HomeMy WebLinkAboutSDP202300005 Review Comments Final Site Plan and Comps. 2023-02-26qoH nt 401 McIntire Road, North Wing
Charlottesville, VA 22902-4579
County of Albemarle
Telephone:434-296-5832
COMMUNITY DEVELOPMENT DEPARTMENT WWW.ALBEMARLE.ORG
Final Site Plan review
Project title:
River's Edge Final Site Plan
Project file number:
SDP202200012
Plan prepares
Shimp Engineering, 912 E. High St., Charlottesville, VA 22902
Michael Chandler, michael(i�shimp-engineering.com
Owner or rep.:
Rivers Edge Holdings, LLC / P.O. Box 6458, Charlottesville, VA 22906-6458
tomatweeksAgmai1. com
Plan received date:
19 Jan 2023
Date of comments:
26 Feb 2023
Plan Coordinator:
Kevin McCollum
Reviewer:
John Anderson, PE/CFM
Engineering Initial Site Plan review comments d. 4/1/22 are basis of Final Site Plan review.
SDP2023-00005
1. CIO: Recommend label trail features presently not labeled. (FSP) Addressed.
2. C11,C12,C13
a. Show /label steep slopes. Additional comments possible once steep slopes overlay shown. (FSP)
Addressed.
b. (C 13) Ensure Engineered level spreader meets design criteria for downslope Max, grade /Min.
slope length listed in VA DEQ Stormwater Design Specification No. 2, Table 2.2. Altematively,
replace ELS with detention that attenuates concentrated storm runoff release at this discharge
point. (FSP) Addressed. Applicant: `The level spreader has been removed from the plans.
Underground detention provided and release directly to the river via conveyance pipes.'
c. 14 Apr 2020 ZMA Application Plan, sheet 20, Note 2 states: `If permitted under applicable
stormwater regulations, stormwater discharge may be to level spreader or similar facility to open
space. If conditions do not permit such discharge, stormwater may be conveyed to the stream or
river in an adequate channel (shown in gray) with slope stabilization as applicable, where stream
bank disturbance occurs.' Conditions likely do not permit ELS; with WPO plan, ensure proposed
drainage /SWM meet VDOT BMP Clearinghouse Min. standards, design criteria, etc. A possible
alternative to ELS is detention pipe along site access /travel way, with gradual release of detained
flow via storm pipe down /across preserved slopes to stream, or river. Also, item 2.b., above.
(FSP) Addressed. Applicant: `The level spreader has been removed from the plans. Underground
detention provided and release directly to the river via conveyance pipes.'
d. Submit WPO Application /plan at earliest convenience. WPO plan approval is required for final
site plan approval. (FSP) Partially addressed. Applicant response (letter d. 1/12/23): `WPO Plan
and Application has been submitted and the most recent comments provided by the county have
been addressed.' As follow-up: Most recent Engineering review comments on WPO202200028 d.
8/17/22 are most recent WPO action. Submit revised WPO in response to 8/17/22 comments at
Applicant convenience —if this appears inconsistent with submittal timeline, please notify reviewer
at earliest convenience.
e. SWM facility easement (plat /deed) recordation is required prior to WPO plan approval. (FSP)
Persists. Applicant: `Acknowledged, the SWM Facility easements will be recorded with an
easement plat on a later date once facilities have been finalized.'
f. Provide private access easement to connect U.S. Rt. 29 with residential development. (FSP)
Partially addressed. Applicant: `The private access easement has been provided along the access
Engineering Review Comments
Page 2 of 6
road and throughout the parking lots.' As follow-up: Ensure that private access easement is
recorded. SWM Facility Maintenance Agreement ensures county access, but recorded /platted
private access easement (for SWM access) is evaluated required, between U.S. Rt. 29 NBL and
SWM facility easement.
3. C4, C5, C6 (and Cl 1, C12, C13)
a. Show and label FEMA mapped floodplain. (FSP) Addressed. As follow-up, pis. see item 21.a.
4. C12
below.
b. Show and label GIS stream buffer overlay. (FSP) Addressed.
a. Retaining walls >3-ft. ht. require a building permit and must include safety railing. (FSP) Persists.
b. Retaining walls >4-ft ht. require PE -sealed geotechnical plans. (FSP) Persists. Also, item 21.b.,
below.
c. Proposed retaining walls along site access require VDOT GR-2 guardrail (unrecoverable slopes,
vertical drop); provide GR-2 and ensure retaining wall (PE -seal design), roadway construction,
and GR-2 installation all conform with VDOT standards for guardrail type (web/post), rail post
spacing, terminal treatment, horizontal clearance to back -slope, etc. (FSP) Addressed. Asfollow-
Up, pis. also see item 18.c., below.
d. Submit retaining wall PE -sealed plans that show GR-2 to Engineering prior to /as condition of
final site plan approval. (FSP) Persists. Applicant: `PE sealed plans for retaining walls will be
provided with a future submission.' Also, pis. see item 2 Lb., below, item 4.b., above.
