HomeMy WebLinkAboutWPO202200038 Review Comments WPO VSMP 2022-10-21a$ County of Albemarle
m COMMUNITY DEVELOPMENT DEPARTMENT
VSMP Permit Plan Review
Project title: Breezy Hill Subdivision — VSMP
Project file number: WPO2022-00038
Plan preparer:
Chris Mulligan, PE, Roudabush, Gale, & Associates, Inc.
999 Second Street SE, Suite 201, Charlottesville, VA 22901
cmull igan(o)roudabush. com
Owner/Applicant:
Breezy Hill at Keswick LLC — 1145 Timber Lane
Boulder, CO 80304 charlesaasouthem-develooment.com
Plan received date:
14 September 2022
Date of comments:
21 October 2022
Reviewer:
John Anderson, PE/CFM
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 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.
Sub SWPPP
1. Please ensure SWPPP cover includes reference to'
2. Submit SWPPP* using county template located at:
httos://www.albemarle.ore/home/showDublisheddocument/ 166/6380161
27329270000
a. Sec. 6.A.: PPP Exhibit: Please show initial location of.
i. Rain gauge.
ii. Portable sanitary facilities (porta-john), as required.
iii. Covered non -hazardous waste dumpster, if required.
iv. 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.)
v. Concrete wash -out.
vi. On -site fuel, if required.
vii. Paint, stucco, chemical storage, if required.
b. Sec. 6E: List named individual responsible for PPP measures.
c. Sec. 8: Although Albemarle County will inspect, Applicant is required to
retain qualified (contractor/third-party) E&S inspection personnel to
perform ESC inspections and evaluate compliance relative to VESCH,
3rd Edition,1992.
d. Sec. 9: Ensure Signed Certification is signed and dated.
B. Pollution Prevention Plan (PPP) — See above item 2.a.
The PPP content requirements can be found in County Code section 17-404.
Engineering Review Comments
Page 2 of 8
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.
1. General
Include WPO# on plan title sheet, SWPPP cover, and Calc. packet cover: WPO202200038.
2. Calculations:
a. Lack context, narrative summary, compliance tables, energy balance equations, index, TOC, pre -
/post -developed drainage maps, VRRM.xls, or compliance narrative in typical format within a
single packet. Instead, 24 files were submitted, including: 21 routings of varying complexity,
with no narrative or index connection to project plan, or graphic elements of SWM practices, 2
sediment basin design data sheets, VA DEQ Stormwater Design Specification No. 2. Engineering
requests a single document that provides items listed as missing or absent such that at plan
approval a single document with cover /title identifying project may be stamped approved, shared,
referenced, etc. It is unorthodox to submit routings with no narrative, summary tables, compliance
tables /equations (Energy balance, VRRM.xIs, for example), to instead submit 21 separate data
input /output files which cannot be interpreted. Please call if questions since plan review is
affected. Review of calculations is unavoidably suspended. Additional comments are virtually
assured relating to calculations, once received, or relating to elements of BMP design dependent
upon calculations. 21 submittals (pg. length): 27, 27, 31, 18, 41, 31, 41, 39, 21, 33, 33, 73, 9, 21,
142, 15, 15, 15, 41, 31, 31. 698 total pages is striking. Calcs require x-referencing to plan SWM
facilities to serve primary purpose of calculations, which is to support and demonstrate compliant
design.
b. Provide VRRM.xIs for project in Calc. packet.
3. Sheet 3
a. Please check legend. Confirm `Perimeter stream' is intentional. Should this label read `perennial
stream'?
b. County GIS /real estate records indicate multiple Carroll Creek Properties, LLC parcels, while
existing conditions appears to consolidate these Carroll Creek Properties holdings with Breezy
Hill at Keswick TMP 09400-00-00-008A0; please revise existing conditions to match current
property ownership records unless county GIS /real estate records do not reflect current ownership
of parcels (depicted in plan as a single consolidated parcel, sheet 3).
c. Please ensure clear labeling of stream buffer and floodplain overlay district boundaries.
d. It is not possible to distinguish between Albemarle County preserved steep and critical slopes
(legend shading virtually identical). Revise shading so possible to distinguish which slopes are
critical (rural district), and which are preserved steep (non -Waal district). Also applies to sheet 4.
e. If pipe structure beneath existing gravel road at entrance from Richmond Road is to remain and
serve the subdivision, perform engineering evaluation of pipe, including pipe video inspection
with Certified Engineers Report that attests to fitness of this existing pipe to serve as primary
entrance drainage structure for specified estimated life of service. If projected life of service is
less than equivalent expected life of service of new HDPE or RCP drainage pipe, replace existing
entrance pipe with new pipe. Provide calculations and details for capacity, velocity, outfall
protection, and list pipe L, DIA, and material. Specify end walls or end sections, as needed.
