HomeMy WebLinkAboutWPO202100059 Correspondence 2022-08-15608 Preston Avenue
P 434.295.5624
Suite zoo F.immo00
TIMMONS GROUP
Charlottesville, VA 22903 wwwww.timmons.mm
August 12, 2022
David James
County of Albemarle
Community Development
401 McIntire Rd, North Wing
Charlottesville, VA 22902
RE: Crozet Self Storage — VSMP Permit Plan Review (Rev. 3) — WP0202100059 - Comment
Response Letter
Dear Mr. James:
We have reviewed all of your comments from July 5, 2022 (Rev. 3) 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 submit the SWPPP.
SWPPP has been included in this submittal.
(Rev. 1): Addressed.
2. (Rev.1): Cover —Add WPO number.
WPO number has been added to the SWPPP cover.
(Rev. 2): Addressed.
3. (Rev.1): Registration Statement— Complete & sign.
Registration statement has been signed and completed.
(Rev. 2): Addressed.
4. (Rev.1): Complete Section 9 prior to plan approval.
Section 9 has been signed and completed.
(Rev. 2): Addressed.
5. (Rev.1): Complete other sections prior to pre -con.
ENGINEERING I DESIGN I TECHNOLOGY
Additional information will be added to SWPPP as it becomes known.
(Rev. 2): Acknowledged.
(Rev. 2/3): Acknowledged.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1. Please submit with the SWPPP.
SWPPP has been included in this submittal.
(Rev. 1): Addressed.
2. (Rev.1): Show SF around stockpile area.
Silt fence has been added around stockpile area.
(Rev. 2): Addressed.
3. (Rev.1): Provide concrete washout detail of containment.
Concrete washout area detail has been added.
(Rev. 2): Addressed.
4. (Rev.1): Provide mortar mixing station detail of containment.
Mortar mixing containment area detail has been added.
(Rev. 2): Addressed.
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. Show the building's roof drain connection(s).
Acknowledged. Roof drain locations will be shown in next submittal.
(Rev. 1): Not addressed.
Roof drain leaders have been added to Grading and Drainage Plan, sheet C6.0.
(Rev. 2): Acknowledged. It appears that the roof drain system ties into str. 302 based on
the drainage area map provided. If so, see comments D11 & 12 below.
Roof leader has been revised to show connection point to building, adjacent to
loading bay entrance. Roof drain ties to inlet 302, see comments D11 & 12 below.
(Rev. 3) Addressed.
2. It appears discharge from the site will enter an impaired waterway. The first assessed
waterway appears to be Lickinghole Creek. If so, it is ok to purchase nutrient credits
from within the HUC 02080204, if credits are available.
Acknowledged.
(Rev.1): Acknowledged.
Acknowledged. Nutrient credit letter of availability included in the Design Calculations
& Narrative book is from the Ivy Creek Nutrient Bank, located in HUC 02080204.
3. Please provide Letter of availability from the nutrient provider on the plans and the HUC
they're in.
Letter of availability will be included in the next submittal.
(Rev.1): Not addressed.
Nutrient credit letter of availability has been included in the Design Calculations &
Narrative book.
(Rev. 2): Not able to locate.
Nutrient credit letter of availability has been added to the Design Calculations &
Narrative book; see section 8.
(Rev. 3): Addressed.
4. Please record the SWM maintenance agreement prior to plan approval.
SWM maintenance agreement will be recorded upon preliminary approval.
(Rev.1): Not addressed.
SWM maintenance agreement will be recorded upon preliminary approval.
(Rev. %:): Not addressed.
Coordination of SWM maintenance agreement is underway with Ana Kilmer.
(Rev. 1/2/3): Not addressed.
Owner/developer is coordinating directly with Ana Kilmer to finalize SWM
maintenance agreement.
5. Provide lining (type) requirements for constructed channels.
(Rev.1): Not addressed.
Ditches have been labeled as grass -lined.
(Rev. 2): Please include the channel cross -sections or a typical section with the
appropriate lining & dimensions labeled.
Ditch sections have been added to sheet C6.2.
(Rev. 3): Addressed.
6. Provide concrete inlet shaping (IS-1) on any structure with a 4' or greater drop.
(Rev.1): Currently addressed.
All structures have less than 4' drop as currently proposed.
7. Pipe 207 (public) should be 15" min. diameter.
(Rev.1): Provide 15" diameter for pipes 210 & 208. The pipes are considered 'public' as it
carries stormwater from offsite and VDOTs ROW through the site and therefore needs
to be 15". [ACDSM, p.14].
Pipes 208 and 210 have been revised to 15" HDPE.
(Rev. 2): Revise size to 15" dia. For pipes 209 & 207 (public). Str. 210 to 200 (end) & 101
is considered public.
All 200-series and 100-series pipes were included as minimum 15" diameter in
previous submittal. No change.
