HomeMy WebLinkAboutWPO201500032 Review Comments WPO VSMP 2018-12-28COUNTY 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: Timberwood Square — VSMP
Project file number: To be Assikned
Plan preparer: Dustin Greene, EIT—Roudabush, Gale & Associates [dareene(abroudabush.com ]
172 S. Pantops Drive, Charlottesville, VA 22911
Owner or rep.: Highlife Townhomes Inc., 307 West Rio Road [rhauser(a)stonehaus.net]
250 Pantops Mountain Road, Charlottesville, VA 22901
Plan received date: 3 Dec 2018 (submitted as WP0201500032)
Date of comments: 28 Dec 2018 (filed with WP0201500032, until App # assigned)
Reviewers: John Anderson
WP02019-xxxxx
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, below. The
application may be resubmitted for approval if all of the items below are satisfactorily addressed. The
VSMP application content requirements can be found in County Code section 17-401.
General
1. Plan is virtually identical with WP0201500032. Please ref. WP0201500032 for background.
2. Albemarle County Code 17-411 indicates WP0201500032 is deemed withdrawn. Please see 17-411.B.
3. A permit fee is required with a new VSMP Application, half at time application is submitted ($1,350).
4. Please submit $1,350 VSMP permit application fee.
5. Review comments below are intended to expedite approval as Applicant submits fee and revises plan for
eventual VSMP/WPO plan approval.
6. Note: Thirty months have passed since last plan submission. Current review identifies limited areas of plan,
SWPPP, or calculations that require revision, update, or clarification. Albemarle is alert to issue of fairness
yet must ensure procedures important to DEQ and county are followed.
7. 15 Oct 2018 initial site plan Engineering review comments (SDP201800071*) include this (item 2b.):
2b. Text, email, Engineering to Planning (6/18/2016 2:11 PM -also RMS docs, SDP201500023):
"(SDP201500023) —Engineering has No Objection to FSP design. Engineering comments addressed with
this or prior submittal. FSP Approval requires ROAD Plan Approval, and requires that roads (Lois Lane,
Landon Lane) be built or bonded. ROAD Plan is not approved. FSP Approval requires that WPO be
approved and bonded. Planning coordinator should confirm that SWM Maintenance Agreements have been
signed, that project has received VPDES Permit coverage letter from DEQ. Please confirm WPO status
with Max Greene, Engineering Div."
* Note: As with WP0201500032, Initial and Final site plans for this project dating to 2015 presented similar design as
the current new initial site plan SDP201800071 (required once 2015 plans expired due to plan inactivity). Planning is
reviewing SDP201800071 as a new project. Engineering must consider the WPO plan with care. In fairness to
Applicant, Engineering limits comments to a minimum. In certain cases, comments request revision, update, or
clarification of items that were reviewed without comment in 2015 and 2016. This is a new VSMP /WPO Application.
Review requirements have not changed appreciably, and blue highlight items above persist as items required for final
site plan approval or WPO plan approval.
Engineering Review Comments
Page 2 of 4
8. Once the $1,350 due with Application is received, a new application number will be assigned. Once a new
WPO# is assigned, please include WPO# in plan title.
9. Prepare SWPPP similar to SWPPP prepared for WP0201500032, which used Albemarle County template.
Experience with DEQ indicates certain items typical of a SWPPP are relatively more important to the state.
The county template reflects this. Current submittal abandons template in favor of a proprietary format.
SWPPP dated 11/28/18 distributes information in atypical fashion, which may introduce issues for
inspectors, owner, county, and contractor. For quickest approval, revert to county template. If Applicant
opts not to use county template, please ensure SWPPP includes ESC plan sheets (Sec. 4 /template); I I" x
17" SWPPP Exhibit (Sec. 6); that Appendix H (equivalent to template Sec. 9, Certification), is signed; and
that the Pollution Prevention Certification is signed (no template equivalent).
10. Provide copy of recorded Stormwater Management Facility Maintenance Agreement that affirms owner of
property to be developed has pre-existing arrangement with Forest Lakes HOA to utilize Arbor Lake for
stormwater management purposes for Timberwood Square. Please furnish bk.-pg. reference to recorded
SWM Facility Maint. Agreement, or enter a Maintenance Agreement with Albemarle County. Ref. 17-415.
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. Link to County template:
hqp://www.albemarle.or2/upload/ima2es/forms center/departments/Communi1y Development/forms/Engineering and
_WPO_Forms/Stormwater_Pollution _ Prevention_Plan _S WPPP_template.pdf
Ref. General item #9, above.
SWM Plan
The Stormwater Management Plan content requirements can be found in County Code section 17-403.
1. Provide reference to a County -approved Site or WPO plan # that includes Applied Technology and
Engineering designs shown on sheet 10 to confirm project eligible for 9VAC25-870-48 as a `grandfathered'
project, subject to water quality requirements at 9VAC25-870-96 (not 9VAC25-870-65).
2. Provide SWM Plan narrative (on the plan) comparing county -approved Site or WPO plan full buildout or
anticipated full buildout of areas draining to Arbor Lake with existing buildout in areas draining to Arbor
Lake. Critical point of comparison is existing impervious area as a percentage of area draining to Arbor
Lake, compared with full buildout percentage of impervious area anticipated by Applied Technology and
Engineering design that would eventually drain to Arbor Lake. Provide narrative to support and clarify
Arbor Lake Drainage Area graphic, sheet 10, of plan. Clarify and compare % design imperviousness with
% current watershed imperviousness, pre -development, and % post -developed watershed impervious area.
