second gasoline station ?) on post - development window,
sheet 3. This detail is new, not shown on corresponding Apr -15 plans; it requires a label that
describes what it is (and reason for showing it). Future development north of Briarwood Drive
does not appear on plans under review. Please confirm and specify future impervious area
calculated to be included with revised underground detention system design (WP0201400030);
area is believed to be 29,500 SF. Currently, proposals for widening Briarwood Drive, constructing
new private roads, and site development south of Briarwood Drive (gas station) are under review.
No assurance is made with respect to review or approval of site or WPO design features tied to
future development. (Rev. 2) Comment addressed via plan revision d. 7/31, submitted 8/1/14.
15. Label L/W of floor of main basin and forebay of extended detention SWM facility #3 detail, sheet
4, since storage at elevation 432' has increased. (Rev. 2) Comment addressed.
16. New -With respect to SWPPP dated 7/20/14 prepared by Collins Engineering for construction
activities at Briarwood Commercial Lots, received 7/24/14:
Registration Statement (General VPDES Permit) latitude /longitude do not match SWPP project
coordinates; please reconcile.
- Estimate start- finish / installation - removal dates throughout the SWPPP.
Revise inspection schedule (p. 26). Inspections are required at least once every 10 business days (plus
additional requirements). [Ref. 9VAC25- 880 -70, Part II, Stormwater Pollution Prevention Plan, F.,
Inspections, 2., Inspection Schedule]
- SWPPP, p. 26, identifies one individual responsible for inspection. Confirm that this individual accepts
sole responsibility for scheduled inspections, reporting, recordkeeping, notification, and for directing
corrective response relating to SWPPP proposed to cover all Briarwood Commercial projects.
EXHIBIT TO SHOW CONCRETE WASH OUT, PORTA- JOHNS, AND FUELING AREA (7/21/14): Show concrete wash
out area (not shown). Concrete wash out area/s may not drain to storm inlets. Propose treatment for concrete
wash waters. [§ 17- 404.B.]
- Show on -site dumpster. Provide treatment (or detention) of dumpster drain water. Dumpster runoff may
contain contaminants that may not discharge freely downslope, to a storm inlet, or to any stream. Provide silt
fence or earthen berm at porta johns as containment in event of spill. Furnish impermeable containment, a
barrier to infiltration designed to hold the entire volume of stored fuel in event of spill, with freeboard measure
of safety, for each fueling tank shown in the SWPP exhibit.
- 17- 404.13. l .a. Wash waters — "Minimize the discharge of pollutants from equipment and vehicle washing,
wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative
control that provides equivalent or better treatment prior to discharge." Propose treatment for wash water.
Construction entrance with wash rack to the north does not drain to a sediment basin; propose treatment.
Engineering Review Comments
Page 6 of 7
Label construction entrance on plan sheets as Paved CE, with wash rack [ref. WP0201300072, E &S
Sequence of Construction Note 3]. Provide detail found at p. 27 of ACDSM —link:
http : / /www. alb emarle. orn /department. asp? d ep artment =c dd &relp age =4447
Transfer SWPPP best management practices to project plan sheets: practices or narrative listed/shown in
SWPPP and on WPO plans should mirror each other.
Revise SWPPP, SWPPP plan sheets, and corresponding WPO plan sheets.
17. New - Furnish letter of coverage, VDEQ General VPDES Permit.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7). (Rev. 1) Comment partially
addressed. With revised ESC, furnish sediment traps at low end of each diversion dike that ends at inlet
(DI) of pipe beneath Briarwood Drive. IP alone is insufficient. [See also WP0201400059, ESC plan
comments, 7/14/14, items #4.] (Rev. 2) Comment addressed.
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29. (Rev. 1) Comment addressed, butplease see #1,
above.
3. Show SAF on plans. (Rev. 1) Comment partially addressed. Show SAF along south edge of Briarwood
Drive. Provide SF, this location, as well. (Rev. 2) Comment addressed.
4. Relocate stone weir outfall, ST 1. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal). (Rev. 1) Comment addressed.
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing) [Rev. 1— Addressed]; check DA, SB
#1 against DA, sheet 7 [Addressed]; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1
[Addressed]; correct t,,, SB #1 [Revise t, to 9.0 min; delete Min. 1.0' dimension label on sediment basin
profiles (emergency spillways are not proposed for either basin) [Review error, comment withdrawn].
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066. (Rev. 1) In combining ESC for
amended underground detention system (WP0201400030) with road plan's two -phase ESC plan, it is
evident that the sequence of construction is problematic. It appears unlikely any downslope controls can be
installed near Wall #3, given space limitations for road, sidewalk, etc. This means there is nothing shown in
Phase 2 design to limit off -site sediment transport, other than IP on new or existing storm drains. Rather,
Phase 1 of the ESC plan shows limited grading for the private road and construction of a portion of the
retaining wall. Without considering the question of whether the wall can be built to design in two
horizontal sections, sheets 6 (phase 1) and 7 (phase 2) as well as sequence of construction notes (sheet 5),
show that sediment basin #1 will serve as perimeter control for grading shown in phase 1 only. Sediment
basin #1 (or alternative, effective ESC measures) must remain in place until grading and improvements,
including widening Briarwood Drive, are complete. Sediment basin #1 must remain in place until upslope
areas are stabilized (graded sections near wall, wall construction complete, private road [to extent shown]
complete, Briarwood Drive widening complete). Installing the 3 -line underground system is only possible
after upslope disturbed areas are stabilized (Sequence Note 12), and should be delayed until such time as
they are. Please revise sheets 5 (sequence of construction; please call to discuss), 6 (ESC -Phase 1), and 7
(ESC -Phase 2). Please re- evaluate sequence and revise to provide adequate ESC measures for all stages of
Engineering Review Comments
Page 7 of 7
road, slope, and wall construction, and during installation of the amended (3 -line) underground detention
system. ESC measures shown for installation of the underground detention system on WP0201400030
(Apr -15) plans did not transfer to these plans. Notably, a sediment trap shown between the system and U.S.
