HomeMy WebLinkAboutSUB201400080 Review Comments Road Plan and Comps. 2014-09-15� 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:
Old Trail Village - Blocks 15 & 12
Plan preparer:
Roudabush, Gale & Assoc., Inc [914 Monticello Road, Charlottesville, VA
22902, bledbetter(&roudabush.com ]
Owner or rep.:
March Mountain Properties [ 1005 Heathercroft Circle, Suite 100, Crozet, VA
22932, dave @oldtrailvillage.com]
Plan received date:
21 May 2014, block 15
(Rev. 1)
30 July 2014
Plan received date:
19 Aug 2014, block 12
Date of comments:
3 July, 2014, block 15
(Rev. 1)
15 Sep 2014
Date of comments:
15 Sep, 2014, block 12
Reviewer:
John Anderson
A. Road Plans (SUB201400080 [block 15] / SUB201400139 [block 12])
1. Furnish pipe and inlet computations (inlets: spread/capacity, elevations, descriptions; pipes: flow, velocity,
L, DIA, inverts, etc). No roadway storm collection system computations or calculations are included with
Road Plan, though computations may have been submitted directly to VDOT. (Rev. 1) Comment
partially addressed. Transfer inlet computations, storm sewer design, storm sewer schedule, and
hydraulic gradeline (tables) to plans (sent to ACCD as email attachment). Specific revisions required:
a. Inlet computations: Capacity - 6.5in/hr
i) Revise inlet lengths (L) for sag inlets if L/Lt <1.0. Lt = design length required for 100% capture. If
L /Lt <1.0, proposed L insufficient —ref. column L/Lt: inlets 11, 13, and 49.
ii) W =2.5 is inaccurate if roll -top curb transitions to CG -6 prior to inlet; W =2' for CG -6 section inlets.
Clarify if intent is no transition to CG -6 upstream of storm drain inlets. ACCD requires transition to
CG -6 prior to storm drain inlets; please revise.
iii) Revise W /T, if W revised (ii, above).
iv) DEPTH /HFT is dimensionless (revise heading, del. FT). Values are inaccurate. For ex.: Inlet 11
(6.5in/hr), 0.23 - 0.46 =0.5, not 0.22; inlet 13 (6.5in/hr), 0.22 =0.46 =0.48, not 0.14. Please check
carefully in the future.
v) Check/revise for accuracy: Qincr + Quo =Qt. For example: Inlet 5 (6.5in/hr), 0.25 +0.23 =0.41; inlet 7,
0.31 + 0 = 0.23; inlet 22, 0.64 + 0.04 =0.52. All values should be reviewed /revised as necessary—ref.
VDOT Drainage Manual, 9.5.3.1.1, step 16.
vi) Replace existing format; use VDOT Drainage Manual format found at Appendix 9B -1, LD -204.
vii) 37A is a pipe (37B is inlet); please revise table entry.
Inlet computations: Spread - 4in/hr
i) W =2.5 is inaccurate if roll -top curb transitions to CG -6 prior to inlet; W =2' for CG -6 section
inlets. Clarify if intent is no transition to CG -6 upstream of storm drain inlets. ACCD requires
transition to CG -6 prior to storm drain inlets; please revise.
Engineering Review Comments
Page 2 of 4
ii) Revise W /T, if W revised (ii, above).
iii) DEPTH /HFT is dimensionless (revise heading, del. FT). Values are inaccurate. For ex.: Inlet 11
(4in/hr), 0.21 =0.46 =0.46, not 0.16; inlet 9 (4in/hr), 0.12 =0.46 =0.26, not 0.06. Please check all
values carefully; revise as necessary.
iv) Check/revise for accuracy: Qincr + Quo =Qt. For example: Inlet 43 (4in/hr), 1.30 +0.48 =1.45;
inlet 45, 0.72 + 0 = 0.54; inlet 49, 0.14 + 0.20 =0.30. Revise all values, if necessary —ref. VDOT
Drainage Manual, 9.5.3.1.1, step 16.
V) Replace existing format; use VDOT Drainage Manual format found at Appendix 9B -1, LD -204.
When using VDOT LD -204, show inlet type. Delete columns not included in LD -204 (DA GUTR,
for example).
