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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
Project title:
Project file number:
Plan preparer:
Owner or rep.:
Plan received date:
(Rev. 1)
Date of comments:
(Rev. 1)
Reviewers:
VSMP Permit Plan Review
Hillbrook
WPO- 2015 -00033
Shimp Engineering, P.C.
Hilltop Partners, LLC
29 May 2015
24 July 2015
26 June 2015
20 August 2015
Justin Deel
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. 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 remove calculation packet. Include only the SWM, itself. Supporting documentation is not
required here.
(Rev. 1) Comment addressed.
2. Provide required signatures (Delegation of Authority).
(Rev. 1) Comment addressed.
3. Reflect below requested changes in resubmitted SWPPP.
(Rev. 1) Comment addressed.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17 -404.
Provide PPP. Provided plan is E &SC Phase 1 plan.
(Rev. 1) 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. " Stormwater that enters inlets 3B and 4 flows to the bioretention until the water surface elevation
reaches 495. 0, then it flows through the bypass structures... "; the consensus among the reviewers
here is that this is impractical. Will all drainage up to 495' go to the biofilter? I think much of it
Engineering Review Comments
Page 2 of 4
will go down the overflow, untreated. The 175' pipe is basically flat. The overflow is 3.6" off the
bottom, which will likely fill with sediment and debris. Please explore alternative options.
(Rev. 1) Comment partially addressed. Please ensure that the entire 1 year storm event will
reach the biofilter. Your invert out elevation at structure 4 is shown at about 497' (labeled as
496. 1, please check) while the 1 year storm elevation is 497.36.
2. The storm drain pipe slopes are too flat. The minimum should be 0.5 %. This includes the 24"
pipes, which are effectively drain pipes, not detention pipes. Please correct. Does the system rely
on 1 /100`h of a percent precision (0.25 %, 0.28 %)?
(Rev. 1) Comment addressed.
3. You cannot claim sheet flow to a conservation area downstream of the bioretention facility, which
requires a 10 year storm (495') to achieve.
(Rev. 1) Comment addressed.
4. If your inlet 3 detail is to be used with the new design, please explain further. What size gravel
will be used to protect the 3" PVC?
(Rev. 1) Comment partially addressed. Please provide a larger more clear detail of your vault
system. Are you accounting for the stone in your calculations? Is it necessary for a self - cleaning
pipe system? If the stone stays in place, it will most likely clog; if not, it will wash away, probably
down the pipe. Please explore an alternative to the gravel inlet protection at the weir orifice. This
also applies to the proposed stone in the detention system.
5. Please clean up storm drainage area maps, clearly showing all acreages used in VRRM.
(Rev. 1) Comment addressed.
6. Please do not place detention pipes beneath structures (sidewalk).
(Rev. 1) Comment addressed.
7. A permanent conservation easement is required for the forested open space claimed in VRRM.
(Rev. 1) Comment addressed.
8. Please identify waste area(s), if needed.
(Rev. 1) Comment addressed.
9. Provide retaining wall plans.
(Rev. 1) Comment addressed.
Revision 1 Comments:
10. Please check invert elevations and pipe slopes on storm sewer profile, specifically structure 4.
11. Please elaborate on the self - cleaning velocity table values from structure 5 to 6. I'd like to see
those computations, as it just meets the minimum 3.0 ft/s.
12. Please provide a larger clearer cross - section of the biofilter. It impossible both to see where the
leaders are pointing and to differentiate the layers. Please specify filter media depth.
13. I realize that the sequence of construction detail in Specification No. 9 is barely legible, but at this
scale on your plan it is completely illegible. Please try to clear this up.
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. The erosion control plan content requirements can be found in County
Code section 17 -402.
Please relocate and redesign Sediment Trap 1. The site will not be stabilized before the trap will
have to be removed to construct the road, sidewalk, and storm sewer. A better location may be in
lot 6?
(Rev. 1) Comment addressed.
2. Please clean up grading lines for sediment traps. Ensure that all proposed contours are solid lines
Engineering Review Comments
Page 3 of 4
and existing contours are dashed. Show grading for downstream dam embankment for ST 2 and
include in LOD. Provide more proposed contour labels for sediment traps. Please provide scaled
cross - sections showing existing and proposed contours.
(Rev. 1) Comment addressed.
3. Provide sediment trap labels.
(Rev. 1) Comment addressed.
4. Please label critical slopes hatching.
(Rev. 1) Comment addressed.
5. Phase 1 drainage divide appears incorrectly drawn, please correct.
(Rev. 1) Comment addressed.
6. Prove more silt fencing at the site's perimeter (southern and northern corners ?).
(Rev. 1) 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.
Engineering Review Comments
Page 4 of 4
County forms can be found on the county website forms center under engineering;
http: / /www.albemarle. org/deptforms .asp ?department= cdengwno
File: WPO201500033 VSMP Review Rl.doc