HomeMy WebLinkAboutWPO201800030 Review Comments WPO VSMP 2018-12-26COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Project title:
Project file number:
Plan preparer:
Owner or rep.:
Plan received date:
(Revision 1):
(Revision 2):
(Revision 3):
Date of comments:
(Revision 1):
(Revision 2):
(Revision 3):
Reviewer:
VSMP Permit Plan Review
Charlottesville Albemarle SPCA
WP0201800030
Timmons Group, John Wilson, P.E.john.wilson@timmons.com
Charlottesville Albemarle Society for the Prevention of Cruelty to Animals
30 April 2018
24 July 2018
18 Oct 2018
21 Dec 2018
01 June 2018
03 August 2018
27 Nov 2018
26 Dec 2018
WW Associates, Inc.
(Rev. 2/3: J. Anderson /Albemarle Co.)
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 denied for reasons listed, below. The
VSMP application content requirements can be found in County Code section 17-401.
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 ESOP, (3) a SWMP, and (4) any TMDL measures necessary.
1. Please add WP0201800030 to the cover sheet of the SWPPP, plans, and stormwater management calculations
package.
Revision 1 Response: WPO# has been added to Plans, SWPPP, and calculations.
Revision 1 Comment: Comment addressed.
2. SWPPP Section 1— Please provide a registration statement that is completed to include the certification. Please
delete instructions for completing the registration statement.
Revision 1 Response: Registration statement has been sent to the owner for signature. We acknowledged that a
signed registration statement is needed for the SWPPP prior to plan approval.
Revision 1 Comment: Acknowledged. (Rev. 3) Not addressed.
3. SWPPP Section 2 Please provide a copy of the DEQ coverage letter when obtained.
Revision 1 Response: DEQ coverage letter will be added when obtained.
Revision 1 Comment: Acknowledged.
4. SWPPP Section 7 Impaired water status cannot be verified as registration statement is not completed.
Revision 1 Response: Acknowledged.
Revision 1 Comment: Comment not addressed. The discharge is to DEQ identified impaired waters.
Please include the verbiage contained in 9VAC25-880-70(B)(4)(b) and (c) and (13)(4)(d)(1) and (2). (Rev.
2) Addressed.
5. SWPPP Section 8 — Please provide the information requested.
Engineering Review Comments
Page 2 of 8
Revision 1 Response: Qualified personnel shall be provided once a contractor has been selected.
Revision 1 Comment: Acknowledged. (Rev. 2) As follow-up: Provide a named individual. SWPPP cannot be
approved without listing an individual. Sec. 10, Delegation of Authority, may be used to transfer authority,
later. Recommend list Timmons Group qualified personnel. (Note: may amend SWPPP at pre -construction, by
which point GC /RLD will be selected /known. Also, item #9, below.) (Rev. 3) Not addressed.
6. SWPPP Section 9 — Please complete and sign the certification.
Revision 1 Response: Certification has been sent to the owner for signature. We acknowledged that a signed
certification is needed for the SWPPP prior to plan approval.
Revision 1 Comment: Acknowledged. (Rev. 3) Not addressed.
SWPPP Section 10 — Per 9VAC25-880-70 Part K, please provide the person with the authority to sign
inspection reports or to modify the stormwater pollution prevention plan.
Revision 1 Response: This information will be provided once a contractor has been selected.
Revision 1 Comment: Acknowledged. (Rev. 2) Asfollow-up: Engineering recommends delegate authority to
GC /RLD at Albemarle County -Applicant pre -construction meeting. (Rev. 3) Acknowledged.
8. Please note that additional comments may be generated based on responses to these comments.
Revision 1 Response: Acknowledged.
Revision 1 Comment: Acknowledged. (Rev. 2) — See item #9, below. (Rev. 3) Not addressed.
