HomeMy WebLinkAboutWPO201400004 Review Comments Erosion Control Plan 2014-07-23Al
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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 28 & 29B (SDP201400009, WP0201400004,
SUB201400092)
Plan preparer:
Roudabush, Gale & Assoc. [cmulligan @roudabush.com]
Owner or rep.:
MARCH MOUNTAIN PROPERTIES LLC [dave @oldtrailvillage.com]
Plan received date:
11 February 2014
(Rev. 1)
9 June 2014 (Road Plans /SUB201400092)
(Rev. 1)
12 June 2014 (Site /WPO)
Date of comments:
21 March 2014
(Rev. 1)
23 July 2014
Reviewer:
Max Greene (initial); John Anderson
Please adequately address the following items for final site plan, ESC, and SWM approval per Albemarle
County Code:
1. Site plan (SDP201400009):
a. Please update the topography to within one year of submittal date. The topography
should at least be field verified and stated on the plan with a date of verification. [ 14 -302,
18- 32.5.2, policy] (Rev. 1) Comment addressed.
b. Lot #20 driveways is shown across "Open Space" and appears to have adequate room on
the lot for the driveway. Recommend moving driveway off "Open Space" lot. (Rev. 1)
Comment not addressed.
c. Storm drain pipes are missing from sheet 5 of 26. (Rev. 1) Comment addressed.
d. Please provide a bench mark location, elevation and datum for topography. [policy]
(Rev. 1) Comment addressed.
e. Proposed grading has a mix of contour intervals making the topography difficult to
decipher. Please pick either the 1' contour or the 2' contour for consistency. (Rev. 1)
Comment addressed.
f. Please make sure match lines are correct and page numbers are accurate. (Rev. 1)
Comment addressed.
g. Please show all buffer limits on plans. (Rev. 1) Comment addressed.
h. Buffer disturbance will need a mitigation plan. (Rev. 1) Comment withdrawn.
i. Please show critical slopes on the plans. [18 -4.2, 14 -304] (Rev. 1) Comment
withdrawn — County -GIS shows trace critical slopes in one location.
j. Please show the easements on the plan and check the depth to easement width for
excavation limits. [18- 32.6.2.g] (Rev. 1) Comment substantially addressed —
Easement schedule, sheet 14, should transfer to plan view; all drainage easements need to
be shown. Easement for 228 LF 36" DIA HDPE (pipe 156) between structure 154 and
proposed sediment basin is not shown; this pipe is not labeled temporary.
k. Please show sight distance lines on landscape plan to verify unobstructed sight easements.
Trees may need to be moved out of lines of sight. (Rev. 1) Comment partially
addressed. As follow -up, defer to Planning on sight distance -tree conflicts at multiple
locations —for example: Addle Hill Road -Golf Drive; Addle Hill -Hazel Grove Lane;
Birchin Drive - Belgrove St.
1. Please show road name and traffic sign locations on the plans. (Rev. 1) Comment
Engineering Review Comments
Page 2 of 4
addressed.
m. Please change the line weight for existing pipes so they will not be counted as proposed.
(Rev. 1) Comment not addressed —sheet 7: Baywick Circle storm drain lines shown with
heavy line weight, identical with proposed lines.
n. New: Show 25' radius at Addle Hill Road -Golf View Drive; Golf View Drive -Hazel
Grove Lane intersections (sheet 5; site /road plans).
o. New: Revise Note, sheet 9, to reference storm sewer schedules on sheet 10, rather than
sheet 17.
2. Drainage and road plan (SUB210400092):
a. Please show the Stormwater drainage easements on the plan views. [Code Sec. 18- 32.5.2,
18- 32.6.2.d] (Rev. 1) Comment partially addressed —see j., above
b. Future storm drainage systems shall have an outlet to prevent them filling with water over
time. [structure 144] (Rev. 1) Comment addressed.
c. Please show VDOT designations for entrances on the plan. (Rev. 1) Comment
withdrawn.
d. VDOT approval is required for final plan approvals. (Rev. 1) Comment
acknowledged -ref General Construction Note 2, title page, 9 -June -2014 plans.
e. Fire /rescue department approval is required for final plan approvals. (Rev. 1) Unclear if
addressed - Please confirm that road plans were submitted directly to Albemarle
Fire /Rescue.
f. Alleys will be designed to prevent stormwater flows from entering intersections. Please
use the rural street intersection criteria of continuing the -2% cross grade for a minimum
20' from the edge of pavement of the intersected street down the alley to provide a low
point off the intersected street for drainage. (Rev. 1) Comment not addressed; see
Belgrove St- Ashlar Ave, Hazel Grove Lane -Golf View Drive intersections. Also: VDOT
comment 44, 7 July 2014. Also, relatively flat grades in block 28 indicate potential for
nuisance ponding. Show spot elevations and furnish drainage for low points.
g. Please show Cross -drain locations on plans at every major cut fill transition or sag with
VDOT designations. (Rev. 1) Comment partially addressed. Provide CD -2 at Future
Sag, Sta. 22 +45.17, Golf View Drive; CD -1 at Sta. 16 +30f, Addle Hill Road.
h. Please update all standard notes as shown in the ACDSM. (Rev. 1) Comment
addressed.
i. Please check angles of deflections on storm water system. Drainage pipe angles need to
be 90 degrees or greater. For example stormwater structures 110 and 117 appear to be
less than 90 degrees. (Rev. 1) Comment addressed.
j. Please provide drainage profiles for the entire stormwater system. (Rev. 1) Comment
partially addressed; See VDOT road plan comment #5, 7 July 2014. (Additional
detail/clarification required.)
k. Please show inlet shaping for stormwater manhole junctions to reduce the risk of standing
water/ breeding areas for mosquitoes. (Rev. 1) Comment not addressed.