4. Sheet 4: Coordinate construction access and MOT /work zone measures and device placement with VDOT,
as needed, as pre -requisite to WPO plan construction entrance approval. A FT flagger with work zone
safety certification /flagger certification may be required to occupy station at particular times, or all times
that construction traffic is likely to use this entrance at U.S. Rt. 250. Albemarle defers to VDOT.
5. Sheet 11
a. Label streets.
b. Include Note to contractor that street -facing roofs that contribute storm runoff to (street) inlet /pipe
conveyance system drainage areas are to be connected to street inlet /pipe conveyance systems.
Engineering Review Comments
Page 3 of 8
6. Sheet 12
a. Circumscribed ditch details partially address need for ditch design stated elsewhere, but these
details are confusing. Sheets 17, 18 may provide most detail required. This plan view should
identify each ditch by number, by reasonable proposed grading (incl. labeled contours), stationing
corresponding with sheets 17, 18 ditch lining.
b. Provide table on this or other sheet/s that list V2-n (velocity) for each ditch.
c. Ensure ditch lining for each ditch section is appropriate for V2-yr peak.
d. Label streets. Label ponds. Also, item q., next comment.
7. Sheet 13
a. Provide base of riser footing elevation, Sir. 142E, in profile view.
b. Provide riser footing dimensions, Sir. 142E, in profile view. (L x W x D)
c. Provide INV OUT, Str. 142E, in profile view.
d. Provide INV IN /OUT, 35' — 24" HDPE pipe.
e. Include comprehensive geotechnical notes for re -furbished dam section, including material
suitability, clay core, collars, collar dimensions, inspection, compaction, etc.
f. Provide SL-1 labels, profile view, Str. 142C, 142B, in profile view.
g. Provide Y2 steel plate (labels) in floor of Str. 142C, 142B, since vertical difference INV IN-INV
OUT' W.
h. Provide buoyancy calculations, riser structures 142E, 142D, since partially submerged.
i. Provide Anti -vortex labels at Str. 142E, 142D.
j. Label `36" by-pass orifice' is unclear, clarify via inset detail installation and DW location of 36"
by-pass orifice, especially relative to riser DIA.
k. Label riser and structure DIA of each vertical structure depicted in profile 142A — 142E Profile.
1. Provide L calculation for salt -treated timber ELS, Note: base L on 10-yr discharge thru pipe.
in. Show /label end wall or end section (provide VDOT designation) at outfall of 152' pipe, at Str
142A.
n. Review /revise 12" pipe sections (152' and 176') downstream of 24" DIA storm pipe. Please
ensure plan /profile PIPE DIA views are consistent, for example: 15" in plan v. 12" in profile.
o. Note: All storm culvert pipe in public drainage easement must be 15" DIA Min.
p. Provide inset detail for 142C that clarifies design intent of this structure, which is labeled `by-
pass' in plan view. It is unclear, for example, if 36" orifice will divert a specified volume away
from later downstream smaller DIA pipes. Plan /profile /calculations need to guide reviewer,
contractor, inspector, and others with sufficient detail as to what, exactly, is to occur at Str. 142C.
q. Please give each on -site existing pond a designation: Pond A, B, C, etc., across all plan sheets, for
reference.
r. Provide existing contour labels.
8. Sheet 14
a. Pipe slope 16.97% exceeds ACDSM Drainage Plan checklist for Plan Reviewers Max. 16%.
