HomeMy WebLinkAboutWPO202100043 Review Comments WPO VSMP 2021-09-02t� OF ALB
County of Albemarle
COMMUNITY DEVELOPMENT DEPARTMENT
VSMP Permit Plan Review
Project title: Crozet Animal Wellness Center— VSMP
Project file number: WPO2021-00043
Plan prepares
Shimp Engineering, 912 E. High St., Charlottesville, VA 22902
Chris Marshall, EIT, chris(d�shimy-engineering.com
Owner or rep.:
AnnMae Holdings LLC
1100 Crozet Ave., Crozet, VA 22932
Applicant:
Hillary Cook, DVM
1100 Crozet Ave., Crozet, VA 22932 — dnccooke(a),gmail.com
Plan received date:
2 Aug 2021
Date of comments:
2 Sep 2021
Reviewer:
John Anderson
401 McIntire Road, North Wing
Charlottesville, VA 22902-4579
Telephone:434-296-5832
WWW.ALBEMARLE.ORG
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 ESCP, (3) a SWMP, and (4) any TMDL measures necessary.
(Items 1, 2, 3 relate to Sec. 1 of SWPPP DEQ CGP Registration Statement)
1. Sec. II, G. —Complete Estimated Project dates.
2. Review /revise Sec. II. C. if estimated area to be disturbed changes in response to comments, elsewhere.
3. Sec. III, Offsite Support Activity — Site is unbalanced. Cut north of existing east parking lot, demolition, a
stream relocation, and excavation (BMPs 1 and 2) will generate excess material. Prior to receiving a
Grading Permit, Construction Activity Operator must identify off -site waste /spoil location, secure an off -
site permit, if needed, and estimate volume and type of material to be exported from this site. Proposed
grading /demolition indicate export is unavoidable. Revise Sec. III of Registration Statement as needed.
4. Provide a complete SWPPP for project, use 12-section county template. Only Sec 1 of the SWPPP
(Registration Statement) appears to have been submitted. Link to template:
httos: //www.albemarle. org/home/shQnublisheddocument/ 166/637202310327530000
5. Include 2019 Notice of Termination form. Link:
6. Revise SWPPP title to include ref. to VSMP
B. Pollution Prevention Plan (PPP) — See above.
The PPP content requirements can be found in County Code section 17-404.
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 reasons listed below. The stormwater management plan content requirements can be
found in County Code section 17-403.
Engineering Review Comments
Page 2 of 6
1. Calculation Packet
a. P. 24:
2S 15 3S
DA3% DA
A 55
DA 5 0 offsite)
1P 4P
DETENTION 2 740 DETEN ON 1 SG740
4S
DA4
1L 2L
POA 1 POA 2
b. p. 25:
PostDev
CROZET ANIMAL WELLNESS POSTDEV Type 1124-hr 1 YR Rainfall=3.07"
Prepared by {enter your company name here) Printed 7/21/2021
HydroCAD®9.10 s/n 07054 m 2010 HydroCAD SoftwareSoluhore LLC Page 2
Time span=0.00-48.00 hm, dt=0.02 hm, 2401 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Link 1 L: PDA 1 Inflovn0.63 cfs 0.165 of
Pnmary=0.63 cfs 0.165 of
Pond 1 P: DETENTION 2 SC-740 Peak Elev--655.86' Storage=0.0" of Inflow--1.61 cis 0.097 of
Outflow=-0.33 cis 0.088 of
Subcatchmentl S: DA 1 Runoff Ama=0459 ac 0.00%Impervious Runoff Depth=0.39"
Tc=12.2 min CN=61 Runoff--0.17 cfs 0.015 of
Link 2L: PDA 2 Inflow=-0.09 cis 0.008 of
Pnmary=0.09 cis 0.008 of
Subcatchmenl2S: DA 3 Runoff Area-0.593ac 75.72%Impervious Runoff Depth=1.96"
To-12.8 min CN=89 Runoff=1.61 cls 0.097 of
Subcatchment3S: DA 2 Runoff Area=0.252 ac 100.00% Impervious Runoff Depth=2.84"
To-12.2 min CN=98 Runoff=0.90 cis 0.060 of
Pond 4P: DETENTION 1 SC-740 Peak Elev-656.08' Storage=0.032 of Inflow=1.05 cis 0.075 of
Outflow=-0.25 cfs 0.066 at
Subcatchment4S: DA 4 Runoff Area=0.330 ac 0.00%Impervious Runoff Depth=0.39"
Tc=10.9 min CN=61 RunofF-0.13 cfs 0.011 of
SubcatchmentSS: DA 5 Ito offsite) Runoff Area=0.230 ac 0.00%Impervious Runoff Depth=0.39"
To-11.8 min CN=61 Runoff=0.09 cis 0.008 of
Total Runoff Area =1.864 ac Runoff Volume = 0.190 of Average Runoff Depth = 1.22"
62.39% Pervious = 1.163 ac 37.61% Impervious = 0.701 ac
c. Please confirm routing output, p. 25, is consistent with p. 24 graphic which appears to group and
show sub -catchments 1S, 3S routing to detention 1 (4P), sub -catchment 2S routing to detention 2
(IP), and then 4S, 1P, and 4P evaluated as POAI. Pg. 25 output appears to group modeled output
differently. We can't follow it, but this may be due to general lack of familiarity with how
HydroCAD organizes data output. Please clarify, for our understanding.