9. New: Provide a named individual responsible for pollution prevention practices, SWPPP, Sec. 6.E.
This may be Timmons Group personnel; SWPPP cannot be approved without listing an individual. (Rev. 3) Not
addressed. Applicant response: `We prefer to wait until the SPCA has selected a general contractor before
providing this information.'
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
SWPPP Section 6 PPP meets Albemarle County Code Section 17-404 requirements.
Revision 1 Response: Acknowledged.
Revision 1 Comment: PPP approved.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This
plan is disapproved for the single reason listed below —item #7. The stormwater management plan content
requirements can be found in County Code section 17-403.
1. Please provide Owner's phone number and email address for the Owner to receive correspondence.
Revision 1 Response: This information has been added to the cover sheet.
Revision 1 Comment: Comment addressed.
Please provide closed conduit storm drain pipe and drop inlet or curb drop inlet calculations using VDOT
LD229 and LD204 worksheets (see VDOT Drainage Manual and Section 6 Drainage Systems of the Albemarle
County Design Standards Manual).
Revision 1 Response: Albemarle County design standards manual calls for stormwater calculations to be
presented in a tabular format. We feel that the calculations as presented provide the pertinent information for
the pipe/inlet design.
Revision 1 Comment: Comment not addressed. The Albemarle County VSMP/ESC Program Authority
Administrator requires submission of inlet computations on VDOT Form LD204 and storm drain pipe on
VDOT Form LD209 or a similar form that includes all the information presented on the sited VDOT forms to
include the required storm event(s) (inlets throats 4"/hour and 10-year check storm and pipe system at the 10-
year storm). (Rev. 2) Partially addressed. At sag inlet 2H: Revise inlet throat length to ensure Spread (T) <
6'. (6' = half 12' parking aisle width.) See Table, C5.1. (Rev. 3) Addressed.
Engineering Review Comments
Page 3 of 8
The drainage area divides on the Phase 2 E&SC plan does not address where roof runoff from the existing
building and the northern most and southern most new building additions enters the closed conduit storm drain
system. It appears that roof drainage is directed to existing structure "A". Please provide closed conduit storm
drain calculations from existing structure "A" to existing structure "G" and reroute the existing underground
detention system.
Revision 1 Response: Roof drainage drains to structure "A". See Sheets C6.2 and C5.1.
Revision 1 Comment: Comment addressed.
It appears that structures "C" and "2F" are stormceptors and appears to be of the inlet type. It appears that an
OSR model is proposed as based on Figure 3 presented in the design calculation booklet. Please provide sizing
calculations and Stormceptor Model No. to demonstrate that proper size unit is being provided as based on the
flow directed to the unit. Also, provide the proper inlet/outlet drop per the stormceptor technical data sheet for
the selected unit (or denote custom design).
Revision 1 Response: Stormceptor sizing information as well as details have been added to Sheet C5.1.
Revision 1 Comment: Comment addressed.
5. Please provide the numeric identifier on each underground detention facility to match that indicated in the
Model Schematic (Figure 4 of the design calculation booklet) and show on plan sheet (C4.2) and detail sheet
(C5.1)
Revision 1 Response: Detention facilities have been numbered to match the calculations. See Sheet C4.2.
Revision 1 Comment: Comment addressed.
Please provide soil group and soil surface description to facilitate verification of weighted CN for each
subbasin's input data in the design calculation booklet.
Revision 1 Response: This information has been added to the calculations book.
Revision 1 Comment: Comment addressed as based on item 2 of the storm sewer computation notes on
sheet C5.1 and the response to Comment 10 below states that the entire site is within hydrologic soil
group B.
Please provide stage discharge curves and routings of 1 and 10-year storm events for New Det 01 and New Det
02.
Revision 1 Response: This information has been added to the calculations book.
Revision 1 Comment: Comment does not appear to be addressed. The requested information was not
observed in calculation package. Please provide requested information. (Rev. 2) Partially addressed. As
follow-up: Please revisit /edit 1- /10-yr pre- /post -development table on C5.1 to clarify pre- /post- point of
comparison (`ditch' v. Kegler's pond). Clarify channel protection and flood protection narrative on C5.0.