Provide anchors for pipe slope >16%. Ref. VDOT Drainage Manual, 9.4.8.7. p. 9-37.
b. ELS #2 is insufficient length for Q(10) =10.6 cfs. ELS design L: 13' /cfs, with 130' Max. L.
c. It appears that Str. 146 provides Q(10) bypass of nearly 20cfs, withjust 10.6cfs continuing
downstream to Sir. 144.
d. Provide riprap dimensions for riprap channel downslope of Str. 146. (L x W x D).
e. Provide Vey, design for this riprap channel.
f. Provide inset detail for Str. 146 that clearly conveys bypass design. `(2) 24" x 6" weir openings'
label in profile view at profile scale is insufficient detail. Provide label on profile, Sir. 146, that
identifies corresponding routings for V2-yr, Q10-yr, at this bypass location.
g. Show in inset profile view for Str. 146 distance from two weir openings to proposed grade; show
whether, for example, bypass flow exits weir opening x' above riprap channel, ht. of weir above
riprap channel, etc.
h. If Bluebird Drive is a public RW, provide public drainage easement over storm pipes that convey
runoff from Bluebird Drive inlets to receiving stream.
Engineering Review Comments
Page 4 of 8
i. Provide maintenance access to outfall of any pipe that is in public drainage easement, easement to
be traversable by vehicle: 10' Min. width, 20% Max. slope.
j. Provide public drainage easement over all storm pipes beyond public RW to point of SWM
detention treatment (existing refurbished ponds, for example), and also over storm pipes beyond
public RW to receiving stream/s.
k. Revise MH spacing between MH 146A and 146 to 300', per VDOT Drainage Manual table 9-3, p.
9-7, Access Hole Spacing.
1. Compare proposed grade downslope of Sir 146A in plan /profile. Profile shows embankment not
visible in plan view. Revise contours /proposed grading so that plan /profile are consistent at this
location. Profile view shows 7' embankment not shown in plan view.
in. 7' embankment in profile view may, with certain storm events, yield 7' ponded depth at this
location. Confirm design intent at this location and suitability of yard swale at this location.
n. Use VDOT nomenclature in all profile views to identify riser type, whether MH, yd grate, or DI.
o. Provide VDOT LD-204 (inlet design) and LD-229 (culvert design) tables: All inlets /pipes.
p. Certain comments, sheet 12, may apply to sheet 13. For example:
i. Provide INV IN /OUT at Str. 146 A (shift proposed grade label so data not obscured).
ii. Provide additional existing contour labels in plan view.
iii. Label end wall or end section at Str. 146. Use VDOT nomenclature, ES-1 for example.
iv. Label riprap dimensions at Str. 144
9. Sheet 15
a. Consider all comments at sheet 13, 14 that may have bearing on sheet 15, especially:
i. SL-1 (Str. 178).
ii. V2" steel plate in floor of MH (Sir. 178, 178A, for example).
iii. Max. pipe slope (16.68% for example, exceeds Max.).
iv. Pipe anchors for pipe proposed to be installed steeper than 16%.
b. Provide compaction note for fill beneath structures or pipes in fill section (Str. 180, 69' 18' HOPE
for example). Note 69'-18" DIA HDPE at this location in this fill section is esp. susceptible to
settling, deformity, deflection, and separation at point of connection with Str. 180 MH.
c. Recommend increase slope of 67' -18" HDPE downstream of 178A to allow slight error during
construction. Min. pipe slope =0.50% and if As -built condition indicates pipe slope <0.50%,
hydraulic analysis of pipe to ensure sufficient capacity and self -scouring velocity will be required
prior to facility acceptance, bond release, etc.
d. Storm Pipe 177A, provide:
i. End wall data in plan /profile view. Provide complete dimensional description for end
walls (skew, ht., tapered ht., L, wall thickness). End walls appear required at this location
ii. In plan view, inlet of pipe appears buried, may fail to extend to proposed grade. Clarify.
iii. Specify storm pipe material (plan /profile).
iv. Provide clear x-ref. (profile or plan view) to HydroCAD routings for this pipe.
e. Please eliminate 2 extraneous vertical lines, Sta. 19+60, Strm 190 — 178A profile.
f. Grading at SWM Outfall 3, stream crossing, creates several steep sections of ditch from road
elevation to pipe end walls. Provide:
i. Labels for these ditches
ii. X-sectional design for ditches
iii. Ditch lining corresponding with V2-y,, each ditch
10. Sheet 16
a. Provide ref to specific outfall protection detail, sheet 20-22, plan view. Label ON in plan view.
b. Consider review comments for proposed 114' — 24" HDPE pipe thru embankment /existing dam
section elsewhere, above. Those comments may apply here, as well. Plan view label that reads:
`Existing Dam Section consult w/Geotech to utilize, refurbish & or reconstruct' is insufficient
design guidance for a dam section upslope of Breezy Hill Lane. Pond WSEL=370.40' is —5'
higher than Breezy Hill Lane (see profile). Comprehensive dam embankment refurbishment
(design) is required prior to WPO or ROAD plan approval. It may not be coordinated at a later
Engineering Review Comments
Page 5 of 8
point in time with a geotechnical engineer. Please present dam embankment design for each pond
embankment proposed to be cut to install storm pipe.
c. Revise 114' — 24" HDPE pipe slope to at least 0.50% Min. slope. Engineering recommends Min.
slope of 0.55% or more to allow slight error during construction. HDPE material can deflect and
deform. RCP is more resistant to deflection and deformation, but design slope at absolute Min.
