HomeMy WebLinkAboutSUB201400141 Review Comments Road Plan and Comps. 2015-10-27 (3)� OF A.
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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:
Fontana - Phase 4C, Section 1 & 2
Plan preparer:
Terra Engineering and Land Solutions, P.C.
Owner or rep.:
Fontana Land Trust
Plan received date:
7 Nov 2014
(Rev. 1)
17 Feb 2015
(Rev. 2)
6 Oct 2015
Date of comments:
19 Dec 2014; rev. 22- Jan -2015
(Rev. 1)
13 Mar 2015
(Rev. 2)
27 Oct 2015
Reviewer:
John Anderson
After further review of SWM report and documents submitted for electronic review, update to road plan
/Advance WPO comments may be helpful. Please accept this letter as supplement (or replacement) to initial
Engineering road plan review correspondence dated 19 Dec 14. Initial comments remain visible as grayscale.
A. Road Plan (SUB201400063) Note: Comments are general in nature since disapproval is thematic.
More detailed comments may apply to future submissions, but detailed review at this stage is not
possible given need to consider Phase 4C as an integrated whole (sections 1, 2, 3). A section 1 & 2
proposal does not work. The main reason for this is that Section 2 SWM is a proposed biofilter with
pipe /ditch/yard systems conveying runoff from a portion of section 1 and nearly all of section 2 to this
facility. Section 1 runoff is divided between section 2 and 3 SWM facilities. As an alternative, if the
applicant coordinates with Planning and receives approval to plat section 2 (Lots 1- 11 /Belluno Lane
RW) alone then Engineering may review Section 2 road plans. There are 2 options; one requires
Planning approval: Phase 4C, Section 2 road plan, or a Phase 4C road plan with storm runoff provided
by biofilter (sections 1 & 2), extended detention basin (sections 1 & 3), and additional measures that
may be required to comply with 9VAC25- 870- 96/ -97. [COMMENT REVISED] - Section 1 and 2 stand
alone. They do not rely upon section 3 extended detention basin. Road plans work from an Engineering
perspective, but Applicant is strongly advised to coordinate with Planning. Applicant is encouraged to
confirm that sections 1 and 2 are eligible to be platted without section 3. Preliminary (approved) plat,
Fontana Phase 4C includes sections 1, 2, 3. If sections presented in road plan are eligible to be platted
without section 3, Applicant should have clear understanding of conditions that apply, for example,
requirements relating to design, construction and bonding of Cascadia Connector. Additional:
Applicant should respond to VDOT road plan review comments to VDOT satisfaction. All roads shown
on plan are public. VDOT review and approval is essential. -Also, Advance WPO comment, item #3
Drainage Area May 1, Section 1 (Drainage Computations & SWM Report/4- Nov -14) shows: 1. 136 Ac. Post to
Sect. 3 basin; 1.197 Ac. Post area to Hyland Ridge, uncontrolled; 0.533 Ac. Post to Sect. 2 Basin.
Drainage Area May 6, Section 2 (Report/4- Nov -14) shows: 4.056 Ac. Post to Luxor Pond (via bio- filter); 1.312
Ac. Post to Hyland Ridge (uncontrolled). [Note —D.A.s carefully drawn. —Ref rev. Advance WPO /VSMP
comments, below —item #5]
Planning must confirm a final plat e€Sec2 that excludes section 4-&-3 is an administrative possibility.
Note - preliminary plat covers all 3 sections. Planning comment (1 -Dec) highlights the need: "The title
Engineering comments
Page 2 of 5
of the road plan reads: "Fontana — Phase 4C, Sections 1 & 2 "; however, when reviewing the plan it
appears to cover all 3 sections. Notably Brunello Court is depicted on sheet C2.1, and Belluno Lane is
depicted throughout various sheets. Please address this inconsistency." (Rev. 1) As follow -up: A FINAL
PLAT may be submitted for Sections 1 and 2, but Final Plat for these two sections must include Cascadia
Connector. Albemarle County Zoning Administrator and Asst. County Attorney have confirmed this.
