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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:
Old Trail Village, Blocks 15 &--14
Plan preparer:
Chris Mulligan, Bill Ledbetter, Raleigh Davis — Roudabush, Gale & Assoc, Inc
914 Monticello Road, Charlottesville, VA 22902, cmulligangroudabush.com,
bledbetter(a)roudabush.com, rdavis(&roudabush.com
Owner or rep.:
March Mountain Properties LLC [1005 Heathercroft Circle, Suite 100]
Dave Brockman, davegoldtrailvilla ee com
Plan received date:
15 May 2014, block 15
(Rev. 1, block 15)
15 Aug 2014
(15t submittal, block 12)
15 Aug 2014
(Rev. 2, block 15)
18 Feb 2015
Date of comments:
30 June 2014 (block 15)
(Rev. 1, block 15)
29 Sep 2014 (block 15, 12)
(Rev. 2, block 15)
12 Mar 2015
Reviewer:
John Anderson
Comments addressed with this or prior plans were removed to streamline document. Pg. 7 -10 intended as guidance.
RGA response to 18- Feb -15 email (preliminary comments) is helpful [review comments —pg 9 -10]. If bioretention
proposed with WP0201300021 as (future) SWM facility for blocks 11 and 14, and recently, block 12 (Phase 1
/WP0201400071) is now to be replaced, there is no process for simply switching one SWM facility for another.
Four plans are connected: WP02012- 00013, WP02013- 00021, WP02014- 00071, and WP02014 -00047 (a 5th if
include Master Plan). If this Application replaces an approved SWM facility under a prior WPO (blocks 11, 12, 14)
in such way that an approved SWM facility will not be built, there are permit/bond implications. Prior SWM plans
are void if prior- approved SWM facilities will never be built. Bond amounts or agreements and SWM Maintenance
Agreements may require review, and revision. Interdependence between block 11, 12, 14, and 15 SWM plans, or
future development blocks, illustrates need to submit a Master Plan that avoids rezoning to aid with stormwater
management design and review, and ease approval.
There is complexity specific to development of block 15 given its relationship with prior- approved SWM plans.
This Application appears to rely upon a reading of e -mail guidance that, prior to approval of a SWM Master Plan,
individual block design may depart from Zoning SWM Plan, which is not the case. It appears 21- Nov -14 guidance
has been misapplied to a degree with this Application.
Current Application depends upon a SWM Master Plan that avoids the need to amend the zoning. That is, this
Application may work, with revisions, but not before a Master plan which effectively sets interpretative limits on
Old Trail Subdivision's approved Zoning SWM Plan and which avoids need for rezoning is reviewed and approved.
WP0201400047, block 15, discards design concept tied to existing Zoning SWM Plan (ZMA200400024) and
cannot be approved since it proposes alteration to the Zoning SWM Plan.
Master plan development guidance is topic of 21- Nov -14 email, was discussed 9- Mar -15, Pre -App (OTV block 27
and blocks 10, 16, 17 & 18 /1). Brockman, B. Ledbetter, Valerie Long, Esq., ACCD). SWM Master Plan review and
acceptance is pre- requisite to proposal to replace the currently- approved (future) SWM facility with an alternative.
Note: VSMP Application, WP0201400047, block 15, was discussed with Mark Graham, Director ACCD, 6 -Mar-
15, and with Alb County Engineer, 10- Mar -15. Comments relating to SWM Master Plan reflect a consensus view.
Engineering Review Comments
Page 2 of 10
A. Stormwater Pollution Prevention Plan —block 15 ( SWPPP)
The SWPPP content requirements can be found in County Code section 17 -405. A SWPPP must contain (1)
a PPP, (2) an ESOP, (3) a SWMP, and (4) any TMDL measures necessary.
1. (Rev. 2) As follow -up: DATE OLD VILLAGE BLOCK 15 SWM POLLUTION PREVENTION PLAN SPILL
PREVENTION AND CONTROL PLAN, submitted on 9- Mar -15 is sealed with PE stamp, but not dated.
Arrange to visit to date PE seal.
2. (Rev. 2) Prior comments addressed, NA, void, or withdrawn. Prior comments available in CV
database system.
B. VSMP: SWPPP: Stormwater Management and Mitigation Plan —block 15 (WP0201400047)
— The stormwater management plan requirements can be found in County Code section 17 -403.
1. (Rev. 1) Addressed.
2. (Rev. 2) Addressed.
3. (Rev. 2) Addressed. For claritnortion of comment is reprinted: "Note /see New. #4, below: Bioretention
has been approved for blocks 14 and 11, not the entire 19.25 Ac. area shown on sheet 5, WP0201300021.
While WP0201300021 provides perimeter ESC for block 12 and most of block 15, and provides SWM for
blocks 11 and 14, it does not provide future development (block 15 and 12) stormwater control beyond
46,286 sf of impervious area and 158,208 sf of lawn/cultivated turf area —ref. Short Version BMP
Computation spreadsheet detail shown on sheet 5, WP0201300021."
New: (items 4 -9, 29- Sept -14)
(Rev. 2) As follow up, for clarity, reprinted: "WP0201400021 provides SWM control for 46,286 sf future
development impervious area. WP0201400021 schematic of blocks 11, 14, 12 & 15, as well as drainage
area defined as 19.25 Ac, shows future impervious area = 125,000sf (12 & 15). With revised
WP0201400047, please compare 46,286 sf impervious and 158,208 sf lawn (area) available under
WP0201300021 with proposed block 15 development. If proposed impervious /lawn exceeds what is
available under WP0201300021, provide treatment. Note: Please see water quality narrative, bullet 3,
sheet 5, WP0201300021: 8,700sf X 12in/ft — 104,400cu.in; 104,400 in3, under this methodology, provides
WQ control for Y2" runoff for 208,800sf of impervious area. Ave of 208,800 and 348,000sf = 278,400sf.
Taking block 11 and 14 impervious areas into consideration, 46,286sf is available not 50,330sf listed in
bullet 3. This calculation does not affect block 11 or 14 approvals, but bioretention basin (treatment)
volume available for future (block 15 and 12, ) development is central to current reviews. We discussed this
briefly 24- Sep -14." With proposed conversion of bioretention basin to retention basin 11 (ref. Attached
Table 1), comment is less relevant, but new issues arise. Reference additional new comments, below.
5. Part II -B water quality criteria appear to apply to stormwater facility design of future development, to block
15 areas not covered by WP0201300021 (ref. 9VAC25- 870 -63). Please utilize VaRRM spreadsheet
design methodology for areas not covered under WP0201300021. Link: http://lis.vir inia.gov /cgii-
bin/legp604.exe ?000 +rea +9VAC25- 870 -63 . (Rev. 2) As follow -up, Stantec, Williamsburg, VA, is
preparing a SWM Master Plan to avoid rezoning (21- Nov -14 guidance, Attached —Also, Glenn Muckley,
Stantec, email, `Master Plan Update': Fri 3/6/2015 4:56 PM).
