HomeMy WebLinkAboutWPO201900021 Review Comments WPO VSMP 2019-12-06COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project:
Plan preparer:
Owner or rep.:
Plan received date:
(Rev. 1)
(Rev. 2)
(Rev. 3)
Date of comments:
(Rev. 1)
(Rev. 2)
(Rev. 3)
Reviewer:
WP02019-00021
VSMP Permit Plan review
UVA Research Park Loop Road — VSMP Plan
Jonathan Showalter, Timmons Group f onathan.showalter(a)timmons.com]
608 Preston Ave., Suite 200 / Charlottesville, VA 22903
University of Virginia Foundation / P.O. Box 400218
Charlottesville, VA 22904 [tmarshallAuvafoundation.com]
25 Mar 2019
21 Jun 2019
3 Sep 2019
15 Nov 2019
8 May 2019
9 Aug 2019
17 Oct 2019
6 Dec 2019 —Approve pending Nutrient credit purchase: 0.27 lb.
John Anderson
County Code section 17-410 and Virginia Code §62.1-44.15:34 requires the VSMP authority to act on any
VSMP permit by issuing a project approval or denial. This project is approved pending Nutrient credit
purchase (0.27 lb.). Maintenance Agreement at Book/Page 05245 / 0492-00500. Bonds in process.
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.
a. Sec. 1 (Registration Statement): Revise to include:
i. An e-mail address for Todd Marshall, UVA Foundation (Rev. 1) Addressed.
ii. Registration Statement signature (Rev. 1) Acknowledged. Applicant response: `A
signature will be provided once a contractor has been selected.' Acceptable to
Engineering
b. Sec. 9 (Signed Certification): Please sign (Rev. 1) Acknowledged. Applicant response: `A
signature will be provided once a contractor has been selected.' Acceptable to Engineering.
c. Sec. 11 (General Permit Copy) Please include 2014 VAR10 (Rev. 1) Partially addressed. As
follow-up: please replace 23-pg. 2014 General VPDES Permit with 2019 General VPDES Permit
(link:
https://www.deq.vir ig nia.gov/Portals/O/DEQ/Water/StormwaterManagement/CGP%20ADA/CGP2019.pdf?v
er=2019-05-06-131630-407 ) (Rev. 2) Addressed.
d. List WP02019-00021 on cover of SWPPP (Rev. 1) Addressed.
e. New: Sec. 7, Enhanced inspection frequency changed with 2019 General VPDES Permit. Please
ref. II G.2.a (pg. 13 /.PDF —ref. link, above). Revise Sec. 7, SWPPP. (Rev. 2) Addressed.
The PPP content requirements can be found in County Code section 17-404. Rev. 2 Although comment
response letter, August 27, 2019, indicates items 1,2,3, below, were addressed, Exhibit included in SWPPP
Engineering Review Comments
Page 2 of 6
d. 27 Aug 2019 (sent w email 10/16/2019 8:25 AM) does not address these items; suspect prior version of
Exhibit sent inadvertently. Please send revised PPP Exhibit.
1. If Sec. 6 PPP Exhibit is revised, please provide an updated Exhibit (Rev. 1) Partially addressed. As
follow-up: Include rectangle labeled concrete washout for dedicated concrete truck washout (differs from
mortar mixing station). (Rev. 2) Comment persists. (Rev. 3) Addressed.
2. New: Indicate rain gauge location (`x' or rectangle or similar). Label rain gauge. (Rev. 2) Comment
persists. (Rev. 3) Addressed.
3. New: Recommend revise construction entrance label /legend to ref. paved construction entrance (PCE).
(Rev. 2) Comment persists. (Rev. 3) Addressed.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP.
This plan is approved.
Revise plan title to include ref to VSMP /WPO20900021. (Rev. 1) Addressed.
VSMP Plan and Road Plan Design Calculations & Narrative, 3/25/19:
a. SWM Quantity Narrative —Include information highlighting (via prior -approved graphic, narrative,
zoning, site, or WPO data) how eastern side of project drains to a large wet pond that was designed
to handle stormwater quantity for the full build out of the research park. Recommend information
identical to Timmons Group Lewis and Clark Drive Road Extension VSMP Plan and Road Plan
Design Calculations & Narrative booklet, d. 3/25/19, pg. 18-19. (Rev. 1) Addressed.
b. LD-229: Provide computational data requested at D. ESC Plan, items 7 and 8. (Rev. 1)
Addressed.
c. Revise SWM routings — see items 14, 15, below. (Rev. 1) Addressed. Also, items 14, 15, below.
