HomeMy WebLinkAboutWPO200600053 Review Comments Stormwater Management Plan 2009-06-09� 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: Charlottesville Kingdom Hall [SDP200600002, WPO200600053]
Plan preparer: Hardee Johnston [hardeejohnston @earthlink.net]
Owner or rep.: Charlottesville South Haven Congregation
Plan received date: 24 April 2009
Date of comments: 9 June 2009
Reviewer: John P. Diez — Current Development - Engineering Technician
A. Final site plan (SDP200600002)
1. Please provide the date of topographic information. [18- 32.6.6]
2. VDOT approval must be obtained prior to final site plan approval.
3. Please replace the Construction Notes on Sheet T.1 with updated Albemarle County General
Construction Notes, which are available in the Design Standards Manual.
4. Please provide pavement designs.
5. Per RWSA Note #14 on Sheet T.1, trees are not permitted within the RWSA easement, however, a
tree Conservation Area is shown to encompass a portion of the easement on Sheet C.O. Please
clarify.
6. A 2" Sanitary Sewer Force main shown on Sheet B.1, does not show up on subsequent sheets,
including the Utility & SW Plan. Will these buildings be serviced by a septic field, or the force
main?
7. Is Sheet C.1 a Demolition Plan or an Erosion Control Plan? It appears to be labeled as both and it
is difficult to determine if the E &S features shown on the plan are for demolition or new
construction. The new building and parking lots are also shown on this plan. The approval of the
Erosion & Sediment Control Plans is separate from the Site Plan, it is therefore recommended that
a `demolition phase' be added to the Erosion Sheets (X -EC) if necessary (it appears it could be
incorporated into EC Phase 1), rather than these features being shown on the Demolition Plan. It
is also suggested that to provide a clearer overview of the items to be demolished, the proposed
facilities, like the new building and parking, not be shown on the Demolition Plan.
8. Travelways without parking must be a minimum of 20' wide measured from curb faces. [18-
4.12.17.2]
9. Sidewalks abutting parking must be a minimum of 6' wide, or bumper blocks are provided. Please
refer to the Design Standards manual.
10. Is the porte cochere on the west side of the building a one -way or a two -way? Please provide road
markings. Travelways must be 20' wide for two -way travel. [18- 4.12.17c.I]
11. Dumpster pads must be a minimum 10' X 10' with 8' in front for wheel bearing (total 18' depth).
Please provide dumpster pad detail or specifications. [18- 4.12.19]
12. Proposed slopes at the western edge near the new travelway and proposed slopes between the
travelway and retaining wall near the intermittent stream appear to be steeper than 2:1. Proposed
slopes may not be greater than 2:1.
13. Please label all retaining walls with top and bottom elevations and/or maximum height.
14. It appears that the entrance grade exceeds the maximum allowable 4% within 40' of Old
Lynchburg Rd. [18- 4.12.17]
15. Please provide arrows indicating direction of flow on all existing and proposed sewers.
16. The direction of flow change in MH -4 is greater than 90 degrees.
Engineering Review Comments
Page 2 of 3
17. There is a structure shown in the storm profile between 2C and 2A that is not in the utility and
stomwater management plan view. The structure's tag is illegible due to overlapping text.
18. Please correct the pipe slopes between structures 1F and 113, 2F and 2C, 2D and 2C, and unknown
and 2A.
19. Please demonstrate that the curb chase directing flow to 1 -F will not overtop during a 10 year
storm. If the 10 -year storm is not captured by 1 -F and directed to the pond, then the site's release
rates will need to be modified to reflect this.
20. Storm sewer structure designations (DI, MH) do not correspond between sheets.
21. There is no drainage area shown for 1 -C and the profile does not correspond with the plans.
22. It's unclear if all of Drainage Area 2 will flow to 2 -E. The island north of the porte cochere may
impede flow.
B. Stormwater Management Plan (WPO200600053).
23. Please include the County's most current Construction Notes for Stormwater Management plans
which can be found in the Design Standards Manual.
24. Drainage areas are unclear, please show the pre - development and post - development drainage areas
on separate base maps.
