HomeMy WebLinkAboutWPO201700016 Approval - County WPO VSMP 2017-11-20
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: Old Trail Blocks 5, 20 & 21
Project file number: WPO201700016
Plan preparer: Shimp Engineering P.C. [justin@shimp-engineering.com]
Owner or rep.: March Mountain Properties, LLC
Dave Brockman [dave@oldtrailvillage.com]
Plan received date: 16 Feb 2017
Rev.1 received date: 05 June 2017
Rev. 2 received date: 03 Aug 2017
Rev. 3 received date: 04 Oct 2017
Rev. 4 received date: 07 Nov 2017
Date of comments: 20 Mar 2017
Rev. 1 comments: 30 June 2017
Rev. 2 comments: 15 Sept 2017
Rev. 3 comments: 03 Nov 2017
Rev. 4 comments: 20 Nov 2017
Reviewers: Emily Cox
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 approved
pending execution of the SWM agreement and the plat/deed. The rationale is given in the
comments 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.
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. Please provide a signed registration statement (Section 1) and a signed certification (Section 9).
Rev. 1: Comment addressed.
2. Ensure that any revisions to the E&S Plan and SWM Plan are inserted into the SWPPP. Rev. 1:
Comment addressed. Rev. 2: Please provide 2 copies of the SWPPP with the latest plans inserted.
Ensure the signed registration statement and certification are included (from comment 1). Rev. 3:
Comment addressed.
3. Two copies of the SWPPP are necessary for plan approval. Rev. 1: Comment addressed.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17 -404.
1. Provide a plan sheet showing all of the required PPP elements in County Code section 17-404.
Rev. 1: Comment addressed. Rev. 2: Please provide 2 copies of the latest PPP for plan approval.
Engineering Review Comments
Page 2 of 5
Rev. 3: Comment addressed.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is disapproved, and the reasons are provided in the comments below. The
stormwater management plan content requirements can be found in County Code section 17-403.
1. Since this plan is part of the approved stormwater master plan for Old Trail, please provide an
updated water quality compliance tracking ledger which includes the facilities on your site. Along
with this tracking ledger, please submit the Old trail village SWM master plan reference
checklist.(Appendix D of the master plan). Rev. 1: Tracking ledger only shows 2 facilities, when
there are 5 proposed on site. Planned target drainage area was 8.39, and design drainage area was
6.58, therefore the surplus should be (-1.81). Rev. 2: Again, the tracking ledger should accurately
show the proposed facilities. There are 5 proposed on site, therefore there should be 5 items in the
spreadsheet. Also, as previously requested, along with this tracking ledger, please submit the Old
trail village SWM master plan reference checklist. (Appendix D of the master plan, also attached
to these comments). Rev. 3: Comment addressed.
2. Please provide the date of the topographic information. Source was provided. Rev. 1: Survey was
from 2012. Was this field verified? If so, provide the date. Rev. 2: Comment addressed.
3. Please reference the approved zoning/master plan number on the cover sheet. Rev. 1: Comment
addressed.
4. Please provide labels for stormwater structures on the plan as well as their drainage divides.
References to the profiles is very confusing. It is hard to identify the structures. Drainage divides
in calculation booklet were very hard to read/identify. Rev. 1: Comment addressed.
5. Please provide structure type labels on the profiles (ex: DI 3B L=6’). Rev. 1: Comment addressed.
6. The calculations in the SWM book do not appear to match the profiles in several locations. Please
check the slopes, inverts, lengths of pipe, etc. Also, ensure that all pipes are included in the
calculations. Rev. 1: Show calculations for Out 6 to Out 7 and Out 9 to Out 10. Rev. 2: Comment
addressed.
7. The Str 5 to Str 4 profile shows a slope of 0.43%. Please revise. Minimum slopes are 0.50%. Rev.
1: Comment addressed.
8. Ensure the following notes are on the plan, “concrete inlet shaping (IS-1) required on any structure
with a 4’ or greater drop and safety slabs (SL-1) required in any structure taller than 12’.” Rev. 1:
Comment addressed.
9. Slopes throughout the site should be 3:1. If 3:1 cannot be achieved, 2:1 may be proposed, but
ground cover(not grass) must be specified on the plans. (per the Design Standards Manual Section
8) Rev. 1: Comment response letter says a note was added on Sheet C8. Note does not appear to
be there. Please clarify. Rev. 2: Comment addressed.