6. In reporting post - development characteristics for use with VaRRM (or Short Version BMP , CN,
drainages, and land use /cover (including future blocks -17, 18) should be checked. Fielding Run Drive is
east boundary of block 15, and appears a divide, with areas just SW and to the east draining east. It appears
that proposed contours do not allow runoff from certain areas within the 19.25 Acreage on sheet 5
(WP0203100021) to reach the modified sediment basin/future bioretention facility. Underlying
Engineering Review Comments
Page 3 of 10
suppositions bear review. It appears a portion of runoff from `current' (9.32 Ac) and `additional' (9.93 Ac)
areas depicted as reaching the modified facility does not. Figures used to show compliance for blocks 11
and 14 appear problematic or invalid, and require revision to show SWM compliance for blocks 15 and 12.
(Rev. 2) Comment restated. Also, additional comments, below.
7. (Rev. 2) Addressed.
8. Furnish pre- /post - development drainage area maps. (Rev. 2) Comment partially addressed. As follow
up, sheet 8 is unacceptable. Furnish contours across full extent of drainage area map. Contours may yield
follow -up comment on flow lines (sheet flow, OLF, CF), or time of concentration.
9. Propose mitigation for stream buffer impacts (utility work; sheet 3) - § 17 -406. (Rev. 2) Comment not
addressed. Ref sheet 4: HATCHED stream buffer impact area =850 S.F.( ±)
New: (12- Mar -15)
Sheet 8
10. Indicate relative location of blocks 11, 14, 12, 15.
11. Use CN = 55 (Pre -Dev to Pond, 15.1 Ac.), consistent with WP0201300021.
12. Eliminate reference to Pond. A best management practice wet pond, is not proposed.
13. Show contours over full extent of drainage area map to aid evaluation. -Also, item 8, above.
Sheet 9
14. Retention basin II ( 4 x WQ Vol) is inappropriate if post - developed condition percent impervious cover
>66 %. Using revised .xls (.xls sent as e- Attachment, 10- Mar -15), I(post) appears to be 71 %.
15. Avoid 4 *WQV Wet Pond Conversion label if it refers to a 9VAC25- 870 -96.C. Table 1 BMP. Wet ponds
are a Part IIB BMP. Use only Part IIC Table 1 labels to identify Part IIC BMPs, to avoid confusion.
16. Post - development drainage area map: Eliminate proposed contours unrelated to block 15. Minimal
proposed contours east of Fielding Run Drive are required to develop block 15. Specifically, eliminate
land disturbance (contours) that drains to ESC measures for which no proposed or approved SWM facilities
yet exist, unless shown on block 15 phase 1 and phase 2 Road and utility plan (SUB201400080).
17. Furnish table with pipe lengths for 1,000 of pipe @ 2% used to calculate post - developed T,. List Str. IDs.
Sheet 12
18. Routings -If using 2 -yr, 10 -yr pre -post development peak velocity/volume calculations to show compliance
with MS -19, provide 2 -yr, 10 -yr routings. 1,000 -yr event is not required.
19. *15.23 Ac. used instep 2, on -site post - developed phosphorus loading (.xls, sent 10 -Mar). 15.23 Ac.
conflicts with 15.1 Ac. value used elsewhere. [* not sheet 12]
20. Provide post - developed routed 2 -, 10 -yr event peak velocity (fps), volume (cfs) for proposed Part IIC SWM
facility.
21. As elsewhere, please revise /replace Wet Pond - 4* WQV label with Part IIC, Table 1 label (table, below).
22. Revise column headings or add note to indicate that routed results are peak values.
23. Furnish pre - developed peak velocity for pre - developed 2 -, 10 -yr events, 15.1 Ac. DA.
24. Revise Vol. required/provided by Part IIC BMP using VSMH, 1999, Vol. II, Appendix 5D Methodology.
(Worksheets - situation 2. Avoid Short Version BMP Computations .xls, used in past, since discontinued)
Engineering Review Comments
Page 4 of 10
25. Summary for Pond 15P: #1 primary routing device invert = 635.6' while on sheet 2 = 636.11' and sheet 11 =
632.00' (As- built, Dec, 2014). Three different values — revise, ensure accurate values in routing.
26. Summary for Pond 15P: routing device #3 invert = 643.25' while on sheet 2 = 641.07' and sheet 11 = 640.9'
(As- built, Dec, 2014). Three different values — revise, ensure accurate values in routing.
27. Summary for Pond 15P: routing device #2 invert does not match As -built profile iNv elevation, sheet 1I—
revise. Ensure accuracy in routings.
28. Note: Routing results do not make clear that post peak velocity /discharge rates (2410 -yr) are less than pre -
developed peak rates. It is essential for approval to make simple, clear demonstration (via calcs /routings)
that post - developed 2 -, 10 -yr event peak discharge rates are less than pre - developed peak discharge rates.
Sheet 11
29. Sheet 11/12 —Sequence of Construction Note 8 indicates that existing sediment basin 30" riser and 24"
barrel will be replaced during conversion of basin to SWM facility with 48" riser and 36" barrel. 24" barrel
is used in routings. Revise.
30. Review Mgmt Strategies (runoff considerations), Sediment Basin Narrative, and Sequence of Construction
for accuracy. If proposed SWM facility will not be a basin/forebay biofilter, delete reference to this
practice.
31. Sediment basin narrative — Expand on statement that "the base of the sediment basin (635.0) was adjusted to
provide wet storage." Provide proposed SWM facility basin floor dimensions.
32. Show proposed SWM facility basin floor dimensions in plan view (at least one sheet).
33. Sediment basin narrative: 24" outlet and berm geometry is to be preserved upon conversion to a
combination basin /forebay biofilter is inconsistent with Sequence of Construction Note #8 (36" outlet).
34. Sediment basin schematic —Ref VESCH, Plate 3.14 -2: dry storage vol. is measured at riser crest. Revise dry
storage volume =5,776 cy.
35. If add wet/dry volume, total =7,215 cy, or 1694,805 cf. Compare, sheet 2: 76,000 cf storage. Reconcile.
36. Sediment basin schematic: 3 volumes reported for 2 elevations (638', 640'). Revise.
37. Sheet 11/12 — Sediment basin schematic Vol. data is inconsistent with 11 -28 -2014 As- builts cumulative
storage data at these elevations. Reconcile, ensure accuracy.
38. Stormwater runoff considerations: Revise reference to existing SWM basin. There is only a future basin.
C. VSMP: SWPPP: Erosion Control Plan —block 15 (WPO201400047) — The erosion control plan content
requirements can be found in County Code section 17 -402.
1. Sheet 2, sheet 3 —turn off drainage structure layer (inlet and stormwater pipe layer). (Rev. 1) Comment
partially addressed. Proposal to install most of the storm system prior to grading introduces construction
feasibility concerns. Grading is pre- requisite wherever proposed pipe grade is higher than existing grade.
