HomeMy WebLinkAboutZMA201300017 Review Comments Zoning Map Amendment 2014-02-10*-&A
County of Albemarle
Department of Community Development
Memorandum
To:
Claudette Grant, Senior Planner
From:
Michael Koslow, Senior Civil Engineer
Rev. 1: Glenn Brooks, County Engineer
Date:
17 December 2013
Rev. 1: 10 Feb 2014
Subject:
Spring Hill Village (ZMA201300017)
The proposed rezoning of parcel 90 -28 has been reviewed. The following comments are provided for your
review:
1. Please provide more information regarding the proposed underground manufacturered 30,000 cft
Stormtrap Best Management Practice (BMP) proposed. Will need to know if conceptually this
could provide the treatment for Virginia Stormwater Management Permit (VSMP) requirements
for at least 12.99 Ac of contributing watershed area.
Rev. 1: Underground facilities are not recommended in this setting. Adequate runoff capture will
be too difficult, and treatment solely by manufactured underground facilities does not appear
adequate under anticipated new water quality regulations.
2. It appears that the application proposes internal private roads with slopes up to 12%. County
ordinances require private streets serving 6 or more lots need to follow VDOT standards. The
VDOT Geometric Design Standards for Residential and Mixed Use Subdivision Streets (GS-
SSAR) Table 1 — Curb and Gutter Section (pg. B(1) -7) indicates that for a proposed road with
traffic volume up to 2,000 ADT, 2011 AASHTO Green Book Chapter 5 (Page 5 -12) provides
guidance as to the maximum grade. The Green Book page indicates local residential streets should
be less than 15% (see attached guidance). However, the application proposes a range of uses for
each block. These uses could potentially generate traffic volumes greater than 2,000 ADT. Please
provide an analysis indicating the maximum anticipated traffic volume impacts for the most
intense proposed uses for each proposed private road. Please reference the ITE Trip Generation
Manual and the proposed Code of Development in the analysis.
Rev. 1: The street network is not recommended for approval. Right -angled turns must be
eliminated. There is no private or public road standard which allows this. Road D requires a
turnaround. The main through -way (Road A to B) should be a public road. Alleys should be
secondary access, and not used as sole access to units, such as with 11 -15.
3. Recommend a separate structural certification for proposed Stormtrap BMP. Because this is
proposed under a travel way, the potential for structural collapse needs to be investigated prior to
engineering recommendation for approval of this proposed stormwater management (SWM)
treatment system.
Rev. 1: See comment 1.
4. Recommend application include ranges of proposed uses instead of exact numbers of proposed
dwelling units and commercial square footage. If approved, providing these exact numbers would
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Albemarle County Community Development
Engineering Review comments
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become the zoning for this property and the site would be locked into potentially non - viable
construction solutions without revisiting the rezoning process.
Rev. 1: not relevant to engineering review.
5. Recommend dedication of right of way along Avon Street and SR 20 for public maintenance of
sidewalks (or a Code statement which addresses their maintenance) and sidewalk extensions to
adjacent neighboring driveways for pedestrian continuity.
Rev. 1: no change.
6. Recommend adjusting proposed Block Plan on sheet 3. Please include entire proposed roadway
easement width for proposed private roads or entire proposed public right of way width with
phases for blocks proposed to serve specific lots. For example, please include the entire width of
proposed access easement for Road "A" as part of the area proposed for Block A.
Rev. 1: This road layout is not recommended for approval. See comment 2.
Recommend an overlot grading plan should accompany each proposed site plan due to the existing
steep topography. Engineering policy is that runoff should not cross more than three lots before
being collected into storm sewers.
Rev. 1: The concept grading provided with the zoning plan is not recommended for approval. It
does not meet the conditions of the proposed overlot grading proffer. There are areas where
drainage from lot to lot will be an issue.
8. Recommend proposing an active pedestrian crossing system and crosswalk across Avon Street
between proposed Spring Hill Village and existing Avon Park to address pedestrian connectivity
between these planned residential developments.
Rev. 1: addressed.