10. Building permit will be required for the retaining walls. Provide retaining wall detail and certified
computations (per the Design Standards Manual Section 8). Rev. 1: Comment still valid. Rev. 2:
Comment addressed. As discussed in our meeting, this will be provided at time of building permit.
11. Although this project is grandfathered, please design the bioretention facilities to the current DEQ
stormwater design specificaiton No. 9 in all aspects if possible. In particular, the required section
of stone, media, etc has been improved with the new design specifications to ensure proper
function of the bioretention facility. The phosphorus removal and the surface area sizing can be
calculated per the old minimum standard 3.11. Note that the max. side slope of the bioretention is
3:1 and the max. ponding depth is 6 inches. Rev. 1: Comment mostly addressed. Please ensure
the side slopes of the bioretention areas are 3:1 max. There are not enough labels to tell, but the
slopes appear to be 2:1. Rev. 2: Biolfilters B&C were the only ones labeled with 3:1 side slopes.
Please ensure that side slopes of all bioretention areas are 3:1. Rev. 3: Comment addressed.
Engineering Review Comments
Page 3 of 5
12. Provide a planting plan for the bioretention areas. Rev. 1: Ensure plantings are from the attached
list. Rev. 2: Betula Nigra and salix nigra were not on the list. Please revise. Planting list attached to
these comments. Rev. 3: Comment addressed.
13. Please explain the nyloplast grate in the bioretention areas. What do they connect to? Rev.1:
Please label the top elevation of these grates. Ensure they are above the 6”ponding depth so that
water will still filter through the media. Rev. 2: Biofilters A, C, and D did not provide 6” ponding.
Rev. 3: Comment addressed.
14. Please provide a detail for the concrete risers and anti-vortex devices. Rev. 1: Comment addressed.
15. Provide maintenance requirements for the bioretention areas on the plan (can be found in section 9
of the DEQ specification). Rev. 1: Comment addressed.
16. Provide a ‘SWM facility’ easement around each bioretention facility. Rev. 1: Comment
addressed.
17. A Stormwater Management Maintenance Agreement and an Easement Plat with a Deed of
Dedication will be needed before the VSMP plan can be approved. Please contact Ana Kilmer to
begin the process of completing the Maintenance Agreement. The application for an easement plat
can be found in the Community Development Documents section of the County's website under
Subdivisions. The fee for the easement plat will be the one shown for the easement plat required
with a site plan. We recommend you begin this process as soon as possible. Rev. 1: Comment still
valid. Rev. 2: The maintenance agreement should be coordinated with Ana Kilmer. The plat was
received and is under review. It will also need a deed to go with it. The deed cannot be completed
until the maintenance agreement is executed. Rev. 3: Plan cannot be approved until SWM
Agreement is executed and the deed/plat are recorded.
18. Provide a separate plan sheet for the mitigation plan. Ensure that all areas are clearly hatched and
provide a legend for the hatching(disturbed area, mitigation area, etc). Rev. 1: Comment
addressed.
19. Provide a planting plan for the mitigation plan (spacing, species, sizes, etc.) Rev. 1: Mitigation
planting area does not meet the 2:1 ratio. Provide explanation of available area. Rev. 2: As
discussed in the meeting, please clearly show the areas to be used for mitigation. Rev. 3:
Comment addressed.
20. Rev 1: Provide labels for all existing and proposed contours throughout the plan. Rev. 2:Contour
labels are still insufficiently shown. Ensure the existing and proposed contours are labeled and are
at a legible height. Rev. 3: Comment addressed.
21. Rev 1: There are two Sheet C10s. Please correct the second to be Sheet C11. Rev. 2: Comment
addressed.
22. In the SWM booklet, on the drainage map, please revise St 14 to be St 15 in the table. Rev. 2:
Comment addressed.
23. In the SWM booklet, on the inlet computations, ST-2 and R-1 DA appear incorrect. Rev. 2:
Comment addressed.
24. In the SWM booklet, in step 7 of the water quality calculations, the EFF should be 6.07, not 6.98.
Also in worksheet 2, step 3, the drainage areas and Ibmp used for D & E appear incorrect. Please
double check. Rev. 2: Comment addressed. Areas were updated, but the EFF and Ibmp still appear
incorrect (based on master plan and the provided BMP drainage map). However, comment
dismissed as provided calculation appears more conservative. No further revision necessary.