Connector location is shown in Zoning, ZMA2004- 00018. Applicant interest in exploring option of
revising ZMA2004 -00018 proffers, including the Cascadia Connector, was discussed on 9 -Mar 2015
(Pre -App: T. Nichols, Zoning, Planning, Engineering, S. Driver). Also: item #2, New #1 below. (Rev.
2) Addressed.
Comments
1. Road plans must provide adequate SWM facilities for storm runoff increase. Please submit
WPO/VSMP Applications, either for Phase 4C, Section 2 (biofilter), or entire Phase 4C. Note:
Engineering preliminary plat comment, 7- Nov -14: "preliminary review of extended detention SWM
facility indicates proposed (or similar) design could provide 2xWQV (210.9cy x 2) needed to treat
113,256 SF impervious, 292,426 SF turf runoff (post- development- /section 3, portions sec. 1) if basin
depth = 4.6'(f), x- sectional basin area 2.3' above floor = 2,475SF. Statement does not indicate SWM
plan or basin design approval. ACCD will furnish supportive detail. It is imperative that design
consider: direction of section 1 runoff, and whether runoff is routed to section 2 bio- filter, to section 3
extended detention basin, or is uncollected (front of Lots 16, 17, 18; essentially all of Lots 12, 13)."
(1/22/15) Comment withdrawn — Applies to section 3 —Also, Advance WPO/VSMP comments, #4.
2. Ref 14 -409, Planning comments on road plan (sent as email, 18 -Dec; Also available in Count..):
"[ 14- -409, 14 -410, 14 -411 ] The Cascadia Connector is depicted on sheet C2.1 and is designated as
being 12' w/ 4' shoulders, 50' R/W. As depicted this road design does not meet the requirements of
the ordinance which dictate it to meet VDOT standards (per section 14 -409, 14 -410, and 14 -411).
Please work with VDOT, Engineering, Planning, and Fire & Rescue to assure this connection is
designed appropriately. Revise." Engineering concurs with Planning comment request for revision;
please provide Cascadia Connector design. Ref. VDOT road design manual. (e- review) Comment
restated. See A., ROAD PLAN, above. ACCD Planning is point of contact for questions relating to
specific expectations concerning elements of Cascadia Connector required for Planning Division
approval of road plan (and final plat), sections 1 and 2. (Rev. 31) Partially addressed. As follow -
up: see New #1, below. (Rev. 2) Addressed.
3. Recommend FH, cul -de -sac Belluno Lane since distance from hydrant on Via Florence to Lot 5
residence is 620' (t). (1/22/15) Comment withdrawn — review error.
4. 42.75 LF 18" DIA pipe (inlets D4 - 133) is less than minimum 0.5% slope; please revise. (e- review)
Addressed, or in process.
5. P. 31, Report: slope of pipe, YD1 to pond, is 0.33% ( <0.5% min.); please revise. (e- review)
Addressed, or in process.
6. C3.5 —there are two details #3 — please renumber one or the other. (e- review) Addressed.
Advance WPO /VSMP comments VSMP Application received (WP02015- 00006, 17 -Feb); under review.
(Rev. 2) VSMP WP02015 -00006 was approved 14 -Oct 2015.
Please REF email, October 31, 2014 5:12 PM, ACCD to Terra Engineering:
"of relevance-
1. Please use, complete, and include the (Attached) SWPPP template, with VSMP (WPO)
Application
2. Attached: Application review process diagram. This process reflects adoption of revised County
Code, Ch. -17, Eff. 1 -Jul -2014
3. Attached: VSMP Permit Application form, with fee schedule
4. Link, Additional VSMP resources:
http: / /albemarleengineer.blogspot.com /2014_ 10_ 01_archive.html
5. Link, VPDES Registration Statement:
http: / /www.deq.vir ig'nia.jzov/Portals /O/DEQ/ Water / Publications/ CGPRe,gistrationStatement2Ol4.p
df
6. Relevant sections of Albemarle County Code: § 17- 104.B.; § 17 -400, - 401, 402, -403, -404, -405;
§ 17 -412; § 17 -417 [other sections may apply]"
