HomeMy WebLinkAboutWPO202100049 Correspondence 2021-12-29 (2)Kimley>>> Horn
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December 29, 2021
Albemarle County Department of Community Development
401 McIntire Road
Charlottesville, VA22902
Wawa - Route 29 & Greenbrier
Comment Responses
VSMP
rmwater Pollution Prevention Plan
1. SWPPP not approved. The registration statement and section 9, signed certification, must be signed before the
plan can be approved. Approved plans must be inserted at appropriate locations as well.
Response: Acknowledged.
Pollution Prevention Plan
1. Ensure the PPP is inserted in the SWPPP.
Response: Acknowledged.
Stormwater Manaaement Plan
1. Stormwater management agreement must be recorded before this plan can be approved. Please contact Ana
Kilmer to complete this process.
Response: Stormwater management agreement will be recorded prior to plan approval.
2. Nutrient credits must be purchased before this plan can be approved. Please contact Ana Kilmer to complete
this process.
Response: Nutrient credits will be purchased priorto plan approval.
4. Structure 100 should not be in the middle of a travelway. Also the SWM facility should be located so it doesn't
impede the Greenbrier entrance if maintenance or replacement is necessary. Rev. 1: Please showthat structure
100 is at least outside of the wheel path ofthe travelway. Please show that structure 100 is at least outside of the
wheel path of the travelway.
Response: Stormwater design updated so that structures 100 and 100A are not in the wheel path of the
travelway. Dimensions have been added to sheet CG-101 accordingly.
5. Please show a SWM facility easement around the facility and a public d rainage easement around the outfall
pipes. Rev. 1: The SWM facility easement seems inadequate to perform maintenance or replace the SWM
facility. Ensure there is room for equipment within the easement. See the design standards manual, page 15 for
guidance.
Response: Easement has been expanded to offer room for equipment within the easement as requested.
See sheet CG-101.
6. Per county code 18-4.12.17.a, vehicle access aisles that are not adjacent to parking spaces, shall not exceed
a g rade of ten percent. The entrance off Greenbrier Dr. appears to exceed 10%. Rev. 1: Comment not
addressed. Special exception (SE202100048) is under review.
Response: Acknowledged.
8. Please show DEQ approval of remedial activities for the leaking underground storage tank and show any
necessary notes on the plan for the contractor. Rev. 1: Comment not addressed.
Response: The DEQ approval letter has been included with this submittal.
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10. Please show storm pipe calculations including velocity and hydraulic grade lines. Rev. 1: Velocity should not
exceed 15 ft/s. Per VDOTdrainage manual 9.4.8.7, 10 ft/s max is preferred.
Response: Storm pipe calculations have been updated to reflect velocities of less than 15 ft/s. The pipes
run under the steep hill adjacent to Greenbrier Drive and would require extreme drops to achieve
velocities of less than 10 ft/s.
12. Ensure the SWM facility has adequate access manholes at each inlet and at the outlet. Rev. 1: Comment not
addressed. Maintenance ports are shown, however manholes are necessaryfor access at each inlet and outlet.
Response: Through discussion with Emily Cox, the maintenance ports on the SWM facility are
acceptable as they provide easy mechanical access to cleaning the SWM facility. Trash Guard Plus
(Catch Basin Screen/Filter) from ACF Environmental is used for pre-treatment. See sheets CG-505 and
CG-506 for details.
14. Rev. 1: Please provide the Rtank details as part of the plan set.
Response: See sheets CG505 and CG-506 for details of the R-Tank system.
15. Rev. 1: Please clarify and show on the plan and profile that structure 100A is the stormcepter.
Response: No stormcepter is proposed. Structure 100A is the proposed control structure for the
underground detention. See sheet CG-501 for details.
16. Rev. 1: Based on Sheet CG-203, you appear to have 2 outfall points: 1 is ex. Structure 97 and the other is
and Ex D 1-2B. You must show channel and flood protection is met at each outfall.
Response: Per conversations with Emily Cox on 12116/2021, only one outfall needs to be analyzed as
both points lead ultimately to an existing stormwater conveyance system down Greenbrier Drive. The
narrative on sheet CG-201 has been updated to accurately reflect this calculation.
17. Rev. 1: In your narrative on Sheet CG-201, you reference 97 as your outfall analysis
point, but then in flood protection you reference 100A.
Response: Narrative has been updated to reflect existing structure 97 as being the outfall.
18. Rev. 1: The outfall table on Sheet CG-201 does not showflow, only area and other
des ig n factors.
Response: Flow in CFS has been included in the stormwater management summary on sheet CG-201 as
requested. Flows are computed in HydroCAD and the report has been added to sheets CG-503 and CG-
504.
19. Rev. 1: Please provide thefollowing on the plan:
http s://www.albemade.ora /home/shQ=ublis heddocumenV212/637202327505370000
Response: The document has been provided on sheet CG-502 as requested.
20. Rev. 1: Please provide maintenance requirements for the Rtank on the plan.
Response: Maintenance requirements have been included in the R-Tank details. See sheets CG-505 and
CG-506.
Erosion and Sediment Control Plan
3. [CG-101 ] Maximum slope allowed is 2:1. Grading appears to exceed this in a few places. Rev. 1: Comment not
add ressed. Contours are still measuring steeper than 2:1 slopes. Revise the grading or provide spot shots and
label the distance between the spots to show the max grade is 2:1 over the slope. For example, this is 5ft of
vertical chance in less than 10 ft of horizontal change.
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Response: The sidewalk has been shifted to ensure adequate spacing for 2:1 tiedown slopes.
4. [CG-101 ] Please check 2:1 and 3:1 labels. Slope appears to be steeper than 3:1 where it is labeled as 3:1.
Rev. 1: Comment not addressed. For example, this should measure 15 ft to be 3:1:
Response: The label has been revised on the grading plan.
5. Please show permission forthe offsite work. Sheet CE-501 mentions an easement. This plan cannot be
approved until that is provided. Rev. 1: Comment not addressed.
Response: Acknowledged. The agreement will be provided prior to plan approval.
11. What is the purpose of this excavation shown below? Can it be part of the overall sediment trap? Rev. 1: The
slopes are not measuring as shown. This should be 10 ft for a 2:1 slope and 5 ft vertical change.
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WIDE RIPRAP OUTTALL �
WFT STORAGE- 453.50 l'"�/
Response: The grading has been revised to a maximum slope of 2:1. See sheet CE-101.
13. Ensure landscaping that can withstand steep slopes is specified for the slopes steeper than 3:1. Rev. 1:
Please show ground cover or steep slope grass seed in this area:
Response: Ground cover planting have been added as requested. See sheet CPA 01.
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4'
453