HomeMy WebLinkAboutWPO200800059 Review Comments Erosion Control Plan 2008-10-16� OF AL
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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project: Airport Runway 21 Extended Runway Safety Area (WP0200800059)
Plan preparer: James D. Nixon, Jr. P.E. Delta Airport [fax (804) 275 -8371]
Owner or rep.: Barbara W. Hutchinson C.M. Exe Director [fax (434) 974 -7476]
Plan received date: 29 August 2008
Date of comments: 15 October 2008
Reviewer: Max Greene
The Erosion and Sediment control plan submitted 29 August 2008 has received Engineering
review. The plan submittal is missing several pages as listed on the cover that may contain the
information required for approval. The following comments are to address the plan as submitted
and may not be a complete list of requirements for approval due to the completeness of the
submittal.
1. The Fire Marshall will be the entity to review burn pit areas and permits and is not
included in this review. Please remove these items from the E &SC plan.
2. Limits of disturbance are not congruent. Please make all plan sheets match.
3. Sheet 20A appears to require an update to match the rest of the submittal.
4. This office assumes page 22 of 72 is showing areas to be cleared for borrow. If so, please
show erosion and sediment controls per VESCH. Appears basins will be required in the
valleys as needed for protection. Please label all E &SC measures on all pages.
5. Page 22 of 72 does not appear to show the actual existing topography. In lieu of an actual
survey, the Albemarle County GIS maps are available in 4' contour intervals.
6. Please show all water protection buffers as found in the County GIS on the plan sheets.
7. Please state the acres of proposed land disturbance in the "Project Description" section of
the narrative.
8. Channel design assumes a grass lined condition. Will the channels have sod installed
upon completion of grading? Please show /describe how the channels will be protected
from erosion prior to grass lined stabilization.
9. The response to comment #13 refers to "Phase B- Erosion and Sediment Control Layout ",
Sheet 25 of 72. Sheet 25 was not included in this submittal and could not be reviewed for
compliance.
10. The response to comment #25 claims a 3' height of dam on all sediment traps. The plan
sheets appear to show trap #1 @ 6' in height, trap #2 @ 7' in height, and trap #3 could
not be determined due to the placement of the match line and 100' scale of the plan.
Please clarify this discrepancy and show the details in a more legible scale.
11. The response to comment #26 is related to the discrepancy in the plan view of the
sediment traps. Please see VESCH plate 3.13 -1 for top widths per height requirements.
Engineering Review Comments
Page 2 of 3
12. Sediment trap design table on sheet 26 of 72 appear to have bottom dimensions that do
not support the required volume for the traps. Please include more information on the
size and construction of perimeter control structures and increase the scale from 1' =100'
to a more legible scale.
13. The E &SC perimeter control basins appear undersized for the drainage areas. Please
design the perimeter control basins (EO, D, WO) for the total drainage areas. Please
include more information on the size and construction of perimeter control structures and
increase the scale from 1' =100' to a more legible scale.
The E &SC proposal appears to have some major conceptual problems and has been reviewed by
the County Engineer and Director of Community Development. The following is from the
County Engineer.
As we stated in our previous meeting, this plan does not appear
conceptually able to meet the minimum state standards. In
addition to the lack of perimeter controls in many areas, and the
failure to size facilities for the total contributing drainage,
the concept does not appear workable without sacrificing sediment
trapping measures at various stages of construction. Trying to
build the road and embankment, and permanent basins, directly
upstream or in erosion control measures is counterproductive. It
appears to us that, either the road must be moved, or a larger
facility must be placed downstream, off the airport property,
where the stream valleys have converged. The former concept is
outlined in the attached sketch. Please consider one of these
two concepts. As stated to the Board of Supervisors, this
project should provide exemplary erosion control, and as
variances are already being granted to reduce wet- storage, care
must be taken to provide other measures that meet or exceed
standards.
Engineering Review Comments
Page 3 of 3
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