Rte 29 is eliminated, and no ESC measures take its place. There is no apparent provision for ESC during
installation of the underground detention system north of Briarwood Drive. Please provide ESC for this
phase of work. [Ref. 5/22/14 Underground Detention ESC plan review comments, #3, specifically] (Rev.
2) Comment addressed.
7. All basin and trap profiles on sheet 9 should be to scale. (Rev. 1) Comment addressed.
8. Identify any off -site borrow or waste sites. (Rev. 1) Comment not addressed. (Rev. 2) Comment
addressed.
9. (New) Sheet 7 proposes grading affecting 30 -ft of vertical contours, near Wall #3. Provide ESC measures
and sequence of construction that prevent sediment -laden runoff from reaching Briarwood Drive or off -site
receiving streams or entering 3 -line amended underground detention system during all phases of grading.
(Rev. 2) Comment addressed.
10. Minor, new, sheet 8 — revise crest of stone weir elevation in sediment trap I profile to read 427.00'; revise
30" DIA riser top elevation (sediment basin #2 profile) to read =428.96'. (Rev. 2) Comment addressed.
11. (New) SEE ESC comment #1, WP0201400059, 7- 14 -14: MS -19: photos indicate erosion down slope of
pipe outfalls beneath U.S. Rte. 29, an indication that receiving channels are inadequate. The computations
should reflect this, and appropriate measures should be specified to correct the problem. The computations
(roughness and velocities) appear to indicate conditions of adequacy that do not exist. (Rev. 2) Comment
addressed.
D. Final Plat
1. Must match road plan.
File: VvP0201300072, SUB201400066- briarwood- 080414rev -2
Review Comments
Project Name: Briarwood Commercial Lots Erosion and Sediment Control Plan
Date Completed: Thursday, July 24, 2014
Reviewer: Glenn Brooks
Department /Division /Agency: Engineering
Reviews
Review Status: QC Denied
�pF A
�'717G1L31P
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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scottAcollins- engineering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
(Rev. 1) 12 June 2014 [Road], 16 June 2014 [WPO /SWM &ESC]
Date of comments: 22 May 2014
(Rev. 1) 15 July 2014
Reviewer: John Anderson
Please contact reviewer to schedule a meeting to discuss comments, if helpful.
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT. (Rev. 1) TIA lends question: Briarwood
Commercial Development TIA (Table 4.2 ITE Trip Generation) by Davenport (Project # 13 -338,
11/20/13, rev. 3/7/14) shows 24 -hr two -way volume trip generation for Areas A -B -C as 10,896.
Sheet 6 displays this data (Elm Tree Court) using a double -end arrow and label: 5,448 VPD. TIA
shows 24 -hour two -way volume trip generation for Areas D -E -F as 11,324. Sheet 6 displays this
data (Road `A') as 5,662 VPD. Revise labels to show that 10,896 and 11,324 VPD are TIA 2 -way
estimates. The figures 5,448 and 5.662 may be mistaken as total 2 -way estimates, which they are
not.
2. ove entrances from the road plans. These must be approved with site plans. (Rev. 1)
Comment addressed.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
(Rev. 1) Comment addressed. [Jun -I1 letter: "Existing grading easement allows for disturbance
10' into the existing lot. No lot disturbance occurs outside of this area. "]
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan. (Rev. 1) Comment addressed —Bonds will need to be signed by the owners of all
properties on which construction takes place, or legal easements will be needed [ref – Albemarle
County Design Standards Manual [ ACDSM], 8. Grading; C. Off -site work]. [Jun -11 letter:
"Townhouse grading approved under SDP - 2010 -84 and is an existing condition for this road plan.
Proposed grading ties into the approved grading as shown on Sheet 4 "].
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6). (Rev. 1)
Ref Planning Division comments dated July 3, 2014, comment #4 — "A waiver request [for 3'
wide planting strips] shall be taken to the Planning Commission for consideration."
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger. (Rev. 1)
Comment not addressed. [See ACDSM 8.B.2.b. /c.] Please provide specific, geotechnical
engineering details for all retaining walls, including Redi -rock Ledgestone gravity wall system.
Revise handrail /fence post detail, sheet 5: show a zero (0 %) slope extending at least 24" behind
Engineering Review Comments
Page 2 of 6
wall (railing post may not coincide with drainage swale low- point); show drainage swale in every
view of Wall #3 —D, E, F, G, H, I. Consider, show, and detail sub - surface drainage features.