Please bridge statements that `the post developed flow is being reduced to be less than the pre -developed flow'
(channel protection) and (flood protection) that `post -development flows are confined to the stormwater
conveyance systems' with Fig. 4 schematic, which is somewhat difficult to interpret. It is difficult, for example,
to identify Kegler's Pond (Fig. 4). Engineering appreciates 1 % point of analysis (Pond), and 110 pg. of
supporting data /graphs, but requests C5.1 and Cale. package distill relevant pre- /post, 1- /10-year routings at
point of discharge to manmade (ditch) conveyance. Nothing between site discharge to ditch and Kegler's Pond
should reduce or increase 1- /10-yr peak discharge from on -site detention systems. Also, provide explicit
computations that show ditch conveys the 10-yr event at point of site discharge to ditch. Engineering welcomes
.PDF preview.
Fig. 4 — Model schematic, Cale. Package, p. 5:
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C5.1 1- /10-yyear pre- /post -development peak flow table
THE PEAK FLOWS LISTED BELOW ARE FOR PRE AND POST RUNOFF
CONDITIONS AT THE POINT OF ANALYSIS, AS NOTED IN THE
STORMWATER MANAGEMENT NARRATIVE. THE PEAK FLOW REDUCTION
OCCURS DUE TO THE INSTALLED DETENTION SYSTEMS
1 YEAR, 24 HOUR STORM
PRE -DEVELOPMENT SITE
12.03 CFS
POST -DEVELOPMENT SITE
11.80 CFS
10 YEAR, 24 HOUR STORM
PRE -DEVELOPMENT SITE
57.20 CFS
POST -DEVELOPMENT SITE
54.46 CFS
Engineering Review Comments
Page 4of8
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(Rev. 3) Partially addressed. Asfollow-up: Please revise W5.1-up: Please revise W5.1) to include 2-yr. Veloci!Y, 2-yr, Ditch to Kegler's
Pond /Post (Ref 9VAC25-870-66.B.1.a. Provide soil stabilization blanket, VESCH Std. & Spec. 3.36, if necessary.
(Ref. C5.1 image, below)
rOf\ I /QQ ti
GRASSCHANNEL�
ROUGHNESS = 0.05
SLOPE = 2.5%
01 = 11.80 CIS
C54 46 cfs
OCITY = 3.28 FPS
DEPTH = 1.92'
DITCH TO KEGLERS POND POST
No Scale
Engineering Review Comments
Page 5 of 8
9 VAC25-870-66.B.1.a.
B. Channel protection. Concentrated stormwater flow shall be released into a stormwater conveyance system and shall
meet the criteria in subdivision 1, 2, or 3 of this subsection, where applicable, from the point of discharge to a point to the
limits of analysis in subdivision 4 of this subsection.
1. Manmade stormwater conveyance systems. When stormwater from a development is discharged to a manmade
stormwater conveyance system, following the land -disturbing activity, either:
a. The manmade stormwater conveyance system shall convey the postdevelopment peak flow r e from the two-
year 24-hour storm event without causing erosion of the system. Detention of stormwat r or do ream
improvements may be incorporated into the approved land -disturbing activity to meet this criterion, at the
discretion of the VSMP authority, or
b. The peak discharge requirements for concentrated stormwater flow to natural stormwater conveyance systems
in subdivision 3 of this subsection shall be met.
8. Please provide the name of the DEQ certified facility that is intended to provide nutrient credits. Provide
VAHUC for the project site and for the nutrient credit facility.
Revision 1 Response: This information has been provided with this submission.
Revision 1 Comment: Comment addressed.
It appears that the existing underground detention upstream to the existing bioretention facilities is modeled
with a Tc of 5 minutes. Please provide calculations demonstrating a Tc of 5 minutes.
