HomeMy WebLinkAboutWPO201000056 Review Comments Erosion Control Plan 2010-10-27� OF AL
,. vIRGINIP
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: Ashcroft Phase 3, E &SC plan (WP0201000056)
Plan preparer: Dominion Engineering & Design LLC. [fax (434) 979 -1681]
Owner or rep.: Liberty Land Ltd. c/o Richard L. Beyer [fax (434) 977 -7219]
Plan received date: 09 September 2010
Date of comments: 21 October 2010 (REVISED 10/27/2010 Comments in bold)
Reviewer: Max Greene
During review of the Road and Stormwater plans inconsistencies were discovered in the
submittals. The following addendums to the E &SC plan review have been added to clarify
discrepancies. Please note all plans will have to be congruent prior to final approvals.
The E &SC plan for Ashcroft Phase 3 resubmitted per County Code 17 -204.17 has received Engineering
review. The E &SC plans cannot be approved as submitted. The following comments are designed to
help the owner achieve E &SC approval per current County code, ordinance and regulations as of the
date of this review.
SWM and Road Plan comments for WP0200700053 and SUB200600411 respectively, will be sent
under separate cover.
1. Temporary Construction Entrance, (Std. & Spec. 3.02) needs to be shown located at the beginning of
the proposed project in order to meet the minimum State requirements. Once the grading and road
surface has been installed, the Owner can work with the E &SC inspector to move the Temporary
Construction Entrance as needed to protect the pavement as required per State regulations.
a. Please correct the narrative accordingly (B12).
State Law requires a temporary construction entrance located at the edge of pavement into work
areas to minimize transport of sediment onto paved roads. Please move temporary construction
entrance location to adequately address State law.
2. Please show the Road stationing on the WPO plans for ease of review, inspection and enforcement.
This is a design request to help with communication between the parties involved and is not required
for plan approval.
Basins per VESCH, Std. & Spec 3.14:
a. Require risers to establish a "dry Storage" area. Please show risers in the basins.
b. Please submit temporary sediment basin design calculations and details for review and
construction.
c. Appears Sediment Trap # 9 has a drainage area that requires a Sediment Basin.
d. Please show both Water Protection ponds on the plan as stated in the narrative (B10).
This is required by State Law for plan approval.
4. Silt fence does not work unless it is installed on level grade. Silt fence not parallel to grade is a
diversion and will need to be shown as a diversion. The ends of silt fence should be turned uphill to
force water through the filter fabric. The bottom of the ends should be higher than the top of the
middle of the silt fence so there's no end -run erosion from impounded water waiting to be filtered
Engineering Review Comments
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through the fabric.
This is a warning of non - compliance to State E &SC law for plan design. E &SC measures used
improperly can create more damage than protection. Measure may be excluded from plan with
adequate perimeter controls such as basins to capture subsequent sediment.
5. Diversions per Std. & Spec. 3.09:
a. May require sediment control /energy dissipater structures located at the terminus to capture
the sediment and to act as an energy dissipater for the concentrated flow. Please show
sediment control /energy dissipater structures as required by VESCH.
b. (CW) is not the State symbol for Std. and Spec. 3.09 (Temporary Diversion Dike) as stated in
the Legend and E &SC narrative. Please correct the submittal to reduce potential confusion
between the inspector and owner /contractor.
c. Temporary Diversion Dike (Std. and Spec. 3.09) have a maximum allowable drainage area of
5 acres. Drainage areas of 5 acres or more should have a Stormwater Conveyance Channel
(Std. & Spec. 3.17) with the minimum 10 year storm event designed per methods noted in
Chapter 5 (Engineering calculations) to adequately protect the disturbed areas. VESCH
d. Please show the required grading for diversions to verify they are constructible as proposed.
Diversions on/across fill slopes will move the location of either the top and/or toes of slope
when properly constructed and may interfere with other design features if not shown
correctly.
e. Please label what appears to be a Right -of -way Diversion near the entrance to the project.
This is a warning of non - compliance to State E &SC law for plan design. E &SC measures used
improperly can create more damage than protection. Measure may be excluded from plan with
adequate perimeter controls such as basins to capture subsequent sediment.
6. Silt fence Check Dams (Std. & Spec. 3.05) are for drainage areas less than 1 acre and with flows no
grater then 1 cfs due to the significantly lower flow rates compared to Rock Check Dams (Std. &
Spec. 3.20). Please verify the E &SC structures are adequate for the applications shown on the plan
due to "End -run" storm flows washing the roadbed stone out prior to paving.
This is a warning of non - compliance to State E &SC law for plan design. E &SC measures used
improperly can create more damage than protection. Measure may be excluded from plan with
adequate perimeter controls such as basins to capture subsequent sediment.
7. Culvert Inlet Protection (Std. & Spec. 3.08) is for drainage areas up to 1 Acre. Culvert inlet protection
can be installed for drainage areas up to but not exceeding 3 acres if they are designed per Std. &
Spec. 3.13 (Temporary Sediment Trap). Drainage areas 3 acres and more will be designed per Std. &
Spec. 3.14 (Temporary Sediment Basin). Due to the location and grade of the site additional measures
such as temporary slope drains may be required.
This is a warning of non - compliance to State E &SC law for plan design. E &SC measures used
improperly can create more damage than protection. Measure may be excluded from plan with
adequate perimeter controls such as basins to capture subsequent sediment.
8. Plan appears to have a breach point in the roadside ditch on Meadow Crossing Trail between Crofton
Woods Pointe and Cedar Croft Way where the proposed grading is flat in the ditch and would allow
for storm flows to bypass the perimeter control structures and treatment prior to existing site. Please
show adequate depth in road side ditch.
Grading adjustment to assure capture of stormwater runoff is required. If grading cannot be
adequately shown due to proposed contour spacing then a detail and note will be added to area of
concern to assure contractor is aware of conveyance requirements.
9. The culvert pipe across Cedar Court Way does not appear to meet the minimum requirements of Std.
& Spec. 3.18 (Outlet Protection) see page III -155 for design criteria. Pipe will be extended to toe of
Engineering Review Comments
Page 3 of 3
fill slope and have at least the minimum outlet protection per State Requirements.
This item appears adequately addressed on the road and SWM plan submittals and needs to be
shown on the plan that requires it. All plans for projects will be congruent prior to final approvals.
10. Culvert pipe in access road to ST -9 does not appear to have adequate cover or depth of ditch. Please
review for constructability.
This is a warning and is not required for plan approval. Additional depth and width of ditch may be
required to adequately install pipe. Owner may work with the inspector to field fit the pipe and
ditch as required to meet minimum requirements.
11. Please show the stockpile and staging areas on the plan as noted in the narrative (138).
This item may be worked out between the owner and Inspector during the preconstruction meeting
and is not required for plan approval.
Due to the extent of requested changes /corrections to E &SC plans, additional comments or conditions may
apply. Please request a meeting to discuss the project. Once these comments have been addressed, please
submit 2 copies of the revised plans, calculations, and narratives to Current Development Engineering.
Current Development Engineering is available from 2:30 -4 PM on Thursdays to discuss these review
comments. Please contact Max Greene at 434 - 296 -5832 ext. 3283 or email to mareene @albemarle.org to
schedule an appointment.
File: El esc MRG Ashcroft Phase 3.doc