HomeMy WebLinkAboutWPO202000039 Review Comments WPO VSMP 2020-09-23� AI
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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
VSMP Permit Plan Review
Project title:
Crozet Elementary School Addition, Renovation and Site Improvements—VSMP
Project rde#:
WPO2020-00039
Plan preparer:
Kim Mellon /Timmons Group [ kim.mellongtimmons.com ]
608 Preston Ave., Suite 200 / Charlottesville, VA 22903
Owner or rep.:
Albemarle School Board, Arm. Superintendent
COB, 401 McIntire Road, Charlottesville, VA 22902
Matt Wertman, Sr. Project Manager, FES /FPC
mwertmanOW bemarle. org
Plan received date:
10 Aug 2020
Date of comments:
23 Sep 2020
Reviewer:
John Anderson
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 in comments
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.
1. Revise to include ref. to WP0202000039 in title.
2. Sec. 1, Registration Statement, is blank. Complete with care. Additional comments possible.
3. Sec. 3, Nature of Activity references construction dates as indicated on the Registration Statement. No
dates listed on Registration Statement.
4. Sec. 4, 5: Update once all ESC /SWM-related review comments addressed.
5. Sec. 6.A.: SWPPP does not appear to include I I" x 17" SWPPP Exhibit. Provide exhibit that shows:
a. Rain gauge
b. Non -hazardous solid waste dumpster, with cover
c. Portable sanitary facility ( ports John)
d. Solvent -chemical -paint storage
e. Concrete /stucco washout
f Paved construction entrance, draining to trapping measure
g. On -site fuel storage containment, as required by site contractor [better to show and not need, than
not to show], design secondary, impermeable lined containment (10ml plastic -lined) sized to hold
[stored Vol. of fuel + 10-yr. storm event (cf)] x 1.1.
6. Sec. 6.E.: The SWPPP cannot be approved until named individual responsible for PPP is identified. The
VSMP cannot be approved unless SWPPP is approved. A VAR10 permit cannot be requested until the
VSMP plan is approved. A grading permit cannot be issued until the VAR10 permit is issued by DEQ.
7. Sec. 8, Qualified Personnel: Similar to item 6., SWPPP cannot be approved until named individual is listed
as qualified inspector.
8. Sec. 9, Signed Certification: Please sign.
9. Sec. 12, Inspection Logs, Inspection frequency: 2019 VAR 10 inspection frequency differs from 2014 VAR
10, slightly. Please revise inspection frequency text consistent with 2019 VAR10, Part II.G.2.a. L/2. link:
Engineering Review Comments
Page 2 of 6
httos://www.deq.virainia. pov/Portals/0/DEO/ W ater/StormwaterManagement/CGP%20ADA/CGP2019.pdVver2019-
05-06-131630-407
B. 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. Design Calculations and Narrative. Aug-10, 2020:
a. Revise cover to include ref. to WP0202000039.
b. Pg. 3: Revise Water Quality Narrative to include ref. to proposed new bioretention facilities.
c. Pg. 5-6: Include pipes 501 and 505 in VDOT LD-229 Storm Sewer Design Computation Table.
d. Include Ex. storm pipe at Ex. central /main elementary school entrance. Assign ID to this pipe.
e. Ensure Ex. main entrance storm pipe conveys Qio-y, without flooding (Note: Ex. pipe is 15" DIA
while proposed upstream pipe 505 is 18" DIA (both 501 and 505 are 18" DIA).
f. Include Exhibit or DA Map such that review can correlate VaRRM.xls with DA A, B, C, D, and
with HydroCad routings.
F—AW4illf l
a. Revise plan title to include reference to WP0202000039.
b. Note 4: Revise floodplain effective date to May 16, 2016, rather than Feb-4, 2005. [18-30.3.2,
httos:/AibEM.municode.com/va/albemarle_county/codes/code of ordinances?nodeld=CH18ZO ARTIIIDIR
E S30OVDI S30.3FLHAOVDIH. S30.3.2FLINRAMAFLINST]
3. C2.2: Cale. packet explains existing bioretention [south edge of site?] is removed with this project, but Ex.
SWM does not appear to be removed on this demolition sheet. Further, site outfall 2 is only accurate for a
13.77 Ac. area if Str. 202 outfall combines with bioretention facility 2B outfall, and it appears this does not
occur with proposed grading in proximity of bioretention 2B outfall, Str. 100. Please ensure facilities to be
removed are shown demolished, and that outfall 2 and corresponding calculations are accurate. See C5.0
image, below:
4. C4.0, C4.1: Label outfalls 1, 2, 3, consistent with Calc. packet.
5. C5.1: Label riprap outfall protection, L x W x D.
6. C5.4:
a. Label SWMI, and bioretention 2A, 2B.
f.
