HomeMy WebLinkAboutWPO202100024 Correspondence 2021-08-23•����01
0 608 Preston Avenue
P 434.295.5624
Suite 200 F 434.295.1800
T I M M O N S GROUP
Charlottesville, VA 22903 www.timmons.com
August 23, 2021
Emily Cox
Count of Albemarle
Community Development
401 McIntire Rd, Rm 227
Charlottesville, VA 22902
RE: Old Trail Village —Block 7C— VSMP Permit Plan Review — WP0202100024 -Comment Response Letter
Dear Ms. Cox:
We have reviewed all of your comments from dated May 27, 2021 and made the necessary revisions. Please
find our responses to the comments below in bold lettering.
A. Stormwater Pollution Prevention Plan (SWPPP)
The SWPPP content requirements can be found in County Code Section 17-405. A SWPPP must contain
(1) a PPP, (2) an ESCP, (3) a SWMP, and (4) any TMDL measures necessary.
1. Please provide an updated coverage map for the Old Trail DEQ CGP. If this area is not already
included, please provide an updated registration statement with the added area.
Based on the latest coverage map provided by Roudabush in 2019, this area is not currently
covered. A new registration statement with the updated acreage has been submitted as part
of this re -submission.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code Section 17-404.
1. PPP was not provided. Please provide a PPP to insert into the master Old Trail SWPPP.
A PPP for Block 7C has been provided as a part of this re -submission.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This
plan is denied, and the reasons are provided in the comments below. The stormwater management plan
content requirements can be found in County Code Section 17-403.
1. Please put WP0202100024 on the cover sheet.
Acknowledge and updated the cover sheet with WPO number.
2. [Cover Sheet] Please insert the total disturbance. It currently says #### acres.
Total disturbance of 2.73 acres is updated on the cover sheet.
ENGINEERING I DESIGN I TECHNOLOGY
3. Please remove sheets that do not apply to the WPO, such as 1.1-1.3.
Sheets 1.1-1.3 are removed from sheet set.
4. Please provide previous approval or special exception for the proposed lots to be within the 100
ft buffer.
The BOS action letter has been provided with the re -submission. They approved the motion on
03/06/2019.
S. Please provide mitigation plan for disturbance to the buffer for the storm outfall or show where
the disturbance has already been mitigated/accounted for in the master plan.
The plan for the impact area (1,847 sf) is shown on sheet 1 of 4 known as "WPO Stream Buffer
Impact Exhibit" by Roudabush, Gale & Assoc., dated January 23, 2018 and last revised
December 6, 2018 and provided to the BOS during the special exception requests. The exhibit
has been included with the re -submission and conditions noted below.
Special Exception to Vary the ZMA201500001 Old Trail Code of Development
and to Modify the Application Plan Special Exception Condition
1. Stream buffer mitigation shall be provided at a 2:1 ratio in accordance with a buffer mitigation
plan for Old Trail Village ZMA2015-001, as approved by the County Engineer.
2. Disturbance to the buffer shall be limbed to the areas depicted on pages 14 of the exhibit
prepared by Roudabush, Gale & Associates, Inc., entitled' WPO Stream Buffer Impact Exhibit
Blocks 19. 24-25, 3243' dated January 23, 2018. with a revision date of December 6, 2018,
3. Modification of the 'Open Green Space' shall be limited to the areas depicted on pages 1-4 of
the exhibit prepared by Roudabush, Gale & Associates, Inc., entitled VPO Stream Buffer Impact
Exhibit Blocks 19, 24-25, 32-43' dated January 23, 2018, with a revision date of December 6,
2018.
6. Please specify where roof drains will outlet or tie-in to storm system.
Roof drains have been noted to provide splash blocks at the terminal ends.
7. Proposed storm easement must be public since it is collecting runoff from the public street,
Orion Lane.
The label has been revised to reflect a public easement.
8. Please show how this proposed plan complies with the master stormwater plan. For example,
show overall proposed CN or total impervious area (CN 77.7 and 52.7% impervious was
approved for area 516-2). This plan shows a CN of 85.
