HomeMy WebLinkAboutWPO202200032 Correspondence 2022-10-13•see
0 f 608 Preston Avenue
P 434.295.5624
Suite 200 IF434.295.1800
T I M M O N S GROUP
Charlottesville, VA 22903 www.timmons.com
October 13, 2022
John Anderson, PE, CFM
County of Albemarle
Community Development
401 McIntire Rd, North Wing
Charlottesville, VA 22902
RE: Berkmar Self Storage — VSMP Plan Review - Comment Response Letter
Dear Mr. Anderson:
We have reviewed your comments from August 25, 2022, and made the necessary revisions.
Please find our responses to the comments below in bold lettering.
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 disapproved for
reasons listed below. The VSMP application content requirements can be found in County Code
section 17-401.
A. Stormwater Pollution Prevention Plan (SWPPP)
The SWPPP content requirements can be found in County Code section 17-405. A
SWPPP must contain (1) a PPP, (2) an ESCP, (3) a SWMP, and (4) any TMDL measures
necessary.
SWPPP
1. Revise SWPPP cover to include ref. to WP0202200032.
A reference to the WPO number has been included on the cover.
2. Registration Statement, SWPPP Sec. 1
a. Sec. IA and Sec. V of Registration Statement are the same entity. If Sec. IA is TBD,
then statement should remain unsigned until Construction Activity Operator is
named /listed.
Signature has been removed from Registration Statement. LOD has been
revised to reflect all plan revisions.
b. Sec. IB: Once Construction Activity Operator named /listed, please include valid
email.
ENGINEERING I DESIGN I TECHNOLOGY
Once contractor is selected, the section will be completed (understood prior to
receiving grading permit).
c. Sec. III, off -site support activity: If anticipate off -site disposal, please complete
this section.
No off -site activity is anticipated at this time.
3. Sec. 4 5: Update once ESC /SWM plan sheets revised.
Updated ESC and SWM sheets have been included with the SWPPP.
4. Sec. 6.A.: SWPPP Exhibit (11" x 17"), update as needed.
Updated PPP sheets have been included with the SWPPP.
5. Sec. 6.E.: List named individual responsible for PPP. Not required for plan approval but
required to receive a grading permit.
Once contractor is selected, the section will be completed (understood prior to
receiving grading permit).
6. Sec. 8: List named individual responsible for VESCH /SWPPP compliance inspections. Not
required for plan approval but required to receive a grading permit
Once contractor is selected, the section will be completed (understood prior to
receiving grading permit).
7. Sec. 9: Signed Certification: complete /required prior to plan approval.
Signed Certification is included with this submission.
B. Pollution Prevention Plan (PPP) —See above, items 4, 5.
The PPP content requirements can be found in County Code section 17-404.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is disapproved for reasons listed below. The stormwater management plan
content requirements can be found in County Code section 17-403.
1. C0.0
a. Revise plan set title to include ref. to W13O202200032.
Title has been revised to include reference to WPO number.
b. List associated (off -site) SDP-WPO plans, including:
i. W13O201800030, Charlottesville -Albemarle SPCA
ii. WPO201600011, Harvest Moon
iii. WPO201600011, Kegler's Pond As -built
iv. WPO201100076, Rivanna Plaza
v. Rivanna Plaza easement plat @ DB-PG 3839-301
vi. SDP199500087, Lowe's Home Improvement Center (Calculations
/approved site plan)
vii. SDP200300102, Lowe's Minor Amendment
The above -mentioned plans have been listed under "SITE DATA" on
Sheet C0.0.
2. C6.2
a. Revise capacity of pipe 127 such that Q provided > Q required (24.466cfs v.
38.16cfs).
We think reviewer means pipe 103 (not 127). Pipe 103 has been upsized. See
Sheet C6.2.