Please consider OSHA trench shoring requirements, VDOT storm sewer note (block 15 final site plan,
sheet 12), and logistical needs (block 15 road plan, storm sewer profile Ex. #32 427A). From a review
standpoint, proposed sequence is problematic. (Rev. 2) Comment not addressed. Mass grading should
precede storm line installation.
2. Prior ESCP comments #2 — 16 (Rev. 2) Addressed, NA, void, or withdrawn.
Comment # 17: (Rev. 2) Addressed. Plans show sediment basin block 14 elevation data; plans reference
As- builts: 11 -28 -2014 (sheet 12). Elsewhere, As -built date reported as December 2014 (sheet 11).
Engineering Review Comments
Page 5 of 10
New, ESOP
Prior #18: Please revise plan note that states: "All run -off is conveyed to the same original outfall location
and outfalls into Lickinghole Creek. Additional offsite and developed onsite runoff is being diverted
through an existing sediment basin for water quality treatment and detention" (bottom of 1 s` col., sh. 8).
0.14 Ac. of block 15 runoff will not reach the modified sediment basin. The sediment basin is not
recognized as providing water quality treatment. A future bioretention facility is. (Rev. 2) Addressed.
Prior #19: Label all drainage easements beyond public RW PRIVATE. Comment applies to blocks 12 and 15
— please check labels carefully (existing /modified sediment basin, Rowcross St, Court Mont Way, Private
alley `A'), and please accept apology for error. This will be a standard item of review with future VSMP
plans. Easements beyond public RW are Private. (§ 18- 32.7.4.2.a.1.) (Rev. 2) Partially addressed. As
follow -up, show proposed public or private drainage easements.
Additional New, ESOP, 12- Mar -15
1. Sheet 2 — Existing conditions: Gray basin shading appears to indicate expanded condition, not existing.
Check against As- built. Show existing condition, Ex. sediment basin. [Ref WPO201300021, sheet 2]
2. Sheet 2 — Show sediment basin spillway, drawn to scale.
3. Sheet 2 — Label additional contours around Ex. sediment basin, so top of embankment easily identified.
4. Sheet 4 — Gray shading is confusing. If shading relates to future SWMfacility, remove shading from
EC Plan Phase 1. If shading relates to expanded basin dimensions, provide proposed and existing
contours using heavy (proposed) and light (existing) lines, or alternative standard convention.
5. Sheet 4 — Proposed sequence, with storm sewer installed prior to site grading, is infeasible. Remove
storm drain lines from this sheet. Ref. sheets 5, 7, which show storm lines with/after mass grading.
Also, sequence of construction, Notes 1 -4 (sheet 11), which lists rough grading prior to storm sewer.
6. Sheet 6 — Proposed contours south of Claremont conflict with proposed contours (EC Plan, Phase II)
Sheet 4, WP0201400071. Two sets of contours differ. Revise contours to match WP0201400071.
7. Sheet 7 — Sediment trap sizing tables: include (top of) bank width for each sediment trap.
8. Sheet 5 — Label construction entrance PCE.
9. Sheets 4,5,6,7 — Calculate, show, label Limits of Land Disturbance. Ensure consistency across plan
sheets, and consistency with pre- /post - development runoff routing calculations.
Engineering plan review staff is available from 2 -4 PM on Thursdays, should you require a meeting to discuss this
review. Plan review staff are also available at 434 - 296 -5832 ( -ext 3069) should you have 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
Engineering Review Comments
Page 6 of 10
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.
*Note: VPDES Permit VAR100043 disturbed area acreage may require revision
Applicant 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 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.orWdel2tforms.asp?department--cdengMpo
File: WPO201400047- WPO201400071 -OTV -block 15 031215 rev2
Engineering Review Comments
Page 7 of 10
Attachments
Sec. 17 -301 — Amended, 1- Jul -14 —Water resource areas, 3.33% I(pre), drinking water watershed, eliminated. Short Version
BMP Computations discontinued. Use VSMH, 1s` Edit, 1999, Vol. II, Appx 5D Worksheets /situation 2.
By Amending, Renumbering and Renaming:
Old New
Sec, 17 -301 See, 17 -600 Designation of water resources areas Extent of stream buffers
retention and establishment
9VAC25- 870 - 96.13.2. —Water Ouality(Grandfathered projects)
2. Situation 2 consists of land- disturbing activities where the existing percent impervious cover is less than or equal to
the average land cover condition and the proposed improvements will create a total percent impervious cover that is
greater than the average land cover condition.
Requirement: The pollutant discharge after disturbance shall not exceed the existing pollutant discharge based on
the average land cover condition.
9VAC25- 870 -96.C. — Technology -based Criteria (PART IIC)
C. Technology -based criteria. For land- disturbing activities, the postdeveloped stormwater runoff from the impervious
cover shall be treated by an appropriate BMP as required by the postdeveloped condition percent impervious cover as
specified in Table 1 of this section. The selected BMP shall be located, designed, and maintained to perform at the target
pollutant removal efficiency specified in Table 1 or those found in 9VAC25- 870-e5. Design standards and specifications for the
Bi in Table 1 that meet the required target pollutant removal efficiency are available in the 1999 Virginia Stormwater
Management Handbook. Other approved Bi available on the Virginia Stormwater BMP Clearinghouse Website may also
be utilized.
Table 1'
Target Phosphorus
Water Quality BMP'
Percent Impervious Cover
Removal Efficiency
Vegetated filter strip
10%
1C -21%
Grassed swale
15%
Constructed wetlands
20%
Extended detention (2 x WQ Vol)
35%
22 -37%
Retention basin 1 (3 x WQ Vol)
40%
Bioretention basin
50%
Bioretention filter
50%
Extended detention - enhanced
50%
38 -66%
Retention basin 11 (4 x WQ Vol)
50%
Infiltration (1 x WQ Vol)
50%
Sand filter
65%
Infiltration (2 x WQ Val)
65%
67-100%
Retention basin 111 (4 x WQ Vol with
65%
aquatic bench)
'Innovative or alternate Bl not included in this table may be allowed at the discretion of the local
program administrator or the department. Innovative or alternate 3l not included in this table that
target appropriate nonpoint source pollution other than phosphorous may be allowed at the discretion
of the local program administrator or the department.