(Rev. 3): Acknowledged.
8. Size storm inlet 208 & 100 (DI-1) for half -clogged condition. [VDOT DM]
(Rev.1): Provide for inlets 204. You may want to consider for inlets 100, 210 & 402.
Calculations for inlets 100, 204, 208, 210 & 402 have been revised for a half -clogged
condition.
(Rev. 2): Acknowledged.
9. Show SWIM Facility Easement for basin.
(Rev.1): Addressed.
10. Locate trees outside of drainage easements and basin embankment.
(Rev.1): Not addressed. Storm line from Str. 210 to 200 is considered public with a 20-ft
wide minimum easement and trees will need to be removed.
Easement along storm line from structure 210 to 200 has been revised to 20' wide.
Landscaping has been relocated to avoid widened easement.
(Rev. 2): The trees & shrubs within 20' buffer of embankment will need to be removed.
Trees and shrubs have been removed from stormwater maintenance easement.
(Rev. 3): Not addressed.
Stormwater maintenance easement has been revised, and landscaping has been
relocated to remain out of easement.
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11. (Rev.1): Sheet 7.0: Show the HGL in the profiles.
Hydraulic grade lines have been added to profiles.
(Rev. 2): Add note to provide water -tight seals/joints where HGL is above pipes and at
connections between dissimilar material types.
Note has been added to all storm profiles that all joints between pipes and structures
shall be water -tight.
(Rev. 3): Addressed.
12. (Rev.1/2): Note: Currently '.�Pcredits to be purchase prior to WPO bond request.
Current design requires 1.40 TP credits, which is reflected in the nutrient credit letter
of availability.
Currently needs 1.40 Ib/yr TP.
(Rev. 1/2/3): same as above.
Documentation of nutrient credit purchase has been provided to Ana Kilmer and
included in Design Calculations & Narrative book.
D. Erosion and Sediment Control Plan (ESCP)
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. Cover:
a. Add WPC# under title.
WPO number will be added in the next submittal.
(Rev. 1): Not addressed.
WPO number has been added to cover sheet.
(Rev. 2): Addressed.
b. Remove signature panel (not needed for WPO plan approval).
Signature panel will be removed in the next submittal.
(Rev. 1): Not addressed.
Signature panel has been removed from the cover sheet.
(Rev. 2): Addressed.
2. Sheet 3.0: The narrative, sequence should mention the cleanout and conversion of
sediment trap to a permanent basin.
Removal of sediment trap is included in Phase II item #5. Additional information
regarding cleanout and conversion will be included in the next submittal.
(Rev. 1): Not addressed.
Phase II sequence item #5 has been revised to clarify that accumulated sediment shall
be removed and the sediment trap shall be converted to the approved stormwater
management facility.
(Rev. 2): Acknowledged. Revise as necessary to account for area(s) draining to phase 2
sediment trap.
Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been
added to plans, and sediment trap has been calculated as sediment basin. Updated
interim drainage area has been shown on sheet C3.3. Additional information regarding
the conversion of the temporary basin to a permanent dry pond has been added to
the Sequence of Installation on sheet C3.0.
(Rev. 3): Addressed.
3. There appears to be 2+ acres drainage area that is not going to the sediment trap (ST1)
and rather the drainage is divided between the two existing culvert inlets to the south.
a. Please verify the area going to the silt fence first (no more DA than % acre per
100 LF). [VAESC HB, 3.051
(Rev. 1): Not addressed.
A diversion dike has been added to ensure that area flowing to silt fence does
not exceed 100 LF.
(Rev. 2): Addressed.
b. May need to show diversion to IP or trap.
Drainage area to the silt fence and existing inlet on the west side of the site will
be reevaluated in the next submittal.
(Rev. 1): Not addressed.
A diversion dike has been added to ensure that area flowing to silt fence does
not exceed 100 LF.
(Rev. 2): Addressed.
4. Sheet 3.3:
a. Label the inlet and/or sediment traps for this phase. Provide design & details.
No sediment traps are included on Phase II. Label will be added on the next
submittal, indicating that the dry pond will be in place.
(Rev. 1): Not currently addressed. The trap for ESC phase II will need to remain
until conversion, so it still needs to be labeled and shown. The trap appears to be
acting as a SB this phase with the riser & spillway present. Provide SB design &
details if so, or ST #2 design & details for this phase.
Erosion & Sediment Control approach has been revised per May 31 meeting,
with the riser structure installed during Phase I to allow the facility to function
as a sediment basin and to add and interim E&S phase with a dewatering
structure during basement excavation. Sediment basin design calculations have
been added to see C3.0.
A note has been added to sheet C3.4 (sheets renumbered to account for new
interim E&S phase) to indicate that the sediment basin shall remain functional
until all contributing drainage area has been stabilized, before converting to
the permanent stormwater management facility. Because the E&S Phase III
drawings are intended to show the various measures that are installed and/or
removed over the course of Phase III, the permanent dry pond is shown
graphically on this plan sheet.