Engineering Review Comments
Page 3 of 6
d. Pg. 11, PDF report:
i. Provide RV p,,d,, RP pn1_d, calculations. Clarify source of these energy balance
equation values, which do not appear to derive from VRRM.xls provided in calculation
report.
2. C 1: Please revise to include ref. to W 02021-00043 (Applies to Calc. packet, SWPPP cover, as well).
3. 3,
a. Show /label SWM Facility /Access easement. Ref easement diagram, ACDSM, p. 15, image
below, ensure easement is adequate. [ httos://www.albemarle.org/Home/ShowDocument?id=270 ]
b. Provide public drainage easement downstream of BMPs 1 and 2 to point of confluence with
relocated stream.
c. Respond to (any) County Water Resources review comments on design, generally, or effect of
design on downstream county BMP (constructed wetland), specifically.
4. Submit separate plat application for SWM Facility /access and public drainage easements. A deed is
required to be recorded with this easement plat. Link to easement plat application:
httos: //www.albemarle. org/home/shgW ublisheddocument/ 1052/637624089314100000
Albemarle County Design Standards Manual — Engineering '
c. Drainage easements are to be labeled on plans and plats; "Drainage Easement' and
"dedicated to public use".
d. Drainage easement plats must be accompanied by a deed. Standard deeds are
provided by the Count Attorney, along with administrative guidelines. These are also
available in the documents forms center of the county website;
http://www.albemarle.org/deptforms.asp?departrnent-=cdengwpo.
5. C4 proposes BMP 42, Str. B 1, nearly coincident with the relocated stream. Provide additional plan detail
to show how design will effect intersection between B 1 riprap outfall and the relocated stream, resistant to
erosion. Provide labels, notes, elevations, etc., to ensure outfall riprap is resistant to 2-yr event velocity of
the relocated stream, not just BMP #2 discharge velocity. This outfall will experience erosive forces of the
relocated stream.
6. C4: Label L x W x D riprap dimensions, at Str. BL
7. C5: Provide a storm profile for the entire length of BMP #2. Provide prominent existing grade linework,
since this BMP occupies a former streambed. On this profile, please include notes, labels, etc. that specify
suitable fill in area (former streambed) undercut to provide adequate material and compaction for BMP #2.
8. C5: Provide adequate cover above crown of pipe at ES-1, Str. A5. Crown of pipe may not be exposed.
Engineering recommends MH with grate inlet at this location for performance, safety, and maintenance
Engineering Review Comments
Page 4 of 6
reasons. Proposed grade Str. A5 may concentrate debris, occlude inlet, or partially block 15" HDPE pipe,
if no grate, or if poorly maintained. Proposed design may inadvertently admit substantial debris directly
into BMP # 1.
9. C9
a. Revise so that —70-deg proposed bend in stream is less severe. Revise to maximum extent, using
as much space as is available on site to create a less severe bend around the new parking area.
Area 1, image below.
b. Design and label structural bank stabilization (riprap /grouted rip rap) for streambank, Area 2,
image below.
c. Provide details for natural design concept (channel re-routing), including: in -stream structures,
bank stabilization, riffle -run, etc. Reference Albemarle County Chapel Hill Stream Restoration
project plans for example of detail provided with a natural design concept. [WP0201800038]
�1
�660� NATURAL EDCHG CONO TS I \ • 11
-
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I
BMN 2: ADS STORMTEC \\-,J
ISOLATOR ROW E-kOUfE ENGME
(24) C-740 CHAMBERS 5 ;CHANNEL a R DET IL[
IN 3.8 ' �'S7 VDOT STONE 58
BOTTOM OF STONE
CHAMBER
VER65 3�58 TS
R I T=65383.83 -
TOP OF S NE=656.83
COORDINATE :38.066787. ,p w
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our STORM
s $7„ w
s> [� " iR WALL A STR. 82 8w S9
SSMH� 54 ? �
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10. CIO: Provide (small diameter orifice) debris cage detail.