3. Note: Engineering cannot perform research that may be required by items 1 or 2.
4. Coordinate purchase of 3.31 lb. phosphorus nutrient credits with Ana Kilmer prior to purchase. Please see
6/27/16 Engineering review comments: C. SWM Plan (pg.-2, review comment memo /Attached).
5. Hydraulic Calculations, pg. 2, table, lists SWF Original Design, Qto peak, post-dev =277.4 cfs, inconsistent with
(RGA) Hydraflow Autocad Qto peak, post-dev routing =376.88cfs (pg. 4, Hydrologic /Hydraulic calculations
report). Provide narrative that discusses/clarifies:
a. Discrepancy in design then vs. design now values. (Applied Technology & Engineering vs. RGA)
b. How /where hydraflow hydrographs indicate stage/discharge elevation=475.73 (Qlo-n; p• 2 of
calculation report) when Stage/Discharge graph (p. 7 of report) shows discharge Elev. =480 @
180.00 cfs. Revise calculations, as needed.
c. Provide Qio hydraflow inputs/outputs that include Arbor Lake basin volume, as well as spillway
data, and that include discharge elevation for Qto-peak that corresponds with RGA reported value,
376.88cfs.
d. Calc. report /(cont.):
i. Revise worksheet 513-5 consistent with sheet 2 proposed/existing impervious values. 513-
5 lists 1.58 Ac. parking /roadway; sheet 2 lists 1.52 Ac.
Engineering Review Comments
Page 3 of 4
ii. Revise worksheet 5D-6 consistent with sheet 2 existing impervious values. 5D-6 lists
0.61 Ac. parking, no roadway; sheet 2 lists 0.77 Ac.
C. Erosion and Sediment Control Plan (ESOP)
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESOP. This plan
is disapproved, for reasons listed, below. The erosion control plan content requirements can be found in
County Code section 17-402.
Sheet 2
1. Source of topography Note indicates survey by RGA, April 1989, field verified by Dominion Engineering
July, 2014. Engineering ESC Plan review checklist, p. 1, existing conditions plan view information states
`topography should be at least visually field verified by the designer within the last year.' Please field
verify topography and update sheet 2 topo note.
Sheet 4
2. Along NE boundary of LOD, within LOD, provide and show contoured depressions similar to sediment
traps, if not sediment traps, to capture and redirect diversion dike channelized flow at two locations with
abrupt direction change. Channelized flow may either break through the dike, or invade the site, unless a
depression /stilling basin capture flow, prior to redirecting it.
3. Revise construction sequence:
a. Item 6; list Ex. Str. 4, 4A, 5, 5A, 6.
b. Switch items 5 and 6.
c. Item 4: clarify. What existing 54" storm pipe inlets?
d. Include phase 2 inlet /storm pipe installation in sequence.
e. Revise to include installation of ST (shown on sheet 6).
f. Revise item 9 to clarify county inspector approval is required prior to removal of SB-1.
g. If SB-1 installed after step/item 3, show SF downslope of storm pipe (step 3), until SB-1 is
installed.
4. Relocate lavatory, given construction at Ex4A.
5. Show swale /proposed grading required to route parking lot runoff from Ex3A1 to SB-1.
6. Label rectangular shape to left of soil/stockpile area.
7. Provide caption for ** (symbols), SB-1.
8. Label SB-1 floor dimensions.
9. The 2 arrow flow lines north of SB-1 don't work; flow is perpendicular to contours. Revise.
10. Recommend remove `provide riprap distilling basin' label and leader line.
11. Provide riprap outfall L X W X D dimensions /label at toe of 14' emergency spillway.
12. Show /label Arbor Lake waters edge.
13. Add SFF to legend.
14. Sheets 5, 6: Remove label reading: `Install 24" pipe run 1-2-3-Ex4 and...' since installed with ESC phase 1.
15. Sheet 6: Provide riprap L X W X D dimensions, ST outfall.
16. Sheet 7:
a. Provide buoyancy calculations: 6' X 1.5' SB-1 primary spillway riser base.
b. Revise SB-1 Calculations:
i. Preliminary design, 11: provide Q25 routing to support design high water=479.55'.
ii. Revise distance from dewatering orifice to C/O level; should be 1.0.
iii. Required principal spillway capacity appears to be 9.2 cfs (ref. Runoff), but is listed as
5.7 cfs at item 15 (principal spillway design). Revise design to ensure the principal
spillway passes the peak rate of runoff from the basin drainage area for a 2-yr storm event
(ref. VESCH).
iv. Using Q peak2_yr=9.7cfs and VESCH, it appears (item 17) riser diameter should be 21".
Confirm 24" DIA is the smallest diameter required to pass Q peak2_yr.
v. Item 23 /Anti -seep collar design:
1. Slope upstream face of dam is 2: 1; please revise.
2. Slope of barrel=1.16%; please revise.
3. Length barrel in Sat. zone (Ls) appears to be 18.9. Please verify Ls.
Engineering Review Comments
Page 4 of 4
4. Provide anti -seep collars; provide ct. /dimensions (2 @ 2.5' X 2.5', for example).
5. Show anti -seep collars in SB-1 profile schematic.
c. Recommend show storm pipe, 1-2-3-Ex4 in SB-1 profile schematic.
17. Include VESCH Plate 3.14-10, Anti -vortex device design detail on plans.
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
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 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;
httt): //www. albemarle. org/dei)tforms. asp? department--cdenawn o
Thank you
J. Anderson 434.296-5832 —x3069
WP0201500032 App to be reassigned Timberwood Square 122818