1. Pipes with slopes less than 0.5% are too flat and may not be self cleaning. Albemarle
County Policy is for all stormwater systems will have a minimum 0.5% slope. (Rev. 1)
Comment addressed.
m. New: Show 25' radius at Addle Hill Road -Golf View Drive; Golf View Drive -Hazel
Grove Lane intersections (sheet 5).
n. New: Defer to ACSA on design considerations for MH depth >10 -ft; sheets 13/14.
o. New: Separate out on -grade and sag inlets. Use VDOT template or format to show flow,
right/left along approach curb at sag inlets. Ensure spread is acceptable, even when
temporary.
3. Stormwater Protection (WP0201400004):
Engineering Review Comments
Page 3 of 4
a. Stormwater management proposal will be addressed by the County Engineer. Update:
Meeting scheduled 28 July 2014 to discuss Stormwater Master Plan.
b. New: Sheet 9 table values listed: Existing & Direct Runoff Diverted into Upper Ballard
Farm Pond; Pre - Developed Ballard Pond Drainage; Post - Developed Ballard Pond
Drainage. Purpose of table unclear. Please explain. DA, existing /diverted = 46.6 Ac;
pre - developed = 100.94 Ac; post - developed = 152.64 Ac. (There appears to be an MS-
19 issue).
c. New: sheet 10 furnishes routing data for sub - catchments and ponds not immediately clear
or traceable to post -dev. pond routings (ultimate onsite development) values shown on
sheet 9. Sheet 20, 11 Feb 2014 plans included peak discharge graphs that may be helpful,
but these are not included with current plan set. We do not understand the sheet 10 data.
4. Erosion and Sediment Control (WP0201400004):
a. Blocks 29A & 35A do not appear to be shown correctly. Please show the existing
topography now that grading has occurred on Blocks 29A & 35A. [14 -302, 18- 32.5.2,
policy] (Rev. 1) Comment addressed.
b. Bulk grading plan has a mix of 1' and 2' contour intervals and is inconsistent. Please
pick one contour interval to reduce misinterpretation of proposed grading. (Rev. 1)
Comment addressed.
c. Double row of silt fence do not typically work and are difficult for the contractor to
maintain. Please show a sediment trap in the lowest area near the pond. It can be filled in
after site stabilization to finished contours shown. (Rev. 1) Comment addressed.
d. Please show temporary /permanent seeding on the `Bulk grading Plan ". Seeding will not
be required unless project or portions of project will not be completed within the 9 month
land disturbance time limit. [Code Sec. 17-207.13.21 (Rev. 1) Comment partially
addressed; show permanent seeding (PS) if portions of site will not be completed within
the 9 month disturbance limit.
e. Sediment basin construction details are required. (Rev. 1) Comment not addressed.
Furnish profile view of sediment basin; draw to scale. Show L X W floor dimensions of
sediment basin. Provide computations for outlet structures per VESCHB.
f. Sediment traps with diversions that bisect the site do not work in the field and are a
burden to both the contractor and inspector to maintain the drainage divisions. (Rev. 1)
Comment not addressed. This site appears to require a sediment basin.
g. Blocks will need E &SC protection to keep mud off the new road construction. This
office recommends a sediment trap behind inlet structure #112 with a pipe into the back
of structure #112. (Rev. 1) Comment not addressed.
h. Silt fence or earth berm draining to control structures should be placed behind sidewalks
to protect the new road and sidewalk areas from sedimentation until the vegetation is
established. (Rev. 1) Comment addressed.
i. Please remove proposed 1' contours or make the whole plan with 1' contours. (Rev. l )
Comment addressed -see b., above.
j. Please show the stock pile locations on the plan. (Rev. 1) Comment addressed.
k. Please show staging and parking areas for the contractors and other construction related
areas. (Rev. 1) Comment addressed.
1. New: General Construction Notes, title sheet, #18 — revise `straw mulch is to be applied at
80 lbs /100 SF' to read `80 lbs /1000 SF.'
m. New: Sheet 2, cannot locate adjoining parcel 11; label parcel 11.
n. New: Show mulch/dust control (MU/DC).
o. New: Show entrance pipe at CE. Furnish IP /OP for this pipe.
p. New: Sheet 4, dimension riprap apron (L X W X D), pipe 156 leading to sediment basin.
q. New: Add silt fence to tree protection, block 29B, to prevent off -site sediment transport.
r. New: Revise DV, north boundary, block 35C, to discharge to existing sediment trap near
Upper Ballard Pond (DV appears to discharge on top of embankment, near ST outfall).
Engineering Review Comments
Page 4 of 4
s. New: Sheet 5: list ST outlet embankment width as 5' for ST 1 and ST2, as 4' for ST 3.
t. New: relocate OP2 landward of Upper Ballard Pond; do not show extending into pond.
u. New: Show ESC needed to install pipe 155 leading to Upper Ballard Pond.
v. New: Sediment basin baffles: show if needed. Specify SB side slopes (2:1, 2.5:1, etc).
Due to the level of completeness of this submittal additional comments or conditions may be forthcoming.
Also, please refer to the letter on Albemarle County's website regarding the VSMP and future submittals. Link:
http:// www.albemarle.or,gLupload/images /forms center/ departments /Community Development/forms /En ing eerina a
nd WPO Forms /Albemarle County VSMP Letter 07- 08- 2014.pdf
Current Development Engineering is available from 2:00 -4 PM on Thursdays to discuss these review comments.
Please contact John Anderson at 434 - 296 -5832 ext. 3069 or email janderson2(d)albemarle.org to schedule an
appointment.
File: WP0201400004- SDP201400009 -OTV Blocks 28 & 29B- 072314