Label and dimension aggregate prism installed immediately behind SRW blocks in handrail /fence
post detail. Specify drainage at foundation (or higher levels) as necessary to ensure areas
immediately behind each wall have adequate drainage. Do not show unbroken 2:1 slope behind
wall #3, but in each section view (D -1), break slope with drainage swale located at least 24" behind
wall. Furnish qualified Engineer's report that life cycles and surcharge of plantings shown in
schematic and table views on sheet 5 and 15, and on sheet 2 of (SDP201300035) Briarwood Site
Plan Amendment #2, Briarwood Phases IA -A, IB -1, 4 -8, received 23 -June 14, will not
compromise integrity of walls or geogrid, if geogrid is used. Avoid planting within drip -line
distance of walls. A 314 sf canopy tree, for example, should not be planted within 10 -ft of walls.
Explanatory note that "final structure wall design to be submitted with final structural engineering
plans " does not meet review requirements. Retaining wall design is a precondition to approval of
road plan, mitigation plan [SDP201300035], and site plan [SDP201400047] since integral to
infrastructure of the site (Road `A').
7. Delete Notes 1 and 2, sheet 5. These notes are invalid. (Rev. 1) Comment partially addressed;
sheet 5 segmented retaining wall (SRW) and geogrid reinforcement details removed. New sheet
5 Wall Cross- sections and Details are inadequate. Ref. ACDSM, 8.13.2.c.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient. (Rev. 1) Comment partially addressed. Handrail shown for Wall #3, only (see
sections D -1, sheet 5). No railing shown for sections of Wall #1 or 2 (sections A, B, C, sheet 5).
Furnish safety railing for all proposed wall sections 4' or higher. Also, see comment #6, above.
9. Show managed slopes on Wall Number 3 detail –sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly. (Rev. 1)
Comment addressed.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown). (Rev. 1) Comment addressed.
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive –sheet 3. (Rev. 1)
Comment addressed.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3' R, Minimum. (Rev. 1) Comment addressed.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %. (Rev. 1)
Comment addressed.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around. (Rev. 1)
Comment addressed.
15. Sheet 6 – Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
(Rev. 1) Comment addressed.
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
(Rev. 1) Comment addressed.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details. (Rev. 1) Comment addressed.
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable. (Rev. 1) Comment addressed.
19. Str -8 (type, DI -7) – the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12). (Rev. 1) Comment partially addressed; 10 -yr design storm
table, sheet 14, lacks column headings - please provide column headings.
20. Str -24 (type, DI -7) – Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
Engineering Review Comments
Page 3 of 6
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in /hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate. (Rev. 1)
Comment addressed.
21. VDOT approval is required. Comments are attached. (Rev. 1) Acknowledged.
22. For Road `A', Road B', Briarwood Drive, each entrance and intersection, "a . design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71. (Rev. 1) Acknowledged.
NEW
23. Increase radius of curve at NE corner of Road `A' -Road `B' intersection to 30 -ft, Min, to allow
longer vehicles to clear opposing traffic when turning [Ref. AASHTO /Minimum Turning Paths of
Design Vehicles —link: http: / /design transportation. or / Documents /TumRadii,GreenBook2004.pdf ]
24. Provide stationing for Briarwood Drive to aide design, review, bond estimate, bond reduction,
inspection, and maintenance: begin with station 10 +00 at CL intersection Briarwood Drive and
Elm Tree Court. In addition, furnish: CL profile for Briarwood Drive; typical cross sections at
these points: tip of median near Rte. 29; widest and narrowest widths east of Road `A'; and
between Road `A' and Elm Tree Court. Indicate drainage patterns. Show symmetrical transition
of pavement at intersection with existing street (Rte. 29) [18- 32.6.2.f].
25. Provide storm drain inlets to capture uncollected runoff from Briarwood Drive; these inlets should
be located as close to Rte. 29 as possible, included with median design. To this end, furnish inlets
along each side of the proposed median on Briarwood Drive, just prior to Rte. 29. Propose
structures within the median structure, on each side. 1/4' per ft. crown for the 3 lanes into the
subdivision and the 4 lanes out should transition smoothly to U.S. Rte 29, existing EP.
26. Inlet structures Ex -38 and Ex -37, sheet 4: One or the other will be relocated; please indicate which.
27. Sheet 5: for Wall sections A,B,C,D,E,F,G,H,I, show road station that corresponds with each
section ( Briarwood Drive, or Road `A'). There is no clear reference to locate these sections.
28. Add County `General Construction Notes for Streets' to plans —ref. ACDSM.
29. Supplement Retaining Wall Notes, to include, at a minimum: i) The Owner shall engage inspection
and testing services (quality control) during construction to ensure project design requirements are
met; the lack of quality control by the owner does not relieve the contractor of these requirements;
ii) quality control shall include but not be limited to: foundation soil inspection, verification of
geotechnical design parameters, and verification that construction is in general compliance with the
design drawings; iii) only qualified and experienced technicians shall perform testing and
inspections services.
30. VDOT approval is required for improvements to Briarwood Drive and the new intersection design
and location.
Engineering Review Comments
Page 4 of 6
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change. (Rev. 1) Comment addressed.