Engineering Review Comments
Page 8of10
E -mail. ACCD
From: Mario Graham [mailto:mgrahamoalbemarle.ong
Sent: Friday, November 21, 2014 4:36 PM
To: Dave Brockman; Bill Ledbetter, olenn.muckley0stantec.com; ron.boydOstantec.com
Cc: Amelia McCulley; David Benish; Glenn Brooks; Rebecca Ragsdale; Doug Walker
Subject: FW: DRAFT - FOR INTERNAL REVIEW ONLY
To follow up on our Monday meeting, Glenn and I have met with Zoning and Planning to make sure we are staying consistent
with the approved zoning plan and stormwater requirements. In doing this, we've tried to set the limit on what is expected
and what we can approve. Please do not take this as a negotiation offer, it is not. Instead, we've realistically looked at what
is needed to comply with the VSMP and without first amending the current property zoning. From that, I am offering the
following as a set of guidelines to follow in development of a stormwater master plan that avoids the need to amend the
zoning. To assist in understanding, I have attached Glenn's illustration at the end ofthis message. The following are what I
believe are the important points:I
Zoning SWM Plan (excerpt): Timmons Group, Old Trail Village Rezoning, Stormwater Management and Stream Conservation
Plan, 8/26/05, ZMA200400024.
r
Design Illustration (once SWM Master Plan reviewed/approved, for circumstance where SWM departs from ZMA200400024):
Ref. Table 1, Part IIC technology -based criteria/BMP, above. Select BMP appropriate to % impervious cover. Avoid
Short Version BMP computations .xls (discontinued). Use VSMH, Vol. II, Appx 5D, situation 2.
Revising .xls data sent as e-mail Attachment 10- Mar -15, I(post) appears to be 71 %, meaning retention basin II is
inappropriate (post- developed impervious cover >66 %). Data revised to include turf, woodlands /good condition,
runoff coefficient =0.05. (Attachment, below)
If, for illustration, post - developed cover requires retention basin III or equivalent Part IIC BMP (67 -100% impervious),
an approved type ofSWM.facility (21- Nov -14 email, bullet 1) means an appropriate BMP. Avoid (do not select) a less
efficient BMP and request Lickinghole Basin credit for any shortfall. Please ref 21- Nov -14 email, bullet 3: "For all the
areas not being routed through BMPs (this area plus uncaptured areas within the red and blue areas), a 30% reduction
Engineering Review Comments
Page 9 of 10
credit can be provided by Lickinghole."
Use treatment trains (best management practices in series) as needed.
Short Version BMP Computations, received 10- Mar -15, revised to reflect post - developed turf Areas, pre- existing
woodlands in good condition; Note: post - developed impervious Area =71 %, approx.
Gale & Associates Date: 23- Feb-15
Project Drainage Area Designation
Blocks 11!14112!15
L storm pollutant export in pounds, L= [P(Pj)Rv112][C(A)2.72]
Rv mean runoff coefficient, Rv= 0.05 +0.009(1)
Pi small storm correction factor, 0.9
I percent imperviousness
P annual precipitation, 43" in Albemarle
A project area in acres in subject drainage area, T
C pollutant concentration, mgA or ppm target phosphorus
f factor applied to RR
V required treatment volume in cy, 0.5" over imperv. area = A(I)43560(0.5112}127
RR required removal, L(post) - fxL(pre)
%RR removal efficiency, RR1001L(postj
Impervious Cover Computation (values in feet & square feet)
18em
pre- devebpment
Area
post -devebpment
Area
Length
Width
subtotal
Roads Length Width subtotal
0
0 0
0
0
162354
0
0 0
20986
0
0
0
45228
0
0
0
0
0
228568
Driveways Length
Width
no.
subtotal
Length Width
no.
subtotal
and walks 1 01
0
01 0
01 0
0
32756
01
01
01 0
01 0
0
1 13793
0
0
1
1 14328'
60877
Parking Lots 1
2
3 4
0 0
0
0
01
1
1
0
01
1
1 0
0
Gravel areas Area
Area
x0.70=
0
x0.70=
0
Structures
Area
no.
subtotal
Area
no.
subtotal
01
01 0
DI
0
86510
01
01 0
DI
DI
40351
0
1
01 0
0
I
I 285112
155363
Actively - grazed pasture&
Area
Area
yards and cultivated turf
x o.o8 =
0
207268 x 0.08 =
16581.44
woodlands, good condition
Area
Area
657756 x 0.05 =
32887.8
x 0.25 =
0
Other Impervious Areas
0
Untreated SE Int. Fielding Runntow Cross
5680
rnpervious Cover
5%
71%
KIP-)
Rv{post} Y
0.69 720.8
Kpost}
Block 1714
Block 12
Block 15
Block 11114
Block 12
Block 15
Block 11114
Block 12
Block 15
E -mail, J.Anderson to RGA f Wed 2/18/2015 8:03 PMl
Please:
1. Furnish VSWMH, Appendix 5D worksheets. BMP Removal Rate Computations .xls is discontinued.
2. Use I Watershed = 16% w /App 5D worksheets. Use precise estimates of post - developed land use cover.
3. 6.0 Ac. turf/open; 9.1 Ac. impervious appear imprecise values — revise to nearest .O1 Ac.
4. Identify CN source —if TR -55, provide table #, fig., etc.
5. Furnish schedule /table that reports impervious area. Identify surface type (walks, streets, structures, etc).
6. Separate block 12, phase 1, and block 15 when constructing table /schedule, item #5, above.
7. Do not rely on WP0201300021 (.xls) Areas unless current development is identical with that proposed under
WP0201300021.
8. Explain how block 12, phase 1 (Lots 1 -7) aligns with proposal. WP0201400071 relied upon WP0201300021, and the
arrangement worked. With proposal to construct a wet pond, we move away from bioretention design approved under
Engineering Review Comments
Page 10 of 10
WP0201300021. WP0201300021 is aligned with WP0201400071, but AT0201300021 is less relevant if we switch
to a wet pond. Apply to AMEND WP0201400071.
9. We cannot approve WP0201400047 without amending WP0201400071 since this plan eliminates on -site bioretention
SWM facility approved to treat runoff under WP0201400071. —Also, #8, above.
10. Detail the share or portion of 4 X WQV required to treat block 12, phase 1, lots 1 -7 runoff [WP0201400071]. Provide
detailed data to correlate WP0201400071, and this plan (WP0201400047).
11. Furnish calculations to yield: 4 X WQV = 67,704 cf
12. Review attached block 12, Phase 1 WPO Approval —Note limitations: "WPO plans are not approved for block 15 phase
2 road plan." [Also, SUB201400080]
13. NOTE: block 15, Phase 2 road plan approval is contingent upon VSMP /WPO approval (WP0201400047). VDOT has
approved block 15 phase 1 and phase 2.