3. C6.3
a. Revise Calculations (7/15/22), SWPPP, and plan to reference:
i. Existing dry detention basin, SWM facility ID 0021.01 rather than 'Keglers
Regional Pond' since Kegler's is not a regional pond within regulatory
meaning of the definition, but rather a typical SWM facility immediately
adjacent to development areas which drain to it. Many developments
drain to it, but it was constructed primarily to serve Kegler's (bowling
alley) and Lowe's 30 years ago. As development has progressed along
Berkmar (Harvest Moon, UVA Credit Union, ACSPCA /improvements
pending, Berkmar Overlook, now Berkmar Self -Storage /hotel), reliance
on the small detention basin is a proposition Engineering evaluates with
care since the Ex. detention basin is not a 'regional' facility. VAC states:
"A locality's VSMP authority may develop comprehensive stormwater
management plans to be approved by the department [DEQ] that meet
the water quality objectives, quantity objectives, or both of this
chapter." (9VAC25-870-92). 9VAC25-870-69 outlines offsite compliance
options that a VSMP authority may allow an operator to use to meet
required phosphorus nutrient reductions, including "Offsite controls
utilized in accordance with a comprehensive stormwater management
plan adopted pursuant to 9VAC25-870-92 for the local watershed within
which a project is located." The small detention basin was not developed
by Albemarle as a regional SWM facility —it is simply a detention basin.
Reference to Kegler's Regional Pond has been removed.
b. Include supplemental narrative in Calc. packet:
Please state: "Albemarle SWM facility database states existing dry
detention basin watershed is 61.87 Ac. with 21.37 Ac. impervious. Plan
approval date is 11/19/87. Facility is listed in county SWM database (co -
owned by) Keglers of Charlottesville and Lowes Investment Corp #341."
Proposed development, Berkmar Self -Storage, appears to lack ownership
in the facility, or privilege to use it. Applicant parcel is not child to parent
subdivision that might assign use rights to Applicant. Applicant should
coordinate /execute notarized Agreement with owner to use the existing
dry detention basin, and furnish copy to Albemarle. Albemarle would not
be party to this Agreement, but relies on prior -recorded instruments —
see item iii. If Applicant is aware of an implicit right to rely upon the
existing dry detention basin exists (via recorded instrument), please
advise Engineering so we may forward document/s to county attorney's
office for their review.
The supplemental narrative has been added as requested to the
calculations packet. The owner/engineer are working with the County
regarding legal documentation.
ii. Add Note ref. to: Deed of Easement (establishes right of County to
Maintain), DB-PG: 1786-0734, recorded 2/9/99.
Note has been added to the stormwater narrative.
iii. Add Note ref. to: Detention Pond Easement Plat, DB-PG: 1786-0737; plat
by Wiley & Wilson, Lynchburg, April 15, 1994.
Note has been added to the narrative.
iv. Add Note ref. to: County of Albemarle deed of easement with Keglers of
Charlottesville (item iii, above).
Note has been added to the narrative.
c. Revise ex. detention basin detail rim of riser label to read 471.0 rather than
417.0.
Note has been revised on Sheet C6.3.
4. Calculation packet/Additional:
a. Revise title /cover of calc. packet to ref. to WPO202200032.
Title has been revised.
b. Please review, compare (with calcs), and incorporate, as needed:
i. SDP200300102, Lowe's Home Centers Inc. Minor Amendment, and
ii. SDP199500087, Lowe's Calculations and Approved plan in Berkmar Self -
Storage evaluation of ex. detention basin (design, parameters, As -built
volume /structures, routings, etc.), and revise design /calculations, as
needed. Note: Albemarle sent link to files /plans: County Engineer (Frank
Pohl) to Timmons Group (C. Kotarski) and Milestone Partners (Frank
Stoner), Sep. 28, 2021, 4:30 PM.
The Lowes calculations (SDP-1995-0087) packet has been referenced on
Sheets C6.0 and C6.1. SDP-2003-00102 was a minor amendment to the
photometrics of the parking lot and not applicable to hydrology.
c. Separate post-DEV offsite drainage areas into discrete areas since CN / Tc differ
for off -site DAs.
i. Tc, Berkmar Overlook residential development, for example, C
should be routed with Tc=7.2min, not 20.5min, as appears to be the
case on pg. 25 of calc. packet. Please route offsite Areas A, B, C as
distinct separate DAs in HydroCAD pre- /post-DEV routings.