2. Treatment must be provided for all improvements (see also WP0201400030). (Rev. 1) VDOT
restrictions on use of Filterra units within public RW set practical limits on extent of water quality
treatment. Nevertheless, collection, rather than release of runoff from expanded width of
Briarwood Drive is possible with storm inlets positioned within new proposed median close to
U.S. 29 ( #25, above).
3. Sheet 2 and 3 existing (pre - development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4). (Rev. 1)
Comment addressed.
4. Do not show the proposed three line SWM underground detention system as pre - development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
(Rev. 1) Comment withdrawn.
5. Compare sheet 4, post- development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn. (Rev. 1) Comment addressed.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length. (Rev. 1) Comment addressed.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest. (Rev. 1) Comment addressed.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b). (Rev. 1) Request for anti - vortex device withdrawn — detained 2410 -yr storm elevations
are below crest of extended detention facility #3, 30" riser; sheet 4.
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2X WQV = 3,715 cf, but sheet 5 lists 2X
WQV required = 2,583 cf Also, WQVprovided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design. (Rev.
1) Comment addressed.
10. All details on sheet 5 should be to scale. (Rev. 1) Comment addressed.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road. (Rev. 1) Comment withdrawn.
Engineering Review Comments
Page 5 of 6
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition. (Rev. 1) Comment addressed.
NEW
13. Remove image of extended detention facility from pre - development window, sheet 3.
14. Label schematic of development feature (second gasoline station ?) on post - development window,
sheet 3. This detail is new, not shown on corresponding Apr -15 plans; it requires a label that
describes what it is (and reason for showing it). Future development north of Briarwood Drive
does not appear on plans under review. Please confirm and specify future impervious area
calculated to be included with revised underground detention system design (WP0201400030);
area is believed to be 29,500 SF. Currently, proposals for widening Briarwood Drive, constructing
new private roads, and site development south of Briarwood Drive (gas station) are under review.
No assurance is made with respect to review or approval of site or WPO design features tied to
future development.
15. Label L/W of floor of main basin and forebay of extended detention SWM facility #3 detail, sheet
4, since storage at elevation 432' has increased.
C. Erosion Control Plan - Roadplan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7). (Rev. 1) Comment partially
addressed. With revised ESC, furnish sediment traps at low end of each diversion dike that ends at inlet
(DI) of pipe beneath Briarwood Drive. IP alone is insufficient. [See also WP0201400059, ESC plan
comments, 7/14/14, items #4.]
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29. (Rev. 1) Comment addressed, but please see #1,
above.
3. Show SAF on plans. (Rev. 1) Comment partially addressed. Show SAF along south edge of Briarwood
Drive. Provide SF, this location, as well.
4. Relocate stone weir outfall, ST I. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal). (Rev. 1) Comment addressed.
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing) [Rev. 1— Addressed]; check DA, SB
#1 against DA, sheet 7 [Addressed]; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1
[Addressed]; correct t,,, SB #1 [Revise t, to 9.0 min; delete Min. 1.0' dimension label on sediment basin
profiles (emergency spillways are not proposed for either basin) [Review error, comment withdrawn].
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066. (Rev. 1) In combining ESC for
amended underground detention system (WP0201400030) with road plan's two -phase ESC plan, it is
evident that the sequence of construction is problematic. It appears unlikely any downslope controls can be
installed near Wall #3, given space limitations for road, sidewalk, etc. This means there is nothing shown in
Phase 2 design to limit off -site sediment transport, other than IP on new or existing storm drains. Rather,
Phase 1 of the ESC plan shows limited grading for the private road and construction of a portion of the
retaining wall. Without considering the question of whether the wall can be built to design in two
horizontal sections, sheets 6 (phase 1) and 7 (phase 2) as well as sequence of construction notes (sheet 5),
Engineering Review Comments
Page 6 of 6
show that sediment basin #1 will serve as perimeter control for grading shown in phase 1 only. Sediment
basin #1 (or alternative, effective ESC measures) must remain in place until grading and improvements,
including widening Briarwood Drive, are complete. Sediment basin #1 must remain in place until upslope
areas are stabilized (graded sections near wall, wall construction complete, private road [to extent shown]
complete, Briarwood Drive widening complete). Installing the 3 -line underground system is only possible
after upslope disturbed areas are stabilized (Sequence Note 12), and should be delayed until such time as
they are. Please revise sheets 5 (sequence of construction; please call to discuss), 6 (ESC -Phase 1), and 7
(ESC -Phase 2). Please re- evaluate sequence and revise to provide adequate ESC measures for all stages of
road, slope, and wall construction, and during installation of the amended (3 -line) underground detention
system. ESC measures shown for installation of the underground detention system on WPO201400030
(Apr -15) plans did not transfer to these plans. Notably, a sediment trap shown between the system and U.S.
Rte 29 is eliminated, and no ESC measures take its place. There is no apparent provision for ESC during
installation of the underground detention system north of Briarwood Drive. Please provide ESC for this
phase of work. [Ref. 5/22/14 Underground Detention ESC plan review comments, #3, specifically]
7. All basin and trap profiles on sheet 9 should be to scale. (Rev. 1) Comment addressed.
8. Identify any off -site borrow or waste sites. (Rev. 1) Comment not addressed.
9. (New) Sheet 7 proposes grading affecting 30 -ft of vertical contours, near Wall #3. Provide ESC measures
and sequence of construction that prevent sediment -laden runoff from reaching Briarwood Drive or off -site
receiving streams or entering 3 -line amended underground detention system during all phases of grading.