Pg. 8, Albemarle County Design Standards Manual (ACDSM), Section deleted Eff. 29- Apr -2014 —Avoid Lpre, Lpost
formulae visible mid -page. Discontinued. — REF /USE ACDSM, rev. Eff. 29- Apr -14
4. Removal Rate computations:
a. Simple Method: water quality requirements for design follow the simple method
given in Chapter S section 10 of the Virginia Stormwater Management Handbook,
with some modifications. Given simply, for each drainage area on the site, or for
each facility's drainage area, the pollutant loads and removal rate are computed as
follows:
Lpre = 8.77 *(0.05 +0.9 *Ipre) *Cw *A
Lpost = 8.77 *(0.05 +0.9 *Ipost) *Cw *A
t3R — (Lpost- f *Lpre) *100 /Lpost
Where;
- L is the pollutant loading or export
- Cw is a Constant for the watershed equal to;
0.7 for development areas,
0135 for drinking water watersheds, and
0.4 for other rural lard
- A is the drainage area in acres
- I is the fraction of imperviousness in the watershed
- RR is tte removal rate
13. An MsExcel spreadsheet is provided for the removal rate calculation.
c. Imperviousness is counted for more than simply hard surfaces. Below is a chart of
typical overall values;
Land Use
Equivalent %
impervious cover
Forest
0
Un¢razed rassfshrubland
2
5+ acre residences in woodlands
2 -5 acre residences in woodlands
5
Mowed lawns, moderately- grazed pasture,
golf courses
8
1 acre residences
to
Orchards
12.5
Cropland
25
0.5 acre residences
25
0.33 acre residences
30
0.25 acre residences
35
Townhouses
50
Apartments
70
Light CommerciallIndustriallSchools
70
Heavy CommerciaUlndustrial
40
Pavement
1,00
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k7n
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: Old Trail Village, Blocks 15 & 12
Plan preparer: Roudabush, Gale & Assoc, Inc [914 Monticello Road, Charlottesville, VA
22902, cmulligan @roudabush.com]
Owner or rep.: March Mountain Properties LLC [1005 Heathercroft Circle, Suite 100]
Dave Brockman, dave@oldtrailvilla ee com
Plan received date: 15 May 2014, block 15
(Rev. 1, block 15) 15 Aug 2014
(15t submittal, block 12) 15 Aug 2014
Date of comments: 30 June 2014 (block 15)
(Rev. 1, block 15) 29 Sep 2014 (block 15, 12)
Reviewer: John Anderson
Note: Since blocks 12 & 15 are adjacent and could be developed simultaneously, comments affect both blocks.
Comments are presented under separate block headings. This is the initial VSMP review for block 12, second
VSMP/WPO plan review for block 15.
A. Stormwater Pollution Prevention Plan —block 15 (SWPPP)
The SWPPP content requirements can be found in County Code section 17 -405. A SWPPP must
contain (1) a PPP, (2) an ESOP, (3) a SWMP, and (4) any TMDL measures necessary.
OLD TRAIL SUBDIVISION STORMWATER POLLUTION PREVENTION PLAN AND POLLUTION PREVENTION
PLAN, April 16, 2014 is commendable. The SWPPP/PPP covers 86.5 Ac. under General VPDES
Permit VAR100043, areas shown on sketch dated September 29, 2014. Bracket references VAR10,
July 1, 2014; htW: / /www.deq.vir inia. gov/ Portals/ 0/ DEO /Water/Publications /CGP2014.pdf . Please
revise SWPPP/PPP (P. # /17 -pg. SWPPP):
1. Number each page.
2. In addition to Concrete Wash -out Area [Part ILAA(e)(5)], Fueling Area [Part ILAA.(e)(2)],
Stockpile Area, and Porta -potty [Part ILAA(e)(7)] labels, furnish specific prevention design
information, including: secondary containment for fueling area; concrete washout area located
upstream of a sediment basin/trap; silt fenceiberm for portable sanitary facilities and solid
waste dumpster to prevent or limit stream or environmental impacts. Labels are insufficient
preventive design measures. [Details shared with ACCD during project meeting Sep -25
would be ideal.]
3. Show paved construction entrance with wash rack on SWPPP, block 15. [ACDSM, p. 27]
4. (P. 1) Revise Anticipated Project Completion Date to 5 -31 -2019, consistent with registration
statement.
5. Attach copy of VAR10 to SWPPP /PPP (link above): print /attach. [Part II.A.1.c.]
6. Revise SWPPP whenever development increases quantity of pollutants /stormwater [Part III,
J.l.b.]
7. SWPPP Availability — provide means of public review [Part II.D.3.]
8. (P. 2.) Runoff Coefficient /Site Map /Description of Existing Vegetation —ref. "SWM Plan," not
"Final Site Plan." Site plans are not approved as part of VSMP /SWM plans.
9. Site Area — Define site area consistent with sketch dated 9/29/14 (86.5Ac). [Part I1.1.4.]
10. Scott Bradshaw is identified as SWPPP contact: submit qualifications. List additional
personnel if any others qualified/expected to perform SWPPP inspections. [Part II.F.1.]
11. (P. 3) Item #3 — Revise "All points of construction ingress and egress shall be protected by a
temporary construction entrance" to reference paved construction entrance with wash rack.
Engineering Review Comments
Page 2 of 7
[ACDSM; also, #3, above]
12. (P. 4) Item #4 - Preconstruction meeting shall be held at county office building.
13. Item #4 -Name individuals who will be responsible for ensuring maintenance of installed
measures on a daily basis. ( #10, above) [Part II.A.6.]
14. Item #4 - Contact ACCD to schedule a preconstruction conference. ACCD schedules this
meeting.
15. Item #6 - Revise "Any necessary maintenance of the measures shall be accomplished
immediately upon notification by the County and shall..." -REF Part II.G.1 - notification by
County not prerequisite to corrective action.
16. Item #10 - "from traversing slopes or by installing mechanical..."
17. Item # 12 - Clarify: "...soil stockpiles at the locations shown on this plan or as directed by
engineer..." Design engineer /ACCD engineer? Stockpile area shown on SWPPP plan, block
15, sheet 1 /1, Aug -12, 2014, governs stockpile location.
18. (P. 5) Item #14 - Compare with ESC plan sequence of construction. ESC plan states storm
drainage facilities will be installed prior to rough grading, a problematic proposition.
19. Item #15 - Revise "which may be at final grade but will remain dormant (undisturbed) for
longer than 30 days" to read "for longer than 14 days" [Part II, A.2.c,(8)]
20. Item 417 -Edit. See VESCH listed temp seed mix, Piedmont, winter months.
21. Item #19 -For slopes stepper than 3:1, specify vegetative ground cover hardier than grass.
[ACDSM, 8.A.2.]
22. Item 421 - Clarify meaning. Statement is problematic, inconsistent with VESCH.
23. (P. 6) Item #22. - Clarify /confirm 3 percent grade.
24. Structural Practices: please also include: Paved Construction Entrance with Wash Rack;
Storm Drain Inlet Protection (VESCH 3.07); Mulching (3.35); Dewatering Device (3.26);
Slope Drains (3.15); Paved Ditches /Flume (3.16)
25. Stormwater Mana eg merit: Delete reference to "Final Site Plans "; reference "SWM plan."
26. Waste Materials: show waste dumpster location on SWPPP plan, block 15.
27. (P. 7) Maintenance and Inspection Procedures - Revise: 2" paragraph - identify personnel
[Part II.A.6. /7.]; 3rd paragraph periodically is non - specific [Part ILF.2.(a)/Part II.G.11; 3rd
paragraph - repairs within 7 days [Part II.E.1]; 4d' paragraph - "at least once every 10 days"
[Part II.F.2.(a)(2)].
