HomeMy WebLinkAboutWPO201800078 Review Comments WPO VSMP 2020-01-15COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
VSMP Permit Plan Review - Amendment
Project title: Keswick Hall Spa
Project file number: WP0201800078
Plan preparer: Timmons Group, Craig Kotarski, P.E. craig.kotarski(c-i),timmons.com
Owner or rep.: Historic Hotels of Albemarle, LLC, John Trevenen jtrevenen(&,keswick.com
Plan received date: 6 Jan 2020
Date of comments: 15 Jan 2020
Reviewer: John Anderson
County Code section 17-410 and Virginia Code §62.1-44.15:34 requires the VSMP authority to
act on any VSMP permit by issuing a project approval or denial. This project is denied for reasons
listed, below. The VSMP application content requirements can be found in County Code section 17-
401.
C0.0
1. In text box /lower left, ref. 5/21/19 purchase of 1.09 lb. phosphorus nutrient credits, which, combined with
on -site BMPs, met WP02018-00078 phosphorus load reduction requirement of 1.65 lb. Amendment 1 total
phosphorus load reduction reduces the initial 1.65 lb. requirement to 1.28 lb. A surplus, 0.36 lb./yr. (on -site
BMPs provide 0.55 lb.) is available to Keswick Hall for future development. A note is recommended as
CDD has no reliable means to track on -site phosphorus credits that accrue from Amendment 1. CDD urges
Applicant to rely on credits purchased, and Amendment BMP design; these combined exceed 9VAC25-
870-65 requirements, and yield a 0.36 lb. surplus.
Note: Amendment (on -site) BMP provides 0.55 reduction. Initial on -site BMP design provided 0.56 lb./yr.,
which, combined with 1.09 lb/yr. purchase, met 9VAC25-870-65 requirements.
2. Revise Plan title (line 2) to: WPO Plan Amendment 1.
3. Ensure C3.0 project description LOD (2.60 Ac.) and plan labels are consistent (during 1/15 meeting,
discussed possible revision to LOD).
4. Note: Initial ESC Plan bond amount is based on 2.67 Ac. LOD, 1 sediment trap (2.10 Ac. DA), 340 LF of
diversion dike. Amendment 1 ESC plan requires 2 STs (2.82 Ac. DA z $ expense), and 1,280'f diversion
dike ($5,170 increase). Current ESC plan bond incl. $3,987.95 (10% contingency), sufficient to meet
required (Amendment) ESC plan bond amount (Q.1).
5. Note: Initial SWM Plan bond is based on 2 detention systems, while Amendment 1 proposes a single,
slightly larger DIA and longer detention system. Applicant may request a bond reduction based on
difference in installed expense (material /labor + contingency) between 2 facility and 1 facility designs. A
bond inspection request form and revised, design- and Wn-furnished estimate of installed expense of larger
/longer single detention vs. two -system detention would be required in order to process SWM plan bond
reduction request. Likewise, there appears to be a reduction in permeable paver qty., a bonded SWM line
item. Any reduction in permeable pavement materials, earthwork, or labor is basis for bond reduction
request, if inspection request form, revised qty. estimates are submitted, and bond reduction process
followed.
6. C4.0 —Increase proposed 3' walkway width to 4', min. —see image, below.
Engineering Review Comments
Page 2 of 3
-' ---- -�� 1l �GN 2 \\ •Oi
IMUNICATIONS
HOLE.
(11) 4" SCH-00 PVC CONDUITS ti��. `
FOR POWER SERVICE
5
SIDEWALK WITH
HANDRAIL
LOADING DOCK
EMERGENCY DUMPSTER AREA
-ESS PATH
PROPOSED
SPA
5' x 5'
VDOT RW-3 '
RETAINING WALL
MECHANICAL
YARD 1
7. C5.0 — Relocate structure 100 (24" DIA pipe outfall) to a point not more than 50' stream -ward of the WPO
buffer. Ref. 17-604.A. (storm line within landward 50' of WPO buffer is permissible) Also image, below.
23
4" HDPE"FO TIE TO R60F
` 2 �✓ LEADER. MAINTAIN 1%
42,1 SLOPE MIN. (TYP.)
