HomeMy WebLinkAboutSUB202100116 Review Comments Preliminary Plat 2021-08-05V
401 McIntire Road, North Wing
County of Albemarle Charlottesville, VA 22902-4579
COMMUNITY DEVELOPMENT DEPARTMENT Telephone:434-296-5832
WWW.ALBEMARLE.ORG
Preliminary Plat review
Project title:
Granger Property Preliminary Plat
Project file number:
SUB202100116
Plan preparer:
Scott Collins, PE, Collins Engineering [ scotte collins-en ing eering.com ]
200 Garret Street, Suite K, Charlottesville, VA 22902
Owner or rep.:
Stribling Holdings, LLC
P.O. Box 1467, Charlottesville, VA 22902
Applicant:
Alan Taylor [ alan(a),,riverbenddev.com ] Riverbend Development
455 Second Street SE, Suite 201 / Charlottesville, VA 22902
Plan received date:
30 Jun 2021
Date of comments:
5 Aug 2021
Plan Coordinator:
Kevin McCollum
Reviewer:
John Anderson
Engineering has reviewed the preliminary plat and offers these review comments.
1. General
a. Provide drainage system profile, Engineering accepts that complete details will be shown with
ROAD plan, but needs preliminary storm system (drainage) profile information before design
proceeds too far.
b. Please submit WPO plan for Granger property subdivision. WPO plan approval and FDP
approval are required prior to Final Plat approval.
c. Please submit a ROAD plan application for Granger property. ROAD Plan must be approved,
and roads either built or bonded prior to Final Plat approval.
d. Bridges and Emergency access that serve the proposed road network, or that serve as second
point of (emergency) access must also be built or bonded prior to Final Plat approval.
e. SWM detention (stormwater quantity) design is shown (conceptual, UG detention). Please
provide narrative and schematic conceptual stormwater quality (SWM) design for Granger
property subdivision.
f. 14-304 appears to require that since the proposed subdivision will require disturbing steep
slopes, `the subdivider shall submit ... a written request or application under the applicable
sections of the zoning ordinance.' Engineering reminds that subdivider /developer has an
apparent obligation to submit written request to disturb both managed and preserved steep
slopes. Engineering defers to Planning Division.
g. Note: It is difficult given extent of interrelated comments to specifically separate and identify
which might be required for preliminary plat approval, which may be deferred until final plat
submittal, but Engineering understands that Planning Division may require preliminary plat
resubmittal (i.e., intends to issue an action letter as opposed to an SRC comment letter). To
the extent Planning guides Applicant resubmittal of a preliminary (subdivision) plat for the
Granger property, please address as many Engineering review comments with preliminary
plat resubmittal as is practically possible.
h. Given extent of comments, additional preliminary plat comments are possible with
preliminary plat resubmittal.
Engineering Review Comments
Page 2 of 8
2. Sheet 2
a. `Limits of WPO buffer and 100 year floodplain' (single label) identifies separate line types.
Please revise label to read 100 year floodplain and provide separate label for WPO buffer, and
provide leader lines to WPO buffer and 100 year floodplain, independently, consistent with
GIS, to avoid confusion. Different limits apply to development within WPO buffer and
floodplain.
b. Submit a floodplain development permit (FDP) application for development within the
floodplain.
c. At existing Southern railroad underpass, there appears to be heavy line -type that may indicate
proposed grading. Please confirm whether grading or structural work to underpass within
Southern Railroad RW is proposed with preliminary plat, and if so, please furnish evidence of
agreement and approval to grade or construct improvements within Southern RR RW.
Engineering will consider proposed grade shown on WPO plan at this location with care.
d. Sheet 2 shows an 8' x 8' concrete arched culvert beneath Southern Railroad. Sheet 11 does
not show this portion of the development. Please resubmit with all portions of developed
property displayed in adequate detail. Note: 8' x 8' culvert is shown on Sheet 4 but should
display on smaller -scale Grading and Layout sheets, if only as an inset detail.
e. Please add label to existing 2 Story building (to be removed) since layout sheet shows
building is removed with cul-de-sac development /building lots on Serra Drive.
