HomeMy WebLinkAboutWPO202300001 Review Comments WPO VSMP 2023-02-14�q oe nt 401 McIntire Road, North Wing
Charlottesville,VA22902-4579
County of Albemarle Telephone:434-296-5832
COMMUNITY DEVELOPMENT DEPARTMENT WWW.ALBEMARLE.ORG
VSMP Permit Plan Review
Project title: Old Trail Blocks 24, 33, & 34, Water Protection Ordinance
Project file number: WP02023-00001
Plan preparers Jeremy Fox, PE / Timmons Group [ Jeremy.foxatimmons.com ]
608 Preston Ave., Suite 200 / Charlottesville, VA 22903
Owner or rep.: March Mountain Properties, LLC
1005 Heathercroft Circle, Suite 100 - Crozet, VA 22932
Dave Brockman, dave@oldtrailvillage.net
Plan received date: 3 Jan 2023
Date of comments: 14 Feb 2023
Reviewer: John Anderson, PE/CFM
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 —SWPPP not submitted: SWPPP for VAR100043 and assoc. WPOs is maintained on -site.
1. Revise (on -site) SWPPP cover to include reference to WP0202300001.
2. [SWPPP cover should ref. VAR100043; it may also list WPO ID #s covered by
VAR100043]
3. Provide VAR10 Permit Registration Statement (Modification with Acreage Increase) to
VAR100043.
4. Provide update/s to OTV (on -site) SWPPP with Sec. 4, 5 ESC-SWM plan sheet updates.
a. Include any required update to Sec. 6.E.: List named individual responsible for
PPP.
b. Provide PPP Exhibit (SWPPP Sec. 6.A. that covers each ESC constructive phase.
c. Sec. 8: List named individual at Sec. 8, Qualified Personnel for WP0202300001
d. Provide Sec. 9 Certification Signature (for WPO202300001).
5. If o -site activity (fill or waste area) is required, pls. provide off -site information on VAR10
permit registration.
B. Pollution Prevention Plan (PPP) — See above, items 4.a./b.
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 stonnwater management plan content
requirements can be found in County Code section 17-403.
Engineering Review Comments
Page 2 of 7
1. C0.0
a. Revise title to include ref. to WPO202300001.
b. Recommend list associated development plan #s (A Note that lists):
i. WPO201600009, repository of Old Trail Village Stormwater Master Plan (OTV
SWM MP), approved April 15, 2016.
ii. SUB202300018, Preliminary Plat
iii. SUB202300002, Road Plan
iv. ZMA201500001, ZMA
v. OTV SWM MP, SWM Facilities S-6, S-6A
2. C2.0
a. Ref to special exception to ZMA250100001 to allow site access impact to stream buffers, is
helpful. [Also, OTV SWM MP, Table 9 Conceptual Buffer Encroachment Summary, lists
5,112 SF and 751 SF buffer encroachments for Facility IDs S-6 and S-6A, respectively.] On
this and sheets C3.3. C6.5, provide label estimates of stream buffer impact associated with
SWM Facility IDs S-6, S-6A (SF). Review does not reference Table 9 limit, but rather
allowance under special exception to ZMA201500001, which is higher than Table 9 values.
Stream buffer impact may not exceed approvedZ/MA201500001 15,112 SF value.
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3. C3.0
a. Update Stormwater Runoff Considerations to ref. SWM facilities S-6, S-6A, each a biofilter,
for blocks 24, 33, 34 of development, consistent with OTV SWM Master Plan (MP), Fig. 9.
4. C3.4 C3.5
a. Show yard inlet /pipe systems required (if/as needed) to collect and convey surface runoff
across blocks of developments to limit surface storm runoff to 3-lot maximum, before runoff
is collected by a yard inlet. It appears a yard inlet /pipe conveyance may not be required.
Please check, however.
b. Ensure street -facing roof drains connect with storm pipe system, since freezing of roof runoff
that discharges to splash blocks may create sidewalk pedestrian ice hazard.
c. Show yard inlet /roof drain connection with storm pipe /inlet trunk system.
d. Show VDOT UD-1 /-2 collection locations, likely known since Road Plan submitted, for
roadway cut -fill transition points; show connection with main stone conveyance system.
