HomeMy WebLinkAboutWPO201400095 Review Comments WPO VSMP 2015-05-29�pF A
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:
Glenmore K2C
Plan preparer:
Graham Murray, Collins Engineering [200 Garrett St., Suite K, Charlottesville,
VA 22902, agr ham@collins -en ing eering com, scott(a�collins -en ing eering com]
Owner or rep.:
Glenmore Associates Limited Partnership, P.O. Box 7623
Charlottesville, VA 22906
Plan received date:
13 Mar 2015
(Rev. 1)
7 May 2015
Date of comments:
10 Apr 2015
(Rev. 1)
29 May 2015
Reviewer:
John Anderson
Note: Encourage.PDF preview (re- )submission prior to hard -copy resubmission.
Three (3) major comments: Floor Elev. SWM bioretention basin A relative to SB1 /floor (C.6.1 -New); SB1
Embankment ht. (C.61-New); and, Energy balance Eq. 11.3, follow-up). Also, 28 -May (e- Attachment)
revisions should be included with next /final WPO/VSMP plan submittal — please call if any questions.
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. Number pages. (Rev. 1) Addressed.
2. Registration Statement/Application: Multiple Owner /Applicant /Operators identified. Construction
Activity Operator and SWPPP Certification list different entities. Delegation of Authority appears
unnecessary. Revise SWPPP Certification, Delegation of Authority, and Registration Statement
Construction Activity Operator to make reasonable, accurate reference to Owner and Construction
Activity Operator (entities). (Rev. 1) As follow -up, with final hard -copy submittal, furnish
(Andrew Holzwarth) signature. Not yet ready for hard -copy SWPPP —see items #8/9 below.
3. Complete Registration Statement, block 1, E -mail. DEQ sends notice of CGP issuance via email.
(Rev. 1) Addressed.
4. Complete Registration Statement, block 1, phone number. (Rev. 1) Addressed.
5. Registration Statement, block 1: Indicate if DEQ may transmit GP correspondence electronically.
(Rev. 1) Addressed.
6. Nature of Activity — Describe nature of activity beyond limited description of ESC measures.
(Rev. 1) Addressed.
7. Revise Nature of Activity Notes #12, 14, per Sequence of Construction comments, C.7., below.
(Rev. 1) Addressed.
8. Sec. 4, ESCP — Revise per comments, Sec. C., below. (Rev. 1) Partially addressed. Revise per
Engineering Review Comments
Page 2 of 5
comments.
9. Sec. 5, SWMP —Wait to rev. 11" x 17" SWM plan sheets until design issues resolved. —B., below.
(Rev. 1) Partially addressed. Revise per comments /28 -May (.PDF) revisions /e- Attachment.
10. Sec. 6, PPP /C. — Revise Dewatering operations prevention practices /control measures — Delete `as
shown on plan,' since not shown. (Rev. 1) Addressed.
11. Sec. 6, PPP /C. —Solid waste disposal: propose location for covered solid waste container /dumpster.
(Rev. 1) Addressed.
12. Sec. 12, Inspection Logs /Standard Frequency Delete reference; remove standard inspection
checkbox. USEPA 2010 Waterbody Report for Carroll Creek indicates stream is impaired.
Increased frequency applies. (Rev. 1) Addressed.
13. Sec. 12, Inspection Logs /Increased Frequency — Revise, consistent with VAR10, Part I.B.4.d.(1):
[p. 1- 2NAR10] —at least once every 4 business days, or at least once every 5 business days and no
later than 48 hr following a measurable storm event. (Rev. 1) Addressed.
14. Note: Please do not resubmit SWPPP until SWMP and ESCP revisions are reviewed and
approved, to save time and resources (glad to review .PDFs). —Thank you
B. VSMP: SWPPP: Stormwater Management Plan (WPO201400095)
VSMP Regulation 9VAC25- 870 -108 requires the VSMP authority to approve or disapprove a SWMP. This plan
is disapproved for reasons provided in comments below. The stormwater management plan content requirements
can be found in County Code section 17 -403.
1. Sheet 8 —Note Q: Clarify reference to pervious pavers. (Rev. 1) Addressed.
2. Sheet 9 — Provided riser /low -flow orifice (biofilter) design meets VA DEQ Stormwater Design Specification
No. 9 (DEQ guidance pending), then:
a. Biofilter planting specification is unreadable. Furnish clear copy. (Rev. 1) Addressed.
b. Plan view, bioretention basin `A' —A single underdrain appears insufficient if compared with
underdrain maximum separation between lines, 10' OC. Please provide an additional underdrain.