11. C11
a. Please confirm that BMP #2 4" SCH. 40 perf PVC underdrain 114V =653.00 beneath the BMP, is
intended to transition to INV IN -653.83 at Manhole B3.
Engineering Review Comments
Page 5 of 6
b. It appears from CI I (and C 13 Stormtech details) that both BMPs 1 and 2 are effectively
submerged during the 10-yr event to a stone -void saturated depth higher than the top of each
system. Please:
i. Confirm whether this is the case.
ii. Calculate buoyant force on Std. MH and provide buoyancy calculations for Stormtech
system, and MH. Albemarle Engineering cannot assume or interpret Mfr. literature for
ADS SC -740 Stormtech chambers with isolator row, in this regard. Provide
conventional buoyancy calculations, assuming 0.4 stone void ratio.
iii. List C 13 Table 1 Acceptable Fill Material A, B, C, D specs on C 11. i.e., label foundation
stone, embedment stone, initial fill, final fill (unless NA) on CI I profiles for BMP 1, 2.
c. Stability of MHs is a particular concern with this design given WSL, 10-yr. Provide narrative,
notes, labels, specifications as needed to ensure MH-to-Stormtech connection is rigid and
inflexible, if consistent with manufacturer's recommendations and design/performance intent.
Long-term performance and system integrity pose concern, given 10-yr WSL.
d. List SC-740 top of pipe elevation on CI I profile, BMP 1 and 2.
12. Show /label debris cage for 3" orifices, weir A2, weir B2 details, CI 1.
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 for reasons listed, below. The erosion control plan content requirements can be found in
County Code section 17-402.
1. C6
2. C7
3. C8
a. Management Strategy and Sequence of Construction
i. Phase 1 lists clean water diversion of existing engineered channel, but provides no
narrative detail relative to this aspect of construction. C7 shows a line with arrows which
corresponds to Phase 1 clean water diversion of existing engineered channel, but no other
details. C9 includes label that reads: `re-route channel using natural design concepts.'
Please provide general detail, a detailed sequence, labels, natural design concept details,
VESCH diversion channel (crossing) plates (may modify), VESCH dewatering details,
channel lining, etc.
ii. Specifically, include VESCH Std. & Spec. plates, details, notes, guidance, installation
sequence for:
1. 3.25
a. Include plate 3.25-1 (may modify, as appropriate)
b. Include plate 3.25-2
c. Notes concerning undercutting material unsuitable to serve as subgrade
to BMP #2
2. 3.26
a. Revise stone CE to paved CE.
b. Where CWD crosses paved CE, label diversion paved RWD. In effect, construct paved berm
across paved construction entrance, or provide suitable alternative diversion across site entrance.
c. N-S CWD traps water just south of existing entrance to site against N face of E-W CWD. Revise
to avoid ponding, or diversion break-thru at this location.
d. C7 or C8: Indicate pavement TBR. Revise SWPPP, Sec. 1 (Registration Sec. 1II) to indicate off -
site demolition debris export.
a. Label ST floor dimensions (L x W) to aid review, bond estimate, inspection.
b. Label Area of Limits of Disturbance (x.xx Ac.).
c. Provide ST design table, and data. If overlooked, please notify reviewer.
Engineering Review Comments
Page 6 of 6
d. Note: Limits of Disturbance are anticipated to increase and appear somewhat arbitrary to limit
LOD <1.0 Ac. Revising grade to introduce a gradual stream bend N of new parking west of
building will increase LOD.
e. Label proposed grade N of building (3:1, 2:1, etc.).
f. Any grade steeper than 3:1 requires permanent vegetative stabilization hardier than grass. Specify
permanent stabilization for grade steeper than 3:1.
Process:
After approval, plans will have 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 have to be completed by the owner and submitted along with cash,
certificates or sureties for the amounts specified. The agreements will have to be approved and signed by the County
Attorney and County Engineer. This may take 24 weeks to obtain all the correct signatures and forms.
Stormwater Management Facilities Maintenance agreements will also have 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 have to be submitted along with court recording fees.
This project requires separate easement plat application, review, and approval. Once plat is reviewed and comments
are addressed, Engineering will format template deeds (SWM / public drainage) to be recorded with the plat. Please
submit easement plat application at earliest convenience. Note: easement plat with deeds must be recorded prior to
receiving a Grading Permit.
After bonding and agreements are complete, county staff will (if LOD > 1 Ac.) 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 have to be paid directly 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 must 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,
hftl)://www.albemarle.org/dei)tforrns.asv?department--edengwpo
Thank you.
Please call if any questions — tel. 434.296-5832-x3069, or email IanderOsn2(a),albemarle.OrR.
WP0202100043 Crozet Animal Wellness Center 090221