Engineering comments
Page 3 of 5
1. SWM hydrologic modeling must utilize TR -55 (MRCS) 24 -hr distribution rainfall in SWM design.
Rational, modified rational, and/or Manning equations, while acceptable for pipe /ditch conveyance
system design, are not acceptable for SWM facility design [9VAC25- 870- 95.General, B.]. [Phase 4C,
Sections 1 and 2, Drainage Computations and Stormwater Management Report, November 4, 2014]
Also, please use curve numbers (CN) in hydrologic calculations consistent with NRCS, rather than
runoff coefficients (C /rational formula). (e- review /.PDFs) Comment addressed —TR -20 Analysis;
bio- retention pond (Belluno Lane) volume increased —ref. revised SWM report (electronic format).
2. Ref. item #6, 31- Oct -14 email, above —with emphasis on Sec. 17 -403 (documentation demonstrating
compliance), 17 -404, (PPP), 17 -405 (SWPPP), and 17 -4052 (ESCP). (e- review /.PDFs) Comment in
process. Anticipate WPONSMP permit application will address these items. (Rev. 1) Addressed.
VSMP Application received (WP02015- 00006, 17 -Feb); under review. (Rev. 2) VSMP WPO2015-
00006 was approved 14 -Oct 2015.
3. VDOT approval is required. Please furnish VDOT LD -204 (stormwater inlet computation sheets), and
LD -229 (storm sewer design computations) or required information in equivalent (table) format.
Engineering cannot evaluate inlet systems based upon Drainage Computations and Stormwater
Management Report (4 -Nov, 2014) alone. VDOT comments on road plan design will be forwarded
when received. (As of 1/22/15) Coordination issues remain. Applicant is encouraged to work
directly with VDOT in response to VDOT plan review comment letter, 12/23/14. (Rev. 1) Addressed.
Applicant has coordinated design with VDOT. Partial text, VDOT email, T. Austin to S. Driver: "All
in all, I think that we are very close..." [Fri, Feb 13, 2015 11:04 AM]. As follow -up: VDOT approval of
Cascadia Connector design (to public street standards) is required. —Also, New #1, below. (Rev. 2)
"The design for the Cascadia Emergency Access Road appears to meet VDOT standards." Shelly Plaster,
27 -Oct 2015.
4. Email -Wed 10/29/2014 12:21 PM —ACCD to Terra Engineering: "If a WPONSMP application for
section 1 and 2 is submitted prior to section 3, please note that natural and final contours (back yards,
Lots 14 -18) direct a portion of post - development runoff to the proposed extended detention basin.
This basin treats section 3, primarily, but also receives section 1 runoff. In effect, WPONSMP
applications for all sections should be coordinated for near - simultaneous submission. There is no
advantage to the owner in splitting sections (though I will review and comment on section 1 and 2
separately) since there is no feasible way to authorize land disturbance in section 1 without also
obtaining section 3 WPO approval." As stated at the outset in this letter, sections 1 and 2 do not
work from a WPONSMP Application perspective, without section 3. (1/22/15) Comment
withdrawn — Applicant shows that sections 1 and 2 work from a WPONSMP Application perspective.
