HomeMy WebLinkAboutSDP201500026 Review Comments Minor Amendment 2015-08-01YlAGIl`11A
County of Albemarle
Department of Community Development
Project: Avinity 1, Phase IV —Minor Site Plan Amendment
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(gacollins -en ing eering com]
Owner or rep.: Avon Properties LLC, P.O. Box 1467, Charlottesville, VA 22902
Plan received date: 29 May 2015
Plan received date: 29 Jul 2015
Date of comments: 9 Jun 2015
Date of comments: 31 Jul 2015
Planning Coordinator: Johnathan Newberry
Reviewer: John Anderson
Engineering has completed review of proposed plans.
Minor Site Plan Amendment (SDP241500026)
1. T -1 — (Proposed changes, Item 3) Modifications to existing travelway may require adjustment to existing
Avinity 1 road/drainage subdivision bond. Contact Engineering to discuss bond requirements attending
proposed change to existing travelway, or attending revision/deletion/addition of drainage items. Minor
Site Plan Amendment #2 changes requiring new or increased bond amounts must complete bond process
prior to Minor Site Plan Amendment Approval. (Rev. 1) Partially addressed. Kaitlyn Walthall, Collins
Engineering, provided bond estimates via email, 17 -Jul, at reviewer's request. With better guidance, Ms.
Walthall's estimates would be helpful, but issues complicate Minor Site Plan Amendment bonds. First,
Alb. County uses template forms with unit prices that tend to be higher than rates available to developers.
Second, Approved preliminary plat for Avinity II shows identical portions of Avinity Loop addressed under
this (Avinity I) MIA. There is uncertainty whether features considered under this MIA that appear on
Avinity II plat will continue to be carried under Avinity I bond. Please notify County of preference:
whether to amend Avinity I subdivision bond, or to simply double -bond roadway /drainage features that
appear on both Avinity I site plan and Avinity 11 plat. Revising existing Avinity I subdivision bond would
require calculating the difference between initial Avinity I site plan design for just that portion affected by
the MIA, and change proposed for this portion (Avinity Loop). Calculation requires using County template.
Alternatively, it may be simpler to bond portions of Avinity Loop that are shown on both Avinity I MIA
and Avinity II Plat, but this would appear to double bond roadway /drainage features. Attachment to
comments presents bond values for Avinity I for comment response purposes. MIA does not require
adjustment to WPO bond since net impervious area increase (11,250 sf) does not require SWM redesign
(WP02010- 00057/WPO2013- 00044). Letter from Collins dated July 8 states existing retention basin
design provides 1,882 cf excess volume. This volume provides 65% pollutant removal for V2" runoff from
the additional 11,250 sf (required Vol. =1,875 cf /runoff WQV x 4). Further, Avinity II preliminary plat
approval proposes revision to Approved WP02013 -00044 with WPO /SWM bond adjustment appropriate at
that time. (Advanced WPO Engineering plan review comment #11, SUB2014- 00201, 12- Jan -15.)
2. To extent changes affect Approved WPO ESC /SWM plans for Avinity 1, provide letter (if only trivial
change), or revised WPO plan sheets for insertion into Approved WPO to guide review and inspection. All
sheets that reference `Approved impacts to stream (Typ.)' or make reference to WPO Approval must
reference Approved WPO# for Avinity 1, or Amended WPO# for Avinity 1. Add WPO# to labels that
reference WPO Approval Approved impacts to stream, for example —S -1, S -2, S -3, LL -1. (Rev. 1)
Addressed.
Engineering Review Comments
Page 2 of 3
3. Contact engineering to discuss possible change in WPO bond amounts for Avinity 1 (ESC measures /SWM
facilities), unless proposed ESC measures /SWM facilities are covered by existing bonds. Riprap outlet
protection for pipe 1, for example, may be candidate for new or increased WPO bond amount. (Rev. 1) See
Item #1, above. WPO bond not an issue.
