HomeMy WebLinkAboutWPO201800023 Correspondence 2018-07-19r�0000
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YOUR VISION ACHIEVED THROUGH OURS,
July 19, 2018
WW Associates
County of Albemarle
Dept. of Community Dev.
401 McIntire Rd.
Charlottesville, VA 22902
608 Preston Avenue P 434.295.5624
Suite 200 F 434.295.8317
Charlottesville, VA 22903 www.timmons.com
RE: Keswick Hall Energy Plant Demolition and Renovation — VSMP Permit Plan Review —
WP0201800023 - Comment Response Letter
Dear WW Associates:
We have reviewed all of your comments from April 27, 2018 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. SWPPP Section 1 — Please have the owner execute the Registration Statement Certification
(Item 12) and resubmit. Delete instructions for filling out the Registration Statement.
The registration statement shall be signed prior to final site plan approval. Instructions
have been deleted from the registration statement.
2. SWPPP Section 2 — Please provide a copy of the DEQ coverage letter when obtained.
Acknowledged, DEQ coverage shall be provided upon receipt.
3. SWPPP Section 7 — Please add the verbiage from subparagraphs (b) and (c) of 9VAC25-880-70
Part I(B)(4).
Language from 9VAC25-880-70 Part 1(B)(4) subparagraphs (b) and (c) has been added to
Section 7 of the SWPPP.
4. SWPPP Section 9 — Complete and sign the certification.
Certification to be completed and signed prior to final site plan certification.
5. SWPPP Section 10 — Per 9VAC25-880-70 Part K, provide the person with the authority to sign
inspection reports or to modify the stormwater pollution prevention plan.
Section 10 to be completed once a contractor has been selected.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1. SWPPP Section 6 PPP meets Albemarle County Code section 17-404.
Acknowledged.
CIVIL ENGINEERING I ENVIRONMENTAL I SURVEYING I GIs I LANDSCAPE ARCHITECTURE I CONSTRUCTION SERVICES
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP.
This plan is disapproved, 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 provide pre- and post -development hydrographs for Water Quantity Analysis Points 1, 2
and 3 and place on the plans.
Pre and Post -Developed stormwater calculations can be found in separate documents
titled "Design Calculations & Narrative" submitted separately to the County for review. A
digital copy shall be provided for your use and review.
2. Please provide the pre- and post -development flow path and calculations for all pre- and post -
developed drainage areas shown on the plans.
Pre and Post -Developed flow paths can be found on Sheets C6.0 & C6.1.
3. Please provide complete VRRM spreadsheets for Water Quality Analysis and place on the plans.
A VRRM spreadsheet can be found in separate documents titled "Design Calculations &
Narrative" submitted separately to the County for review. A digital copy shall be provided
for your use and review.
4. Please provide routing of the Bioretention Facility No. 1.
Routing for Bioretention Facility No. 1 can be found in separate documents titled "Design
Calculations & Narrative" submitted separately to the County for review. A digital copy
shall be provided for your use and review.
5. Please provide the planting plan and schedule for Bioretention Facility No. 1.
See Sheets L1.00 & L2.00 for planting plan and schedule.
6. Pretreatment of runoff entering Biofilter No. 1 is required. Please provide.
A gabion basket forebay wall has been provided as a method of pretreatment. See Sheet
C5.0.
7. Please provide ratio of shortest flow path to overall length calculation and graphically show on the
plan.
All nyloplast riser structures elevations shall be 0.5 ft above the bottom of the biofilter.
System short-circuiting will not occur.
8. Please note that additional comments may be generated based on response to these comments.
Acknowledged.
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. Please add WPO201800023 to the cover sheet of the plans and SWPPP.
Cover sheet and SWPPP have been updated accordingly. See Sheet C0.0 and SWPPP
documentation.
2. The County's Critical Resource Plan indicates critical slopes within the limits of clearing and
grading/limits of disturbance. Please add the critical slopes within the limits of clearing and
grading/limits of disturbance to the plan and label whether managed or preserved.
Critical slopes have been added to the plan accordingly. See sheets C2.1 & C2.2. A critical
slopes waiver has been submitted and will be reviewed by the board on September 51n
3. Please add limits of clearing and grading/limits of disturbance to the demolition Sheet Nos. C2.3
and C2.4.
The limits of disturbance have been added to Sheets C2.3 & C2.4.