102 -
441
"-- -lfcv
r
--i-__- - 103
WPO BUFFER
o
r I 100 �
I
1 �
1.0' AVG DIA RIPRAP '
CLASS Al
,{ `WIDTH 1 = 8'
C6.0
8. Please confirm Flood Protection post -developed Q2, Q10 CFS values are consistent, wherever they appear
(apparent typos during plan review on 1/15).
Engineering Review Comments
Page 3 of 3
9. Beneath Water Quality Analysis text box, lower -left, please provide initial WP0201800078 post -developed
impervious area, managed turf, and initial total load reduction required, =1.65 lb.
10. C6.1 - Ensure table below is legible once plan is printed.
HYDRAULIC DESIGN CALCULATIONS
(EQUATION 7.1 - SECTION UDESIGN CRITERIA- SPECIFICATION NO, 7)
DSTONE = [(PwiXRn) + (PXA,)F (N,XAp)
PERMEABLE PAVEMENT DRAINAGE AREA 1 PERMEABLE PAVEMENT DRAINAGE AREA 4
DsTONEIM)N) _ [(0.08FT X 1,753 FT2 X 0.95) + (0.08FT X 1,753 FTZ)] 1(0.40 X 1,753 FT2) DSTONE(MiM = [(0.08FT X 645 FT2 X 0.95) + (0.08FT X 1,917 FT2)] 7 (0.40 X 1,917 FT2)
= 0.39 FT = 0.26 FT
P - 0.08 FT Ap - 1,753 FT2
P, = 1,753 FT2 N, = 0.40
Raj = 0.95
PERMEABLE PAVEMENT DRAINAGE AREA 2
DSTONE(MIN) _ [(O.OBFT X 1,750 FT2 X 0.95) + (0.08FT X 1,750 FT2)] 1(0.40 X 1,750 FT2)
= 0.39 FT
P = 0.08 FT Ap - 1,750 FT2
A = 1,750 FT2 N, = 0.40
R�) = 0.95
PERMEABLE PAVEMENT DRAINAGE AREA 3
DSTONE(MiN) _ [(O.OBFT X 3,793 FT2 X 0.95) + (0.08FT X 1,296 FT2)] 1(0.40 X 1,296 FT2)
= 0.75 FT
P = 0.08 FT Ap = 1,296 FT2
A = 3,793 FT2 N, = 0.40
RVj = 0.95
P = 0.08 FT Ap = 1,917 FT2
A = 654 FT2 N, = 0.40
P = 0.95
PERMEABLE PAVEMENT DRAINAGE AREA 5
DSTONE(MiN) _ [(0.08FT X 962 FT2 X 0.95) + (0.08FT X 962 FT2)] / (0.40 X 962 FT2)
= 0.39 FT
P = 0.08 FT Ap = 962 FT2
Ai = 962 FT2 N, = 0.40
R i = 0.95
PERMEABLE PAVEMENT DRAINAGE AREA 6
DSTONE,W) _ [(0.08FT X 2,765 FT2 X 0,95) + (0.08FT X 864 FT2)] 1 (0.40 X 864 FT2)
= 0.81 FT
P = 0.08 FT Ap = 864 FT2
Ai = 2.765 FT' N, = 0.40
Raj = 0.95
11. C6.2 -Str. 120 allowable ponding depth, 0.4', appears to exceed height of curb opening, 0.333'. Review
/revise Str. 120 DI length, as needed.
12. C6.6 -Recommend revise SWM facility easement plat, since easement for SW4 is not needed (SW4
eliminated) and trim SW3 easement dimensions so future improvements may be built outside recorded
easement. Without easement plat revision, SWM facility easements appear excessive and may conflict with
future development in proximity to revised building footprint.
13. Provide sheet similar to L3.30, Mitigation Planting Plan. Ensure proposed mitigation meets required 2:1
ratio offset required of buffer impact, which may be less than initial WP0201800078 WPO buffer impact.
Engineering plan review staff are available from 2-4 PM on Thursdays, should you require a meeting to discuss this
review.
County forms can be found on the county website forms center under engineering;
htt2://www.albemarle.org/deptforms.asp?departrnent--cdengmMo
WP0201800078 -Amendment 1 -Keswick Hall Spa 011520