Revision 1 Response: Water is conveyed to the existing detention facility via the onsite storm system.
This area is primarily asphalt and has a low time of concentration therefore the minimum allowable Tc
was used.
Revision 1 Comment: Comment addressed.
10. Please correct the VRRM site summary as per sheet No. C5.3 denotes a portion of the site is in hydrologic soil
group B Glenelg and a portion is within hydrologic soil group C Elioak.
Revision 1 Response: The plan sheet shown on C5.3 is from an older plan and is provided for reference only.
Current soils information is shown on Sheet C6.1, which shows that the entire site is within soil group B.
Revision 1 Comment: Comment not addressed. No soils information is shown on sheet C6.1 as stated.
Please turn on the soils layer to include soils boundary and soils designation and add to the legend. (Rev. 2)
Addressed. Soils boundary and designation information are shown on C5.3 and C6.2.
11. Please note that additional comments may be generated based on responses to these comments.
Revision 1 Response: Acknowledged.
Revision 1 Comment: Please note that additional comments may be generated based on responses to
these comments.
12. New: Please revise C3.0 sheet title to read 'Site Layout.' A WPO plan cannot approve a site plan. (Rev. 3)
Addressed.
13. New: Copy Figs. 2 and 3 (Detention Pipe Maintenance /Stormceptor Maintenance Depth), pg. 3, Stormwater
Management Calculations Package (10/12/18), to WPO Plan sheet/s. (Rev. 3) Addressed.
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. The County's Critical Resources Plan denotes managed critical slopes throughout the parcel. Please denote the
Engineering Review Comments
Page 6of8
location of the managed slopes with a symbol and add to the legend.
Revision 1 Response: Critical slopes have been added to Sheets C6.0 and C6.1.
Revision 1 Comment: Comment addressed.
Please provide a top of wall spot elevation at the northeast corner of the eastern most new parking lot to verify
that retaining wall height is not greater than six feet as it appears that the retaining wall is located within a
managed critical slope area.
Revision 1 Response: A spot has been shown in the requested area. See Sheet C3.1.
Revision 1 Comment: As based on the elevations given, the height of the retaining wall north of the terminus of
the northern most new parking area exceeds 6 feet and is within the managed steep slope overlay district. Either
reduce the wall height to under 6 feet of provide a double tiered wall system. (Rev. 2) Partially addressed.
BOW spot elevation (27.87') is shown. Please provide /restore TOW spot elevation. TOW appears to tie to
elev. 534'. (Rev. 3) Addressed.
Please address pedestrian access as it is noted that Phase 1 and Phase 2 CE will conflict with sidewalk to
remain.
Revision 1 Response: A portion of the sidewalk where the CE is shown is to be removed as a part of this
project. A note has been added to Sheet C6.2 stating that the contractor is responsible for maintenance
of traffic (including pedestrian) during construction.
Revision 1 Comment: Comment addressed.
Please add dust control symbol to the E&SC plan sheets legend and add locations to the plan. Provide same
information for temporary and permanent seeding as well.
Revision 1 Response: This information has been added to the plans. See Sheets C6.0 and C6.1.
Revision 1 Comment: Comment addressed.
A DD is shown in a portion of the area to be filled to construct a new parking lot (eastern most new parking
area). Please explain the DD status during earthwork operations.
Revision 1 Response: The DD shall remain in place, and be adjusted by the contractor during earthwork
operations.
Revision 1 Comment: Please note that the Albemarle County VSMP/ESC Authority Administrator does not
permit the placement of erosion and sediment control measures in the way of grading during construction (see
attached Engineering E&SC Plan checklist. Item circled on sheet 3 of 4). Please provide E&SC controls for
this area that do not conflict with grading operations. (Rev. 2) Addressed.
6. Please add soil boundary to the Phase 2 E&SC plan sheet.
Revision 1 Response: Soil boundaries have been added to the plans. See Sheet C6.1.
