HomeMy WebLinkAboutWPO202100034 Review Comments WPO VSMP 2022-03-18�.i OF AL8
County of Albemarle
m COMMUNITY DEVELOPMENT DEPARTMENT
VSMP Permit Plan Review
401 McIntire Road, North Wing
Charlottesville, VA 22902-4579
Telephone: 434- 29 6 - 5 832
WWW.ALBEMARLE.ORG
Project title:
Victorian Heights
Project file number:
WPO202100034
Plan preparer:
Collins Engineering [scott@collins-engineering.com]
Owner or rep.:
Riverbend Development [alan@riverbenddev.com]
Plan received date:
June 16, 2021
Oct. 5, 2021
Dec. 18, 2021
Feb 12, 2022 (Rev. 3)
Date of comments:
July 16, 2021
Nov. 4, 2021 (Rev. 1)
Jan. 26, 2022 (Rev. 2)
March 18, 2022 (Rev. 3)
Reviewer:
David James [djames2@albemarle.org]
Emily Cox (Rev. 3)
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/approved.
The rationale is given in the 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.
Registration Statement - Under Section II. F. the MS4 is Albemarle County.
(Rev.1) Not addressed. (Rev.2) Addresser+
2. Provide Section 4 & 5 plans for SWPPP.
(Rev.1) Add to SWPPP once approved. (Rev.2) Update prior to approval. Rev. 3:
Comment addressed. Stamped approved plans must be inserted after approval.
3. Rev. 3: The registration statement shows 5.04 AC total disturbed, but the plan shows
5.13 AC. Please clarify and ensure they match.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1. Jentify & show staging, stockpile, paving operations, landscape op., fueling, chemical,
waste disposal, vehicle/equipment washout locations, concentrated discharge locations
to/from site. (Rev.1) Partially addressed. Please identify (use symbols) these items on
the PPP. (Rev.2) Addressed.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is denied, and the reasons are provided in the comments below. The
Engineering Review Comments
Page 2 of 7
stormwater management plan content requirements can be found in County Code section 17-
403.
1. General. Cover - Add WPO202100034 under project title. (Rev.1) Addressed.
2. Provide inlet drainage area map. (Rev.1) Not currently addressed. There is no site plan
that has these inlet maps on them to review, so the comment remains until a site plan is
submitted with what's requested shown. (Rev.2) Addressed.
3. SWM Plan/Calc Packet - Include/Account for disturbed area that fronts Berkmar Drive
in your SWM analysis to ensure Part 1113 is met. (Rev.1) Acknowledged; see comment #4
below.
4. Sheet 8 - Revise (as above) & show the common downstream point/s (POA). (Rev.1)
Addressed.
a. (Rev.1) It's not clear how half the runoff from Subarea C will reach the culvert
(LOA) because the grade goes down along Berkmar Dr after the culvert.
(Rev.2) Not fully addressed. While you show you are reducing the amount of
runoff to'Portion of Subarea C' in your'Sheetflow Analysis Exhibit' this area will
need to be further evaluated. The managed slopes next to road need to be evaluated
for potential impacts prior to plan approval. It's clear (from Tc path) not all of
Subarea B in the pre -development is sheet flow. According to 9VAC25-870-66: D.
Water Quantity requirement, "Increased volumes of sheet flow ... If all runoff from
the site is sheet flow..." Based upon the proposed steep grades and retaining walls I
believe any sheet flow will quickly concentration. I believe erosion will occur and
sediment will get onto existing sidewalks and road before reaching inlets. How will
this be avoided/addressed?
b. (Rev.2) I do not agree with the second paragraph under'Stormwater Quantity'.
'Subarea D' is going to be routed through site and must be evaluated for
channel/flooding requirements at the discharge point.
c. (Rev.2) Tc flowpaths:
do not agree with your Tc for Subarea A. A longer flowpath can be
shown starting from upper corner. Pre -development calculations likely
affected. See comment 21.
ii. Please show post-dev Tc flowpaths. Post -development calculations in
packet may need revision.
Rev. 3: Comment addressed.
5. Include VSMP (As -built) checklist -
https://www.a I bema rle.org/home/showr)u bl i sheddocu ment/3381/6373275105367000
K 8'
Engineering Review Comments
Page 3 of 7
(Rev.1) Addressed.
6. Sheet 9 -
a. Show SWM facility easement over detention system to weir. (Rev.1) Addressed.
b. Decrease slope under 16% or provide pipe anchors. (Rev.1) Addressed.
c. Specify inlet shaping IS-1 on any structure with a 4' or greater drop & at flow
intersections. (Rev.1) Addressed.
d. Specify safety slabs SL-1 in any structure taller than 12'. (Rev.1) Addressed.