Engineering Review Comments
Page 3 of 7
5. Please review all sheets of WPO plan since several appear rotated. If appearance of source file seems
fine, this may trace to county process, but please check to ensure the WPO plan is compiled with
sheets oriented to landscape. Sheet 28, for example, appears upside down.
6. Across plan sheets, label perennial streams.
7. C4.1 C5.0
a. Inset obscures design information.
b. Eliminate C4.1 Inset on C4.1. Instead, on C4.1, add label at west end of Road D that lists
distance from radius return to face of curb (FC) at west end of Road D, and refers to layout on
C4.0.
c. Ensure all roads are labeled for ease of reference (Road A, B, C, etc.).
8. C6.5
a. Lower left, Proposed Site Land Cover:
i 2°d paragraph reference to SWM Facility L-1 is confusing since this Facility ID is
associated with OTV blk. 10 L-1 also appears in table to right). Revise 2"d
paragraph to remove ref to blk. 10 SWM Facility L-L
ii. Approved drainage calculations provide accurate ref. to OTV SWM MP values, but
Present Day Drainage Area Calculations require clarification, or correction:
1. Provide present day DA maps consistent with S-6 S-6A minimums.
2. Show proposed design meets OTV SWM MP, Fig. 9, DA and impervious
area, with DA, impervious area, impervious area %> MP Fig. 9 table
values, which are:
a. Biofilter S=6 (DA Ac./Impervious Ac./%): 1.40, 0.91, 65%
b. Biofilter S-6A (DAl[mpervious/%): 12.5, 8.13, 65%
iii. Clearly indicate Min. Area /Min. impervious route to these biofilters (S-6, S-6A).
iv. Using table values on this sheet for 5 Watershed IDs framed with red lines, 2213,
23B-1, 23B-2, 23B-3, 23B-4, .xls weighted CN for these 5 DAs=74.45. Revise bold
calc. statement `Proposed CN of 74.2 <Approved CN of 85.1' to ref. 74.45, rather
than 85.1. Please notify reviewer of any review error, or misunderstanding of plan.
v. Present Day Drainage Area Calculations are ambiguous: Clarify that 9.04 Ac.
impervious Ac. route to SWM biofilters S-6, S-6A. Total Drainage Area 15.70 Ac. >
MP DA, 13.90 Ac., but plan design should indicate that 9.04 Ac. impervious
development routes to S-6, S-6A, or, alternatively, provide detailed calculation of
proposed CN value of 74.2.
vi. Note: OTV MP depends upon Min. DA capturing minimum impervious (Ac.), routed
to two SWM facilities. It is unclear design achieves this, based upon information
presented.
b. Provide .PDF scan /update of Water Quality Compliance Tracking Ledger that captures all
Old Trail development values required to be captured by the tracker, since OTV SWM MP
was approved April 15, 2016. The ledger is a tracking tool that shows, block by block, how
development with corresponding on -site SWM facilities complies with OTV SWM MP.
Please include .PDF image on the plan and send to reviewer as .xis. [ Engineering intends to
send its version of .xis to TG, for confirmation CDD version is up-to-date, and accurate.
c. WPO plan is striking for absence of design information for SWM facilities S-6, S-6A. Please
ref. OTV SWM MP Fig. 19, Fig. 20 for relevant, approved Master -plan design of these SWM
facilities, and transfer design to this WPO. Please also see WPO201600009, Old Trail
Village blocks 10, 16, 17, 18 & 30 (East Village) for expected, typical, representative detail
required for these two biofilters. Additional comments likely once biofilter design is added to
the WPO. Note: C3.6, C3.7 propose final ESC phase III grade that may indicate permanent
SWM features north of development entrance, and north of arc section of SF lots. If these are
permanent SWM facilities, please label as such. Also, as noted above, relevant graphic
Engineering Review Comments
Page 4 of 7
design that closely adheres to OTV SWM MP Fig. 19, Fig 20 (S-6, S-6A biofilters) must be
presented not as unlabeled final contours on an ESC (Phase III) plan, but on Stormwater
Management plan sheets with complete plan /profile of each, including vertical elements,
underdrains, risers, landscape plan, and essential construction -installation, inspection, or
maintenance notes, since the WPO plan is a primary source document for Old Trail HOA
when the developer cedes maintenance responsibility to the HOA. This first submittal, in
effect, apart from cursory cross-reference to OTV SWM MP on C6.5, does not present a
SWM plan for blocks 24, 33, 34.
