HomeMy WebLinkAboutZMA201300017 Review Comments 2014-07-16*-&A
County of Albemarle
Department of Community Development
Memorandum
To: Claudette Grant, Senior Planner
From: Michael Koslow, Senior Civil Engineer
Rev. 1-3: Glenn Brooks, County Engineer
Date: 17 December 2013
Rev. 1: 10 Feb 2014
Rev.2: 15 Apr 2014
Rev. 3: 4 June 2014
Rev.5: 16 July 2015
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.
Rev.2: Stormwater facilities are better situated toward the lower side of the site with this revision.
Adequate capture of runoff on at -grade inlets along a steep road may still prove unreliable.
Rev.3: No change. This is complete enough to move forward with the ZMA.
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.
Rev.2: The road network is much improved with this revision. The public road and Roads B and
Albemarle County Community Development
Engineering Review comments
Page 2 of 2
C appear acceptable. Road D is conflicted. The initial portion near Avon Street Appears wide
enough, but the road turns sharply and reduces to an alley. For lots 16 -26, a road is recommended,
not an alley, as this is the primary access to units. The sharp turn would not meet any road
standard.
Rev.3: Lots 16 -24 have primary access through an Alley. An Alley is defined as secondary access
in the zoning ordinance. I understand the planning division is willing to accept these, justifying it
as "frontage" on the small park area. Everyone should be aware that this makes the alley serve as
the road frontage. Alley standards are not up to road standards, and pavement durability, drainage,
maneuverability, parking, addressing, emergency services, trash services, all become substandard.
Rev.5: The alley "E" has been widened and labeled as a private road in the pocket park area. This
addresses the above comment. This plan is still using an alley -type layout, with 90- degree angled
turns at either end. This is typically acceptable where an intersection of roads, or a future
intersection is provided. In this case, the intersections are hemmed by retaining walls, making
future connections less likely.