7. Provide all drainage structure profiles. (Rev.1) Acknowledged. (Rev.2) Submit with the
site plan prior to WPO approval. Rev. 3: Comment addressed.
8. The easement over UD system should be sized according to ACDSM, p.15 equation.
Ensure easement's 10' landing and no building/structures in easement allowed. (Rev.1)
Acknowledged.
9. Confirm if 10' diameter pipe lengths are 122.33' from calcs, because the largest length I
measure is 115' on plans. (Rev.1) Acknowledged.
10. Provide access ladder for UD pipes at weir MH locations and at opposite end. Provide
detail of ladder access. (Rev.1) Addressed.
11. Provide drainage design tables/worksheets. (Rev.1) Acknowledged. (Rev.2) Submit with
the site plan prior to WPO approval. Rev. 3: Please provide calculations for the pipes
from the SWM facility to the outfall. Other pipes can be submitted with the site plan.
12. Provide letter of availability from nutrient bank/source provider on the plans. (Rev.1)
Acknowledged; Please include on the plans or the SWPPP. (Rev.2) Addressed.
13. According to current VRRM, 5.59 TIP will need to be purchased. Nutrient credit purchase
will need to be completed prior to plan approval. I will provide Ana the nutrient credit
information once the letter is received and the applicant (owner) wishes to move forward
with purchase. (Rev.1) Please use the new development VRRM worksheet. (Rev.2)
Acknowledged; Currently 5.56 Ib/yr needed for purchase. Rev. 3: Land disturbance
permit cannot be issued until the 5.56 Ib/yr is purchased.
14. The first assessed receiving waterway downstream of the development is the South Fork
Rivanna River with Impairment - Benthic community. It appears that credits will need to
be purchased within the same 10-digit HUC and the closest bank is Ivy Creek. (Rev.1)
Acknowledged.
15. (Rev.1) 1" orifice at bottom is susceptible to clogging. Try to increase to 3". (Rev.2) The
offsite drainage is being re-routed to UD system and then released - Channel & Flood
Protection requirements apply at the discharge point. You chose Energy Balance to
meet requirements. Rev. 3: Comment addressed.
16. (Rev.1) Label the invert on the bypass pipe. (Rev.2) Addressed.
17. (Rev.1) Note: Drainage structures conveying stormwater from R/W will need to be in a
public easement. (Rev.2) Acknowledged. I believe this looks correct.
18. (Rev.2) Sheet 12 - Revise: I don't see these highlighted areas as being captured onsite.
Engineering Review Comments
Page 4 of 7
I m
Rev. 3: Comment addressed.
19. (Rev.2) The storm pipe connections to Underground Detention system must be made
water -tight between the dissimilar material types. Add a note to the contractor to
provide a water -tight connection at those locations. Provide a detail if possible. Rev. 3:
Comment addressed.
20. (Rev.2) Change to Variable width SWM facility & access esmt'. -Add in
W. Rev. 3: Please ensure the easement is sufficient. There should be at least 10' around all
edges:
21. (Rev.2) Revise: Calculations Packet. Rev. 3: Comment addressed.
22. (Rev.2) Please sign & seal the cover of Calculations Packet. Rev. 3: Comment addressed.
D. Erosion and Sediment Control Plan (ESCP)
Engineering Review Comments
Page 5 of 7
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP.
This plan is disapproved, and the reasons are provided in the comments below. The erosion
control plan content requirements can be found in County Code section 17-402.
1. Sheet 2 -Provide accurate 2' (min) contour interval survey. What was the survey
mapping contour precision? (Rev.1) Addressed.
2. Sheet 5 -
a. Show additional contour(s): daylight or tie-in around sediment traps and basin.
(Rev.1) Not addressed. Not shown for area above ST5. Transition the grade for
phase I installation. (Rev.2) Show spillway for ST5. Include a note to dewater and
cleanout SB prior to conversion to a ST. Rev. 3: Comment addressed.
b. Provide TS/PS to sediment basin embankment. (VAESC HB, Ch. 3.14) (Rev.1)
Addressed.
c. Provide B/M to slope at back of dam. (VAESC HB, Ch. 3.36) (Rev.1) Not
addressed. B/M should be added to the 2:1 slope, back of dam, not inside the
trap. (Rev.2) B/M is still shown inside ST3. Rev. 3: Comment addressed.
d. Label the traps (ST#1, ST#2). (Rev.1) Addressed.
e. Show sediment trapping device for the CE. (Rev.1) Addressed.
f. Show baffle placement & the L/W=2 or greater for SB. (Rev.1) N/A; Addressed.
g. (Rev.1) Provide baffle/s for ST3 so runoff doesn't short-circuit to stone weir
outlet. (Rev.2) Addressed.