C. Storm sewer design:
i) Velocity from points 59 -61 and 57 -49 are <3 fps design minimum; please revise.
ii) Slope from point 57 -49 is less than 0.50% design minimum; please revise.
iii) Label inlets 1, 27, and 32 Ex. (existing) only if they exist, not simply if they exist on block 15
road design plans.
iv) Label existing inlets existing only they have been installed or exist beyond design (i.e., exist
on approved plans). Ref. block 12 road plan sheet 7 which shows inlets on Claremont Lane,
Court Mont Way, and Rowcross Street as existing. These inlets are under concurrent review.
Blocks 12 and 15 were simply separated. Labels must be accurate to avoid misunderstanding.
(Block 15 road plan, sheet 6: inlet 27 is proposed; inlets 1 and 32 are existing [sheet 3].)
V) Since development plans and road plan designs for blocks 12 and 15 co- exist, revise D.A. and/or
C values (block 15, sheet 10) to reflect developed condition of block 12; two drainage areas
appear affected. Carry revised DA/C into and through storm sewer design calculations.
vi) Provide time of concentration calculations for drainage areas for inlets: 59, 57, 53, 39, 37B, 20,
24, 13, and 11. Ensure that developed condition is used: impervious pavement, roofs, walks, etc.
Compare inlet 39 and 3713: DA and developed ground cover conditions vary, yet T, is identical.
Time of concentration appears high. Calculations or estimates appear inconsistent.
vii) Revise pipe 15 so that runoff is contained within pipe: runoff cfs exceeds pipe capacity by 27 %.
viii) 27 -27A: pipe L = 73.21' - 1.08 %. Compare with block 12 road plan/sh.10, storm sewer profile
#24 - #14: Ex. 27b is incorrect label; use 25 instead (pipe str. #). Compare with block 15 /sh.13,
storm sewer profile Ex. #32 - #27A: 84 LF of 30" HDPE @0.90 %. Storm sewer design table
includes temp and permanent conditions, which is acceptable, and profile, block 15 /sh.13 is
acceptable, but this profile requires note or label indicating inlet 27 will connect with inlet 20A.
Furnish label or note. (Also, item #25, below.)
d. Hydraulic gradeline:
i) Check/revise for consistency: inlet /outlet H2O elevations. If H2O elev. is reported as x at location y, it should
appear as a single (identical) value throughout the HG table. For example: str. 7 upstream elev. = 658.12'
while str. 9 outlet elev. (same point) = 662.35'. Str. 18, upstream elev. = 652.16' while str. 20A outlet elev.
(same point) = 656.60', a 4.44' difference. Please revise HG data such that a single location has a single H2O
elevation.
ii) Outlet H2O elev. str. 61 is listed = 657.50'. The outlet is outfall with H2O elev. listed = 656.50. Revise.
iii) Design for flow within pipes: H2O elev. < INV elev. + pipe DIA. 22 pipes have H2O elev.> INV + pipe DIA.
Review and revise design as necessary. All pipe sections must be designed to flow within capacity.
2. The profile for Rowcross Street should clearly define where the profile for Block 15 begins and ends
(VDOT comment #16, VDOT comment letter dated June 12, 2014). (Rev. 1) Comment addressed.
VDOT must approve road plans. VDOT comments sent to Applicant (project primary contact) via e -mail
attachment, 12- Jun -14. ACCD reiterates: VDOT approval required for public roads and assoc. elements.
Engineering Review Comments
Page 3 of 4
NEW
1. Show all transitions, roll -top curb to CG -6 prior to storm inlets. Block 15 road plan, sheet 3, east end
Court Mont Way provides an example. Please revise plan view sheets to show how and where transitions
occur: block 15 road plan, sheet 3; block 12 road plan, sheet 4 (Court Mont Way, Pvt. Alley `A').
2. Revise sheet title: a SITE PLAN cannot be approved as part of a road plan. (block 15, sheet 3; block 12, sheet 4)
3. Label pipe 19, between inlets 20 and 27 (block 12, sheet 4).
4. Once pipe 19 is labeled, re- number pipe between inlets 20a -18 (block 12, sheet 4).
5. Locate public /(proposed) private dividing line (Rowcross Street, block 12, sheet 4), the point at which
public portion of roadway ends and private begins, further east to radius return at intersection of
Claremont and Rowcross.
6. Furnish private drainage easements for all proposed drainage elements beyond public RW, including
easements that fall within private access easements (Pvt. Alley `A', for example); do not label public any
easement beyond public RW; such easements will be held private.
7. Revise 20' PUBLIC DRAINAGE ESMT. (labels), block 12, sheet 5, not maintained by Albemarle County or
VDOT. These are private drainage easements ( #6, above). Note inlet 27- outfall (point 14), inlet 11 -1.
