HomeMy WebLinkAboutSDP200800136 Review Comments Critical Slope Waiver 2008-10-29*-&A
County of Albemarle
Department of Community Development
Memorandum
To: Elizabeth Marotta, Current Development planning and zoning review
From: Phil Custer, Current Development engineering review
Date: 29 October 2008
Subject: Airport Road Office Plaza critical slope waiver (SDP- 2008 - 00136)
The critical slope waiver request has been reviewed. The engineering analysis of the request follows:
Description of critical slope area and proposed disturbance:
The proposed development of TMP 32 -41E consists of a large office building at the intersection of
Timberwood Blvd. and Airport Rd and the necessary parking lot for the building. Construction operations
will disturb approximately 90% of the parcel. Land disturbance will be limited in two areas: to the west
because of a required 20ft undisturbed buffer adjacent to the residential lots and to the south because of
state protected wetlands.
As mentioned by the applicants in their request for the critical slope waiver, the majority of the critical
slopes being disturbed on site are likely manmade. The slope in the southeast portion of the property is fill
from the construction of Timberwood Blvd. However, there are a few small areas of natural slopes being
disturbed in the area of the wetland.
Areas
Acres
Total site
5.02 acres approximately
Critical slopes
0.18 acres
3.6% of the site
Critical slopes disturbed
0.12 acres
1 66% of on -site critical slopes
Exemptions to critical slopes waivers for driveways, roads and utilities without reasonable
alternative locations:
There are no exemptions to critical slope disturbance.
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 downstream channel. However, due to the
protected wetlands at the southern end of the site, erosion and sediment control will be difficult and
will 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.
Albemarle County Community Development
Engineering Review comments
Page 2 of 2
"loss of aesthetic resource"
The majority of 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.
file: El_csw_PBC_Airport Road Office Plaza.doc