10. Minor, new, sheet 8 — revise crest of stone weir elevation in sediment trap #1 profile to read 427.00'; revise
30" DIA riser top elevation (sediment basin #2 profile) to read = 428.96'.
11. (New) SEE ESC comment #1, WPO201400059, 7- 14 -14: MS -19: photos indicate erosion down slope of
pipe outfalls beneath U.S. Rte. 29, an indication that receiving channels are inadequate. The computations
should reflect this, and appropriate measures should be specified to correct the problem. The computations
(roughness and velocities) appear to indicate conditions of adequacy that do not exist.
D. Final Plat
1. Must match road plan.
File: WPO201300072, SUB201400066- briarwood- 071514rev -1
Review Comments
Project Name: Briarwood Commercial Lots- Road Plans New Private Use Road Plan
Date Completed: Thursday, July 03, 2014
Reviewer: Christopher Perez
Department/Division/Agency: CD
Reviews
Comments:
1) [NEW COMMENT]The (AR)Acer Rubrum (red maple) at 2.5" caliper has an approved canopy calc of 234 SF.
The plant schedule on sheet 15 of the plan currently lists 452 SF per tree, revise appropriately.
2) [NEW COMMENT] On sheet 15, the landscaping plan appears to utilize the same tree designations for two
types of trees; the PA— London Plane tree and the UP—Allee Elm. Revise so that each planting type is clearly
distinguishable from the next. Once this minor issue is cleared up, assure that the Quantity of PA— London Plane
Trees provided in the plant schedule matches those provided on the plans.
3) [NEW COMMENT] On sheet 15, there should be six (6) required street trees along the new 3 lane entrance from
Rte 29 into Briarwood Drive. Revise
4) [NEW COMMENT] Planting strips are required to be 6 feet wide; however, the plan relies on 3 foot wide planting
strips. A waiver request has been provided to staff under the subdivision of the commercial lots. The waiver is
currently being processed and shall be taken to the Planning Commission for consideration.
5) [NEW COMMENT] Street trees are required to be planted in the planting strip between the road and the
sidewalk. The plan depicts the required plantings be placed outside of the planting strip, behind the sidewalks. A
waiver request has been provided to staff under the subdivision of the commercial lots. The waiver is currently
being processed and shall be taken to the Planning Commission for consideration.
6) [NEW COMMENT] Sidewalks are required along Briarwood Drive; however, the plan does not depict these. A
waiver request has been provided to staff under the subdivision of the commercial lots. The waiver is currently
being processed and shall be taken to the Planning Commission for consideration.
7) [NEW COMMENT] The proposal has been modified to provide off site plantings on TMP 03200-1 B-02-07100,
owned by Jamila Saleh. Has the owner been contacted with regard to these plantings? Prior to approval please
provide signed off-site agreements for: temporary grading and landscaping easements from affected property
owner.
8) [NEW COMMENT] It appears the proposed private street"Elm Tree Court" has been relocated to line up with
the existing "Elm Tree Court" across Briarwood Drive. The proposal appears to utilize/consume TMP 032G0-1 B-02
-000B0, 0.05 acres of open space which abuts Jamila Saleh's property. This change in property lines will need to
take place on a subdivision plat/ Boundary Line Adjustment plat, as property lines seem to be shifting in this area.
The revised open space calcs for Briarwood subdivision will need to be accounted for on the plat.
Also, in this area the disturbance of the 20' buffer between commercial and residential zoning requires approval of
a waiver/ special exception approved by the BOS per Chapter 18 Section 21.7(c)1. The waiver has been applied
for as part of the Gas Station site plan and is pending approvability of the mitigation plan [SDP2013-35] prior to
moving forward to the BOS.
9) [NEW COMMENT]The private road serving the gas station has been modified to cross a portion of TMP 032G0-
08-00-000A0, which is open space for Briarwood Subdivision. This disturbance of the 20' buffer between
commercial and residential zoning requires approval of a waiver/special exception approved by the BOS per
Chapter 18 Section 21.7(c)1. The waiver has been applied for as part of the Gas Station site plan and is pending
approvability of the mitigation plan [SDP2013-35] prior to moving forward. If the BOS approves the Special
Exception for the disturbance of this area an easement plat or Boundary Line Adjustment plat shall be submitted
for review and approval to the County for the segment of road to be located on a separate parcel.
Review Status: Pending
�pF A
�'717G1L31P
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: Briarwood Commercial Road Plan, & Road Plan WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(&collins- engineering com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embarqmail.com]
Woodbrier Associates L [P. O. Box 5548, Charlottesville VA 22905]
Plan received date: 15 April 2014 [WPO], 16 April 2014 [Road]
Date of comments: 22 May 2014
Reviewer: John Anderson
A. Road plan (SUB201400066)
1. Provide the traffic study approved by VDOT.
2. Remove entrances from the road plans. These must be approved with site plans.
3. Grading off -site for culvert drainage system N of Elm Tree Court requires easement, or remove.
4. Grading on the townhouse lots west of Road `A' cannot be approved as a road plan. This must be
on a site plan.