3. Sheet 6/7 -
a. Label ST#3. (Rev.1) Addressed.
b. Some of the contours are tightly spaced (measures steeper than 2:1). Revise
grading to be 2:1 or flatter. (Rev.1) Addressed.
c. Provide CRS for the streets. (Rev.1) Addressed.
d. Add note & detail that DID (VAESC HB, Ch. 3.09) shown shall be stabilized in
accordance with VAESC HB, Spec. 3.17, SCC where channel slope is greater than
2%. (Rev.1) Addressed.
e. Revise grading: Silt fence should be placed at least 5-7 feet beyond base of
disturbed slope. (Rev.1) Revise: It appears 5' from property line would be in the
proposed grading for slope behind ST5, before Berkmar Dr. (Rev.2) Please adjust
silt fence along Berkmar to be 5' from slope and wall. Rev. 3: Comment
addressed.
f. Revise: A sediment trap will need to be provided at N-W end of site. Runoff will
not go upslope to sediment basin where diversion shown. (Rev.1) Addressed.
g. Include overall grading plan sheet and include utilities. Label TW/BW elevations
at each bend at wall ends. Label walls max. height. (Rev.1) Addressed.
h. Is it correct that you designed the riser to handle more than the 25yr storm? So,
the use of emergency spillway is not required though it's provided? (Rev.1) N/A;
Addressed.
i. (Rev.1) Revise:
KRES
Engineering Review Comments
Page 6 of 7
TIE CONTRACTOR; y
IiR.i N\'T aCOM
1> 1:%
1
BERKMA 11 � �
APTf RDIrtEDRIVE
31403 1 �-
vRRV91E wIo1N
(Rev.2) Addressed.
(Rev.1) Show CE at Berkmar entrance. (Rev.2) Addressed.
CTION WNIENI SIR. )
RLETE TNEINSIAEIN"AL'LAIWN OR STR
4. Ensure channel diversion directional change is not too severe & greater than 90 degrees.
(Rev.1) Sheet 7 - adjust diversion bend is too sharp. (Rev.2) Addressed.
5. Provide dimensions and riprap size requirements for OP. (Rev.1) Addressed.
6. Provide profiles of channels over 2% slope. (Rev.1) Acknowledged.
7. Determine appropriate lining needed for these channels; provide calcs/analysis. (Rev.1)
Acknowledged; I feel appropriate liner is needed for diversion going to ST1 & ST2 where
it goes downhill and bends. (Rev.2) Addressed.
8. For grass stabilization on constructed slopes, the maximum steepness is 3:1. Slopes
steeper than 3:1 must be permanently stabilized with landscaping vegetation hardier than
grass, which will not require mowing. (ACDSM, p.22) (Rev.1) Addressed.
9. Provide ACDSM detail or similar for construction entrance. (ACDSM, p.8) (Rev.1)
Addressed.
10. Provide estimate (cy) of the project's cut & fill. (Rev.1) Addressed.
11. Separate building permit for retaining wall (>3ft) needs to be obtain before constructed
(as currently shown on Phase 11, Sh.6). (Rev.1) Acknowledged.
12. Note: Retaining wall max. height is 6' in managed slopes. [18-30-7.5] (Rev.1) Addressed.
13. (Rev.1) Provide a demo plan or ensure all demo operations are included in your LOD.
(Rev.2) Addressed.
14. (Rev.1) Account for the DA to culvert in the sizing of ST5. There appears to be an
existing culvert under Woodburn Road. (Rev.2) 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 are available from 2-4 PM on Thursdays, should you require a
meeting to discuss this review.
Process:
Engineering Review Comments
Page 7 of 7
After approval, erosion and sediment control and stormwater management improvements must
be bonded. The bonding process begins when the plan is approved, and the applicant submits a
bond estimate request form and fee to the Department of Community Development. A plan
reviewer 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 to the
County, who will record the agreement.
After bonding and agreements are complete, county staff enters project information in a DEQ
database for state application processing, if a DEQ permit is required. DEQ reviews 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, which must be posted at the construction site.
After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction
conference. Applicants must complete the request for a pre -construction conference 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;
https://www.al bemarle.org/government/commu nity-development/apply-for/engineering-applications