28. (P. 8) Non - Stormwater discharges: Ref. Part ILAA.(e)(4) for control requirements. Delete
where possible.
29. (P.10) Hazardous products - Identify on -site location of MSDS sheets, a location accessible to
on -site contractors /inspectors.
30. Petroleum products, 2nd bullet - Specify measures intended to reduce potential for
contamination when refueling, changing vehicle fluids, etc [Part II.A.4.(e)(2)].
31. (P. 12) bullet -LIST tel. # for reporting spills /incidents [Part III.G.; Also Note, p. 16, VAR10]:
a. VDEQ, Valley Regional Office, M -F, 8:30 -4:30 - 540.574 -7800
b. VDEM, Nights, holidays, weekends - 1- 800 - 468 -8892
c. Local VSMP Authority: 434 - 296 -5832, M -F, 8 -5.
32. Revise Pollution Prevention Certification [Part II.A.8; Part III.K.1. /4.] exactly as follows:
Certification. Any person signing a document under Part III K 1 or 2 shall make the following
certification:
"I certify under penalty of law that I have read and understand this document and that this document
and all attachments were prepared in accordance with a system designed to assure that qualified
personnel properly gathered and evaluated the information submitted. Based on my inquiry of the
person or persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate, and
complete. I am aware that there are significant penalties for submitting false information, including the
possibility of fine and imprisonment for knowing violations."
33. Sign/Date Certification.
34. (PP. 13, 15, 16) - Revise tables to allow more space for recording description of grading
activity (p. 13); description of the amendment (p. 15), description of BMP deficiency (p. 16).
Also, furnish tables or data sheets to accommodate inspection reporting needs listed at Part
H.F.4.(a) -(j).
Engineering Review Comments
Page 3 of 7
35. SWPPP Plan, block 15:
a. Label Court Mont Way.
b. Receiving Waters – revise "runoff from this entire area currently drains into Slabtown
Creek via an existing sediment basin," since not strictly accurate.
c. Receiving Waters – revise "As such, it will provide full containment for the denuded
areas," since not strictly accurate. Limited areas drain east to sediment traps.
d. Stormwater Management – revise "Approved plans (WP0201300021) shall function
as the SWM facility for this development," since WPO201300021 may not provide
full SWM control (see SWM, comment #3, below).
e. Compare Porta john locations: Potential Pollutant Sources, 2 °a paragraph, with
Installation and Maintenance, 7th paragraph – revise for consistency.
f. Include ESC legend. (see SWPPP plan, block 12, Aug -15, 2014)
g. [ For SWPPP plan, block 12, have design engineer sign plan ]
B. VSMP: SWPPP: Stormwater Management and Mitigation Plan –block 15 (WPO201400047)
– The stormwater management plan requirements can be found in County Code section 17 -403.
Plans reference a bioretention basin approved under WPO201200013 and refer to block 14 SWM Plan
submitted under separate cover (WP0201300021). WP0201300021 modified the approved bioretention
basin, enlarging it to accept runoff from drainage area defined on sheet 5 of this plan set, dated March 20,
2013. This approved SWM plan applies to the 19.25 Ac. DA (sheet 5). Sheet 5 of the current plan set
dated May 9, 2014 shows that runoff from portions of Fielding Run Drive and disturbed, graded areas do
not reach the modified bioretention basin. Please furnish SWM control that meets water quality and
quantity standards under Albemarle County Code, Ch. 17, WPO Ordinance for portion not routed to the
biorctcntion basin (modified sediment basin) under current design. (Rev. 1) Comment addressed; ref,
applicant response letter, 29 -Jul 2014. 3.91 Ac. of development runoff is assumed to route to the modified
sediment basin approved under WPO201300021 (future bioretention facility). 96.6% is routed, while 0.14
Ac. is not (0.11 and 0.03 DAs; Fielding Run Dr /Rowcross St). Design comments and request for design
information, #3 -8, below, however, take priority over examination of 0.14 Ac uncollected storm runoff.
2. Attach or transfer relevant sheets, elements and details of block 14 approved WPO (WP0201300021) to
current application to lend guidance and clarity during WPO review of block 15, during bonding,
inspection, and construction. WPO plans for block 15 may not be approved by simple reference to an
approved WPO without transferring relevant information. To reiterate, please include plan sheets listed
below for purposes of guidance and clarity (not analysis), since nearly all block 15 post - development
runoff routes to an approved modified (future) bioretention facility. (At present, and for some time, the
facility will serve as a sediment basin). Transfer sheets 4, 5, and 6 of approved WPO201300021 plan set
(Mar -20 2013) without change. Please label each sheet as a plan sheet taken from approved
WP0201300021. (Rev. 1) Comment partially addressed: as follow -up: please label each sheet as
originating with WP02013- 00021.
3. In addition, from sheet 2 of Mar -20, 2013 plan set, attach or transfer: sediment basin narrative, sediment
basin schematic elevations detail (including design elevations with emergency spillway), and plan view of
basin —label this information taken from approved WPO201300021. Further, please label major contours
(640', 650'). Confirm and label existing base of sediment basin elevation = 635.0' (Rev. 1) Comment
partially addressed. As follow -up to 10 -Sep discussion, please remove sheet 2 of WP0201300021. The
appearance of existing block 14 ESC measures may confuse. Instead, from WPO201300021 /sheet 2,
please include (with both block 15 and block 12 VSMP plans): Sediment Basin Narrative; Sequence of
Construction; Sediment Basin Schematic Elevations. These details link WPO201300021 modified
sediment basin design data to a future bioretention facility. Note /see New. #4, below: Bioretention has
Engineering Review Comments
Page 4 of 7
been approved for blocks 14 and 11, not the entire 19.25 Ac. area shown on sheet 5, WP0201300021.
While WPO201300021 provides perimeter ESC for block 12 and most of block 15, and provides SWM for
blocks 11 and 14, it does not provide future development (block 15 and 12) stormwater control beyond
46,286 sf of impervious area and 158,208 sf of lawn/cultivated turf area —ref. Short Version BMP
Computation spreadsheet detail shown on sheet 5, WP0201300021.
New:
WPO201400021 provides SWM control for 46,286 sf future development impervious area.
WPO201400021 schematic of blocks 11, 14, 12 & 15, as well as drainage area defined as 19.25 Ac, shows
future impervious area = 125,OOOsf (12 & 15). With revised WPO201400047, please compare 46,286 sf
impervious and 158,208 sf lawn (area) available under WPO201300021 with proposed block 15
development. If proposed impervious /lawn exceeds what is available under WPO201300021, provide
treatment. Note: Please see water quality narrative, bullet 3, sheet 5, WPO201300021: 8,700sf X 12in/ft —
104,400cu.in; 104,400 in3, under this methodology, provides WQ control for 'h" runoff for 208,800sf of
impervious area. Ave of 208,800 and 348,OOOsf = 278,400sf. Taking block 11 and 14 impervious areas
into consideration, 46,286sf is available —not 50,330sf listed in bullet 3. This calculation does not affect
block 11 or 14 approvals, but bioretention basin (treatment) volume available for future (block 15 and 12)
development is central to current reviews. We discussed this briefly 24- Sep -14.