5. C8, C9, C 10
a. Label sanitary pump station with wet well. (FSP) Addressed.
b. Provide sight distance profile south/left at U.S. Rt. 29. (FSP) Addressed.
c. Provide Name for site access /travelway for e-911 purposes. (FSP) Addressed.
d. Obtain VDOT Land Use permit for work within U.S. Rt. 29 RW. (FSP) Addressed.
e. Show proposed sanitary connection with Ex. RWSA /ACSA facility at U.S. 29. (FSP) Addressed.
f If road bore required beneath U.S. Rt. 29 for utility purposes, provide notes, details, schematics,
graphics, Notice to Contractor etc. concerning safe utility operation within VDOT RW, or as
required by ACSA /RWSA to meet utility /Agency requirements. (FSP) Addressed. Applicant:
`Notes provided.' As follow-up: Engineering defers to ACSA /RWSA.
g. Coordinate all aspects of site /entrance work at U.S. Rt. 29 (within RW) with VDOT. A MOT
may be required. (FSP) Addressed. Applicant `The MOT Plan is provided on Sheet C22.' As
follow- u : Engineering defers to VDOT; county has limited jurisdiction within VDOT RW.
h. Provide posted /advisory speed limit signs on site access. (FSP) Addressed.
i. Provide `No parking' signs at intervals along site access. (FSP) Addressed.
j. Recommend `Yield' signs to establish thru movement. (FSP) Addressed.
k. Design site entrance culvert pipe to pass the 25-yr event. (FSP) Addressed. Applicant: `Entrance
is located on a ridge that does not require a culvert.'
6. C11,C12,C13
a. Show /label ACSA sanitary sewer /water line easements. (FSP) Addressed.
b. Label all retaining walls. Assign Wall identifiers (letter, #) for ease of reference. Provide
TWBW elevations. (FSP) Addressed. As ollow-up: pis. see review item 2 Lb. below.
c. (C11) Provide suitable ditch runout for 6' travelway ditch at U.S. Rt. 29. Design must avoid and
limit potential erosion at U.S. Rt. 29, or other locations. Further, this point discharge must meet
state stormwater management (stormwater quantity) regulations. (FSP) Addressed. Applicant:
`Design provides sheet flow off route 29 to stream and ditches along new travelway.'
d. (C 12) Engineering prefers design abandon ditch to Rt. 29, and instead, more nearly approximate
design shown on sheets 20 21 of 14 Apr 2020 ZMA Application plan, which shows no
conveyance to U.S. Rt. 29 RW. (FSP) Addressed. Applicant: `Ditch extents no longer reach route
29.'
e. (C 13) Revise proposed 340 LF 108" CMP underground detention system which presents liability,
with few if any positive offsets (perhaps less initial expense). Unless rock precludes multiple
smaller systems, installation of proposed 340 LF 9' DIA system will require significant SWM
Pil
a
Engineering Review Comments
Page 3 of 6
facility easement width (Ref. ACDSM Easement diagram, p. 15), which requires, for a system this
size, at least 37' wide SWM easement (assume P bedding, 3' cover). In the future, when the
system is replaced, there will be no vehicular access to the entire lower parking area that serves
nearly half the Rivers Edge development. Also, should there be performance issues with a single
detention system, there is no backup to treat a portion of developed runoff If the proposed single
system is bypassed, it is possible the entire volume of impervious area runoff could route across
preserved steep slopes. ZMA Application plan sheet 19 presents a system approximately half the
length proposed. Propose alternate detention that maintains partial access to lower parking lot
should future circumstance warrant excavation of parking areas to repair or replace the UG
detention system. Consider alternative SWM design that locates multiple detention practices
nearer to residences and upper tier parking (for example, 4 — 85 LF systems would provide
identical detention capacity without compromising access to this degree, and would permit at least
partial water quantity treatment should incident affect one of several systems. As it is, incident
affecting a single system may prevent or compromise storm detention, entirely. Engineering
disapproves current proposed SWM design on access /maintenance basis, as well as scale of
departure from ZMA Application plan. With WPO plan, provide bypass of any SWM facility
while mitigating impact of bypass flow to critical resources, especially preserved steep slopes.
(FSP) Addressed. As follow-up: Ensure adequate UG detention system easement width —ref.
ACDSM p. 151. Single system is now divided into two separate systems. WPO plan review will
formally evaluate SWM design /easement width, etc. (WPO2022000281.
f Provide CG-6 or CG-7 along site access/travel way wherever storm runoff concentrates against
curb. If ZMA approval explicitly exempts site from curb -gutter requirements at Ch. 14 /18, please
direct Engineering to exemption. Otherwise, please see 18-32-7.2.2.a. / 14-412.B., provide curb
with gutter. [Note: sheets 20-22 of ZMA Application plan show inlet design along site access.]