3. Ensure dry pond design details on VSMP /WPO match design details on SUB201900049, or preferably
limit design detail provided for dry pond on the Road Plan to conceptual outline, saving details for the
VSMP /WPO Plan. (Rev. 1) Partially addressed. As follow-up: See item 18.d., below. (Rev. 2)
Addressed. Applicant response: `Acknowledged plan is developed as one set with select sheets included in
the road or VSMP plan as necessary.'
4. Show proposed SWM Facility /Access /Drainage Easements. (Rev. 1) Partially addressed. As follow-up:
Revise `10' wide grass access road' label to `SWM Facility Access.' Outline SWM Facility easement/s.
(Please show /label SWM Facility Access on SUB201900106 —UVA Research Park Loop Road Final Plat.)
(Rev. 2) Addressed.
5. Provide curb break /mountable curb to provide SWM Facility Access (ACDSM, pg. 12). Provide access
label or note on plan and linework with proposed grading that meets ACDSM standard, text ifna e, bo!&W,
for dry pond Access: (image removed w/ Rev. 1 comments) (Rev. 1) Addressed.
6. Provide typ. detail, transition from CG-6 to mountable (rolltop) curb at point of SWM facility access. (Rev.
1) Not addressed. Applicant response: `Detail has been added to sheet C 1. L' Sheet C 1.1 is not included
the plan, and C1.1 is not listed in C0.0 sheet list table. Please restore typ. detail from C1.1 to plans. (Rev.
2) Addressed.
7. Recommend ref SUB201900049, UVA Research Park Loop Road (Road Plan), on C0.0. (Rev. 1)
Addressed.
8. Sheet C1.1 is not strictly necessary. Recommend remove this sheet from the VSMP /WPO Plan.
(Rev. 1) Addressed. Also, see item 6., above. (Typ. detail).
9. C1.2: Provide VDOT IS-1 detail (inlet shaping). (Rev. 1) Not Addressed. Ref. items 6./8.; restore
detail to plans. (Rev. 2) Addressed.
10. C4.2, C4.3 are not strictly necessary. Recommend remove these sheets from the VSMP /WPO
Plan. (Rev. 1) Addressed.
11. C5.3 is not strictly necessary. Recommend remove this sheet from the VSMP /WPO Plan. (Rev.
1) Addressed.
12. C6.1 /Stormwater Quality: VSMP Plan and Road Plan Design Calculations and Narrative (booklet)
Engineering Review Comments
Page 3 of 6
3/25/19 submitted with SUB201900049 does not appear to include runoff reduction spreadsheet
(VaRRM.xls); apparently no booklet submitted with WP0201900021. Provide VaRRM.xls.
(Only booklet ref. to Water Quality in booklet, image below —pg. 3) (Rev. 1) Partially addressed. The
only VaRRM.xls data included with Cale. booklet is Drainage Area `A' , which appears three
times: twice with DA total acreage of 2.10 Ac., once with DA total acreage of 2.80 Ac. Please
review /revise calculation booklet to include VaRRM.xls site, water quality compliance, runoff
volume and CN, and summary tab information, and as many discrete drainage area tabs as there
are DAs routing to a BMP practice. It may be that DA `A' appears multiple times to reflect
routing to practices 16 and 17, but all three DA `A' tab data appear to relate to the filtering device.
(Rev. 2) Addressed.
