HomeMy WebLinkAboutWPO200900061 Review Comments Erosion Control Plan 2009-12-04� OF AL
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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project: North Pointe Stream Crossing [WPO- 2009 - 00061]
Plan preparer: Doug March, PE; WW Associates
Owner or rep.: Neighborhood Investments, NP, LLC
Developer: Charles Rotgin; North Pointe Charlottesville, LLC c/o Great Eastern Management
Company
Plan received date: 6 November 2009
Date of comments: 4 December 2009
Reviewer: Phil Custer
The Erosion and Sediment Control Plan for the North Pointe Stream Crossing project, submitted on 6
November 2009, has been reviewed. The following comments must be addressed before approval of the
set is given:
A. General
1. As previously indicated in an email from Amy Pflaum sent 30 October 2009, a road plan will be
required within this set. The road plan must meet all of the conditions outlined in the approval
letter of SP- 2006 -00034 including all detailed landscaping requirements.
2. Approval of the road landscaping plan by the ARB Design Planner is required per SP conditions.
3. VDOT approval of the road plan is required.
4. FEMA approval of the flood map revision is required before a grading permit will be issued. (SP
condition #3)
5. Please provide a copy of the Army Corps of Engineers Permit for this project. Please also supply a
copy of the application submitted to ACE for county records.
6. A mitigation plan will be required prior to the release of final ESC approval for this project.
Please refer to the County's Design manual (pages 11, 12, and 25 of 42) for all mitigation plan
requirements. (SP Condition #5)
7. The county will only be reviewing the culvert to confirm that the 100 -year storm will not overtop
the road because this road will serve as the sole access to the residential community, if only
temporarily. [18- 32.7.2.3] The culvert must be checked with the discharge number, adjusted for
anticipated development in the watershed, used in the existing FEMA model.
8. Please note that the latest rainfall amounts for a 24 -hour ten and hundred year storms are 5.6in.
and 9.1in., respectively, for Albemarle County.
9. The stage - elevation data of the area upstream of the culvert must consider the proposed contours
of the embankment. Because the inlet point is located farther upstream, the current computation
overestimates the volume available uphill of the culvert's inlet.
10. Please provide a low maintenance, non - grassed groundcover on all slopes steeper than 3:1. For
examples of acceptable groundcovers, please refer to Table 3.37C of the VESCH. [DM]
B. Erosion and Sediment Control Comments
1. The ESC measures provided do not appear to exceed the minimum state requirements. (Proffer
4.3.a) For a list of recommended measures above and beyond state minimum requirements, please
Albemarle County Community Development
Engineering Review Comments
Page 2 of 2
refer to the County Engineer's Commentary . Incorporating the use of sediment traps into the
filling operation is also something to be considered as a measure to exceed minimum state
requirements.
2. The diversion above culvert 2 appears to be acting as a `cleanwater' diversion which is not a state
accepted standard. Please remove all diversions that are proposed to direct clean water around
disturbed areas.
3. ESC measures are needed to treat runoff from the haul road. A sediment trap/basin just east of the
box culvert outlets is necessary. (A sediment basin in this location will be needed for the
development of the full site plan and engineering review recommends that the basin is constructed
now if the site plan is anticipated to be constructed soon after this crossing. This basin could also
be converted to a biofilter to help meet stormwater management requirements in Proffer 4.3.b.).
The diversion shown on the plan uphill of culvert 2 can direct runoff into this trap as long the trap
is designed to consider this area. Having two settling facilities in series (the other being the
current proposed trap in the borrow area) would be a step towards satisfying Proffer 4.3.a.
4. Please provide dewatering symbols (DS) on the ESC plan and detail for the installation of the box
culverts.
5. A stockpile and laydown area is needed just east of the proposed earthwork. Please adjust limits
of disturbance and ESC measures accordingly.
6. With regard to the keeping construction activity out of the live stream, the construction sequence is
acceptable. However, the removal of the existing culvert and embankment will limit access to the
majority of site for a considerable amount of time. I recommend a more detailed sequence where
the southern 50ft of the two box culverts are built and a crossing is established before removing
the existing embankment. Again, this is only a recommendation and not a requirement. Please
note that if the contractor wishes to establish a temporary crossing at another location along the
stream, an amendment to the ESC plan will be required.
7. Please specify in the plan where the existing embankment material will be deposited on site if it
turns out to be suitable. Conversely, please also specify where the soil is to be deposited if it turns
out to be unsuitable. If it is to be removed from the site, please state that the soil must be taken to
a property with an approved erosion and sediment control plan
8. Please provide a note in the vicinity of the borrow area which states that at all times the cut
operation must be carried out in a way that directs all runoff to the diversion and sediment trap.
9. The ESC bond will be computed at the time of plan approval.
E1_esc_PBC_North Pointe Stream Crossing wpo200900061.doc