(FSP) Addressed. Applicant: `The ZMA appears to show roadside ditches to DI-7 grate drop
inlets (not curb/gutter). Ditches are provided all along the roadsides and include a 2-ft shoulder.
A 2-ft shoulder was chosen to minimize disturbance of steep slopes. Further, the road entrance
has been relocated and as a result provides for much less steep slope disturbance. This comment
was discussed with John Anderson during a meeting on November 11, 2022 and was resolved to
be appropriate to provide ditches to grate drop inlets.' As follow-up: Pis. check label, east side site
access, Sta. 20+00f: CG2 as well as curb linework along access. If access design is to provide
shoulder -ditch design, pls. revise label /linework, but Engineering approves CG-2, as shown.
g. Provide PE -sealed sanitary effluent pump station design, incl. pump curves, pump type, wet well
design, alarms, remote sensing, etc. as provided with documents or during presentation to PC or
BOS in 2020, or in /with ZMA documents, etc. Recommend furnish evidence of coordination or
approval with or from DEQ, relative to sanitary pump station design. Albemarle will not review
or approve pump station design. ACSA is unlikely to review or approve pump station design. It
is incumbent upon developer (per approved ZMA) to obtain approvals needed to construct the
pump station, to ensure remote sensing system is operational, and that station will be maintained.
(FSP) Persists. Applicant: `PE -sealed pump station plans to be provided with future submittal.'
C15: Show proposed storm lines and utilities (sanitary sewer/water) in light line -type on this sheet, to
highlight potential conflicts. For example, proposed storm lines are proposed to cross at least 5 parking
islands proposed to be planted with large canopy species. Revise storm pipe locations to avoid landscape
conflicts. (FSP) Addressed. Ref. sheet C23.
Ensure steep slopes disturbance is consistent with sheet 23, 14 Apr 2020, ZMA Application, and does not
exceed 39,100 sq. ft. approved with ZMA. Show /label Area (ft) of Preserved Steep Slope impact with
WPO and FSP. (FSP) Addressed. Applicant: `The Preserved Slopes Disturbance has been updated to a
total of 27,254 A. See Sheet C6 of the WPO plan & Sheet C6 of the Final Site Plan.'
Ensure stream buffer disturbance is consistent with sheet 24, 14 Apr 2020, ZMA Application, and does not
exceed—23,000 sq. ft. approved with ZMA. Show /label Area (ft') of stream buffer impact with WPO and
ESP. (FSP) Addressed. Applicant: `Stream buffer disturbance is outlined on Sheet C26 of the Final Site
Plan.' Note: Per 17-604.A., virtually all stream buffer impact occurs within landward 50' of stream buffer,
is along site access, is minimized, with mitigation proposed. Mitigation plan will be formally evaluated
Engineering Review Comments
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with WPO plan. Site access is an improvement designed to minimize impacts to stream buffer and is
infrastructure necessary to allow reasonable use of the lot.
10. C14: Public drainage easement (downstream of SWM) should not propose storm pipe beneath /through a
retaining wall. If unavoidable, provide concrete headwall /lintel details with PE -seal, similar to Versa-Lok
TM standard. Comment does not anticipate approval of public drainage easement with pipe penetration
beneath or through a retaining wall, a configuration to avoid. (FSP) Addressed. Applicant: `A grass slope
has been provided to replace the section of wall at the public drainage easement and pipes no longer run
below retaining walls.'
11. C 16: Include Site Access (travelway) section with stone /pavement depths, see River's Edge Street Section,
sheet 28 ofZMA Application plan. Provide site access pavement design based on full buildout ADT.
(FSP) Partially addressed. As ollow-up:
a. C 19: Provide stationing and sheet ref for road cross-section XS-1, XS-2, XS-3.
b. C20. C21: Provide Travelway section 1 and section 2 (details) site access /parking stationing.
12. Provide VDOT LD-229 (storm drain design computations) and LD-204 (stormwater inlet computations).
(FSP) Addressed. Ref. WPO202200028 Calc. packet.
13. Provide complete storm profiles with labels, rim /INV elevations, slope, DIA, compaction notes, etc. (FSP)
Partially addressed. As ollow-up:
a. C 17
i. At H1, provide label, description, design of OP, Str, Hl at discharge to Rivanna River.
ii. Revise caption Storm sewer profile Hl-H3 to read `... Hl-H4.'
iii. Ensure public drainage easement width downslope of Str. H2 is sufficient to
accommodate storm pipe at > 14-fit burial depth.
iv. Recommend increase pipe slope, F2A-F2 slightly, to allow slight variation during
construction; proposed 0.51% allows no construction error. 0.50% is minimum allowable
storm pipe slope.
v. Revise caption Storm sewer profile Jl-J3 to read `... Jl-J4.'
vi. Specify VDOT ES-1 and OP at Str. Jl.
vii. Eliminated storm inlet at F2B (Now MH-I) yields significant spread at this location
/parking lot. Engineering recommends DI at this location, to limit spread <13'. Ref.