ii. Specifically, the following (see C6.1) should route as sub -catchments, not
a weighted Tc /CN, single, off -site contributing DA to the dry detention
basin:
1. DA Area_A (S of Berkmar Overlook Development): 36.6 Ac, CN
=70, Tc=20.5min
2. 36.6 DA: Delineate developed v. undeveloped; route developed
areas and one undeveloped area to obtain a composite pre-
/post-DEV (pre- /post, identical) peak flow for each inlet
discharging to the basin:
a. Developed parcels NW of Int. Woodbrook Drive /Berkmar
Drive.
b. Charlottesville -Albemarle SPCA
c. Harvest Moon
d. UVA credit union
e. Undeveloped
Note: At first glance, SPCA, Credit Union and Harvest
Moon appear to have high CN /low Tc, and may be
anticipated to deliver peak flow rates nearly
simultaneously. Also, pre- /post-DEV rates for all off -site
areas will be identical, since not affected by Berkmar Self -
Storage development, but it is important to discriminate
between off -site developed v. undeveloped areas as was
done for Berkmar Overlook. Timmons Group likely has
reliable post-dev H&H data for ACSPCA (WPO201800030),
having prepared the design.
Revisions have been made to the H&H calculations
packet per above directive.
3. Route Lowe's to basin, along with areas discussed in items
4.c.ii.1.-2., above.
This area is accounted for in the H&H model.
4. Route Kegler's (bowling alley) to basin, along with 1,2,3.
Note: Engineering does not use /run HydroCAD; we comment on
methodology.
This area is accounted for in the H&H model.
5. Route Rivanna Plaza to basin, along with 1.-4.
This area is not accounted for in the H&H model since this site
does not drain to the pond. In the "Berkmar Drive North
Extension Drainage Map 03-30-1994, this area is listed as
"undetained". Please see plans by DDR showing storm network
connecting directly to storm pipes along Route 29.
6. DAB (Berkmar Overlook development): 6.78 Ac., CN =80.9, Tc
=7.2min.
This area is accounted for in the H&H model. Area is 7.43 acres
and CN is 79.2 per amendment 2 of the plan.
7. DA C (Berkmar Overlook development): 0.90 Ac., CN =65.8, Tc
=6min.
This area is accounted for in the H&H model.
Notes:
1. Berkmar Overlook west of Berkmar Drive employs on -site
detention; detained offsite Q peak more accurately models
(HydroCAD) post-DEV Q peak rates.
The Berkmar Overlook basin has been added to the model.
2. Berkmar Self -Storage should rely on post-DEV scenario
anticipated by WPO201800030 which proposes on -site detention
with improvements at ACSPCA. HydroCAD for ACSPCA
(anticipated future development) and Berkmar Overlook (existing
development) should reflect detained off -site pre- /post-DEV
discharge rates when evaluating Berkmar Self -Storage stormwater
quantity compliance.
The ACSPCA model has been incorporated into the routing
calculations for this plan.
3. Analysis that may not consider detained release from off -site
sources that contribute runoff to ex. dry detention basin (Kegler's
Pond) requires revision, and may ultimately require Berkmar Self -
Storage on -site detention similar to on -site detention practices
proposed at ACSPCA (design stage) /Berkmar Overlook
(construction stage).
The model has been revised.
4. To the extent Berkmar Self -Storage relies on off -site dry detention
(Keglers) for water quantity compliance, Applicant should furnish
notarized Agreement between Berkmar and Keglers. Agreement
should outline shared maintenance responsibility for the off -site
SWM facility (Ex. detention). Initial WPO plan indicates that the
existing detention basin cannot provide detention for Berkmar
Self -Storage without structural modification [Stormwater
Narrative, sheet C6.31.
Applicant will coordinate this item with the County.
iv. Lowes: 15.40 Ac., CN =92, Tc = undefined; route Lowe's storm runoff in
pre- /post-DEV with defined Tc.
The information used in the model has been taken from the
approved Lowes plan.
Keglers (bowling alley): 5.61 Ac., CN =84, Tc = undefined; route Kegler's
in pre- /post-DEV with defined Tc.
The plan did not disclose what Tc they used. The site is mostly
impervious utilizing mostly concrete pipe conveyance resulting in a
low Tc. A minimum Tc of 6.0 min was used for the most conservative
approach.
vi. Please include Construction Record Drawing, Kegler's Pond (As -built) by
Dominion Engineering, dated 3/16/16 (approved 4/7/16
=WPO201600011 Rev. 1 comment date) with Berkmar Self -Storage
plans. Print /digital As -built available to Applicant.