WATER QUALITY CALCULATIONS:
SUMMARY FROM RUNOFF REDUCTION SPREAD SHEET FOR
REDEVELOPMENT (SEE CALL. BOOK1:
DISTURBED AREA (SOUTHERN PORTION OF PROJECT AREA): 2.10 ACRES REQUIRED REMOVAL: 1.29 LBSIYR
POST -DEVELOPMENT LAND COVER. 1.02 LBS1YR TO BE TREATED VIA MANUFACTURED TREATMENT DEVICE. TREATMENT WILL RUN IN
B SOILS.- LINEAR SERIES THROUGH BARRACUDA TO SC-740 STORMTECH CHAMBER WITH ISOLATOR ROW
1.40 AC TURF REMAINING 0.27 LBS) YR OF REQUIRED NUTRIENT CREDITS TO BE PURCHASED FROM A
0,70 AC IMPERVIOUS DEO-APPROVED NUTRIENT CREDJT BANK IN ACCORDANCE WITH VA CODE 62.1-44.15:35
13. Note: Applicant must coordinate nutrient credit purchase with Ana Kilmer, Albemarle County,
once plan review comments are addressed prior to purchasing credits. Purchase of nutrient credits
is required for VSMP plan approval. (Rev. 1) Partially addressed. Applicant response: `Design
has been revised so that offsite credit purchase is no longer necessary.' This is not immediately
apparent. See item 12, above. Include VaRRM.xls data with calculation booklet, or VaRRM.xls
data clearly presented on plans so that site and summary data depict phosphorus load reduction
required, and practices which reduce phosphorus to the point that offsite credit purchase is not
required. Please do not send VaRRM.xls to reviewer to address this comment, since email or e-
attachments are not approved with a VSMP /WPO plan. Engineering, however, appreciates digital
VaRRM.xls submittals. Please confirm if .xls sent via email, and if so, date sent. (Rev. 2)
Addressed. Applicant response: `Offsite credits will be purchased. Credit availability letter has
been included with submission. Digital version of VaRRM spreadsheet was emailed to John
Anderson 8/27/2019.' Note: Plan proposes purchase of 0.27 lbs/yr phosphorus nutrient credits.
14. C6.1: A fair portion of the 3.10 Ac. off -site post -development area cannot reach the dry pond
without inlet west of N-S leg of loop road similar to inlet south of E-W section of the loop road.
See images, >, (blue outlined area) (images removed w/ Rev. 1 comments). Please provide inlet
/pipe connection to route this off -site runoff to the dry pond, to qualify for quantity compliance as
well as to collect flow at an otherwise low -point that lacks drainage outfall, unless runoff is to
sheet over the curb onto the paved surface. (Rev. 1) Withdrawn. Review of development plans
for areas west will likely accommodate drainage needs at this location. Applicant response
(acceptable in interim): `The area indicated sheet flows over the curb or across the edge of
pavement and flows to the gutter and inlet.' (inlet 114)
C5.1: offsite routed low point without collection — blue circle /highlight (contour 576'f):
15. Ensure plan CN /Acreage match routing report values. Sub -catchment 3S, 9S report values do not
match plan data. Revise routings, consistent with plan sheet C6.1. /" (images removed w/
Rev. 1 comments): (Rev. 1) Addressed.
16. L10: VDOT Std Class Al riprap dimensions need not appear on this sheet. (Rev. 1) Addressed.
Sheet L1.0 removed from WPO plan set.
17. L10: Recommend shift leader line of label reading `Tie to nearest inlet (Typ.)' to more clearly
indicate UD-4 (Typ) is to tie to nearest inlet. (Rev. 1) Addressed. L1.0 removed from WPO plan
set.
18. Choose BMP practice from approved list, or an approved proprietary measure
i. Use plan labels that identify /match a best management practice listed at
https://www.swbmp.vwrrc.vt.edu/ (text image below) (images removed w/ Rev. 1
comments): (Rev. 1) Partially addressed. Applicant response: `Labels added to
sheet C5.0 calling out Stormtech Isolator Row (Practice 17, filtering device) and
Engineering Review Comments
Page 4 of 6
Baysaver Barracuda (Practice 16, hydrodynamic device).' As follow-up: Please
provide design plan /profile details for Str. 102 (flow-splitter) —see example;
photos, below. (Photo below removed with Rev. 2 comments.) Include elevations.