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.
9. C3.0
a. Phase I sequence, Note 3. Add: `No site work, no grading. Limited inlet and storm pipe
installation only prior to installation of ESC perimeter controls. If traps or sediment basin
evaluated essential by ESC inspector prior to inlet -pipe installation, then these (step 4.) ESC
measures shall be installed, at county request, prior to pipe or inlet installation.'
b. Phase II: Eliminate Note 5, which is out of sequence. Sediment traps /basin may not be
removed prior to rough grade of project area (step 6.). Phase III, Note 31 is sufficient.
10. C3.1
a. Revise SB design table to list principal spillway rim elevation.
b. Ensure at least 2.0' Min. freeboard for 25-yr WSL below top of embankment.
c. Ensure at least 3.0' Min. freeboard between rim of principal spillway and top of embankment.
d. Ensure at least 1.0' freeboard between rim of principal riser and 25-yr WSL.
e. ST2 table: Check bottom of trap, bottom of stone weir, crest of weir elevations; revise as
needed. Pls. observe VESCH limits. Also, ensure elevations consistent with C3.2 values.
11. C3.2
a. Show and label Old Trail Drive ROW, relative to concrete washout.
b. Provide 20' offset from VDOT ROW to concrete washout. At this location, a mix truck will
stop to wash the concrete chute. Proposed placement immediately adjacent to ex. sidewalk,
relative to position of truck (straddling walk) is problematic. Existing sidewalk (portion
removed) is frequented by many students (elementary -MS, HS). Provide 15' offset Min. to
prevent truck on ex. sidewalk /paved entrance, which would obstruct student /pedestrian use.
c. Provide many more ex. grade labels in vicinity of Old Trail Drive, and across site, to aid
review.
d. Provide /show /label 12"-15" entrance pipe beneath Paved CE at Old Trail Drive.
e. Obtain VDOT Land Use permit for work within VDOT ROW (Old Trail Drive).
f. Provide SAF along full extent of existing sidewalk, between sidewalk and development site,
Old Trail Drive, except at paved CE.
g. Indicate portion of sidewalk and curb/gutter removed (see C2.0) to facilitate paved CE.
It. Provide RWD, not DD, at portion design allows interior construction road to penetrate site.
DD must be crossed at some point; provide 12"-15" storm pipe at /with RWD.
i. As DD falls across site, at approx. contour elev. 671.5', DD breaks 105-110 degrees. Provide
depression /stilling basin lined with riprap with outlet to DD at lower elev. to redirect DD
runoff that will not make this turn on its own, else provide HDPE pipe to receive upslope DD
runoff, and redirect DD flow within HDPE pipe, with discharge to lower elev. DD for
(significant site -clearing phase) runoff to continue downslope to eventual sediment basin.
Engineering Review Comments
Page 5 of 7
j. ST2: 6'-8' interior cut slopes that receive DD flow are likely to erode; please provide interior
ST2 side -slope BM at DD locations with ST2 installation. Recommend EC -III.
k. CWD: Diversion approaches sidewalk at Old Trail Drive at approx. 45-deg angle, and clean
water diversion runoff will at that point jump walk and curb, into Old Trail Drive. 10' from
sidewalk, similar to above, pls. provide stone -lined depression to receive MD runoff, stop it,
and redirect it downslope parallel with walk, and not onto sidewalk or into Old Trail Drive.
1. SAF: Provide SAF adjacent to U.S. Rte. 250.
12. C3.3
a. Although SB design table incl. bottom of basin dimensions, label SB floor dimensions in plan
view.
b. Design table provides that upstream face of SB slope is 2:1. 18-4.3.3.C.1/2.: Provide
upstream -face reverse bench slope since vertical interval >20-ft. Provide SB reverse bench
runoff conveyance to a stable outlet.
c. Provide EC-2 or EC-3 (BM) where DDs discharge to top of SB interior cut slopes.
Recommend EC-3.
d. Provide break in SF across width of SB OP apron, then, 5'-10' beyond edge of stone apron,
show /label short length of SF.
e. Provide SB riser base design (dimensions, thickness).
f. Provide SB riser base buoyancy calculation.
g. If SB earthen embankment is a feature or element of permanent S WM facility, provide
detailed PE-geotechnical inspection, construction, design, and monitoring. It is too late once
construction is complete to obtain PE-geotechnical inspection, testing, and oversight. If SB
embankment design (clay core, for example) is permanent, then provide plan notes that
require PE-geotechnical inspection, testing, reporting, etc.