Since the survey is the most up-to-date it has been used for current
conditions of the pond and structures. Additionally, our survey had
relevant information of the riser and pipe sized that was not included
on the as -built plan. The survey was completed by Roudabush Gale
and Associates (previously Dominion Engineering) earlier this year.
We believe it is a more accurate depiction of the current state of the
pond.
vii. If modification proposed to existing detention (ex. dry detention
basin), please provide plan /profile detail (small-scale) of both existing
structure and any proposed change.
Please see Sheet C6.3 for proposed changes.
viii. Revise calculations, as needed, to reflect ex. detention basin As -built
riser rim elev. /invert out elev. /embankment elev. /ex pipe/s DIA, etc.
Since the survey is the most up-to-date it has been used for current
conditions of the pond and structures. Additionally, our survey had
relevant information of the riser and pipe sized that was not included
on the as -built plan. The survey was completed by Roudabush Gale
and Associates (previously Dominion Engineering) earlier this year.
We believe it is a more accurate depiction of the current state of the
pond.
ix. Rivanna Plaza drains to Ex. detention; revise calculations, as needed, to
reflect pre- /post-DEV flow from Rivanna Plaza. Note: See instrument /
plat at DB-PG 3839-301, 1/13/2010 for easement/s established
/vacated with WPO201100076 (Rivanna Plaza).
As discussed with reviewer, Rivanna Plaza does not drain to the pond
although this area was included as undetained area in the original
pond design.
5. If on -site SWM is required, a recorded SWM facility /public drainage easement plat
(with deeds) is required for VSMP /WPO plan approval.
Acknowledged, our intention is to use the offsite detention pond.
6. If on -site SWM required, please include Construction Record Drawings As -built for
VSMP on the plans, as well as practice -specific SWM installation, periodic inspection
/maintenance information on the plans.
Acknowledged, our intention is to use the offsite detention pond.
C6.0, C6.1
a. Ref. comments elsewhere. Revise pre- /post-DA maps to define discrete
contributing DAs with more accurate CN /Tc values.
Pre- and post-DA maps have been revised as indicated in earlier comment
responses.
8. Letter of nutrient credit availability (5.0 lb.) must be included on the plans.
A letter of nutrient credit availability is provided on Sheet C6.4.
D. Erosion and Sediment Control Plan (ESCP)
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP.
This plan is disapproved for reasons listed, below. The erosion control plan content
requirements can be found in County Code section 17-402.
1. C3.0
a. Indicates 4.74 Ac. limits of disturbance. VAR10 registration statement indicates
5.44 LOD. Please revise plan or registration statement for consistency /accuracy.
The LOD has been updated to be consistent throughout the plan set.
2. C3.2
a. Both sediment traps lie immediately adjacent to a developed property to the
south (Harvest Moon). Provide additional ST2 dry storage capacity.
Adequate dry storage capacity is provided per VESCH. If construction site
conditions require a field change based on reviewer's comment 2.b, we will
work with the County ESC inspector to rectify any issues that might come up in
the field. ST2 is strategically located as to not interfere with the construction of
the Self Storage facility.
b. Recommend provide additional ST1 wet/dry storage capacity.
Note: An incident release of sediment -laden site runoff will route thru ex.
detention basin and may affect ponds in residential areas downstream of the
detention basin located E of U.S. Rt. 29 (Carrsbrook subdivision), a circumstance
to avoid via design. One way is to increase volume of temporary sediment traps.
The storage provided for STl is more than required by code. As mentioned
above, if field conditions dictate a change, we will work with the County ESC
inspector to rectify the problem.
c. Pipe 119 leaves MH Str. 104 at an acute angle. Revise pipe-to-MH design (90-
deg, Min.).
Pipe connection has been revised on Sheet C3.3.
d. Provide double row SF or fence -backed ("super" silt fence) between sediment
traps and Harvest Moon (HG Land, LLC) to the south.
Super silt fence has been added where the disturbance abuts Harvest Moon.