Revision 1 Comment: See Part C Revision 1 Comment 10. Please provide the requested information. (Rev. 2)
Addressed. Soils boundary and designation information are shown on C5.3 and C6.2.
7. Please provide a stockpile and contractor's staging/laydown and parking areas to the E&SC plan sheet.
Revision 1 Response: This information has been added to the plans. See Sheet C6.0.
Revision 1 Comment: Comment addressed.
8. Please verify that cut or fill balances do not exceed a 10,000 cubic yard deficit. If deficit is exceeded, an
approved waste area will need to be identified.
Revision 1 Response: Cut/fill balances for the project are less than 300 cubic yards.
Revision 1 Comment: Comment addressed.
9. SSF is shown crossing contours at several locations on the Phase 1 and Phase 2 E&SC plan. SSF is to run
parallel with contours. Please place SSF on tangents or provide other perimeter E&SC measures.
Revision 1 Response: SSF locations have been revised. See Sheets C6.0 and C6.1.
Revision 1 Comment: Comment not addressed. Please adjust super silt fence as requested. (Rev. 2)
Addressed.
Engineering Review Comments
Page 7 of 8
10. It appears that slopes steeper than 3:1 are proposed on the south side of the eastern most new parking lot and the
north side of the northern most new parking lot. Please provide a symbol for slopes steeper than 3:1 and add to
the legend and to the E&SC plan sheets. These areas are to have low maintenance (not grass) ground cover
specified (what type) on the E&SC plan sheets.
Revision 1 Response: This information has been added to Sheet C6.1.
Revision 1 Comment: Comment not addressed. The criterion is for slopes steeper than 3:1. Then Consultant
has referenced 2:1 slopes. Please correct plan to address comments. (Rev. 2) Addressed.
11. Please provide an alpha or numeric indicator for the two excavated drop inlet traps to facilitate reference.
Provide a stage/storage volume table for each trap and identify the wet and dry storage volumes and elevations,
and a calculation verifying a 2:1 length/width ratio for flow path in consideration of the inflow location.
Revision 1 Response: This information has been added to Sheet C6.0.
Revision 1 Comment: Comment addressed.
12. The clean water DD on the west side of the project site is to discharge to a stable/stabilized outfall. Please
provide appropriate drainage area/flow calculations and size riprap apron or other measures to stabilize outfall.
Revision 1 Response: A temporary level spreader has been added at the end of the CWD. See Sheet C6.0.
Revision 1 Comment: Comment addressed.
13. Please add the drainage area (0.30 acres) to the volume calculation for the eastern most drop inlet sediment trap
on Sheet No. C6.0.
Revision 1 Response: Calculation has been revised to include 0.30 acres.
Revision 1 Comment: Comment addressed.
14. New: Include Paved Wash Rack detail from ACDSM, pg. 8. Albemarle County Engineer requires this detail on
all plans. Albemarle County inspectors may, under rare circumstance, permit construction of a stone
construction entrance, but a paved construction entrance with wash rack is typical. (Rev. 3) Addressed.
The VSMP permit application and all plans may be resubmitted for approval when all comments have been
satisfactorily addressed. For re -submittals please provide 2 copies of the complete permit package with a completed
application form.
Engineering plan review staff are available from 2-4 PM on Thursdays, should you require a meeting 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. 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.
Please coordinate Nutrient Credit Purchase with the County's Management Analyst prior to purchase. Evidence of
purchase of required level of nutrient credits is required prior to Applicant receiving a grading permit.
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.
After bonding (and nutrient purchase, ideally) 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
Engineering Review Comments
Page 8 of 8
to the state. For fastest processing, this is done electronically with the emails provided on the application. 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.
After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants
will need to complete the request for 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 joint VSMP and 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;
http://www.albemarle.orWdeptforms.asp?department=cdengwUo
WPO201800030 Charlottesville Albemarle SPCA 122618 rev3