8. Indicate elements on Claremont (and east) that do not exist. Inlet 1 exists, but many elements are proposed
under block 15 road /site plans. Choose method of line weight or labeling that makes clear which signs,
inlets /pipes, easements, pavement, or curb exist —are constructed or approved to be built. Do not label an
easement existing until and unless recorded. Ref. block 12 sheet 4.
9. Label 13' sidewalk maintenance easement between lots 1 -12 and Old Trail Drive private since neither
Albemarle nor VDOT will maintain this sidewalk. (block 12, sheet 5)
10. Provide temporary barricade at south end Pvt. Alley `A', between end and future development, block 12,
sheet 4.
11. Provide permanent structural barricade at north end Pvt. Alley `A', between end and sidewalk.
12. Relocate street sign coincident with storm pipe at Int. Pvt. Alley `A' and Court Mont Way.
13. Provide Speed Limit sign, Pvt. Alley `A', if less than Rowcross Street or Court Mont Way speed limit –
block 12, sheet 4.
14. Label retaining wall that runs beside sidewalk on Rowcross Street: block 12, sheets 4 and 7.
15. For top of wall (tw) elev ( #14, above), provide corresponding bw elevations. Furnish wall profile,
schematic details. Lines should indicate batter, face of wall, back of wall, block 12, plan sheets 4 and 7.
That is, drawing should reflect actual dimensions, drawn to scale.
16. Locate public /(proposed) private dividing line (Rowcross Street), the point at which the public portion of
Rowcross Street ends and private begins, further east to the radius return at the intersection of Rowcross
and Claremont.
17. Delete Notes 21, 22 (GENERAL NOTES FOR ESC PLANS, sheet 6), since they contain invalid code
references; they no longer appear in the ACDSM.
18. Revise title of Claremont Lane profile to clarify that this section is proposed under road plan 15, and will
be reviewed under road plan 15. This portion of Claremont Lane does not exist. (block 12, sheet 9)
19. Profile of Private Alley `A' shows curb -like feature at lower, south end; transfer, label and show on sheet
4, block 12 road plans.
20. Existing ground ELEV. at Int. Rowcross Street and Alley `A' varies substantially in profile views (650' v.
663'). Revise.
21. Reconcile Rowcross St. profiles (block 12 -15):
• block 15/sh.1 1 shows FUTURE ROAD EXTENSION BLOCK 12: (- )2.0 %, sta. 10 +00- 10 +25; then 100' VC, sta.
10 +25 -11 +25 at (- )2.0 %/2.0 %.
'BLOCK I2 /sh.9 shows (- )2.08 %, 10 +00- 10 +25; then 75' VC, sta. 10 +25 -11 +00 at ?/0.39%.
• Provide seamless or at least consistent design for Rowcross St., without conflict between block 12 and 15.
22. Provide vertical curves at these locations. At entrances, a reduced K value of 5 to 10 can be used to transition
from the intersected cross - grade.
Rowcross St; 10 +08 Court Mont Way; 10 +16 and 14 +45.24 (block 15)
And: 6 +97.78 and 9.84 (block 12)
Fielding Run Drive 17 +58.75 Claremont Lane; 13 +32.17
23. Furnish elev. in profile, Claremont Lane, at Int. Rowcross Street. Confirm elev. block 12 = elev. block
15 (666.69').
24. Existing sediment basin bottom profiles differ in storm sewer profiles, road plan 12 /sh.10; reconcile.
25. Label L /slope of pipes shown in section -view; for example: block 12 /sh. 10 storm profile #13 to Ex. #41,
Ex. 42 (24" HDPE) and Ex. 40 (15" HDPE) connect with Ex. 41, but slope and L are not specified.
Engineering Review Comments
Page 4 of 4
Furnish slope -L for storm sewer pipes shown in section -view in storm profiles, block 12 road plans.
26. See item A.l.c.(viii), above.
27. Include VDOT IS -1 detail with block 12 and block 15 road plans (2008 Road and Bridge Stds, Section 100,
Standard Method for Shaping Manhole and Inlet Inverts, p. 106.08). Image, below:
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METHOD OF TREATMENT IN CROP INLETS
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METHOD OF TREATMENT IN MANHOLES
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SYEET T CF 1 I RE115o DATE MANHOLE & INLET INVERTS 302
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File: SUB201400080 -Old Trail- blockl5 -12- road - 091514