(Rev. 1): Acknowledged; I believe you will need to account for the additional
drainage area (greater than lac) to sediment trap, and ST #2 design or
alternative would be necessary. See comment D11 & D12.
Per May 31 meeting, an additional interim Erosion & Sediment Control phase
has been added to plans, and sediment trap has been calculated as sediment
basin. The new Phase 11 plan also includes dewatering the building's basement
excavation through a Dirtbag sediment filtration device to account for the
additional area disturbed during this phase.
b. Show OP from pipe into basin.
Outlet protection will be added in the next submittal.
(Rev. 1): Not addressed.
Outlet protection has been added.
(Rev. 2): Addressed.
c. Provide B/M for west slope. [VAESC HB, 3.36]
Grading has been revised, and no longer exceeds 3:1.
(Rev. 1): Acknowledged.
d. (Rev. 2): Provide low -maintenance ground cover (not grass) specified on the
plans for the slopes highlighted or reduce slopes to be 3:1 or less.
Low -maintenance ground cover has been provided for slopes exceeding 3:1.
(Rev. 3): Addressed.
5. Provide 5' (min) distance between bottom of slope and silt fence (or diversion)
placement. [VAESC HB, 3.05; ACDSM].
As a result of the updated site configuration, silt fence is no longer required along the
west side of the site and has been removed accordingly.
(Rev. 1): Not addressed.
(Rev. 2): Addressed.
6. Show offsite work in an easement.
Temporary construction for offsite work will be included in the next submittal.
(Rev. 1): Not addressed.
Temporary construction easements have been added for offsite work.
a. Obtain VDOT entrance permit prior to land disturbance.
VDOT entrance permit will be obtained prior to land disturbance.
(Rev. 1): Not addressed.
Entrance permit has been submitted to VDOT and is under review.
(Rev. 2): Acknowledged.
(Rev. 2/3): Acknowledged.
7. Provide cut/fill volume estimate.
Cut/fill report will be included in the next submittal. The current design intent is for
the site to balance when accounting for pavement sections and building foundation.
(Rev. 1): Not addressed.
Cut/fill report has been included in the Design Calculations and Narrative book with
this submittal.
(Rev. 2): Acknowledged; adjust report as needed.
Cut/fill report has been updated to reflect the current design in the Design
Calculations and Narrative book.
8. (Rev.1): Show the drainage area of sediment trap.
Drainage divide to Sediment Trap #1 has been added to sheet C3.2.
(Rev. 2): Addressed for ST#1.
Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been
added to plans, and sediment trap has been calculated as sediment basin. Drainage
area during the new Phase II has been included on sheet C3.3.
9. (Rev.1): SF perimeter control should be placed here:
Silt fence has been added to sheet C3.2 & C3.3.
(Rev. 2): Addressed.
10. (Rev.1): Diversion perimeter control should be placed here:
Grading has been revised to extend ditch to channelize runoff from area behind curb.
(Rev. 2): Addressed.
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11. (Rev.2): Sheet 6.3: Account for the roof drainage area as well in sizing pipe 301.
Roof drainage area has been added to sheet C6.3 and included in the calculations for
pipe 301. HGL on sheet C7.0 has been revised accordingly.
(Rev. 3): Please update the table.
HGL calculations on sheet C6.3 have been revised to match calculations in the Design
Calculations & Narrative book.
12. (Rev.2): Sheet 3.0, 3.2, 3.3: The area to sediment trap given does not account for the
amount of area that will be draining to it during phase II. Please clarify & account for this
area in the total volume needed for the design.
Per May 31 meeting, an additional interim Erosion & Sediment Control phase has been
added to plans, and sediment trap has been calculated as sediment basin. The new
Phase II plan also includes dewatering the building's basement excavation through a
Dirtbag sediment filtration device to account for the additional area disturbed during
this phase.
(Rev. 3) Acknowledged.
Other: Email comments (06/09/2022):
1. Emergency spillway: Provide a 20' control section and extend spillway to channel.
(Rev. 3): Not addressed. Consider UD-3 or similar to drain under proposed sidewalk.
Emergency spillway has been revised to 20' wide and extended to grass -lined ditch.
Shared use path has been removed from this project, so underdrain is not necessary at
this time.
2. Provide safety fence & warning sign around sediment basin.
(Rev. 3): Addressed.
3. Extend the SP to IP at the ex. inlet 100.
(Rev. 3): Addressed.
4. C3.0 — Phase III, #6 mentions trap, change to basin.
(Rev. 3): Not addressed.
Trap text has been revised to basin.
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 434.295.5624 or email at
clint.shifflett@timmons.com .
Sincerely,
Clint Shifflett, PE
Project Manager