(Rev. 1) Addressed.
c. Plan view, bioretention basin `C' — Underdrains /20 OC'. Compare with Max: 10' OC. Revise.
(Rev. 1) Addressed.
d. Plan view, bioretention basin `A' —Label west edge of Emergency spillway. West edge is defined,
but may be mistaken for contour. (Rev. 1) Addressed.
e. Provide typical detail (profile) showing earthen Access crossing grassed Emergency spillway at
each basin (A, C, D). Label side slopes (4:1 or flatter /25% Max, for clearance and to protect
earthen/grass structures). (Rev. 1) Addressed.
f. Provide plan view contours at Access/Emergency spillway to show 1.25' -1.5' stepped transition;
that is, show contours to indicate beginning and end of slope transition to Emer. spillway. (Rev. 1)
Addressed.
g. Adjust location of plants. Remove trees from basin A, C, D down slope embankments. Ref
Appendix A, Earthen Embankment specification for planting guidelines:
(http: / /www.vwrrc. vt. edu/swc /documents /2013 / DEQ %20Introduction _App %20A_Earthen %20Em
bankments_SCraftonRev_0301201 Lpdf ) (Rev. 1) Addressed.
Engineering Review Comments
Page 3 of 5
h. Plan view, bioretention basin `C' —Label north -to -south floor length dimension (ft). (Rev. 1)
Addressed.
i. Profile view, basin C: Orifice /standpipe DIA mismatch: please revise. (Rev. 1) Addressed.
j. Profile views: basins A, C , D — label embankment side slopes (2:1, 3:1, etc). (Rev. 1) As follow -
up: Provide fence /warning signs at detention cell, SWM facility A (Addressed w /.PDF revision).
k. Profile views: Label top of mulch elevation to aid construction and inspection. (Rev. 1)
Addressed.
1. Recommend include note that references OSHA shoring requirements (Note: 6' depths). (Rev. 1)
Addressed.
m. Profile basin C: Align Emergency spillway crest Elev. to match vertical grid (348.5' vs. 350').
(Rev. 1) Addressed.
3. If low -flow orifice design does not meet VA DEQ Stormwater Design Specification No. 9 (relative to 12"
maximum ponding depth, per DEQ guidance), then please revise design. [E -mail: Fri 4/3/2015 11:10 AM,
continuing— I O.Apr.15]. (Rev. 1) Partially addressed. As follow -up: Provide Energy balance; ref.
9VAC25- 870- 66.B.3.a. Note: QPre_developed = QForest; RVPre_developed = RVForest• Reviewer discussed with
Graham Murray, 29 -May. Please call if any questions.
4. New: Profile /Extended Detention basin C: 440' & 444' should read 340' & 344' — several occurrences.
C. VSMP: SWPPP: Erosion Control Plan (WPO201400095)
Virginia Code §62.1- 44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is disapproved
for reasons provided in comments below. The erosion control plan content requirements can be found in County Code
section 17 -402.
Ref. email sent Fri 4/10/2015 (3:03 PM): photos of plan sheet show possible location of diversions
that work with existing grades and clearing /tree preservation concept as a late -phase ESC measure
built with sanitary utility installation across north/back edge of Lots 2 -9, and SE/back edge of Lots
19 -22. Red /yellow lines (photos) intersect diversions that run mid -lot through these lots. A back
edge diversion is required to enable grading of individual lots in any order. Without it, a non-
sequential break (mixed order of development) at any point in either mid -lot diversion means
runoff escapes without reaching sediment basin 1 (Lots 1 -9), or sediment basin 2 (Lots 19 -23).
Alternatively, provide Note on VSMP and Plat that prohibits building permit issuance for any
individual Lot within Glenmore K2C until all upslope Lot disturbance is permanently stabilized,
all upslope sections of mid -lot diversions removed. This note would apply to Lots 3 -9, Lots 19 -21.
(Rev. 1) Addressed.
2. Sheet 4/5 —Add label to Lots 24 -26, similar to label for Lots 20 -23: "Area of select clearing for
buildable area." (Rev. 1) Addressed.
3. Filtrexx runoff diversion product (detail, sheet 3): Indicate where it is to be used. Create symbol
for ESC Legend if to be used broadly, or label sections if to be used sparingly. Label sheets 4, 5.
(Rev. 1) Addressed.
4. Provide culvert pipe crossings to convey diversion runoff beneath basin A and D Earthen SWM
Access ways. (Rev. 1) Addressed.
5. Provide ditch to protect earthen (SWM facility) Access, north side basin C Access, to convey
runoff from Lot 19 to inlet of proposed culvert beneath Access (culvert, sheet 8). (Rev. 1)
Addressed.