5. Part II -B water quality criteria appear to apply to stormwater facility design of future development, to block
15 areas not covered by WPO201300021 (ref. 9VAC25- 870 -63). Please utilize VaRRM spreadsheet
design methodology for areas not covered under WPO201300021. Link: http:/ /Iis.virginia.gov /cg_i-
bin/legp604. exe? 000 +ree +9 VAC25 - 870 -63
6. In reporting post - development characteristics for use with VaRRM (or Short Version BMP), CN,
drainages, and land use /cover (including future blocks -17, 18) should be checked. Fielding Run Drive is
east boundary of block 15, and appears a divide, with areas just SW and to the east draining east. It appears
that proposed contours do not allow runoff from certain areas within the 19.25 Acreage on sheet 5
(WP0203100021) to reach the modified sediment basin/future bioretention facility. Underlying
suppositions bear review. It appears a portion of runoff from `current' (9.32 Ac) and `additional' (9.93 Ac)
areas depicted as reaching the modified facility does not. Figures used to show compliance for blocks 11
and 14 appear problematic or invalid, and require revision to show SWM compliance for blocks 15 and 12.
7. With revised WPO201400047, please furnish existing conditions with soil types/boundaries.
8. Furnish pre- /post - development drainage area maps.
9. Propose mitigation for stream buffer impacts (utility work; sheet 3) - § 17 -406
C. VSMP: SWPPP: Erosion Control Plan —block 15 (WPO201400047) — The erosion control plan content
requirements can be found in County Code section 17 -402.
Sheet 2, sheet 3 —turn off drainage structure layer (inlet and stormwater pipe layer). (Rev. 1) Comment
partially addressed. Proposal to install most of the storm system prior to grading introduces construction
feasibility concerns. Grading is pre- requisite wherever proposed pipe grade is higher than existing grade.
Please consider OSHA trench shoring requirements, VDOT storm sewer note (block 15 final site plan,
sheet 12), and logistical needs (block 15 road plan, storm sewer profile Ex. #32 427A). From a review
standpoint, proposed sequence is problematic.
Engineering Review Comments
Page 5 of 7
2. Sheet 2 - Restore baffle to existing modified sediment basin (ref. WPO201300021). (Rev. 1) Comment
void; baffle field verified 8- Sep -14.
3. Sheet 2 -Show IP and OP, temp construction culvert (ref WP0201300021, sheet 2A). (Rev. 1) Comment
withdrawn; review error.
Temporary diversion dikes (DD, labeled DV on sheets 3/5) are a perimeter control and should not be used
on constructed fill slopes (VESCH, p. III -53). Either relocate DD (with sediment traps) to toe of slope,
avoiding placement in stream buffer, or eliminate grading operations below diversion dikes (revise final
grades). Eliminate the circle inset details for grass lined channel (DV). These details with v- shaped
conveyance differ from VESCH typical detail for DD. Ref. Plate 3.09 -1. (Rev. 1) Comment withdrawn
- review error: temporary diversion dike (VESCH 3.09) is not selected. Diversion (VESCH 3.12) is control
ESC option shown on sheet 3 -see 29- Jul -14 comment response letter.
5. Sheet 5 -show non - erodible channel from the outfall of structure 63 at the south end of Fielding Run Drive
to sediment trap #1. Eliminate circle inset showing v- shaped grass lined channel section and select ESC
from VESCH. V -shape is prone to higher and erosive channelized flow. (Rev. 1) Comment addressed.
6. Show boundaries of sediment trap drainage areas, listed as 3.0 Ac. for each sediment trap (sheet 3). (Rev.
1) Comment addressed.
7. Show critical slopes, if any. (Rev. 1) Comment partially addressed. Clarify Critical Erosion Areas note,
which states critical erosion areas exist on this site (identify type /location of critical erosion areas). Also,
we recommend recurrent phrase "There are no critical areas onsite," be revised to state there are no seeps or
live watercourses -more precise descriptions that agree with Critical Erosion Areas note.
8. Remove floating SF labels, sheet 2. (Rev. 1) Comment addressed.
9. Show wash rack water supply for CE, sheet 2. (Rev. 1) Comment addressed
10. Indicate stockpile and staging areas. (Rev. 1) Comment addressed; see Adjacent Areas Note, ESC
Narrative, sheet 8.
11. Identify off -site borrow or fill sites. (Rev. l) Comment addressed; see Off -Site Areas Note, ESC
Narrative, sheet 8.
12. Existing contours south of Glen Valley Drive differ from both existing and proposed contours on Mar -20,
2013 Approved WPO for block 14. Please confirm that existing contours immediately south of Glen
Valley Drive and east of CE are accurate as shown. (Rev. 1) Comment addressed; contours confirmed
accurate.
13. Show orange SAF around modified sediment basin. (Rev. 1) Withdrawn; SAF at basin verified 8- Sep -14.
14. Show SAF along south side of Glen Valley Drive, to prevent trespass, sheets 2 and 4. (Rev. 1) Proximity
to residences on Glen Valley prompts request. Appreciate discussion with project representatives, 8-/10 -
Sep-14, relative to safety and welfare. No SAF requested along Old Trail Drive. (§17-102.A)
15. In areas shown to receive temporary seeding (sheets 4 and 5), include permanent seeding, mulch, and dust
control (PS, MU, DC). (Rev. 1) Comment partially addressed; letter, 29 -Jul, indicates misunderstanding
- request is for straw mulch (VESCH 3.35), with TS/PS (see Vegetative Practices, Note 4, Mulch (3.35),
80 # /1000sf, sheet 8).
New
Engineering Review Comments
Page 6 of 7
16. Calculate area impact to stream buffer for sanitary sewer line activity in stream buffer (sheet 4). (Rev. 1)
Comment addressed.
17. Confirm as -built modified sediment basin dimensions; compare with dimensions shown on approved
WP0201300021, sheet 2. Report any discrepancies between the two. (Rev. 1). Comment not addressed.
Much depends on modified sediment basin, approved to be converted to a bioretention facility designed to
treat 19.25 Ac., including block 15 and 12 runoff. Code basis for as -built data request for (future) SWM
facility —§ 17 -422. Although basin continues to serve as a sediment basin, WPO201300021 (block 14)
approved basin modification as preliminary step to conversion to SWM facility. Sheet 4, WPO201300021,
shows extent to which contours approved under WPO2012 -00013 change. Request for basin dimensions is
to confirm that modified basin matches design criteria, sheet 2, WPO201300021.
