HomeMy WebLinkAboutWPO202200011 Review Comments WPO VSMP 2022-03-31�q off nig 401 McIntire Road, North Wing
Charlottesville, VA 22902-4579
County of Albemarle Telephone: 434-296-5832
COMMUNITY DEVELOPMENT DEPARTMENT WWW.ALBEMARLE.ORG
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VSMP Permit Plan Review
Project title:
Rio Point
Project:
WP02022-00011
Plan preparer:
Jessica Denko, PE / Timmons Group [ iessica.denko6d�timmons.com ]
608 Preston Ave., Suite 200 / Charlottesville, VA 22903
Owner or rep.:
Rio Point, LLC / 200 Garrett St., Suite 0, Charlottesville, VA 22902
kmiller@stoLiypointdiz.com
Plan received date:
11 Feb 2022, check received [ CV received date: 3/21/22 ]
Date of comments:
31 Mar 2022
Reviewer:
John Anderson, PE
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 disapproved 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.
SWPPP
1. Revise SWPPP cover to include ref. to WPO202200011.
2. Complete and include CGP (VAR10) permit registration, SWPPP, Sec. 1.
3. Sec.1, SWPPP; Sec. III: If unbalanced cut/fill requires material export, identify off -site waste site prior to
pre -construction (notify county of waste site to receive a Grading permit, or state VAR10 permit).
4. Sec. 3 /Nature ofactivity: Reconcile 18.86 Ac. LOD with plan LOD, 18.44 Ac.
5. Sec. 4/5: ESC-SWM—Revise consistent with revised WPO plan.
6. Sec. 6.A.: PPP Exhibit: Please show initial location of.
a. Rain gauge.
b. Portable sanitary facilities (ports John), as required.
c. Covered non -hazardous waste dumpster, if required.
d. Vehicle wash waters, draining to trapping measure (Not a sediment trap design, per se, but
shallow depression — 1-2 backhoe buckets. Avoid direct drainage to Ex. storm system, or pond/s.)
e. Concrete wash -out.
f. On -site fuel, if required.
g. Paint, stucco, chemical storage, if required.
7. Sec. 6E: List named individual responsible for PPP measures.
8. Sec. 8: List named individual responsible for ESC inspections /compliance with VESCH, 3`d Edition, 1992.
9. Sec. 9: Ensure Signed Certification is signed and dated.
10. Sec. 12: Furnish [blank] inspection log /form.
B. Pollution Prevention Plan (PPP) —see SWPPP item 6.. above
The PPP content requirements can be found in County Code section 17-404.
C. Stormwater Management Plan (SWMP)
Engineering Review Comments
Page 2 of 5
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.
1. Revise VSMP plan title sheet to include ref. to WPO202200011.
2. C 1.3 may be removed from the WPO plan set.
3. Across plan, on every sheet that depicts existing contours, please provide sufficient existing contour labels.
Additional review comments relating to existing or proposed contours are possible.
4. C2.0, C2.5, C2.6, C3.16-C3.18, C4.0, C5.4, C5.5, C6.1, C7.0, C7.1, and C8.0-C8.2 display as portrait,
please use landscape format. Please ensure WPO plan consistency (landscape /correct orientation).
5. C7.4 indicates 3.82 remaining TP load reduction (lb./yr.) required, while calculation packet, p. 16 (of .PDF)
indicates 2.54 lb./yr. Please reconcile.
6. Provide wet pond design, please include this information (or design elements) from BMP Clearinghouse
VA DEQ Stormwater Design Specification No. 14:
1. Fig. 14.1: Please incl./revise Clearinghouse figure to include project -specific elevations, datum.
2. Installation, maintenance, and periodic inspection notes.
3. Pretreatment forebay details. If overlooked, please direct reviewer to details.
7. Please incorporate ISP (SDP202200009) Engineering review comments (3/24/22) in revised WPO plan.
8. Although C6.0 and C6.1 show bioretention facilities and wet pond, depiction is incidental to inlet or
drainage area information and does not provide adequate level of SWM facility plan -view detail.
Please provide:
1. Distinct SWM plan sheet/s, sheet title: Stormwater Management. In plan view sheet/s, label each
SWM facility identical with profile information shown on C7.6, C7.7., C7.8 (Wet pond, Bio IA,
113, 1C, 1D, 2A).