5. Subdivision Ordinance 14.422.D. requires 6' planting strips. Plans show 3' (sheet 6).
6. Retaining Walls: Please provide specific, geotechnical engineering details for all retaining walls.
Proposed walls 1, 2, and 3 each have sections that equal or exceed 6' in height. Proposed Wall 3
located 25 -ft from residential lot lines with 2:1 slopes falling 30 -ft at one point to top of wall
elevation of 440' and further 8' drop to sidewalk, falling elsewhere 2:1 16 -ft to top of wall
elevation of 444' with further 16' drop to concrete sidewalk presents inherent danger.
7. Delete Notes 1 and 2, sheet 5. These notes are invalid.
8. Provide handrail elements on all walls. Given proposed wall heights, a typical detail is
insufficient.
9. Show managed slopes on Wall Number 3 detail —sheet 5. Ref. AC Code Ch. 18 §30.7, Steep
Slopes Overlay District, and §30.7.5, Design Standards for requirements pertaining to managed
slope retaining wall design requirements, or limits. Revise designs accordingly.
10. 125' and 140' Radius curves on Road `A' near Briarwood Drive should be revised to 198' Radius,
minimum, to avoid VDOT super - elevation requirements (Ref. VDOT Road Design Manual,
Geometric Design Standards for Urban Local Street System [GS -8]; Road and Bridge Standards,
Sec. 800, Transition Curves, 803.23, Summary of Standard TC -5.11 ULS [Urban Low Speed]
Design Factors, Minimum Radii for Designs Utilizing -2% Super - elevation Normal Pavement
Crown).
11. Furnish street sign, NW corner of intersection of Camelot and Briarwood Drive —sheet 3.
12. Island at Intersection Road `B' and U.S. Rte. 29 SBL and median islands on Briarwood Drive
should have 3'R, Minimum.
13. Intersection of Road `B' and Road `A' must provide a 40' landing with slope < 4 %.
14. Elm Tree Court profile (sheet 9) note states `End road construction at Sta. 11 +75 with temporary
turn- around, see plans for details.' Furnish design details for temporary turn- around.
15. Sheet 6 — Typical Neighborhood Street Section references Road A, B, and C. Where is Road `C'?
16. Revise sheet 8 label to read "Underground detention facility #1 proposed under WPO- 2014 -30.
17. Sheet 6 presents 13 drainage or roadway details. Details are unreadable. Enlarge details to the
point information is legible, or remove standard VDOT details.
Engineering Review Comments
Page 2 of 3
18. Sheet 7 presents 14 utility details. Details are unreadable. Enlarge details to the point that
information is readable.
19. Sir -8 (type, DI -7) - the DA that lies between the 0.23 Ac. DA for Str -8 and the 0.53 Ac. DA for
Str -6 should be added to the 0.23 Ac. DA for Str -8. Capacity- spread calculations should be
revised (Drop Inlet table, sheet 12).
20. Str -24 (type, DI -7) - Drop Inlet table, sheet 12, shows that under 6.5 in/hr conditions, orifice flow
at Str -24 will lead to depth above grate = 6.8 in (0.56'). Rim elevation of Str -24 is 409.52'. Under
6.5 in/hr conditions, storm runoff would follow the 410' contour into US 29 and travel north in
both south and northbound lanes. Under these conditions, plans show storm runoff at Str -24 >
410' that, for periods of time, evades detention with potential to impact all arterial travel lanes at
the intersection of U.S. Rte. 29 and Briarwood Drive. Str -24 appears inadequate.
21. VDOT approval is required. Comments are attached.
22. For Road `A', Road `B', Briarwood Drive, each entrance and intersection, "all design elements are
expected to be to VDOT standards, including curb, gutter, pavement, striping, etc, unless an
alternative is approved." {Design Manual, sec. 71
B. Stormwater Management Plan -Road plan WPO (WP0201300072)
1. Pre - development is all wooded, without impervious areas. Use 1 -2% existing impervious area
to calculate %RR, sheet 4. Revise 9% pre - development impervious to 1 -2 %. I(post) will
change.
2. Treatment must be provided for all improvements (see also WP0201400030).
3. Sheet 2 and 3 existing (pre- development) topography should match. Eliminate post - development
contours associated with roadway construction from pre - development view (sheet 4).
4. Do not show the proposed three line SWM underground detention system as pre - development;
WP0201300018 approved a two -line system which was never constructed while WP0201300072 made
application for a three line system. Pre - development condition includes a sediment basin that accepts runoff
from a portion of Briarwood Drive. Underground storage is not the pre - developed condition (ref sheet 3).
5. Compare sheet 4, post - development DAs with post - development drainage areas presented in
Briarwood Road Plan (SUB201400066 /Sheet 8) and with WP0201400030. Post - development
drainage areas drawn to reflect effect of constructing Road `A' and Road `B' should not vary
across plan sets that depict the same roadway features. Sheet 8 of Briarwood Commercial Site
Road Plan appears most accurate; please revise pre- /post - development drainage areas; show
drainage divides' upper boundaries coincident with topographical high points. DA #lA should be
eliminated unless drainage features exist to define DA as drawn.
6. Show pipe DIA and L for existing and proposed pipes beneath Briarwood Drive that carry ditch flow south
to north, across Briarwood Drive, near intersection with U.S. Rte. 29. Existing pipe is approx 125 -ft, while
proposed pipe is approx 140 -ft in length.