WPO202200028 Calc. packet, p. 23, LD-204 table.
14. Provide road profile generally consistent with ZMA Application plan ZMA201800018, sheets 17, 18
(revised 14 April 2020) with smooth vertical curves, K-sag /crest values (sufficient sight distance), etc.
(FSP) Addressed. As follow-ua: Provide VDOT CD-1 /CD-2, Sta. 29+10(f) cut -fill transition. Ref. VDOT
Drainage Design Manual 9.4.3.91 p. 9-15.
New
15. Angle/s of pipes entering Aeaving F4, F5, F20 are acute. Angle must be >_ 90-degree unless 8" roof drains
enter 2' above str. floor elev. 2' has no calc. basis, but if vertical interval is 2'-3', inertia is assumed
partially offset by drop. Acute angles direct stormwater entering structure to change course, radically, may
deposit debris in locations that may compromise performance. All storm structures require inlet shaping.
No main storm pipe entering a structure may enter < 90-deg relative to pipe leaving. Roof leader lines with
vertical interval >2' are an exception. Even then Engineering recommends against angle < 90-degrees.
16. Provide bollards to protect pump station with underground wet well, even if wet well lid flush with grade.
This critical infrastructure must be protected against inadvertent traffic /wheel mount.
17. Revise sheet title to: `Stormwater Management Plan - Illustration only, Ref WPO202200028 for Approved
design.' SWM plans are not part of site plans. SWM design is presented and approved with a WPO plan.
18. C12,C13
a. Provide additional existing contour labels.
b. Provide additional proposed contour labels.
c. Label guardrail terminal treatments, use VDOT nomenclature.
d. C 12: Show Aabel 3" FM, similar to C13.
Engineering Review Comments
Page 5 of 6
e. Recommend note or label specify Min. cover for 3" FM, given proximity to guardrail, swale,
retaining wall, etc.
f Recommend show Aabel water line (WL) along private access serving the development.
19. C14
a. Show Aabel VDOT GR-2 at ends of parking lots, at tiered retaining walls.
b. Proposed grade at each face of structure must show 6" fall over 10' (positive drainage away from
structure). Revise proposed grade. Provide spot shots at structure wall. Provide note to specify
positive drainage requirement (see USBC /Uniform Statewide Building Code). Unit 8, as one
example, is problematic.
20. C8
a. Show Aabel outfall protection at III, as needed, similar to JI.
b. Dimension outfall riprap protection at 1, similar to It.
c. Specify SWMfacility access pipe DIA, L, material, and minimum cover, site access Sta. 15+80.
d. Provide public drainage easement, Dry Pond 1 outfall pipe to North Fork Rivanna River.
21. C8, C9, C10
a. Revise 100-yr floodplain to reflect any increase in horizontal extents of floodplain, ref. FEMA
Add yellow -shaded areas, but do not remove /decrease horizontal extents of 100-yr floodplain
(purple -shaded areas), which cannot be removed, except by revised FEMA FIRM.
b. Submit PE -sealed retaining wall design plans to Engineering for review prior to ESP approval:
i. C8: Wall A
ii. C 10: Walls B, C, D, O, P. Note: MAWR are coincident with building foundations or
bldg. walls and will be reviewed with building permit applications, not by Engineering.
c. C 10: All parking spaces fronting 5' sidewalks: Min. L= 18'. Also, each space must have bumper
block. Show Aabel typ. parking space length and show /label bumper blocks. Ref. ACDSM, p.
17.
d. C 10: Provide /label CG-12 (ramps /detectable surface) at 45.1'/57.0' L fire apparatus turnarounds
(x 5).
22. C11
a. FH at N end parking lot requires bollard/s to protect against car strike.
Engineering Review Comments
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b. Stripe parking space immediately adjacent to this FH, since parking is impermissible immediately
adjacent to a FH.
c. Ensure placement of location acceptable to ACF&R, ensure no conflict with retaining wall; ensure
space available for thrust block required to be positioned behind FH, since FH appears coincident
with retaining wall.
23. C15
a. New 40' SWM Easement is labeled. Delineate separate public drainage easement from point just
before 70-LF 36" HDPE SWM detention pipe crosses 5'sidewalk, to 100-yr floodplain, N. Fork
Rivanna. Deeds accompany public drainage and SWM facility easements, but are separate deeds.
Please feel free to call if any questions: 434.296-5832 -x3069
Thank you
I Anderson
SDP202300005 River's Edge ESP 022623.docx