f. Show /label extents of VDPCO facility, TMP 76B-1-71 specifically, please show existing:
i. Entrance to VDPCO facility
ii. Facility fencing
Ref satellite imagery, below; 6/2/20 [ source: Pictometry - CONNECTExolorerT -
3. Sheet 3
a. Show and label OIIP to Wingfield residence, TNT 76-3-34 (Sunset Ave. Ext.). Ref satellite
imagery, blue circle, below (6/2/2020):
Engineering Review Comments
Page 3 of 8
4. Sheet 4
a. Existing 14'-20' paved asphalt road must be capable of supporting 85,000 lb. emergency fire -
rescue apparatus. Provide narrative, evaluation, and propose improvements to ensure ex.
paved asphalt road meets fire -rescue width, geometry, and weight -bearing requirements.
b. Multiple lots are proposed within existing (presumed high voltage) 120' VEPCO easement:
i. Label VEPCO easement.
ii. Engineering defers to Planning Division and VEPCO, but recommends:
1. Applicant coordinate design with VEPCO.
2. Fumish written correspondence between Applicant and VEPCO, that
VEPCO approves preliminary plat for Granger Property, to include specific
acceptance of
a. Portions of Lots (22, 23, 24, 30, 31, 32, 33, 48, 49, 50, 51) within
VEPCO easement.
b. Grading flatter slopes to a steeper proposed final grade, which may
affect VEPCO ability to access or utilize their existing easement.
c. Explicit acceptance on Applicant's part that VEPCO easement
access likely entitles VEPCO to occupy full easement width, with
equipment and /or materials needed to maintain high -voltage lines,
with little or no obligation to repair what will become lawn areas.
d. Explicit acceptance on Applicant's part of future risk to owners of
SF residences on Lots 2, 23, 31, preliminary plat proposes building
sites immediately adjacent to VEPCO easement. In case of Lot 22,
building site effectively touches VEPCO easement. Ref. typical
Lot detail.
Engineering Review Comments
Page 4 of 8
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c. Sunset Avenue Extended
i. Please label existing roadway width.
ii. Ensure existing roadway width at subdivision entrance can accommodate left -turning
inbound single -unit (SU) truck design vehicle, as defined by AASHTO, without SU
vehicle crossing CL (whether CL is marked, or not) of primary subdivision access
(Crespi Bluff Drive), and without crossing CL of Sunset Avenue Ext. except at point
of intersection. Note: Graphic of 20-ft wheelbase SU truck design vehicle' is less
than wheelbase length of typical moving vehicles that will utilize primary
subdivision access, not just with initial owner move -in activities, but perpetually.
iii. Provide Auto -turn figure at intersection of Crespi Bluff Drive and Sunset Ave. Ext.
' Appendix B(1) subdivision street design guide, p. 8. [image, below]
htti)s://www.virginiadot.org/business/resources/LocDes/RDM/AnnendB Lod
FIGURE B(1)-1 MINIMUM TURNING PATH FOR SINGLE UNIT TRUCK SU-30
Rev 10120
d. Provide deed book -page ref. for Stribling Avenue.
Sheets 4-6, Future connector road, multiple issues:
a. Corridor violates ordinance and VDOT standards or requirements, and cannot be constructed
in this location, given:
Engineering Review Comments
Page 5 of 8
i. Preserved slopes
ii. Stream buffer
iii. Sideslope (required deep cut/fill across slopes, or within stream buffer)
b. Illogical or problematic geometry. Proposed future connector road:
i. At south end foams an acute angle intersection with Sunset Avenue Extended.
Revise to provide right-angle or near right-angle intersection with Sunset Ave. Ext.
ii. At north end terminates abruptly at development boundary within or immediately
adjacent to these overlay or zoning features: 100 year floodplain, stream buffer,
preserved steep slopes, it is exceedingly unlikely that a future connector road will
ever need to be, or will actually be, built along this corridor.
iii. Engineering defers to Planning Div. on purpose or requirements that may stipulate a
future (road) connector corridor in this location but lists obstacles to construction of
a future road in this location, given stream, slope and floodplain impacts.
6. Sheet 7
a. Show full extent of proposed emergency access, from proposed bridge replacement for
emergency access to the site, to Stribling Ave. Note: Layout and Grading sheets should show
full extent of development. Albemarle can make no assumptions concerning areas not shown.
b. Show and label footprint of proposed UG detention (SWM facility) on Lot 55.
c. Show and label proposed SWM facility easement on Lot 55. Ref. sheet 11 for schematic.
7. Sheets 8, 10
a. Culvert alignment beneath Sera Drive is problematic, and cannot be approved by Albemarle,
it may be disallowed by VDOT, as well. Alignment shows Moore's Creek streamline striking
at or behind upstream headwall. Moore's Creek must enter drainage structure at this or
revised structure location with very slight (preferably no) angle to avoid long -tern erosion,
embankment failure, and maintenance concerns.
