HomeMy WebLinkAboutSDP201200032 Review Comments Critical Slope Waiver 2012-06-15*-&A
County of Albemarle
Department of Community Development
Memorandum
To: Joanne Tu Purtsezova, Planning Review
From: Phil Custer, Engineering Review
Date: 15 June 2012
Subject: Miller School Entrance Drive; Critical Slope Waiver Request (SDP- 2012 - 00032)
The critical slope waiver request has been reviewed. The engineering analysis of the request follows:
Description of critical slope area and proposed disturbance:
The critical slopes currently proposed as being disturbed are mostly associated with a small intermittent
stream valley. Half of these slopes are natural and the other half appear to be manmade slopes created
when baseball field was constructed. The applicant is requesting to disturb these critical slopes to create a
new main entrance drive to the school that is both safe and aesthetically pleasing. The school has two
existing entrances, but one has poor sight distance and the other accesses the site through a not -so- scenic
route, is narrow, and possesses steep grades. In 2010, the Board of Supervisor's authorized the
construction of this new entrance drive through a stream buffer which is normally restricted by ordinance.
This request to disturb critical slopes is essentially the same.
Areas
Acres
Total site
1047 acres approximately
Critical slopes
incalculable
10 -20% of site
Critical slopes disturbed
1.25acre
0.05 -0.1 % of critical slopes
Exemptions to critical slopes waivers for driveways, roads and utilities without reasonable
alternative locations:
This disturbance could possibly be considered exempt since the reason for disturbance is to access the site.
However, since an existing entrance with adequate sight distance exists, not disturbing these critical slopes
to construct a new entrance needs to be considered as a reasonable alternative when evaluating whether the
disturbance is exempt.
Compliance with Zoning Ordinance 18 -4.2:
"movement of soil and rock"
Proper slope construction, control of drainage, and vegetative stabilization will prevent any movement
of soil. There are additional concerns with this application compared to average critical slope
disturbance requests because of the restricted space for ESC measures. Engineering staff will only
approve a plan compliant with state standards.
"excessive stormwater runoff'
Stormwater runoff will increase for the area where critical slopes are disturbed, but most of this runoff
will be conveyed in a stable ditch to an existing stream with a large enough watershed that this
increased runoff will be insignificant.
"siltation"
Inspection and bonding by the County will ensure siltation control during construction. Proper
stabilization and maintenance will ensure long term stability. There are additional concerns with this
Albemarle County Community Development
Engineering Review comments
Page 2 of 2
application compared to average critical slope disturbance requests because of the restricted space for
ESC measures. Engineering staff will only approve a plan compliant with state standards.
"loss of aesthetic resource"
Engineering staff rarely provides opinion of aesthetic value of critical slopes but will point out that this
disturbance was previously unanimously authorized by the Board of Supervisors though in reference to
the stream buffer.
"septic effluent"
No information regarding the septic fields for the parcel has been provided so engineering staff cannot
conclusively state that the current proposal's effects in the event of a septic system failure. The
applicant should provide more information on this subject so this health, safety, and welfare factor can
be put to rest.
A final recommendation cannot be provided by engineering until information regarding the septic systems
is provided. Absent any negative septic systems revelations, engineering review will have no objection
regarding the approval of this critical slope waiver, mostly on the basis that this disturbance has already
been approved by the Board of Supervisors in relation to the stream buffer, acknowledging that challenges
may materialize with ESC plan review.
file: El_csw_PBC_Miller School Critical Slope Waiver SDP201200032.doc