HomeMy WebLinkAboutWPO200800085 Review Comments Stormwater Management Plan 2008-11-20ALg�,��
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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: WPO- 2008 - 00085; SDP - 2008 - 00128; Sieg Maintenance Facility
Plan preparer: Mr. Brajesh Tiwari, PE; McKee Carson
Owner or rep.: Rectors and Visitors of the University of Virginia
Date received: 12 August 2008
(Rev. 1) 03 October 2008
Date of Comment: 11 September 2008
(Rev. 1) 20 November 2008
Engineer: Phil Custer
The final site, ESC, and SWM plans for the UVA Sieg Maintenance Facility Site have been reviewed.
The following comments are provided.
A. SDP - 2008 -00128 General Review Comments
Please show an access and parking easement over all spaces and drive aisles on the property.
(Rev. 1) Comment will be addressed through the parking agreement approved by the Zoning
Administrator.
2. The handicap ramps do not appear to meet the VDOT standard. (This may be a building official
comment as well). The applicant may design the sidewalk at the pavement elevation around the
handicap spaces as long as bumper blocks are provided and taper the curb back to the 6" height.
(Rev. 1) Comment has been addressed.
3. Please provide a date for the topographic information.
(Rev. 1) Comment has been addressed.
4. Please show the WPO buffer line. This should not affect the development at all.
(Rev.]) Comment has been addressed.
5. What is the purpose of 30ft easement on the western boundary of the property? Is this the access
easement that will be abandoned with the plat?
(Rev. 1) Please remove this easement from the site plan if it is to be abandoned with the plat
that has been submitted to the planner.
6. The parking calculations submitted in this site plan need to be approved by the Zomi._
Administrator. After taking part in a meeting with Charlie Hurt, I understand that a separate study
will be submitted to the County.
(Rev. 1) Comment has been addressed.
B. SDP - 2008 -00128 Final Site Plan Comments
1. VDOT approval of the site will be required. VDOT comments will be forwarded once they are
received.
(Rev. 1) At the time of this letter, approval from VDOT has not been given.
2. The applicant must provide a traffic generation and distribution summary for the site development.
The traffic impact analysis was not submitted with this application and must be submitted prior to
final approval. (PC condition #2)
(Rev. 1) Comment has been addressed.
3. All slopes steeper than 3:1 need a low- maintenance, non - grassed groundcover. [DM]
(Rev. 1) Comment has been addressed.
4. It appears that some of the wall elevations along the southern side of the property have typos.
(Rev. 1) Comment has been addressed.
5. All retaining walls 4ft or taller require a safety railing. [DM]
(Rev. 1) Comment has been addressed.
6. A detail showing the retaining wall used near the Northridge interconnection drive is required in
this set. This detail should include any safety railing. [DM]
(Rev. 1) Comment has been addressed.
7. A drainage easement is needed along the pipe system on the Moser property carrying Sieg
drainage. The width of the drainage easement must be computed using the equation listed in the
design manual. The existing trees on the Moser Radiation site will be allowed to remain in the
easement. This drainage easement must be recorded with a deed of easement before the site plan
can be approved.
(Rev. 1) Comment has been withdrawn.
8. The existing entrance on the Moser radiation site must be called out as a VDOT Standard
entrance. If this entrance does not meet the VDOT standard referenced, it must be upgraded with
this application.
(Rev. 1) Comment has been addressed.
9. Please show adequate sight distance from the entrance onto Route 250. [DM]
(Rev. 1) Comment has been addressed.
10. Please provide a VDOT designation for the curbing. [DM]
(Rev. 1) Comment has been addressed.
11. A dumpster and pad are needed for this use. The dumpster should be located in a convenient
location away from any concentrated surface stormwater runoff. [18- 4.12.13e]
(Rev. 1) Comment has been addressed.
12. Please move the curbs on the drive aisle south of the Sieg maintenance building so that it is closer
to the travelway lane so the loading spaces are protected by a curb and to prohibit unauthorized
parking along the travelway. [18- 4.12.15f]
(Rev. 1) Please extend the curbed island at the west end of the building towards the travelway.
13. The maximum grade for parking areas is 5% in any direction. [18- 4.12.15c]
(Rev. 1) Comment has not been addressed. The slope in the southwest parking area is greater
than 5 %. Please also note that the grade adjacent to the loading space at the western end of the
building cannot exceed 5% as well. Currently, there are grades exceeding 15% in this area.
14. The maximum grade allowed on the travelway connecting the two adjacent parcels is 10 %,
measured from any direction. [18- 4.12.17a, and PC Condition #4]
(Rev. 1) Comment has not been addressed. The slope of the travelway is steeper than 10%
along the southern curb of the interconnector. Please also note that the grade adjacent to the
loading space at the western end of the building cannot exceed 5 %. Currently, there are grades
exceeding 15% in this area.
15. Engineering review maintains a policy of overland flow relief to prevent damage to buildings and
structures in case of inlet/drainage system failure. Along the loading spaces and at the
northwestern end of the building, water appears to be directed towards the building.
(Rev. 1) Comment has been addressed.
16. Please include in the sheet set the standard County notes for General Construction, verbatim. [DM]
(Rev. 1) Comment has not been addressed. The notes appear to be from an older version of the
design manual.