18. Please revise plan note that states: "All run -off is conveyed to the same original outfall location and outfalls
into Lickinghole Creek. Additional offsite and developed onsite runoff is being diverted through an
existing sediment basin for water quality treatment and detention" (bottom of 1St col., sh. 8). 0.14 Ac. of
block 15 runoff will not reach the modified sediment basin. The sediment basin is not recognized as
providing water quality treatment. A future bioretention facility is.
19. Label all drainage easements beyond public RW PRIVATE. Comment applies to blocks 12 and 15 — please
check labels carefully (existing /modified sediment basin, Rowcross St, Court Mont Way, Private alley `A'),
and please accept apology for error. This will be a standard item of review with future VSMP plans.
Easements beyond public RW are Private. (§ 18- 32.7.4.2.a.1.)
A. VSMP: SWPPP and Pollution Prevention Plan —block 12 (WP020140007l) — §17-405
(The Virginia stormwater management program, stormwater pollution prevention plan application and
documents
Refer to block 15, above: Comments virtually identical. Oct -2 meeting scheduled for questions.
B. VSMP: SWPPP: Stormwater Management Plan —block 12 (WPO201400071): Refer to block
15, above. WPO201400047 SWM comments (2.4.) apply to blocks 15 and 12, equally.
C. VSMP: SWPPP: Erosion Control Plan —block 12 (WPO201400071) —The erosion control plan content
requirements can be found in County Code section 17 -402.
1. Provide diversion dike or ditch, west side of modified sediment basin, sheet 3.
2. Revise CE to paved CE with wash rack, sheet 2.
3. Revise 668' contour to 666', lower right quadrant, sheet 2, near Future Development Area label.
4. Label all drainage easements beyond public RW PRIVATE. Comment applies to blocks 12 and 15 — please
check labels carefully (existing /modified sediment basin, Rowcross St, Court Mont Way, Private alley `A'),
and please accept apology for error. This will be a standard item of review with future VSMP plans.
Easements beyond public RW are Private. (§ 18- 32.7.4.2.a.1.)
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. No fee is required for VSMP re- submittals.
Engineering plan review staff are available from 2 -4 PM on Thursdays, should you require a meeting to discuss this
review. Plan review staff are also available at 434 - 296 -5832 ( -ext 3069) should you have questions.
Engineering Review Comments
Page 7 of 7
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;
htt2://www.albemarle.ora/dgptforms.asp?department=cdengnMo
File: WP0201400047- WPO201400071 -OTV- blocks 15, 12- 092914
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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: Old Trail Village, Block 15
Plan preparer: Roudabush, Gale & Assoc., Inc [914 Monticello Road, Charlottesville,
VA 22902, cmulligan @roudabush.com]
Owner or rep.: March Mountain Properties LLC [1005 Heathercroft Circle, Suite 100]
Plan received date: 15 May 2014
Date of comments: 30 June 2014
Reviewer: John Anderson
A. Stormwater Management and Mitigation Plan (WP0201400047)
1. Plans reference a bioretention basin approved under WP0201200013 and refer to block 14 SWM
Plan submitted under separate cover (WP0201300021). WP0201300021 modified the approved
bioretention basin, enlarging it to accept runoff from drainage area defined on sheet 5 of this plan
set, dated March 20, 2013. This approved SWM plan applies to the 19.25 Ac. DA (sheet 5).
Sheet 5 of the current plan set dated May 9, 2014 shows that runoff from portions of Fielding Run
Drive and disturbed, graded areas do not reach the modified bioretention basin. Please furnish
SWM control that meets water quality and quantity standards under Albemarle County Code, Ch.
17, WPO Ordinance for portion not routed to the bioretention basin (modified sediment basin)
under current design.
2. Attach or transfer relevant sheets, elements and details of block 14 approved WPO
(WP0201300021) to current application to lend guidance and clarity during WPO review of block
15, during bonding, inspection, and construction. WPO plans for block 15 may not be approved
by simple reference to an approved WPO without transferring relevant information. To reiterate,
please include plan sheets listed below for purposes of guidance and clarity (not analysis), since
nearly all block 15 post - development runoff routes to an approved modified (future) bioretention
facility. (At present, and for some time, the facility will serve as a sediment basin). Transfer
sheets 4, 5, and 6 of approved WP0201300021 plan set (Mar -20 2013) without change. Please
label each sheet as a plan sheet taken from approved WP0201300021.
3. In addition, from sheet 2 of Mar -20, 2013 plan set, attach or transfer: sediment basin narrative,
sediment basin schematic elevations detail (including design elevations with emergency spillway),
and plan view of basin —label this information taken from approved WPO201300021. Further,
please label major contours (640', 650'). Confirm and label existing base of sediment basin
elevation = 635.0'
B. Erosion Control Plan (WP0201400047)
Engineering Review Comments
Page 2 of 2
I . Sheet 2, sheet 3 —turn off drainage structure layer (inlet and stormwater pipe layer).
2. Sheet 2 — Restore baffle to existing modified sediment basin (ref. WPO201300021).
3. Sheet 2 —Show IP and OP, temp construction culvert (ref WPO201300021, sheet 2A).
4. Temporary diversion dikes (DD, labeled DV on sheets 3/5) are a perimeter control and should not
be used on constructed fill slopes (VESCH, p. 111 -53). Either relocate DD (with sediment traps) to
toe of slope, avoiding placement in stream buffer, or eliminate grading operations below diversion
dikes (revise final grades). Eliminate the circle inset details for grass lined channel (DV). These
details with v- shaped conveyance differ from VESCH typical detail for DD. Ref. Plate 3.09 -1.
5. Sheet 5 —show non - erodible channel from the outfall of structure 63 at the south end of Fielding
Run Drive to sediment trap # 1. Eliminate circle inset showing v- shaped grass lined channel
section and select ESC from VESCH. V -shape is prone to higher and erosive channelized flow.
6. Show boundaries of sediment trap drainage areas, listed as 3.0 Ac. for each sediment trap (sheet
3).
7. Show critical slopes, if any.
8. Remove floating SF labels, sheet 2.
9. Show wash rack water supply for CE, sheet 2.
10. Indicate stockpile and staging areas.
11. Identify off -site borrow or fill sites.
12. Existing contours south of Glen Valley Drive differ from both existing and proposed contours on
Mar -20, 2013 Approved WPO for block 14. Please confirm that existing contours immediately
south of Glen Valley Drive and east of CE are accurate as shown.
13. Show orange SAF around modified sediment basin.
14. Show SAF along south side of Glen Valley Drive, to prevent trespass, sheets 2 and 4.
15. In areas shown to receive temporary seeding (sheets 4 and 5), include permanent seeding, mulch,
and dust control (PS, MU, DC).
16. Calculate area impact to stream buffer for sanitary sewer line activity in stream buffer (sheet 4).
17. Confirm as -built modified sediment basin dimensions; compare with dimensions shown on
approved WPO201300021, sheet 2. Report any discrepancies between the two.
File: WPO201400047 -01d Trail -block 15- 063014 -geb