(0.50%) allows no room for error during construction.
d. Provide end wall or end section label at Str. 100, profile view. Use VDOT nomenclature. ES-1,
for example.
e. Check all plan profiles, all sheets, for clear outfall protection cross-reference to outfall protection
details on sheets 20-22.
11. Sheets 17, 18
a. Provide Velocity table for all ditches, all ditch stations, table to include lining appropriate to V2_,,.
b. Provide Cl. 1 riprap dimensions for riprap at each ditch outfall (L x W x D). 18" depth specified.
c. Sheet 18: Delete Note 1.
12. Sheet 19
a. Provide plan view for these storm profiles: STRM 190-178A, STRM 164-192A.
b. Show missing structure, profile view, upstream of 42' -15" DIA HDPE @ 1.20%, and Str. 164.
c. Note 1., sheet 18, states Y2" steel plate required at Str. 180, but profile does not appear to indicate
dill. INV IN-INV OUT>4'. Please check, revise note as needed.
d. See prior comments on Max. pipe slope /anchors. 16.68%> Max. pipe slope and requires anchors
unless revised to 16%, Max.
e. See prior comment on Compaction Note for pipes or structures in fill section. Provide compaction
note for pipe sections or structure in fill section.
f. STRM 190 — 178A profile appears on Sheet 15. Profile, this sheet, appears to be a duplicate.
Delete profile on this sheet unless it presents information not shown on profile on sheet 15.
g. Provide safety slab label (SL-1) for any structure ht. >12' (Str. 156, for example).
h. Provide pipe DIA, L, slope for pipe downstream of Str. 170.
i. Provide buoyancy calc. Str. 192, 194.
j. Clarify design intent with riprap shown at Str. 194: An emergency spillway, for example.
k. Feature labeled SWM #3 requires clarification and x-ref. to HydroCAD routings if it serves a
SWM purpose. For example: If SWM #3 is intended to reduce pre- /post-dev 2- or 10-yr Q aA,
plan and calculations should present water quantity compliance information as clearly as possible.
1. Note: If any existing pond is to provide storm water quality function, provide detailed design data
that corresponds with VA DEQ Stormwater Design Specification No. 14, Wet Pond.
13. Sheet 20
a. For ELS#1, 2, 3: Please disregard design length comments pertaining to Q(10) design L of these
ELSs that may appear with review of earlier plan sheets, since appropriate L is presented on this
sheet.
14. Sheet 21
a. It is unclear how SWM (pond?) design for DAs A, B, C, D reduce TP by 16.56, 5.30, 1.76, 3.26
lb., respectively. Provide separate DA A, B, C, D tabs that from VRRM.xls New Development
worksheet that shows clearly which BMP measures in these DAs reduce TP by listed amounts.
Include individual DA tabs with BMP measures with Calc. packet, or on the plan.
Engineering Review Comments
Page 6 of 8
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.
15. Sheet 5
a. Phase I1 Sequence Note 2: Provide copy of COE permit (USACE) as prerequisite to WPO plan
approval.
b. Phase I1 Sequence Note 10: typo /correct to read: `Soils on -site are noted to be poor...'
c. Phase I1 Sequence Note 11: revise section to read: `Install outlet protection at each outfall ...'
16. Sheet 6
a. Revise PLD to include topsoil stockpile area.
b. Label each sediment trap and sediment basin floor dimensions (L x W).
c. Depict Aabel sediment basin riser /outfall pipes (thru embankment): DIA, L, and material type.
d. Revise stone construction entrance (CE) at U.S. Rt. 250 to paved construction entrance (PCE).
e. Include paved wash rack detail on plans. Ref. ACDSM p. 8.
f. Provide SAF/TP orange fencing between PLD and adjacent residential parcel lawn areas.
g. Please provide several proposed contour labels at each sediment trap or basin to aid review,
inspection, and bond estimate.
h. Show sediment basin baffles, if /as needed.