2. Label floor w x d dimensions (ea. SWM facility) to aid review, bond estimate, construction, and
compliance (this information currently displays on layout sheets).
3. Provide distinct profiles for each biofilter; provide profile captions that reflect plan view labels.
4. For each biofilter profile, provide discrete elevations for:
i. base of #57 stone
ii. 4" PVC underdrain
iii. #8 stone
iv. Filter mix
v. Mulch
vi. INV Nyloplast dome grate, as needed
vii. 15" HDPE INV out, as needed
9. Multiple impervious area inlets /pipes are proposed to route directly to the wet pond without encountering
forebays. Pg. 8, VA DEQ Stormwater Design Specification No. 14, 6.4, Pretreatment Forebay, states: `A
forebay must be located at each major inlet to trap sediment and preserve the capacity of the main treatment
cell.' Note, for example, all areas upstream of pipes 301, 225, and 203 collect parking lot /rooftop runoff
and discharge directly to the floor of the main treatment cell. Provide forebay at each major inlet.
10. C5.4, C6.1: Wet pond (plan view) proposed floor elevation is shown as 413' while INV out is given as
418'. This appears inconsistent with C7.6 profile view (INV out =417', profile view). Please reconcile.
11. Provide required geotechnical testing: Please see p. 8, VDEQ specification No. 14.
12. Please provide pond drain. Please see Pond drain, p. 9, VDEQ specification No. 14.
13. Provide Landscaping and planting plan: Please see p.11, VDEQ specification No. 14.
14. Provide Water balance analysis: p.7, VDEQ Spec No. 14. to account for routing significant runoff thru
bioretention, concern being possible insufficient runoff to support a wet pond.
15. Label wet pond side slopes. Please see p. 10, 6.6 Internal Design Geometry, side slopes: 411:1 V or
5H:1 V (mild side slopes).
16. Wet pond floor should be lower than SBI floor elevation, please revise (see p. 16, Spec. No. 14).
17. (C3.2, C6.1) Q 2_y,=37.00cfs at outlet 200 in floor of wet pond. Str. 200 design directs energy toward the
inner far wall of the pond. Energy of 37.00cfs (not to mention higher -energy, less -frequent storm events)
Engineering Review Comments
Page 3 of 5
may cause near -immediate destabilization of inner wall of wet pond. Revise design to attenuate energy of
2-yr event prior to discharge to pond floor to protect interior fill slopes/walls of pond against erosive force.
18. Outfall 300 should be revised to avoid alignment with /toward outfall 200. Erosion /undermine of outfall
200 is a concern with current alignment.
19. It is unnecessary to include Drainage Area A and B VaRRM.xls excerpt data on the plan, but if it remains,
please also include VaRRM.xls summary site data.
20. C5.1
1. Evaluate increased volume of sheet flow at proposed graded slope along Rio Road East for
stormwater quantity compliance. Provide pre- /post -development calculations for this area, or
direct reviewer to pp. in calc. packet that consider increased volume of sheet flow at this location.
2. Area does not qualify as exempt from quantity controls, but rather, represents increased volume of
post -developed sheet flow /runoff at this location.
3. Post -developed runoff at this location may not cross either existing or future sidewalk at this
location, or skip curb into Rio Road East.
4. Capture runoff at base of proposed slope along Rio Road East, and convey to SWM facility (see
9VAC25-870-66.D.)
21. Famish stormwater quantity and quality narratives on the plan.
22. Bioretention (IA, B, C, D, 2A):
1. Provide design that meets Level 1 or 2 design criteria listed at Table 9.3, VA DEQ Stormwater
Design Specification No. 9; for example:
i. Level 2:
1. A pretreatment cell plus one of the following: a grass filter strip, gravel
diaphragm, gravel flow spreader, or another approved (manufactured) pre-
treatment structure.
2. Planting plan
3. Overflow for on-line bioretention (p. 22, VA DEQ Spec. No. 14)
4. Show underdrain which appears in C7.7 Level 2 typical in plan view/s.
ii. Leven
1. Planting plan
2. Overflow
3. Show underdrain in plan view/s.
2. Provide bioretention (Clearinghouse) installation, maintenance, periodic inspection notes.
23. Calculations should include explicit ref to wet pond forebay volume provided by biofilter 1B, 1C, 1D
forebays. Biofilter sediment forebays are not a forebay for the wet pond but are sized for areas draining to
each biofilter. Compare biofilter sediment forebay total with design criteria at VA DEQ Stormwater
Design Specification No. 14. Revise wet pond forebay design, as needed.