Engineering Review Comments
Page 3 of 6
Clarify pre-treatment (other than pretreatment cell) for bioretention facilities 2A, 2B. Ref. VA
DEQ Stormwater Design Specification No. 9, Table 9.3.
Underground or direct piped discharge to a Level 2 bioretention facility does not qualify as
bioretention pre-treatment.
Label Emergency Access. Also label this access SWMAccess (bioretention 2A, 2B). [ No
proposed easement linework or easement plat is required, since parcel is county -owned.]
Confirm that bioretention facility 2B obtains building setback requirement, 25' downgradient from
building.
Flow splitter (Str. 126) and direction of flow in several pipes (circled) is unclear. Please add flow
direction arrows, and small-scale plan /profile detail for splitter structure 126.
i. C7.0 Sir. 108-Str 126 notes that Str. 126 is MH-1 with splitter weir. Unless plan /profile
detail overlooked, please provide.
ii. Ensure 6' MH has steps, that steps do not conflict with multiple pipe connections, or
weir.
iii. Revise C7.0 profile label (Str. 126) to read:
1. INV IN from Str. 128, else revise C5.4.
2. INV OUT to Str. 106 else revise C5.4.
3. INV OUT to Str. I10 else revise C5.4
4. INV OUT to Str. 122 else revise C5.4
Additional comments Dossible.
7. C5.5:
a. Label SWM2, and bioretention 2C, 3A.
b. Clarify pre-treatment (other than pretreatment cell) for bioretention facilities 2C, 3A. Ref. VA
DEQ Stormwater Design Specification No. 9, Table 9.3.
c. Label geothermal well field (linework around TMP 56-64E label).
Engineering Review Comments
Page 4 of 6
d. Provide bioretention 2C, 3A close -approach vehicular access. Current design forces use of bus
parking lot with no path for equipment or material to access either facility. A possible access
exists through curbing in bus circle, between circle and basketball court (though this may be
complicated by geothermal well field). Provide roll -type curbing and a traversable, stable SWM
facility access downslope to contour elevation 680'f.
e. Label proposed (gradually -falling) looping asphalt path.
f. Reinforce a 12' long section of this asphalt path with material sufficient to support 6-ton vehicle
or track equipment that may need to cross to the infield to reach biofilter 2C.
g. Propose pre-treatment for bioretention 2C, show in plan view (also, 7.b., above).
8. C6.0: Provide inset plan view, F =10', for each of the six (6) SWM facilities. Label L x W (x DIA)
dimensions in each small-scale view of biofilter, or underground detention. Please consider As -built
requirements when providing SWM facility design features, dimensions, and details.
9. C6.1: Provide label for debris cage to be installed to prevent obstruction of 4.32" slot weir (SWMI), and 4"
x 11.5" slot orifice.' Note: Precision to a hundredth of an inch may impose fabrication or post -construction
expense to either manufacture to this tolerance, or to perform routings, if As -built condition differs. Design
rarely specifies plate openings to this degree of precision, if tenth of a foot precision works nearly as well.
10. C6.2: Revise bioretention profiles:
a. Label top or bottom of hardwood bark mulch layer
b. Label media invert elevation
c. Label #8 stone invert elevation
d. Provide small-scale, scale -accurate cross sections that include:
i. Pretreatment
1. Cell
2. Labels
3. Critical elevations
e. Show additional pretreatment.
f. Provide media mix specification (ref. DEQ Design Spec. No. 9, Table 9.3).
g. Ensure Max. ponding depth is 6 to 12 inches. Also, VA DEQ Design Spec No. 9, Table 9.3
footnote 2.
h. Show cleanout graphically accurately, with 45-deg bends, not 90-deg T connection.
i. Include plant details (Recommend L-series landscape plan sheet for bioretention SWM facilities):
i. Level 2 design requires plantings in addition to turf.
ii. If turf proposed, label /specify turf type.
iii. Provide plant schedule, to be drawn from list of Albemarle County native plants: provide
common or scientific name, qty. to aid review, inspection, and As -built review.
j. Consider plan and profile elements and dimensions to be reported as As -built condition, deemed
necessary for proper detention or bioretention performance. Label, show, and provide items
needed to report As -built conditions.
11. C6.2 or CL2:
a. Provide Nyloplast dome grate detail.
b. Provide Nyloplast Mfr-recommended installation notes, as needed.
c. Provide Typ. details:
i. VDOT PB-1
ii. Nyloplast pipe bedding
iii. VDOT IS-1 (inlet shaping)
d. 5.96 Ac. total disturbed area is inconsistent with SWPPP, Sec. 3, and C3.0 Project Description
(6.51 Ac). Please reconcile.