(Rev. 2) Addressed.
b. If design proposes an Extended Detention (ED) Pond, use link to visit the Clearinghouse
and carefully consider design criteria listed at VA DEQ Stormwater Design Specification
No. 15, Section 6, including:
i. 6.1 — Overall Sizing
ii. 6.2 — Treatment Volume Drawdown and Detention Design
iii. 6.3 — Requied Geotechnical Testing
iv. 6.4 — Forebay Design
v. 6.5 — Conveyance and Overflow
vi. 6.6 — Internal Design Features
vii. 6.7 — Landscaping and Planting Plan
viii. 6.8 — Maintenance Reduction Features
ix. 6.9 — ED Pond Material Specifications
c. Provide detailed plan and profile for a listed practice that meets design criteria.
d. Provide Landscaping and Planting Plan
Example of partially approved Ex. Det. Pond profile /recent VSMP /WPO Plan submittal
(photo, below): (photo removed w/ Rev. 1 comments) (Rev. 1) Partially addressed. Applicant
response: `Extended detention is not provided as part of this project. A dry pond will be used
to control stormwater quantity, but it will not be considered a BMP for stormwater quality.'
As follow-up: A SWM quantity measure requires design plan /profile detail and calculations
comparable to a SWM quality facility. Provide plan /profile, design and calculations that
demonstrate design intent, consistent with HydroCAD routings. Profile information, in
particular, is essential for construction, inspection, bond estimates, and As -built comparison
with design. C6.0 /C7.0 plan and riser details are insufficient. Label pond floor dimensions.
(Rev. 2) Partially addressed. Note: Dry pond is a SW quantity measure. Design detains the
100-yr event volume, with 1-ft. freeboard with no emergency spillway. Ref. plan sheet 7.0.
Asfollow-up: Dry Pond DI -I Riser Structure 302 Detail and Str. 302 profile remain
confusing. Provide sufficient detail to clarify design; plan view design data is essential:
• Structures:
o DI-1 wall
■ show location of DI-1 wall relative to what appears to be a
weir structure (see detail).
o Weir: ffweir plate proposed, show location relative to DI-1, and riser.
o Riser:
■ Diameter if cylindrical; dimensions if rectangular.
■ Location /design relative to outfall, DI-1 structure, weir.
• Clarify whether there are 3, or 2, or 1 structure/s (Riser, DI-1, weir).
• Include profile, detail, and especially plan views that make clear how these
structures function, relate, and will be installed. Clarify meaning of 12 " thick DI-1
wall beyond, and since DIs are typically closed at the top (with horizontal not vertical
openings), clarify how riser is to be built. It appears almost as if a DI-1 is proposed
behind a weir wall, but if this is the case, how will a trash rack work or be affixed.
Please study final submittal for clarity with respect to dry pond structure outfall.
(Rev. 3) Addressed.
19. Additional SWM Plan (VSMP /WPO) review comments possible, once plan re -submitted. (Rev.
1) Applicant response: Acknowledged.
20. New: Provide additional legible terrain contour labels west of Loop Road. (Rev. 2) Addressed.
21. New: Compare C3.3 pipe layout, which appears to route runoff north, then east, off -site, bypassing
dry detention pond, with C6.1 post -developed routed area/s. If area shown in top image below
bypasses dry detention pond, please revise relevant plan sheets, revise routings, design, etc. (Rev.
2) Addressed. (Images incl. with Rev. 1 comments removed with Rev. 2 review comments.)
22. New: Revise typo at 8/26 Calculations Report,.33, Water Quality: `The remaining 0.28 lbs/yr of
Engineering Review Comments
Page 5 of 6
required nutrient credits area to be...' to read "The remaining 0.27 lbs/yr of required nutrient
credits are to be...' (Rev. 3) Addressed. As follow-up: please send pg. 3 of Cale. report to confirm
revision (.PDF).
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 approved.
1. C3.1: Provide Paved Wash Rack detail (ACDSM, pg. 8) (Rev. 1) Addressed.
C3.2:
2. Show break in SSF at stone weir outfall, ST2. (Rev. 1) Addressed.
3. Label ST1, ST2 stone weir dimensions (L X W) in plan view. (Rev. 1) Addressed.
4. C3.3: Provide Str. # consistent with C3.0 Phase II Sequence. (Rev. 1) Partially addressed. As
follow-up: Please see /address New SWM Plan comment 21, above. (Rev. 2) Addressed. Note:
bypass pipe has been removed from phase II.