25. Please provide a profile of the pipe exiting the stormwater basin.
26. Please provide a cross section and profile of the rip -rap ditch from the stormwater management
facility to the intermittent stream.
27. It is difficult to conclude that the requirements of 17 -314 of the Water Protection Ordinance are
being met. Please provide pre - development and post - development release rates at the point of
analysis of 2A and the pond outlet (Detention Compliance Table) so that run -off control can be
verified.
28. Compliance with VECSH Minimum Standard 19 must be demonstrated starting at these two outlet
points. The adequate channel analysis should be done along the reach of the intermittent stream to
the culvert under Forest Ridge Road, at a minimum. It needs to be demonstrated that this stream
will act as an adequate channel to carry the new flow created by this development, and the new
flows will not cause erosion to or flooding on the downstream properties.
29. The size and capacity of the pond will be reviewed when the drainage area to it is better
understood and any issues with downstream adequate channels are presented.
C. Erosion Control Plan (WPO200600053)
30. Per RWSA Note #8 on Sheet T.1, please provide approval from RWSA of erosion & sediment
control facilities, including division dike and rip -rap channel, within the RWSA easement.
31. Please refer to the Virginia Erosion and Sediment Control Handbook for all E &S details.
32. All E &S measures must be within the limits of work within each phase.
33. Please update Sheet X -ECA with the most current County Erosion & Sediment Control Notes
which can be found in the Design Standards Manual.
34. Please show on the plans the location of the staging area throughout all phases of construction.
35. There are no E &S measures proposed to protect the downhill side of the proposed 10 -foot
retaining wall, the silt fence is on the uphill side of it. This is a critical area along the edge of the
intermittent stream that requires protection during construction.
36. The phasing plan on sheet X -ECA does not the match the phases on sheet X -EC. 1 through X-
EC.3.
37. A sediment trap detail is found on Sheet C.6, however, its volumes and elevations do not
correspond to either trap shown on the plans. There is a detail for Sediment Trap #1 on Sheet X-
ECA stating it has been designed for 266 CY of storage, however, plan views on the EC sheets
label it as the required minimum 118 CY of storage. Please clarify.
38. The detail of Sediment Trap #1 shows the wet storage with 4.5 feet of depth, the maximum
Engineering Review Comments
Page 3 of 3
allowable by VESCH is 4 feet.
39. Sheet X -ECA volume of Sediment Trap #2 does not match the previous sheets. The details on
sheets C.5a and C.6 are also different.
40. The conservation areas shown on the Conservation Plan should also be designated on the E &S
sheets. Tree protection should be shown around these areas during all phases of construction. Tree
protection should be outside of the drip line of the trees to be preserved.
41. The E &S Narrative, dated April 20, 2008, makes reference to bio- filters. However, the plans state
that Sediment Trap #2 will be converted to a pond. Please update the narrative.
42. The 24" pipe from 2C to drainage ditch is not shown on any of the E &S sheets.
43. It appears that the riprap (outlet protection) 2A should be extended to the center of the ditch.
44. Please address MS -19 (adequate downstream channel) with the emergency spillway on Sediment
Trap #2.
45. In reference to the diversion dike behind the existing building outside the limit of disturbance; It is
unclear what area above the diversion dike in Phase #1, will be disturbed.
46. Status of the existing riprap ditch from the 15" culvert is unclear in Phase #1.
47. The approval of the Erosion & Sediment Control Plans is separate from the Site Plan process. It is
suggested that to help streamline these plans, the E &S sheets may be made into a separate, stand-
alone package. In doing this, all E &S Details and Notes could be placed in the E &S package,
rather than spread throughout different sheets of the Site Plan set.
Once these comments have been addressed, please submit two (2) copies of the revised plans, calculations,
and narratives to Current Development Engineering.
Current Development Engineering is available from 2:30pm — 4:00pm on Thursdays to discuss these
review comments. Please contact Amy Pflaum at 434 - 296 -5832 or apflaum @albemarle.org to schedule an
appointment.
If you have any questions, you can reach me, John Diez, at (434) 296 -5832 ext. 3025, or my email:
jdiez @albemarle.org.
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