12. C6.4: Include attached file as text, on C6.4 (bioretention periodic inspection).
CTO:
13. Label SWMI, SWM2.
14. Label underground detention system slope, if any.
Engineering Review Comments
Page 5 of 6
C. 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. C3.0:
a. ST L Check bottom of stone weir elevation (possible error, since higher than crest of stone weir).
b. ST2: List bottom of trap elevation, likely 678.0'.
2. C3.1: Include paved wash rack detail (PCE), ref. ACDSM, p. 8 (link:
httus://www.albemarle.org/Home/ShowDocument?id=270 )
3. C3.2, C3.3: Although design tables include ST floor dimensions, label trap (L x W) dimensions in plan
view.
4. C3.3: ST3 bottom of trap elevation (680.5') is lower than bioretention 2C No. 57 stone invert elevation
(681.00'). Please ref. VA DEQ Design Stormwater Specification No. 9, Sec. 6, 8.1, Construction
Sequence, Construction Stage E&S Controls which requires notes and graphic details on the E&S plan
specifying that (1) the maximum excavation depth at the construction stage must be at least 1 foot above
the post -construction installation, and (2) the facility [sediment trap] must contain an underdrain.
5. C3.3, C3.4: Show and label STI, ST2, ST3 underdrains in plan view, each sediment trap. Show ST
underdrains running through embankments to daylight.
6. C3.3: Revise ST3 bottom of trap elevation, per VA DEQ Design Spec. No. 9 guidance.
7. C3.5:
a. Label ST3
b. 2 sets of proposed contours at future SWM bioretention 3A, resolve contour conflicts.
c. Evaluate swale /ditch velocity (Q2_y,) to ST3 to ensure velocity in swale is non -erosive.
8. C3.5, C3.7: Proposed grading shows -10' vertical interval across outdoor activity Aoop trail area. While
ST3 is provided at N end of this area of disturbance, SF, or even SSF is inadequate ESC at S end of this
relatively large disturbed area. Moreover, the 100' stream buffer in several locations lies inside and
upslope of proposed super silt fence (SSF /wire -backed silt fence). This ESC design and level of stream
buffer protection is inadequate. Maximum length of graded slope draining to silt fence is 100'. Provide
additional measures, including diversion to additional trap/s. Additional review comments possible.
9. C3.7, C3.9: Sheets indicate looping asphalt trail is constructed prior to completion of bioretention facility
2C. This trail is likely to incur significant damage during transition of ST3 to bioretention facility 2C.
Please ensure design allows construction of ST3/SWM facility 2C without damaging other improvements.
10. C3.5, C3.7, C3.9: These sheets show grading and construction of SWM bioretention facility 3A. This
future SWM facility receives swale runoff from contractor staging and storage area. That area, in turn, will
transition to temporary classrooms, first, then a basketball court. These transitions involve land
disturbance, meaning the swale shown in ESC Plan, Phase II, II1, IV appears to need to drain to a sediment
trap, that may transition to bioretention facility 3A once all contributing upslope drainage areas are
stabilized. Please consider sequencing and likely need for a fourth sediment trap to receive sediment -laden
runoff until contributing drainage areas are stabilized. SWM facilities may not be constructed until then.
11. C3.8:
a. Label Emergency Access.
b. Provide note that Emergency Access will be utilized once upslope areas stabilized to construct
bioretention facilities 2A, 2B.
12. C3.9: If ST3 in ESC Plan Phase IV is actually, by this point, SWM bioretention facility 2C, include note
similar to note on C3.8 for permeable pavers, i.e.: `Install bioretention 2C once all uphill drainage area has
been stabilized.'
13. General: Coordinate SDP202000058 Major Site Plan Amendment Engineering review comments with
VSMP Plan revisions.
D. Pollution Prevention Plan (PPP)- See Sec. A., SWPPP, above.
Engineering Review Comments
Page 6 of 6
The PPP content requirements can be found in County Code section 17-404. This plan requires an Exhibit.
1. Include WP0202000039 on 11" x 17" Exhibit.
The VSMP permit application and all plans (Calcs /SWPPP) may be resubmitted for approval when all comments
have been satisfactorily addressed. For re -submittals, given pandemic, we strongly encourage digital plan submittal;
print plans must be quarantined.
Due to safety concerns, Engineering has discontinued plan review /comment meetings (24 PM on Thursdays), but
CDD will gradually work toward partial re -opening to the public.
Process;
After approval, 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 to the state. For fastest processing, this is done
electronically with the entails 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 (NA /$0 for this county project). The form identifies the contractor and responsible land disturber,
and the F e _emaining to be aid 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.
Forms can be found on the county's recently redesigned website (forms center) under Engineering Applications,
httos://www.albemarle. org/govemment/community-development/aoly-for/engineerinQganolications
httos: //www. albemarle. org/government/community-development/reque st/pre-construction-meeting
WPO202000039 Crozet Elem Addition Renovation Site VSMP 092320.doe