25. Rev. 2: Provide calculation for pipe Out1B to Ex. 1. Rev. 3: Comment addressed.
26. Rev. 2: Why are c-factors for roof drains not all 0.9? Rev. 3: Comment addressed.
27. Ensure adequate outfall for all pipes.
https://www.vbgov.com/government/departments/planning/DSC/Documents/MS19%20Plan%20C
hecklist.pdf MS-19 states, “Concentrated stormwater runoff leaving a development site shall be
discharged directly into an adequate natural or man-made receiving channel, pipe or storm sewer
system.” Rev. 3: Comment not addressed. Sheet C6 and C11 show proposed ditches. This is
Engineering Review Comments
Page 4 of 5
concentrated stormwater. This needs to be converted to sheet flow or sent directly to an
existing adequate stream/ditch. This can be done w ith a level spreader.
http://www.vwrrc.vt.edu/swc/documents/2013/DEQ%20BMP%20Spec%20No%202_SHEE
T%20FLOW_Final%20Draft_v1-9_03012011.pdf
http://www.deq.virginia.gov/Portals/0/DEQ/Water/StormwaterManagement/Erosion_Sedim
ent_Control_Handbook/Chapter%203%20-%203.21.pdf
Rev. 4: Comment addressed.
28. Rev. 2: Check E1 roof area in table. Rev. 3: Comment addressed.
29. Rev 2: ST-1 inlet computation shows a depth of 1.45 ft. Per VDOT Drainage Manual Section
9.3.1.4, this should be a max. of 0.50 ft. Rev. 3: Comment addressed.
30. Rev. 3: Ensure the correct TMP is shown (cover sheet and ex condition sheet). Old Trail
TMPs have recently been revised. Rev. 4: Comment addressed.
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 approved, 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. A wash rack is required with the paved construction entrance. Please provide a wash rack with an
area to detain the sediment-laden runoff. (per the Design Standards Manual Section 3 F) Rev. 1:
Detail provide, however plan view still does not show WR symbol. Rev. 2: Comment addressed.
2. Ensure that the sediment basin embankment cross section requirements per VESCH 3.14 are met
(page III-80). Embankments of sediment basins should be 2:1 or flatter. Please label the
embankment top width on the plans. Rev. 1: Please label contours on the basin details. Are they
basins or traps? Please clarify per your comment. If they do not meet basin designs, they cannot
and should not be labeled as basins. Label the basins, B, D, etc on sheet C6. Minimum top widths
per page III-80 of the VESCH are 6 ft. Provide the emergency spillway design and show it on the
detail (Sheet C10). Rev. 2: If D&E are traps, they should show the calculations and specifications
for traps, not basins. Rev. 3: Comment addressed. Rev. 3: Comment addressed.
3. Provide the top of dam elevation on all sediment basin details. Ensure that there is 3’ between the
top of the riser structure and the top of the dam (per the detail in the VESCH and provided on the
plans – design elevations without emergency spillway). Rev. 1: Basins D & E do not have
spillways, therefore they need the 3’ clearance from the top of the riser to the top of the dam. Rev.
2: Rev. 2: If D&E are traps, they should show the calculations and specifications for traps, not
basins. Rev. 3: Comment addressed.
4. On Sheet C6, please show silt fence in the western corner (continue it all the way from sediment
basin B until Golf Drive) Rev. 1: Comment addressed.
5. Rev. 2: Please clarify the sequence of construction. Bioretention cannot be built until the site work
is complete and stabilized. Also, ensure that references to traps/basins are correct. Phase 3 on
sheet C6 contradicts itself as it says to backfill basins in an earlier step and then in a later step is
says basins must stay active until site work complete. Rev. 3: Comment addressed.
6. Rev. 2: Show drainage divides to basins/traps for all phases on construction. Drainage divides
only provided in Phase 1. Rev. 3: Comment addressed.
7. Rev. 2: Sheet C9 shows traps 1, 2, 4 and 5. Please correct. It should be 1, 2, 3 and 4 . Rev. 3:
Comment addressed.
8. Rev. 3: Sheet C6 shows grading outside the limits of disturbance without E&S protection. Please
update the limits and the total disturbed area. Also, provide adequate E&S measures. Rev. 4:
Comment addressed.
9. Rev. 3: Regarding previous comment, the DEQ registration statement must be updated with the
Engineering Review Comments
Page 5 of 5
latest total disturbed acreage. Rev. 4: Comment 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;
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;
http://www.albemarle.org/deptforms.asp?department=cdengwpo