13. C3.4-0.7
a. C3.4
i. Delete ESC legend, which obscures proposed grade. Instead, provide label ref. to
ESC legend on sheet C3.3.
ii. Reduce inset detail 50% and relocate to sheet C3.3 with label ref to sheet C3.4.
[Key Plan may remain. ] Note: it is typically unacceptable to obscure proposed
grade or ESC measures with a legend, notes, or other information.
iii. Provide rock -lined catchment, depression at end of DD which, as shown, ends at
sidewalk, with release of runoff to walk, development entrance.
b. Provide additional proposed contour labels such that each section of development may be
easily evaluated for drainage, elevation, etc.
c. As may be noted elsewhere, label inlets, at a minimum, for ease of reference (shown on site
layout and utility plan, but inlet labels needed on ESC sheets, as well).
d. Provide drainage directional arrows for storm system.
e. Provide EC2 (BM) for ditch created with proposed grade, north of US 250, between receiving
grate inlet (681.5't) and elevation — 696' to prevent ditch erosion and sedimentation of storm
system, for this and later phases of construction.
f. Provide EC2 (BM) for ditch created with proposed grade west of Old Trail Drive between
receiving grate inlet (675't) and elevation — 680' to prevent erosion and sedimentation of
storm system.
14. C3.7
a. Show SB outfall protection shown on C3.5.
b. For SF homes arrayed along (outside) arc of road: To direct storm water runoff away from the
foundation around each building, slope permeable surfaces away from the structures at least
0.5 inch per foot for 10 feet [UBC requirement].
Engineering Review Comments
Page 6 of 7
c. Identify /label any permanent SWM facility, consistent with OTV SWM MP. This comment
may repeat, elsewhere.
15. C3.4 C3.5
a. Pipe outfall may not discharge storm runoff to plateau area at top of fill slope, approx.
contour 668'. Rather, provide permanent non -erodible ditch or pipe conveyance down fill
slope to a defined channel (point storm conveyance reaches natural terrain feature).
b. C3.5
i. First inlet on right, development entrance: Revise inlet structure outfall pipe to >90-
deg, relative to pipes that enter the inlet structure (angle shown <90-deg).
ii. Scale — N arrow obscure design: revise to reveal underlying linework, similar to C3.4
(N arrow /scale).
iii. May apply to other sheets: Revise fill slope grading in vicinity of sidewalks as
needed to ensure a min. 5' separation from the edge of sidewalk to the top of slope.
This requirement (VDOT Road Design Manual, Appendix B 1, p. B(1)-34) applies to
shared -use paths. Engineering does not view 5' (narrower) sidewalk exempt from
safe landing requirement when 8'-10' wide shared use paths are subject to safe
landing requirement. This pedestrian facility (sidewalk) will see shared use (walk,
run, skateboards, strollers, etc.) which may crowd users off the walk surface and onto
steeply graded slopes, absent 5' landing.
16.C3.4C3.5C3.6
a. Label permanent storm inlets and roads (Road A, B, C, D), for ease of reference. Labels to
match C6.3, C6.4 tables.
`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,
akilmergalbemarle. org
d. Affidavit of Purchase must be provided to Ana Kilmer before a grading permit can be issued.
Engineering Review Comments
Page 7 of 7
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@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 akilmergalbemarle.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.
3. Obtain Modify DEQ Permit (i€ FegciFed; VAR100043 modified to increase LOD, 17.12
Ac.)
After nutrient credits have been purchased and the bond has been posted:
a. County staff will Fegis.�t modify existing VAR10 with DEQ.
b. Applicant/operator 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 charrisgalbemarle.org,
d. DEQ typically will issue a permit within 2 weeks of receiving payment.
e. Pay Lickinghole Basin Fee, cafe. by Albemarle, Engineering.
4. Request pre -construction meeting:
a. Complete and email the Request for a Preconstruction Meeting and GradingPermit
ermit
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 charrisgalbemarle.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:
hqs: //www. albemarle. org/govemment/community-development/applly-for/engineering-applications
Thank you.
Please call if any questions — tel. 434.296-5832-x3069, or email janderson2@albemarle.org.
WP0202300001 OTV blk.24,33,34 021423