HomeMy WebLinkAboutSDP200800003 Review Comments Critical Slope Waiver 2008-04-16*-&A
County of Albemarle
Department of Community Development
Memorandum
To: Patrick Lawrence, Current Development planning and zoning review
From: Phil Custer, Current Development engineering review
Date: 16 April 2008
Subject: Crown BMW Retail, Parts, and Service Center critical slope waiver (SDP- 2008 - 00003)
The critical slope waiver request has been reviewed. The engineering analysis of the request follows:
Description of critical slope area and proposed disturbance:
The construction of the Crown BMW Retail, Parts, and service building will require critical slope
disturbance on 4 parcels near the intersection of Route 250 and Pantops Park Drive (Proposed) on Pantops
Mountain. The majority of the slope disturbance will occur on three parcels: 78 -15 (Existing BMW sales
site), 78 -15B (vacant lot), and 78 -15B 1 (gravel parking area used to support adjacent BMW site). The
fourth parcel is located to the south of the development and temporary disturbance of critical slopes on it
will be required to construct the proposed site.
The critical slope disturbance is requested by the applicant in order to construct a 34'000ft2 building,
surrounding parking areas, travel ways, and retaining walls. The retaining walls proposed by this
development are of concern to engineering review. The wall adjacent to TMP 78 -15C (ACSA property)
ranges in heights from 1 -31ft and is located within 5ft of travel and parking areas.
It appears that the majority of the slopes disturbed by this plan are manmade.
For the purposes of the critical slope analysis summary, all of the BMW parcels have been included in one
table. The adjacent ACSA property has its own summary table.
TMP 78 -15 (Existing BMW Property), TMP 78 -15B1 (Service Center Property -1), and TMP 78 -15B
(Service Center Property-2)
Areas
Acres
Total sites
3.61 acres approximately
Critical slopes
0.74
20.501, of site
Critical slopes disturbed
0.66
90% of critical slopes
TMP 78 -15C (Service Authority Property)
Areas
Acres
Total site
5.018 acres approximately
Critical slopes
unknown
Critical slopes disturbed
0.1
Exemptions to critical slopes waivers for driveways, roads and utilities without reasonable
alternative locations:
There are no exemptions to critical slope disturbance.
Albemarle County Community Development
Engineering Review comments
Page 2 of 2
Compliance with Zoning Ordinance 18 -4.2:
"movement of soil and rock"
Construction of the building and other site features will most likely require a temporary increased flow
down the critical slopes during a rain event. Movement of soil can be caught with an appropriate
sediment trapping measure before site runoff enters the existing stormwater system. However, due to
the fact that area low points exist over the proposed lower parking lot and other fill areas, erosion and
sediment control will be difficult and may require a phased erosion and sediment control plan.
"excessive stormwater runoff'
Stormwater runoff will be controlled on site by an underground detention facility. No site runoff will
run across critical slopes in the post development condition.
"siltation"
Inspection and bonding by the County will ensure siltation control during construction. Proper
stabilization and maintenance will ensure long term stability.
"loss of aesthetic resource"
The critical slopes on site are not an aesthetic resource in the opinion of the reviewing engineer.
"septic effluent"
This site is serviced by public sewer.
Engineering review recommends approval of the critical slope waiver. The design and enforcement of any
erosion and sediment control plan for this layout will be challenging but can be reasonably handled by a
detailed and phased construction sequence.
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