17. Sheet 7
a. Label roads to aid review and for reference. Without labels, for example, difficult to describe next
item: b.
b. Ditch labels are confusing. For example, Ditch 1, POA#6, POA#7 are on far side of development
from Ditch 1, POA#L It is not possible for Ditch 1 to exist in locations remote from one another.
Ditch 2, POA#6, POA#3: same comment. Please review all ditch labels to ensure ditch locations
are clearly understandable, that labels are consistent, and reasonable.
c. Ditches: Refine proposed contours to define ditches. Many ditch labels do not correspond with
grading that would establish or suggest or define a ditch.
d. Provide clear ditch start -end points. Label all ditches. Provide calculations for all ditches with
ditch lining specified to correspond with 2-yr storm event V pk. Provide cross sections /geometry
for each proposed ditch: side -slope, width, depth (all ditches). Additional comments possible.
e. ST3 label is obscured by PS symbol. Please shift symbol.
f. STS, ST6 labels are obscured by stream buffer line type or ULD line type. Shift ST labels so more
easily readable.
g. Note 3: Reassign slope -marking responsibility. Albemarle does not delineate critical or steep
slopes in the field. This is a contractor responsibility.
h. Entrance pipe: Specify new pipe material, length, diameter, end walls or end sections, as needed,
at public road entrance at Richmond Rd., U.S. Rt. 250. Also, please see SWMP comment 3_e. if
existing pipe is proposed to serve Breezy Hill subdivision.
i. OP I, OPS, OP6: It is unclear what outfalls are protected by these outfall protection measures.
j. Rectangular hatching denoting potential non-structural fill locations between long parallel streets
obscures proposed grade lines /proposed contour labels. Adjust line weight or use alt. shading or
line -type to denote potential non-structural fill, this location. Ensure all proposed grade lines and
proposed contour labels are easily readable.
k. STI is located partially off -site. Provide written agreement with Owner, TNT 94-48, Breezy Hill
at Keswick, LLC, to locate ESC measure on this off -site parcel, unless separate plat proposes
boundary line adjustment with off -site parcel. Heavy solid line type appears to delineate
development parcel, which bisects STL Off -site ESC measures require a recorded temporary
construction easement, will require off -site owner to be party to WPO plan bond, else a notarized
written agreement between owner of off -site parcel and development parcel is required. Owner is
Engineering Review Comments
Page 7 of 8
identical, in this instance. Comment withdrawn if development boundary is clarified to include
TNT 94-48, thereby locating STl wholly within Breezy Hill development.
It is unclear how storm pipe leading from inlets on street that runs beneath SBI can be built while
SBl is performing an ESC function. Clarify via sequence of construction. SBl will not function
as an ESC basin if sequence proposes open cut thru sidewall embankments of SB 1 to install a
stone line beneath it.
18. Sheet 8
a. Revise sediment trap table to list wet and dry volume provided.
b. Revise sediment basin table to list wet and dry volume required and provided.
c. Provide sediment basin clean -out elevation.
d. Provide sediment basin spillway, trench cutoff, collar design (# collars /dimensions), and baffle
information. If baffles are required, show in plan view, sheets 6 and 7.
e. Please see sediment basin schematic elevations detail, this sheet, and provide corresponding
design elevations. Ensure relevant elevations which may be contained in sediment basin design
data sheets submitted as separate calculations appear in the sediment basin design table on sheet 8.
f Sediment trap detail (3.13-2) with No. 1, 2 discrete design information is inconsistent with 9-ST
table at bottom of plan sheet. Compare /update 9-ST table as needed, and review recommends
eliminate No. 1, 2 ST design data from Sediment Trap detail (3.13-2), center -left, this sheet.
`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(aalbemarle. ore
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 akilmer(a),albemarle.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(a),albemarle.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.
Engineering Review Comments
Page 8 of 8
4. Request pre -construction meeting:
a. Complete and email the Request for a Preconstruction Meeting and GradingPermit
to charris e albemarle.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 charris e albemarle.org.
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/government/community-develooment/al)ply-for/engineering-anolications
Thank you.
Please call if any questions — tel. 434.296-5832-x3069, or email 4anderson2(a albemarle.org.
WPO202200038_Breezy Hill_102122