This plan only accounts for the CN allocated to Block 7C (-3 acres) of the —42 total acres that
drain to swm facility L-1. The CN of 77.7 is a weighted CN for the entire —42 acres, as some
areas contain more impervious and some contain less. A summary of the land cover to date
has been provided for more clarity on the SWM sheet.
9. The master plan shows this pipe. However, it appears this plan removes it. Please clarify.
The pipe is shown due to the base file used by Stantec during the time of approval of the
master plan. The 48" Riser and a portion of the pipe up to the right-of-way will be removed. A
new storm network will be installed per this plan which will ultimately convey the runoff to
the large pond.
10. Please show proposed permanent outlet protection for structure 300.
Permanent outlet protection is shown for structure 300 on sheet C6.0.
D. Erosion & Sediment Control Plan (ESOP)
Virginia Code 62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is
disapproved, and the reasons are provided in the comments below. The erosion control plan content
requirements can be found in County Code Section 17-402.
1. [Sheet C3.01 The stormwater runoff note appears to be incorrect. Please ensure all notes are
updated and are project specific.
The note has been updated to be project specific on the re -submission.
2. Is the Lindy Bain loop to remain open during construction? If so, please provide plans to ensure
pedestrian safety.
It is believed that Lindy Bain Loop will remain open to pedestrians during construction. Should
any portion of the access trail be blocked during construction, signs will be places on -site for
the safety and redirection of pedestrians. A note has been added to the re -submission to
address this.
3. Does the Lindy Bain Loop have an easement? If so, please show the easement as well as the DB
& PG.
No, there is not an existing easement for the Lindy Bain Loop. An easement will be proposed
with this development for the protection and preservation of Lindy Bain Loop. It will be
platted with the subdivision plat and is shown on the re -submission. An easement sheet has
been added for clarification.
4. [Sheet C3.1] Please provide the paved wash rack detail from page 8 of the county design
standards manual.
The paved wash rack detail from the engineering design standards manual is provided on
Sheet C3.0.
S. Ensure there is a place for wash water from construction entrance wash rack to drain.
The wash water from the wash rack within the construction entrance will drain to the
proposed Excavated Drop Inlet Sediment Trap (ST-1).
6. Please show the existing managed slopes as shown on county GIS.
Existing managed slopes from county GIS have been shown on the re -submission.
7. Slopes steeper than 3:1 must specify plantings that can withstand steep slopes. (one example is
behind lots 43 & 44).
A note has been added to Erosion Control Phase II, Sheet C3.3, stating steep areas, such as
those behind lot 43 and 44, must be planted with covering other than grass, such as Kentucky
Bluegrass.
8. Please provide sediment trap detail and calculations from VESCH 3.13. Ensure the drainage area
to the trap is clearly shown with the drainage divide line.
No traditional sediment traps are proposed. ST-1 is an Excavated Drop Inlet Sediment Trap and
is designed per Plate 3.07-4. The detail and calculation for sizing is provided on Sheet C3.0.
9. Please show the total disturbed area (acreage) on all applicable sheets.
Total disturbed area of 2.73 acres is now shown on all associated sheets.
10. Soil types were not evident. Please ensure they are shown.
Soil types are shown on sheet C3.0 erosion notes and details.
11. Please show a stockpile and staging area.
Stockpile and staging area is provided and shown.
12. Is the site balanced? If not, please show cut/fill quantities.
Yes, the site cut/fill quantities produce a projected balanced site.
13. Please ensure the existing 48" riser and pipe are protected from sediment.
Culvert inlet protection has been added to the 48" riser and pipe.
14. Sediment trap embankment does not appear to comply with VESCH Plate 3.13-1.
No traditional sediment traps are proposed. ST-1 is an Excavated Drop Inlet Sediment Trap and
is designed per Plate 3.07-4. The detail and calculation for sizing is provided on Sheet C3.0.
15. It appears baffles are necessary in the sediment trap as the length to width is not 2:1.
Baffles have been added to the sediment trap.
We have included PDF copies of the plans and calculations for your review. If you have any questions or
comments, please feel free to give me a call at 434.327.5382 or jeremy.fox@timmons.com .
Sincerely,
Jeremy Fox
Project Engineer