5. Report does not lend itself to easy comparison of design against water quality standards found at
9VAC25- 870 -96 / -97. Similarly, a straightforward, (hydrologic) model- supported demonstration of
pre- /post - developed 2 -yr and 10 -yr events for comparison with water quantity requirements is not
included or easily identified in the Report. It is important and necessary to include: TR -55 graphical
peak discharge method, or TR -55 tabular hydrograph method (VSWMH, First Edit., 1999, Vol. 2);
explicit reference to Water Quality BMP Pollutant Removal efficiencies (VSWMH, 5 -14, p. 5 -106
[bio- filter /section 2]); and Appendix 5D worksheets needed to determine: which water quality regime
applies (9VAC25- 870- 96.B.1 -4); post - developed pollutant load; and, load reduction achieved by the
proposed bio - filter and extended detention basin. This information, if implicitly included with
Report, is elusive. Design must reflect procedures found in the VA Stormwater Management
Handbook (VSWMH). Please make explicit connection between design, standards found at
9VAC25- 870- 96/ -97, proposed SWM design, and VSWMH. Although other design methods yield
useful information, for purposes of VSMP Application review, procedures found in VSWMH are
source of reference. It is difficult to evaluate design or calculated data contained in the report against
compliance requirements that are prerequisite to WPONSMP plan approval. (1/22/15) Comment
withdrawn — Further review shows drainage areas properly defined. Hydrologic analysis, inlet
computations, Appendix 5D worksheets, and other data are available to aid and support review.
New
1. Show Cascadia Connector to subdivision property line. Revise profile, C3.4. Also #11, below.
(Rev. 2) Addressed.
2. Show grading for relocated driveway, Lot 118, if owner consents (T. Nichols pvt. residence).
(Rev. 2) Addressed.
Engineering comments
Page 4 of 5
3. C3.0 —Add proposed contour labels to ensure drainage toward street, at driveways: Lots 12 -18.
(Rev. 2) Not Addressed — Please add contour labels, notes, spot elevations, etc. at driveways,
Lots 12 -18, to ensure drainage toward Via Florence. If overlooked, please direct reviewer to
plan sheet with this information.
4. C3.2 —Add Note to pond elevations, section 2 biofilter (bioretention). `Refer to WP02015-
00006 —Road plans do NOT govern SWM facilities.' There is risk if routing or SWM design
change with VSMP plan revision, and revisions fail to transfer to road plans. Alternatively,
eliminate detailed (0.00') storm routing /elevation data on road plans. (Rev. 2) Addressed.
5. C3.3 — Provide spot (design) Elev. at sidewalk at driveway Lot 7 to aid construction and limit
street runoff crossing sidewalk to reach proposed 5.3% gradient toward house. (Rev. 2)
Addressed.
6. Propose private /public drainage easements, Lot A biofilter. If beyond RW, then private. (Rev.
2) Addressed. As follow -up: Deed of Dedication of Easement for Access to Private SWM
Facilities is required for Final Plat Approval. (Word file /Attached)
7. Sheet C2.0 — Several Phase 3 labels (Via Florence) appear confusing. Please confirm accurate.
(Rev. 2) Addressed.
8. Section 2 biofilter appears to lie beyond public RW (Belluno/Via Florence). Please revise to
show proposed 0.33 Ac. Private SWM Easement (to be conveyed to Fontana HOA). (Rev. 2)
Addressed —Ref. Approved VSMP WPO2015- 00006.
9. C4.1 — Biofilter -SWM Facility Section 2 and Cascadia Connector (Lot A) General Planting Notes 1 -7:
May remove. Include with VSMP plans. If retain Notes, ref. Maintenance schedule, sheet
C5.3, VSMP, rather than this sheet (Note 1). (Rev. 2) Addressed —Ref. Approved VSMP
WPO2015- 00006.
10. Remove Sheet C5.3, SWM Details. Include with VSMP plans. (Rev. 2) Addressed —Ref.
Approved VSMP WPO2015- 00006.
11. A possible horizontal- vertical alignment for Cascadia Connector is attached, for illustration.
(Also, New #1, above — revise C3.4 profile 2) (Rev. 2) Addressed.
Please feel free to schedule a plan review meeting to discuss road plan or WPO/VSMP Application requirements for
Fontana, Phase 4C. tel - 434.296.5832 — x3069.
File: SUB201400141- fontana4C -sect 1 2 road- 102715rev2.doc
Attachment
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Engineering comments
Page 5 of 5
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