8. Sheet 8
a. Delete reference to proposed 100' WPO buffer, buffer exists as an overlay, is not proposed
with development.
b. Label proposed secondary subdivision emergency access.
c. Proposed emergency access intersects Stribling Avenue at an acute angle that appears to
require fire rescue apparatus to pass beneath railway, via tunnel. Provide Auto -turn and
coordinate with ACF&R to ensure responding apparatus (likely City of Charlottesville
Fontaine Fire Station 10) can use secondary access, either via tunnel or can navigate acute
angle at intersection of subdivision secondary emergency access and Stribling Avenue.
d. Provide sealed design for bridge capable of supporting 85,000 lb. fire apparatus at Morey
Creek (see emergency access roadway design weight -bearing capacity label, sheet 7).
e. 4-line underground SWM detention system shows easement encroaches within proposed 61'
RW, future connector road. Remove SWM facility (and easement) from future connector
road RW.
f. Please reference easement width image, ACDSM, p. 15, and revise proposed 4-line SWM
facility easement width, per proposed SWM facility design. Proposed easement width will
likely not accommodate SWM facility. From ACDSM, P. 15
Engineering Review Comments
Page 6 of 8
EASEMENT WIDTH . DI METER. ?' . 2 (H-S9. 10' 1-'0' VLV. �
g. Revise sanitary sewer alignment, if possible, from shared lot line, Lots 30-31, to shared lot
line, Lots 31-32, to minimize impact to preserved steep slopes. Recommend examine storm
and sanitary sewer lines within same (or wider) easement, with requisite vertical /horizontal
separation.
h. Show and label SWM facility access to proposed 4-line UG detention system (see pg. 12,
ACDSM for specific requirements).
i. Retaining walls (and nearly all portions of development) will be visible from I-64 Entrance
Corridor. Engineering defers to Planning-ARB, but recommends:
i. Early coordination of retaining wall design (ht., material, color) with ARB.
ii. Submit sealed retaining wall design to Planning Division, ARB, for review of
retaining wall material, color, etc.
j. While development has no apparent obligation to construct barriers between lots and adjacent
railroad or interstate to screen lots or attenuate train or interstate ambient noise, Engineering
recommends developer consider sound attenuation and visual screening shield development
from objectionable levels of ambient rail or interstate sound, likely to increase with time.
9. Sheet 9
a. Ensure primary access to subdivision (Crespi Bluff Drive) conveys the 25-year storm event,
without overtopping roadway surface.
b. Label existing VDOT culvert beneath I-64, label culvert type, and dimensions.
c. Provide drainage structure design for primary access, Crespi Bluff Drive, consistent with
normal design practice, including downstream receiving drainage structure capacity equal or
greater than upstream drainage structures (i.e., culvert beneath 1-64). I-64 is, in effect, a dam,
and it would be unusual to propose primary subdivision access drainage structure smaller than
the structure beneath I-64.
d. Perform hydraulic modeling for the existing drainage structure beneath 1-64 during the 25-
year event to ensure primary access to subdivision has capacity to contend with volume,
velocity, tailwater elevation, etc. discharging from existing structure beneath I-64. Existing
condition (sheet 3) indicates no other drainage structures between 1-64 and this stream's
confluence with Moore's Creek. Only a thorough drainage analysis (especially a design that
may propose a primary access culvert smaller than the upstream culvert beneath 1-64) is likely
to be approved by Albemarle, or VDOT. Provide drainage structure hydraulic calculations,
and watershed routings.
Engineering Review Comments
Page 7 of 8
e. Coordinate stream loss requirements with primary subdivision access, Crespi Bluff Drive,
with USACE (Vinny Pero), provide written evidence of coordination with USAGE.
f. Label managed steep slopes, since grading is proposed across managed steep slopes.
g. Label preserved steep slopes, to aid review, to ensure no grading or other impermissible
activity occurs on preserved steep slopes.
10. Sheet 10
a. Ref. Attached Drainage Plan checklist for plan reviewers, pg. 1, Drainage, last item, and
provide yard inlet capture /conveyance systems for drainage across 3 or more lots: Lots 28,
29, 30. Lots 37, 36, 35. Lots 41, 40, 39, 38. Lots 7, 6, 5, 4, 3, 2, 1. Lots 42, 43, 44, 45.
