HomeMy WebLinkAboutWPO201000038 Review Comments Erosion Control Plan 2010-07-26�'IRGINZ�
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project:
Plan preparer:
Owner:
Developer:
Date received:
Date of Comment:
Engineer:
WPO- 2010 - 00038, Avemore Phase IV
Mr. David Jensen, PE; W & W Associates
Meridian Land Holdings LLC
Peachtree Homes Inc.
28 June 2010
26 July 2010
Phil Custer
The ESC plans for Avemore Phase IV, received on 28 June 2010, have been reviewed. The plans cannot be
approved as submitted and will require the following corrections before approval can be granted:
1. Silt fence is not an appropriate measure for the southern boundary of the property. The drainage area
to silt fence is deeper than 100ft. The existing topography indicates a Swale concentration runoff and
directing water to the existing stormwater drainage system at the southeast corner of the site. Also,
inlet protection is not a great primary measure for sediment control. To solve these issues,
engineering review recommends the applicant construct a sediment trap in the southeast corner of the
site to be used during the first phase of construction. As the pipe system is constructed upstream,
outlet the pipe into the trap shortly after structure D2. This would likely require the construction of
the building for lots 29 -34 to occur after the rest of the site is sufficiently stabilized to the satisfaction
of the ESC inspector.
2. In both sections of the ESC narrative where offsite borrow is mentioned, please specify that it is to be
obtained from a site with an approved Erosion and Sediment Control plan which is to be confirmed by
the Erosion and Sediment Control inspector.
3. The limit of disturbance line disappears. Please make sure the LOD line is outside of all proposed
work.
4. Please show a location for a parking and staging area.
5. Please show a location for a stockpile.
6. An ESC bond will not be provided until the plan is approved.
The final post - development drainage area and impervious percentage is consistent with the original design
parameters of the Retention Pond (Engineering File #2223). Therefore, all stormwater requirements for
this project have been addressed. However, after looking through the file, I couldn't help but noticing the
considerable depth of the wet pond and the percentage of the water quality volume below a 6ft depth (35 %).
The VSMH notes that at depths greater than 6ft anaerobic conditions can easily exist which can release
phosphorous bound to sediment. The depth of the pond can also have detrimental aesthetic implications such
as unpleasant odors. Engineering review recommends adding an aerator to the facility that circulates water
from the lower levels of the pond in an attempt to avoid anaerobic conditions. This would help both the
removal rate and aesthetic concerns. The addition of the aerator is not a requirement.
File: E1_esc_PBC _ wpo- 2010 -00038 Avemore Phase IV ESC.doc