17. Please ptuviuu a calculation for the curb cut provided on the Northridge site to the existing DI -313.
After visiting the site, it appears that there is a low point in the curbline west of this inlet. Please
correct with this plan.
(Rev. 1) Comment has been addressed.
18. Please provide a calculation for the trenchdrains above the rain garden showing that the total
spread will be less than l Oft and that the depth is shallow enough not to spillover towards the
travelway to the north.
(Rev. 1) Comment has been addressed.
19. Please accurately show all existing roofdrains and proposed measures for collecting roofdrains.
All roofdrains (except 1 adjacent to the proposed loading area) appear to come down on the west
and east sides of the building and are currently routed to the north. The roofdrain on the west side
of the building should be extended to pick up all roof leaders. Please adjust the stormwater
analysis based on these conditions.
(Rev. 1) Comment has been addressed.
20. The construction of the interparcel connection will require removing the existing dumpster and
biohazard waste location. Please show where these facilities will be moved to on the Northridge
site.
(Rev. 1) Comment has been addressed.
C. WPO- 2008 -00085 Stormwater Management Plan Comments
1. A SWM facility maintenance agreement will need to be recorded before the site plan can be
approved. Please submit this document with fee directly to Pam Shifflett after consulting the
guidelines available on the county website.
(Rev. 1) Comment has not been addressed.
2. The drainage divides for BMP maps do not appear to be accurate. Water that enters the low point
between the building and the railroad tracks does not drain to the inlet on the Moser site. Please
amend SWM analysis to reflect the true site drainage patterns (including roofdrains).
(Rev. 1) The drainage area to the rain garden is not correct. The drainage area line runs into
the property line. It appears the drainage area to the rain garden stops at the sidewalk along
the landscape walls along Route 250. Please correct and amend the affected calculations.
3. Please provide a routing using the ADS stage - discharge curve. On the plan please specify the
product number of the grate the contractor needs to use.
(Rev. 1) Comment has not been addressed. Please specify the product number on the plan so
the contractor does not purchase a grate that will increase or decrease the hydraulic capacity of
the riser.
4. Appropriate scour protection from the curb cuts and trench drains should be provided into the
biofilter and rain garden. Landscaping should be removed from the scour protection area
measures.
(Rev. 1) Comment has not been addressed. The stone at the trenchdrains should be extended to
the base of the rain gardens and the entire western slope of the biofilter should be lined with
stone. Trees and shrubs should not be planted in the path of discharged water.
5. The biofilter must be planted with at least 3 species of trees and at least 3 species of shrubs.
Please provide a separate planting schedule for the biofilter.
(Rev. 1) All landscaping that is to be counted in the biofilter must located in the bed (602
elevation). Since the bed area of the biofilter is 1,025sf, a minimum of 10 trees or shrubs must
be provided in the bed area. The shrub to tree ratio within the biofilter must be between 2:1 or
3:1. Additional plantings outside of the biofilter bed will not be bonded with the biofilter and
should not be included in the schedule.
6. The rain garden will be considered a measure above and beyond the county's SWM requirements.
Please clearly label this on the plan so future SWM inspectors will not require upkeep of the rain
garden.
(Rev. 1) Comment is no longer applicable because of the required detention because of
inadequate channels downstream of the property.
7. The underdrain in the biofilter must be in the gravel layer.
(Rev. 1) Comment has been addressed.
8. Please provide a modified simple removal rate spreadsheet for each drainage area/facility, not the
entire site.
(Rev. 1) A spreadsheet for the rain garden was not included in the submittal packet.
9. A SWM bond will be computed once the WPO plan is ready for approval.
(Rev. 1) A SWM bond will be computed once the WPO plan is ready for approval.
D. WPO- 2008 -00085 Erosion and Sediment Control Plan Comments
Adequate channel analyses are needed for each discharge point. The analysis should stop once the
development is 1% of the watershed as stated in Virginia ESC law. (The downstream network
appears to need maintenance to clean out debris and riprap that has moved into the culvert.)
(Rev. 1) Comment has been addressed. The county engineer will allow the site discharge into a
downstream inadequate channel with the proposed detention of the existing impervious areas in
the rain garden.
2. Please amend the ESC notes in the plan set to match the notes in the narrative.
(Rev. 1) Comment has been addressed.
3. The limits of clearing and grading should include all construction activity and site disturbance.
(Rev. 1) Comment has been addressed.
4. The limits of clearing and grading should also include the earth disturbance for pavement removal
in the southwest corner of the site. ESC measures should be provided for this work as well.
(Rev. 1) Comment has been addressed.
5. Move the ROW diversion onto the construction entrance showing that water is to drain to the trap.
(Rev. 1) Comment has been addressed.
6. The sediment trap 1 needs to be designed for the total drainage area without the use of the
cleanwater diversion on the west end of the site. The county does not allow the use of diversion
dikes to route clean water around traps and basins to reduce their size.
(Rev. 1) Sediment trap calculations were not submitted with the revised set.
7. An ESC bond will be computed once the WPO plan is ready for approval.
(Rev. 1) An ESC bond will be computed once the WPO plan is ready for approval.
File: E2_fsp swm esc_PBC_wpo0800085- sdp0800128 Sieg Maintenance Facility.doc