4. T -1 —List WPO# with other site data. (Rev. 1) Addressed.
5. T -1 — Confirm via narrative that proposed changes (1. -5.) do not increase impervious area, decrease turf
areas, or affect SWM calculations for Approved WPO, Avinity 1, in any respect. Reviewer received verbal
confirmation of this during brief discussion, 9 -Jun, 10:30am (Scott Collins /COB). (Rev. 1) Addressed.
Ref. 8 -Jul -2015 Letter /Scott Collins to Johnathan Newberry. —Also, item #1, above. 11,250 sf net increase
in impervious area. No effect on SWM facility design of retention basin approved under WPO2010- 00057.
(Also, WP02013 -00044 / Avinity WPO Amendment, 21- Apr -2014, GEB)
6. S -1 — Please revise pavement parameters /design table entries for accuracy: Dp = 16.05; Dr =12.9 (ADT =583,
using Trip Generation Manual values for single family detached (9.57) and Apartment (6.72) to estimate
single family attached (Ave = 8.16). Trip Generation Manual does not list single family attached. Using
townhouse (5.86) to estimate single family attached may be unrealistic. No change in pavement
design/section required. Please revise ADT, Dp, and Dr values to: 583, 16.05, and 12.9, respectively. Feel
free to call to discuss. (Rev. 1) Addressed.
7. S -1 —Add Note: "Phase I, II, III, IV are Avinity 1. Avinity 2, future development, is not depicted or shown
on this sheet." (Rev. 1) Addressed.
8. S -1 — Include 3' -4' (speed limit dependent) buffer between back of curb and sidewalk, Degraw St. to
Avinity Loop merge lane. —Ref VDOT Road Design Manual, Section B(1)- 4.I.Pedestrian and Bicycle
Facilities,l.A.(4). (Rev. 1) Addressed- Applicant response: "The proposed sidewalk location and street
cross section is consistent with the streetscape of Avinity 1." Engineering defers to Planning.
(4) Sidewalks shall be a minimum of 3 feet behind the back of curb on curb
and gutter sections, however, if posted speed is greater than 25 mph a 4
foot buffer is required to allow for the placement of signs in accordance
with the MUTCD, Part 2 and, if trees are to be planted between the curb
and the sidewalk, the buffer strip shall not be less than 6 feet wide with the
trees planted so that the center of the tree trunk is not less than 3 feet
behind the curb. Sidewalk placed adjacent to the curb shall be 8 feet in
width to accommodate the opening of car doors. See Figure 6 and 10.
9. S -1 — Revise Street Pavement sub - caption to read Street Parking Spaces, rather than Parking Spaces. (Rev.
1) Addressed.
10. DP -12 — Provide cross drains at required locations —ref Road Plan review checklist:
cross drain locations shown and labeled with VDOT designations (CD -1,2) at every
major cut and fill transition or sag curve
(Rev. 1) Addressed.
11. DP -12 —Limit profile view of Degraw St. to only that portion included with Site Plan Amendment 42.
Minor Site Plan Amendment approval will exclude portions of Degraw St. included with Avinity 2 site plan.
(Rev. 1) Addressed.
12. DP -13 —Add notes for drainage structure steps and safety slab for structure height > 4712', respectively.
Include VDOT typ. details for drainage structure steps, and safety slab. (Rev. 1) Partially Addressed —As
follow -up, standard utility notes for utility profiles do not make step /safety slab requirement explicitly
clear. Please add notes.
13. DP -13 — Recommend add structure number labels for all pipes in drainage profiles. (Rev. 1) Not
Addressed /oversight —DP -13 inadvertently missing.
14. DP -14 —Add many more contour labels to interim and final drainage area plans, and proposed inlets
drainage area plan. Increase font pitch in all views so contour labels more easily readable. (Rev. 1)
Addressed —thank you.
DP -14 — Revise slope, structure 19, to 0.50, consistent with plan view (Drainage Descriptions table). (Rev.
1) Addressed —As follow -up, there are two DP -12 sheets, and DP -14, but storm profiles are missing.
Engineering Review Comments
Page 3 of 3
Please contact John Anderson at janderson2galbemarle.org, or 434 - 296 -5832 - 0069, if any questions.
File: SDP201500026_Avinity 1- Phase- IV _Minor Amend_073115rev1