HomeMy WebLinkAboutSDP200700065 Review Comments Waiver, variation or substitution requirement 2008-05-07�l
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
To: Megan Yaniglos, Senior Planner
From: Amy Pflaum, Engineering Review
Subject: SDP - 2007 - 00065, Lewis & Clark Exploratory Center, Waiver Request
Date received: 04 February 2008
Date of Comment: 05 May 2008
The applicant has requested a waiver for the new construction proposed on TMP 62 -23. The waiver
request was received on 04 February 2008.
The engineering analysis of the requests is as follows:
Waiver of the requirement for curb and gutter:
The applicant has requested a waiver for the construction of curb and gutter for several portions of the
parking area and travelway as required per County Code Section 18.4.12.15g. The proposed waiver
request is for relief of curb and gutter requirement for the travelway which provides access from Elk Drive
to the building and parking area.
ov�xnsr� -
Proposed tie-
in location
L Proposed
X Existing' parking lot
gravel road
I � f
Elk Drive
I
cowwri
The proposed travelway to the
site connects to an existing
gravel travelway. This
travelway was built before the
County Code required curb
and gutter street design. The
gravel driveway ties into Elk
Drive at the entrance to the
park.
In accordance with County
Code section 18- 4.12.15g, the
County Engineer may waive
or modify this requirement if
deemed necessary to
accommodate SWM/BMP
facility design or the existing
use is located in the Rural
Areas (RA) zoning district.
The site plan is located
entirely within a development
area. Many of the existing
Albemarle County Community Development
SDP - 2007 -00065 Waiver Requests
Sheet 2 of 2
travelways and parking areas in the park have curb and gutter. The use of curb and gutter will assist with
the containment of the travelway drainage.
County Code section 18- 4.12.15g requires curb to be established in all parking areas of institutional
developments. Gutters shall be required where necessary to control or direct stormwater runoff.
Engineering has already waived the curb and gutter requirements for this project in the areas of the
proposed parking lot that drain directly to proposed biofilter (SWMBMP) facilities. The proposed grading
is such that runoff will sheet flow and gutter is not necessary on any portion of the parking lot to direct the
flow to the proposed biofilters. The installation of curb will neither facilitate nor hinder stormwater flow
in the remaining areas of the lot. Engineering concludes that waiving the curb requirement within the
entire parking lot will equally serve the public health, safety or welfare [County Code section 18-
4.12.2.c.2].
The applicant has newly proposed a stormwater swale in lieu of curb and gutter to treat flow from the new
portion of the access road. The applicant anticipates that the Swale is a better alternative to curb and gutter
as it will encourage infiltration and decrease the velocity of stormwater runoff.
For Engineering to administratively waive the requirement of curb and gutter, all new portions of the
access road must drain to and subsequently be treated by a water quality swale or another BMP. The
conceptual stormwater management plan submitted by the applicant does not provide for the swale along
all portions of the road, therefore, Engineering can not administratively waive the requirement for
stormwater purposes.
Engineering basis for not being able to recommend approval of the waiver to the Zoning Administrator is
in the Ordinance, Section 17- 312.C: Stormwater management facilities shall be sited to capture, to the
maximum extent practical, the runoff from the entire land development area. Curb & gutter on both sides
of the road will capture stormwater and direct it to whatever BMP is necessary to achieve the required
removal rate. Allowing water to sheet flow off the road to no BMP does not satisfy Section 17- 312.C, and
does not equally serve the public welfare.
Therefore, Engineering does not recommend approval to this waiver request. Engineering recommends the
use of curb and gutter to direct runoff to a proposed BMP, or a water quality swale on each side of the
access travelway for the entire length of the new portion.
Waiver of the requirement of surface materials for parking areas and access aisles design:
The applicant anticipates that the new development will generate 200 trips per day on the access road,
Engineering is in general accord with this prediction. Per VDOT's Pavement Design Manual, 6 -inch
prime and doubleseal aggregate is an acceptable design for up to 250 vehicle trips per day. Since the
proposed surface for the parking lot and travelway meet VDOT standards, no waiver is required for
installation.
File: \ \Cob- dts01 \cityviewlnk\Docs\2007 Applications\2007 SDPs \SDP200700065 Lewis & Clark Exploratory
Center\E2_wvr_ADP_07 -65 Lewis Clark Exploratory Center.doc