11. Sheets 9, 10
a. Show discharge from proposed UG detention system shown at right margin of these sheets.
12. Sheets 10, 11
a. Match -line is discontinuous in moving from sheet 10 toll, for example: future connector
road displayed on sheet 10 does not display on sheet 11 (comment applies to sheets 6 and 7,
as well). Revise all sheets referenced to display complete layout and grading details.
13. Sheets 9, 10, 11
a. Label:
i. Moore's Creek
ii. WPO stream buffer
iii. 100 year floodplain
iv. Limits of the sunny day dam break inundation zone
b. Show driveways serving each lot, show with VDOT standard private entrance (true scale)
geometry to aid review check of potential conflicts. ROAD Plan will show this detail, but
preliminary plat proposes a level of density that supports request for this level of detail with
the preliminary plat.
c. Provide frequent existing terrain contour labels such that proposed contours, wall, and
proposed grade may be more easily evaluated against existing grade.
14. Sheet II
a. Provide landscape plan for stepped retaining wall system/s (screening shrubs planted on 10'
centers).
b. Provide landscape plan that specifies groundcover /permanent stabilization hardier than grass
for any slopes steeper than 3, 1.
c. Provide retaining wall maintenance easements for any walls that cross individual lot /parcel
boundaries, with final subdivision plat.
d. Provide evidence of recorded retaining wall maintenance agreement/s.
e. Provide drainage calculations and ditch linings consistent with calculations to prevent erosion
over slopes created by existing and proposed slopes, for example, east -west ditch due south of
Lot 73 southeast parcel boundary.
f. Remove lots from stream buffer (applies to multiple sheets). Ref. 17-601.C.: Management of
stream buffer /Incorporation into development design: `Each stream buffer shall be
incorporated into the design of the development by keeping stream buffers in open or natural
spaces, and out of residential lots or areas of active use, to the fullest extent possible.' [Note:
review comment cleared by county engineer.]
g. Note: SWM facility proposed for Lots 55 and 56 poses long-term maintenance obligation on
HOA, not the individual owners of Lots 55 and 56. SWM facility deed of dedication will be
conditioned accordingly.
h. Ensure design conforms with design standards for steep slopes at 18-30.7.5.A./13./C., for
example: at Serra Drive Moore's Creek crossing where there is apparent need for reverse
slope benching with surface water diversion.
i. Retaining wall on Lot 67 appears to lie within 5' of Southern RR property. It is unclear
whether proposed (grading or proposed) retaining walls may be constructed this close (5'-10')
to railway property. Recommend distribute development plan to Southern Railroad, and
coordinate design with Southern Railroad. Provide follow-up to Albemarle, CDD. Railroad
Engineering Review Comments
Page 8 of 8
approval of preliminary plat development design is presumed required prior to final plat
approval.
j. Provide retaining wall maintenance access from Serra Drive to multiple stepped retaining
walls that back lots 67-73.
k. Proposed build sites, Lots 67 and 68, are impractical. In each case, there is 2'-3' offset to
sunny day dam break inundation line, side setback lines, or front setback lines. Lot 68 shows
proposed grade line touching proposed build site. Each structure (SF residence), as well as
residences shown on Lots 69-73 are proposed to be built on fill that approaches 20', in places.
Revise preliminary plat to include specific and general geotechnical testing and reporting
requirements for SF residences proposed on substantial fill, include: clean /suitable earth fill
specifications, testing (Min. compaction, etc.), reporting, qualified professional geotechnical
monitoring and testing during placement of fill, specifically for these lots.
1. Proposed build sites, Lots 67-68, are inconsistent with graphic representation of these sites on
sheet 4. Revise Sheet 4, consistent with proposed Grading, sheet 11.
in. Provide sealed geotechnical retaining wall design for review /evaluation with WPO or ROAD
plan. Sealed Retaining Wall plans for wall ht. > 4-ft are required by Building Inspections and
Engineering. Sealed Retaining Wall plans are required prior to WPO or ROAD plan
approval. Ref. pg. 22, ACDSM.
n. With WPO and FDP, ensure replacement bridge over Morey Creek conforms with
requirements at Ch. 18-30.3, especially concerning fill or impact to horizontal limits of
floodplain, or base flood elevation (BFE).
Please feel free to call if any questions: 434.296-5832 -x3069
Thank you
J. Anderson
SUB2021-00116 Granger Property_prelim plat 080521.doc