5. Cannot locate temporary 15" HDPE pipe. Edit /revise C3.0 Phase I sequence, as needed. (Rev. 1)
Addressed.
6. C3.3: Check C3.0 Phase 11 sequence Note 2.1 against C5.0. Revise if pipe /str. ref, should be Str.
300, 301. (Rev. 1) Addressed. Applicant response: `Note 2.1 on C3.0 has been revised to clarify
that storm system associated with dry pond must be operational prior to removal of temporary
HDPE pipe, which allows offsite runoff to bypass project site during construction' (Image incl.
with Rev. 1 comments removed with Rev. 2 review comments.)
7. LD-229 submitted with SUB201900049 does not appear to include design computations for pipe 301.
Evaluate design flow and discharge velocity against pipe capacity and riprap outfall dimensions. (Rev. 1)
Not addressed. Applicant response: `Pipe 301 is routed as part of the Hydrocad analysis for the dry pond.'
Please indicate, using Hydrocad analysis or other means, that pipe 301 capacity and riprap at pipe 301
outfall are sufficient to meet Q2-ve1./10-capacity (dry pond) routed flows. Also, see dry pond riser structure
detail (image, below). Routings include relevant parameters, but do not explicitly address this comment.
(Rev. 2) Addressed. Note: Cale booklet, p. 8 riprap Min. sizing (w1 =4.5', w2 =5.1', L = 9') is consistent
with plan sheet C5.0: (wl =6', w2 =6', L = 9'). (Images incl. with Rev. 1 comments removed with Rev. 2
review comments.)
8. Evaluate discharge velocity against riprap outfall, Str. 200 /VDOT ES (capacity appears sufficient). (Rev.
1) Addressed.
The VSMP permit application and all plans may be resubmitted for approval when all comments have been
addressed. For re -submittal, please provide .PDF preview prior to print submittal.
Engineering plan review staff is available from 2-4 PM on Thursdays if you wish to meet to discuss this review.
Process
After approval, plans will need to be bonded. The bonding process is begun by submitting a bond estimate request
form and fee to the Department of Community Development. One of the plan reviewers will prepare estimates and
check parcel and easement information based on the approved plans. The County's Management Analyst will
prepare bond agreement forms, which will need to be completed by the owner and submitted along with cash,
certificates or sureties for the amounts specified. [Note: bonds in process] The agreements will need to be approved
and signed by the County Attorney and County Engineer. This may take 2-4 weeks to obtain all the correct
signatures and forms.
Stormwater Management Facilities Maintenance agreements will also need to be completed and recorded. The
County's Management Analyst or other staff will prepare the forms and check for ownership and signature
information. The completed forms will need to be submitted along with court recording fees. [Note: Agreement is
Engineering Review Comments
Page 6 of 6
recorded at Book/Page 05245 / 0492-00500.]
After bonding and agreements are complete, county staff will need to enter project information in a DEQ database
for state application processing. DEQ will review the application information based on local VSMP authority
approval. At this time, the DEQ portion of the application fees will need to be paid directly to the state. For fastest
processing, this is done electronically with the emails provided on the application (SWPPP Registration Statement).
DEQ should notify applicants with instructions on how to pay fees. When DEQ approves the application, they will
issue a permit coverage letter. This should be copied to the county.
Easements must be recorded prior to VSMP approval. Proof of purchase of nutrient credits is required for final
WPO plan approval, and to receive a Grading Permit.
After DEQ coverage is issued, the County can hold a pre -construction conference. Applicants will need to complete
the request using a pre -construction conference form, and pay the remainder of the application fee. The form
identifies the contractor and responsible land disturber, and the fee remaining to be paid. This will be checked by
county staff, and upon approval, a pre -construction conference will be scheduled with the County inspector. At the
pre -construction conference, should everything proceed satisfactorily, a grading permit will be issued by the County
so that work may begin.
County forms can be found on the county website forms center under engineering;
htW://www.albemarle.orgJdeptforms.asp?departinent--cdengno
Ifyou have questions /concerns, please contact me at janderson2galbemarle.org or at 434.296-5832-x3069.
Thank you
J. Anderson, Engineering Div.
WP0201900021 UVA Research Park Loop Road 120619rev3