7. Forebay spillway detail shows spillway crest elev = 428' and 10 -year W.S.E. = 427.74'. Please
show 10 -year W.S.E. below spillway crest.
8. SCS routing shows that the SWM facility contains the 100 -yr storm event with > 2 -ft of freeboard,
without an emergency spillway, but the 10 -year event approaches riser pipe inlet elev. of 428 -ft.
Furnish anti -vortex detail and trash rack for multi -stage 30" DIA riser (VSMH, Figs. 3.07 -3a, -
3.b).
9. Extended Detention Facility Summary and Extended Detention Facility Data are somewhat
inconsistent; for example: V = 68.8 cu.yd. (sheet 4). 2x WQV = 3,715 cf, but sheet 5 lists 2x
Engineering Review Comments
Page 3 of 3
WQV required = 2,583 cf. Also, WQVprovided is listed as 3,205 cf, and elsewhere as 16,828 cf.
Please re -check calculations and compare against extended detention SWM facility design.
10. All details on sheet 5 should be to scale.
11. Stormwater Runoff Considerations Note on sheet 6 does not appear to relate to Briarwood
Commercial Road.
12. Minor: reverse < symbol, sheet 4, Watershed Summary, to indicate present 2- and 10 -year storm
event peak discharges are > developed condition.
C. Erosion Control Plan -Road plan WPO (WP0201300072)
1. Provide diversion dikes below 2.5:1 sediment trap 1 (ST1) fill slope embankment to keep runoff from
jumping the roadside ditch and reaching U.S. Rte. 29 SBL (sheet 7).
2. Provide diversion dikes on south side of Briarwood Drive from the Entrance to Road `A' to the inlet of the
existing pipe beneath Briarwood Drive at U.S. Rte. 29.
3. Show SAF on plans.
4. Relocate stone weir outfall, ST 1. Avoid steep 14 -ft high fill slope. Realign weir outfall to avoid
perpendicular alignment with Rte. 29 (parallel to Rte. 29 would be ideal).
5. Sheet 9 — Revise Existing Sediment Trap #1 detail title (not existing); check DA, SB #1 against DA, sheet
7; revise DIA of dewatering orifice and DIA of flexible tubing, SB #1; correct t,, SB #1; delete Min. 1.0'
dimension label on sediment basin profiles (emergency spillways are not proposed for either basin).
6. Delete reference to underground detention facility #2, Note 9, sheet 6. This facility is not part of
WP0201400030, WP0201300072, WP0201300018, or SUB201400066.
7. All basin and trap profiles on sheet 9 should be to scale.
8. Identify any off -site borrow or waste sites.
D. Final Plat
1. Must match road plan.
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COMMONWEALTH of VIRGINIA
DEPARTMENT OF TRANSPORTATION
1601 Orange Road
Culpeper,Virgins 22701
Charles A.Kilpatrick,P.E.
Commissioner
May 13, 2014
Mr. John Anderson
County of Albemarle
Department of Community Development
401 McIntire Road
Charlottesville,VA 22902
Re: SUB-2014-0046 Briarwood Commercial Lots - Road Plans
Dear Mr.Anderson:
We have reviewed the road plan for the Briarwood Commercial lots dated 411514 as submitted
by Collins Engineering. The proposed commercial road is currently shown to be privately
owned and maintained,however,this road is to be designed to VDOT standards per County
requirements and the plan has been reviewed accordingly.
1. It appears that a sight easement is needed for the sight line to the left at the intersection of
Road"A"and Briarwood Drive. All sight easements should be 5' behind the sight lines
to ensure a clear line of sight.
2. The corner clearance for the proposed connection with Road"A"needs to be shown in
accordance with Appendix F of the Road Design Manual.
3. Warrants for the guard rail along Route 29 need to be provided for review.
4. Warrants for the right turn lane at the right-in/right-out entrance off of Route 29 need to
be provided for review.
5. More detail for the island at the right-in/right-out entrance needs to be provided.
6. More detail for the median in Briarwood Drive needs to be provided.
7. The minimum intersection radii should be 25'. This includes the proposed entrances off
of Road"A".
8. The minimum spacing between the entrances off of Road "A"should be 50' between the
ends of radii.
9. Storm sewer pipe 35 appears to be radial. It is recommended that this pipe be installed
linearly.
10. Structure 12 should be shifted to the south of the intersection with Road`B"so that it
crosses Road "A"perpendicularly.
11. Based on the provided trip volumes,Roads "A","B", and"C"should be designed using
the GS-8 design. standarc found in the Road Design Manual.
12.The proposed navemen. desigr,appears to be inadequate. The pavement des
indicates that the t; c tne:.r index of the proposed pavement design (Dp) the
thickness index required •;fir,. In addition, the A 71' information provided :
New yore
pavement design table does not match the ADT information provided for each road
section.
13. I question the trip generation shown for road sections. There are two differing numbers
provided for Road"A". Also,Road`B"and a portion of Road "A"have higher volumes
than that indicated for the primary access of Briarwood Drive. Additional information
supporting the trip generation should be provided.