24. Revise calculation packet title sheet to include ref. to WPO202200011.
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. C3.2 sediment basin design table indicates L / We = 8.1 (baffles required if>2), then states, No baffles.
Please provide, label, and dimension SB baffles, since baffles appear to be required.
2. Provide existing contour labels across all ESC sheets (all phases).
3. Depict interim mass grade phase with ESC measures, as needed, between Phase I (initial perimeter controls
(SF, diversions) and trapstbasin) and Phase II (build -out /final parking - buildings). Plan should depict
graphically mass grading /partial utility installation, and ESC measures needed to grade site and install pipe
networks. Show relocated traps, perimeter measures, etc. that may be needed during interim phase of site
grading /utility work. Provide graphic complement to text at Sequence of Installation Note. 17. C3.0.
4. C3.3: Provide break in SF, ST #2 at stone weir outfall.
Engineering Review Comments
Page 4 of 5
5. C3.09, C3.10, C3.17, C3.18: Provide existing contours in all areas of land disturbance, including sanitary
sewer corridor.
6. C3.11; Evaluate existing culvert pipe capacity beneath paved walk N of development to ensure capacity
adequate to convey anticipated Q ian peak flow. Avoid unusual circumstance where a new storm pipe may
have a larger DIA than a downstream storm pipe.
7. C3.15, C3.16: Label sediment basin
8. CS.xx series
a. Label proposed TW BW elevations for proposed retaining walls. Assign identifiers to proposed
retaining walls for ease of reference.
b. Establish Aabel proposed SWM facility easements sufficient to construct and perform future
maintenance on SWM facilities.
c. Establish /label public drainage easements downstream of storm drain inlets that receive Rio East
storm runoff, and for pipe systems located downstream of any SWM facility.
'Next Steps' after WPO plan approval
Purchase Nutrient Credits (if required)
a. PLEASE coordinate with the County reviewer before working with a nutrient bank. The reviewer
must confirm if your project must follow the DEQ hierarchy requirements.
b. Letter of availability must be provided on the WPO approved plans.
c. Applicant must contact/coordinate nutrient credit purchase with Ana Kilmer,
akilmer(a)albemarle. org
d. Affidavit of Purchase must be provided to Ana Kilmer before a grading permit can be issued.
2. Post WPO Bond
a. Applicant must submit a 'Request to Establish a Bond'form and fee to CDD.
i. Complete the form and email it to akilmergalbemarle.org, along with proof of payment
(see below).
b. Payment can be made either online or with a check.
i. If paying online:
1. Go to the online payment portal.
a. Select WPONSMP as the application 'type.'
b. Type in the WPO number and project name in the Notes/Details section of the
form.
C. Type in the 'payment amount' as $294.34.
d. Click "Proceed to Secure Checkout" link to make payment.
2. You will receive a receipt in an email.
ii. Email a copy of the receipt to akilmer"bemarle.org.
c. Once the bond request and payment are received, the applicant can provide the bond estimate
(completed on the County worksheet), or Engineering staff will complete the estimate. Once the
estimate is approved, Ana Kilmer will contact and work with the applicant to post the bond.
Obtain DEQ Permit (if required)
After nutrient credits have been purchased and the bond has been posted:
a. County staff will register the project with DEQ.
b. Applicantloperator listed on the Registration Statement will receive an email with instructions on
how to pay the DEQ permit fee.
c. Applicant must email a copy of the DEQ receipt of payment to charris e albemarle.org,
d. DEQ typically will issue a permit within 2 weeks of receiving payment.
4. Request pre -construction meeting:
a. Complete and email the Request for a Preconstruction Meeting and GradingPerini
ennit
to charriskalbemarle.org.
b. Pay the fee via the online payment portal or a check at the pre -construction meeting. If paid
online, email a copy of the receipt to charrisAalbemarle.org.
Engineering Review Comments
Page 5 of 5
All steps must be completed before the grading permit can be issued.
County forms can be found on the county website forms center under Engineering Applications:
httos: //www.albemarle. org/govemment/community-develooment/aoply-for/engineering-aool ications
Thank you.
Please call if any questions — tel. 434.296-5832-x3069, or email 4anderson2(a)a1bemarle.or9 .
WP0202200011 Rio Point 033122