4. Sheet No. C2.3 — Please add removal/demolition X's to the brick walk to the south of the Energy
Plant Building and across the drive aisle. Also, there are removal/demolition X's in the referenced
drive aisle. Please identify what is to be demolished/removed or delete these X's from the plan.
Demolition linework has been revised. The removal/demolition X's within the drive aisle
indicate the portion of the drive aisle that will be required to be removed for building
construction. See Sheet C4.0.
5. Sheet No. C2.3 — On the north side of building to be removed/demolished, a note indicates "see
arch/map plans for building and utility removal." Please note which impervious surfaces in this
area are being removed/demolished and label as such on this plan sheet.
Demolition linework has been revised to reflect the extent of impervious surfaces that are
to be removed. Existing energy building to remain.
& Sheet No. C3.1 — Silt fence along the southeast side of the swimming pool area is proposed to be
installed perpendicular to contours in several locations. Silt fence is to be installed on contour,
not across contours. Please place silt fence on tangent parallel to contour or provide other
measures to contain E&S.
Silt fence has been revised to be parallel with contours. See Sheets C3.1 & C3.2.
7. Sheet No. C3.1 — Silt fence break is noted as a measure to be provided. This control measure is
not a Virginia Erosion and Sediment Control -approved device. Please adjust plan accordingly to
depict approved control measures or submit a variation request.
Acknowledged. The silt fence break has been removed from the plans and E&SC
measures have been adjusted accordingly.
8. Please add TP tree protection symbol to the legend on E&SC Phases I and II plan sheets.
The tree protection symbol has been added to the legend on E&SC Phases 1 and 2.
9. The CWD (Clean Water Diversion) is to be released through a stabilized outlet or channel.
Please provide a stabilized outlet such as rip -rap outlet protection.
CWD will no longer be utilized to convey storm water. See sheet C3.2.
10. It is noted that the Phase I (Sheet No. C3.1) Construction Entrance (CE) is not shown on the
Phase II E&SC plan Sheet No. C3.3. CE's are to be provided until County E&S Inspector allows
removal. Please adjust Phase II E&SC plan to include Phase I CE.
E&SC Phase 2 plans have been revised to show construction entrances. See Sheets C3.3
& C3.4.
11. Sheet No. C3.3 — Please show the drip line of the existing tree to remain located just south of the
SFB symbol.
Acknowledged. This tree is to be removed as part of the proposed demolition and
improvements incorporated within this plan set. See sheet C3.3.
12. The narrative on Sheet No. 3.0 under offsite areas states that some utility connections will be
offsite. These areas are to be shown if ground is to be disturbed to include erosion and control
measures.
This portion of the narrative has been revised. All utility connections will take place onsite.
13. Please show stockpile location on plan.
A stockpile location has been provided west of the Bioretention Facility 1. See Sheet CM.
14. Please verify that cut or fill balances have a deficit of 10,000 C.Y. or less.
Cut or fill balances will have a deficit of 10,000 C.Y. or less.
15. Please identify contractor staging/laydown area and parking area.
Staging/laydown areas have been indicated accordingly. See Sheets C3.1 & C3.2.
16. A closed conduit storm drain system is shown on the north side of the energy plant. Please
provide inlet protection if these structures are inlets.
Inlet protection has been provided accordingly. See profile on Sheet C5.0 for structure
information.
17. Please provide outlet control calculations for the rip -rap at structure 600.
Outlet control calculations have been provided for structure 610 (formerly structure 600).
See Sheet C5.0.
18. In accord with VE&SCH Standards and Specifications 3.13 Sediment Traps, the maximum height
of the sediment embankment shall be 5 feet as measured from the base of the store outlet (see
VE&SCH page III-73 Embankment Cross -Section and page III-74 plate 3.13-1). Sediment trap
ST-1 embankment height exceeds this requirement by approximately 5 feet. Please provide an
erosion and sediment control measure that meets the VE&SCH requirements for this drainage
area.
Proposed sediment trap has been relocated further down the slope. Embankment height
has been reduced to meet VE&SCH requirements. See Sheet C3.2.
19. No drainage computations for the closed conduit storm drain system were provided. Please
provide storm drain inlet and storm drain pipe calculations as well as drainage area map for the
closed conduit storm drain system.
Drainage computations for the closed conduit storm drain system can be found in
separate documents titled "Design Calculations & Narrative" submitted separately to the
County for review. A digital copy shall be provided for your use and review.
We have included hard 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.
Sincerely,
Andrew Allison
Project Engineer