Engineering Review Comments
Page 4of5
6. Sheet 6:
a. Trap #1 plan view —Show weir as stone —see trap #2 detail, for example. (Rev. 1)
Addressed. Now sediment basin #2.
b. Trap #1 data — Bottom trap Elev. :� 0.0 cy Elev. Which correct: 344' or 345' — clarify.
(Rev. 1) Addressed. Now sediment basin #2.
c. Trap #1 data — Provide Vol. at Elev. 349'. (cannot check Vol. against stone weir crest)
(Rev. 1) Addressed. Now sediment basin #2.
d. Trap #2 plan view — Revise stone weir crest Elev. to 419'. (Rev. 1) Addressed.
e. SB #1 design: Revise LS to 57.00'. Revise collar dimensions to 4.5' x 4.5'. (Rev. 1)
Addressed.
f. SB 1 /SB2 profiles: Show approx Ex. ground across basins. This may help ensure a more
accurate bond estimate. (Rev. 1) Addressed. Note — profiles excellent.
g. SB1 /SB2 profiles: Label INV Elev., 6" DIA dewatering devices. (Rev. 1) Addressed.
h. SB1 /SB2 profiles: Provide design of concrete foundation or steel base plate for risers,
specific to each basin. Reference to VESCH is insufficient. (Rev. 1) Addressed.
i. SB 1 /SB2 profile: Show bioretention low -flow orifice (basins A, D) in basin riser, if
present at this stage. (Rev. 1) Addressed.
j. SB 1 /SB2 profile: Label upslope sediment basin slope (2:1, for example). (Rev. 1)
Addressed.
k. New: SB1 exceeds VESCH 3.14 Max. height (15.0') — please revise.
1. New As follow -up: SB 1 floor Elev. must be at least 1' above biofilter A floor Elev.
(328.5'). Initial biofilter A floor Elev. (324.5') raised (4') with re- design. VA DEQ
STORMWATER DESIGN SPECIFICATION NO.9 — image:
SECTION 8- CONSTRUCTION
5.1. Construction Sequence
Consmretion Stage E&S Controls. Micro- bioretention and small -scale bioretention areas should
be fully protected by silt fence or construction fencing, particularly if they will rely on
infiltration (i_e., have no underdrains). Ideally, bioretention should remain outside the limit of
disturbance during construction to prevent soil compaction by heavy equipment. Bioretention
basin locations may be used as small sediment traps or basins during construction. However,
these must be accompanied by 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 must contain an underdrain. The plan must also
show the proper procedures for converting the temporary sediment control practice to a
permanent bioretention facility, including dewatering, cleanout and stabilization.
Version 1.9, March 1, 2011
7. Sequence of Construction/sheet 3:
Page 33 of 54
a. Note 12 — Revise to read: "Once phase II of construction is complete and within 30 days
after final site stabilization or after the temporary measures are no longer needed, and
once the inspector has given approval, the Contractor can remove the erosion control
measures. No item shall be removed unless the upstream areas are stabilized and the
inspector gives permission." (Rev. 1) Addressed.
Engineering Review Comments
Page 5 of 5
b. Note 14 — Revise: "Unless otherwise authorized by the local program administrator,
trapped sediment and the disturbed soil areas resulting from the disposition of the
temporary measures shall be permanently stabilized to prevent further erosion and
sedimentation." (Rev. 1) Addressed.
8. Sheet 5 — Increase pitch of proposed contour labels so readable. (Rev. 1) Addressed.
9. Sheet 5 —Add many more proposed contour labels. (Rev. 1) Addressed.
The VSMP permit application and all plans may be resubmitted for approval when all comments have been
satisfactorily addressed. For re- submittals please provide 2 copies of the complete permit package with a completed
application form.
Engineering plan review staff is available 2 -4 PM on Thursdays, should you require a meeting to discuss this review.
Plan reviewer is available at 434.296 -5832 -0069 should you have any questions.
Process:
After approval, plans will need 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 need to be completed by the owner and submitted along with cash,
certificates or sureties for the amounts specified. The agreements will need to be approved and signed by the County
Attorney and County Engineer. This may take 2 -4 weeks to obtain all the correct signatures and forms.
Stormwater Management Facilities Maintenance agreements will also need 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 need to be submitted along with court recording fees.
After bonding and agreements are complete, 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 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
will need to request a pre - construction conference by completing a 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;
htW: / /www.albemarle.or /g deptforms .asp ?department--cdengMTo
Thank you - 434.296 -5832 —x3069
File: WP0201400095 Glenmore K2C 052915rev1 VSMP