14.There are a few sections of storm sewer in which the velocity exceeds 10 ft's. Per the
VDOT Drainage Manual,it is recommended to maintain velocities under 10 ft/s due to
scour concerns. The design of these sections of storm sewer should be reconsidered.
15. A couple of sections of storm sewer are nearing capacity. HGL calculations should be
provided for review to verify adequacy of the storm sewer.
16. What accommodations are being proposed for pedestrians at the intersection of
Briarwood Drive and Route 29? It seems to me that we should end the sidewalk at the
intersection of Road"A"and Briarwood Drive. I do not think that it serves any purpose
to extend the sidewalk to Route 29. The right-of-way would be available if this would
become necessary in the future.
17.The TIA for the Briarwood Commercial Development calls for an additional left turn
lane on Route 29 traveling north to be added at the traffic signal. This improvement
should be included on the road plans.
18. The TIA for the Briarwood Commercial Development calls for modifications of the
traffic signal at the intersection of Briarwood Drive and Route 29. These modifications
will need to be approved by the VDOT Traffic section prior to approval of the road plans.
19. A maintenance of traffic plan for the improvements on Briarwood Drive and Route 29
needs to be added to the road plans.
If you need additional information concerning this project,please feel free to contact me.
Sincerely,
1/9 1411**
Troy Austin,P.E.
Area Land Use Engineer
Culpeper District
WE KEEP VIRGINIA MOVING
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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
Date of comments
Reviewer:
Briarwood Commercial Lots
Collins Engineering [293 -3719]
Woodbriar Associates
22 Nov 2013
19 Dec 2013
Michelle Roberge
The application cannot be approved per 32.4.2.8, Effect of Approval oflnitial Site Plan on Other
Future and Pending Approvals. The ordinance states, "b. Erosion and sediment control plan and grading
permit; conventional zoning districts. On any site within a conventional zoning district, including any
conventional zoning district also within an entrance corridor overlay district, an approved initial site plan
is an "approved site plan " within the meaning of section 17- 204(E). As such, an erosion and sediment
control plan and corresponding grading permit may be approved under chapter 17, provided that the
developer has satisfied the conditions of approval identified by the agent in the letter required by section
32.4.2.5(c)."
At this point we can only review a separate WPO application for the proposed gas station since a site plan
has been submitted to the County. Even though application WP0201300072 cannot be approved, I have
reviewed the plan to help with your next submittal. Please see the following comments:
A. Erosion Control Plan & SWM (WP0201300072)
1) It appears the impervious areas for treatment may change as the site plan for each lot becomes
known. This will change the reduction rate calcs and will need to be reflected on a WPO plan. One
thing to be cautious of is the pre and post DA when analyzing MS -19. Use the existing contours
in the GIS system to determine the existing drainage areas to the outfalls. The proposed private
road will change the natural drainage divides and shall be reflected when analyzing MS -19 for
release rates at the outfalls.
2) DA #1 has been approved in WP0201300018. It appears that the impervious area in DA #1 has
changed since the previous approval. For example, the proposed road (as you make a left turn from
Briarwood Drive) is now included in the DA #1. It also appears that this impervious area will now
be treated by the water quality swale that was designed for a portion of Briarwood Drive only.
Please clarify. Also, any changes to the calculations should be amended with the WP0201300018
application.
3) Please provide MS -19 with all WPO applications.
4) All details on sheet 4 should be to scale.
5) The accumulated volume for the Extended Detention Facility #2 at the 408 contour is incorrect.
Engineering Review Comments
Page 2 of 2
6) VDOT will need to review the access roads off of Rte 29 to the Extended Detention Facility #2. I
do not recommend having the access road off of Rte 29. Vdot will also need to review the right
in/right out to Rte 29 and the median on Briarwood Drive. This is the reason a site plan submittal
is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
7) There are items on this plan that will need to be reviewed by the ARB; for example, the extended
detention basins, retaining walls, screening requirements, and etc This is another reason a site plan
submittal is necessary. Coordination of site plan with WPO can be reviewed simultaneously.
8) Provide a profile of entire culvert under Extended Detention Facility #2 to ensure pipe has enough
cover. It does not appear to have enough cover.
9) I recommend changing the side slopes of extended detention ponds to 3:1. 2:1 slopes are too steep.
It poses a safety concern since it is near a residential area.
10) The Extended Detention Facility #1 needs to raise the mid flow orifice slightly to contain the
permanent pool for the 30 hour draw down.
11) On sheet 8, the contour 440 is incorrect for SB #2.
12) On sheet 8, there is a label for Sediment Trap #2, but it is actually Sediment Trap #1. Please revise
label and show location of sediment trap on plan.
13) The reduction rate calc for DA #1 can be removed. Any revisions should amend the
WPO201300018 application.
14) Please clarify the area defined as northern commercial site area and southern commercial area in
the reduction rate calcs for DA #1.
15) On sheet 3, remove all items regarding the underground detention facility #1 since that should be
reviewed as an amendment to WPO201300018.
16) The underground detention facility #2 has a site plan for the gas station. This may be submitted as
a separate WPO application for the corresponding site plan.
17) Clarify how DA #2 will be treated. It is not shown on plans. It will be confusing to propose filterras
on another set of plans. For future reference, please provide reduction rates calcs for treatment,
detention and MS -19 on one WPO for a corresponding site plan.
Sincerely,
Michelle Roberge