See Sheets C3.2 — C3.4.
e. Label sediment trap floor dimensions (L x W).
Dimensions have been added to both sediment traps on Sheets C3.2 — C3.3.
3. Provide interim 'Mass grade' ESC plan, a stage intermediate to Phase 1 and Phase 2
(between C3.2, C3.3). Phase 1, C3.2, shows no grading; Phase 2, C3.3, shows complete
build -out, and traps removed. Depict ESC measures required to prevent off -site
sediment transport as site is brought to grade, as improvements are constructed. This
may entail smaller traps, or traps in multiple locations. Also, a primary focus of interim
ESC measures is to avoid discharge of sediment -laden runoff to Harvest Moon or to ex.
dry detention basin from SW quadrant of Berkmar Self -Storage tract, shown as graded
turf at completion.
An interim ESC plan has been added (Erosion & Sediment Control Phase II — Sheet
C3.3).
4. Point of Int. with Berkmar Drive is of special concern; provide interim ESC design to
ensure no tracking of mud or sediment onto Berkmar Drive as grading /building and
parking lot construction proceed.
An interim ESC plan has been added (Erosion & Sediment Control Phase II — Sheet
C3.3).
5. Depict /provide ESC narrative for right turn lane from Berkmar Dr. Depict right turn
lane ESC measures.
Inlet protection has been added to the inlet downstream of the site in all ESC phases
on Sheets C3.2 — C3.4, respectively. This inlet will be relocated with the addition of
the taper. Silt fence has been added to the back of curb to prevent sediment from
entering the road during the construction of the shared use path along the frontage
of the property.
6. Provide and label ESC measures between proposed 10' asphalt sidewalk and Berkmar
Drive.
Silt fence has been added on Sheets C3.2 — C3.4.
C3.3
a. Provide SF between site and Keglers to east to extend from cut /fill transition
(contour 494') to SE corner of parcel.
Silt fence has been added to the area. See Sheets C3.2 — C3.4.
b. Provide RWD at 482' (±) and /or appropriate ESC measures to prevent runoff
reaching U.S. Rt. 29 until relatively steep 40' pvt. ROW between site and Rt. 29 is
paved (25' width).
ESC measure has been added to the end of the proposed improvements. A
note has been added for contract to check area daily. See Sheet C3.4.
8. C4.0
a. SW quadrant of site (layout and utility plan) shows existing grade, inconsistent
with proposed grade shown on C3.3. Revise C4.0 to show proposed final grade.
Grading is not shown on C4.0 to provide clarity for layout dimensions and
labels. All grading, storm network, and utilities are shown on Sheet C5.0.
9. C5.0
a. 40' pvt. ROW includes an existing gravel road half the width (or less) of proposed
final 25' paved width. Ex. drainage with respect to U.S. Rt. 29 is unclear, but final
condition proposes to tie new 25' wide pavement with existing paved road that
then continues and connects with U.S. Rt. 29. Provide /show drainage /storm
conveyance for this 25' paved connection between Berkmar Self -Storage and
U.S. Rt. 29; design should prevent runoff from this facility entering U.S. Rt. 29.
Drainage pipes and inlets have been added, with associated ditch sections, to
convey this drainage to the existing inlet on US Route 29, rather than allowing
the drainage to sheet flow onto US Route 29. See Sheet C5.0.
b. Recommend different hatching for cemetery zone since hatching maybe
misinterpreted as proposed grading across a cemetery.
Hatching of cemetery has been changed to dots on Sheet C5.0 to differentiate.
c. Recommend paved walk /stairs between 9 parking spaces located on 25' paved
road (40' pvt. ROW) and 4-story self -storage since use of slope without a
designated pedestrian facility may direct sediment -laden runoff immediately to
DI 112, and thence to ex. dry detention basin.
It is unlikely that the Storage facility customers will park in those spaces since
they are overflow for the hotel. Parking for the Storage facility is provided in
front of the building and not expected to exceed 8 spaces provided.
We have included PDF copies of the plans and calculations for your review. If you have any
questions or comments, please feel free to give me a call at 434.295.5624 or email
Jessica.denko@timmons.com .
Sincerely,
Jessica Denko, PE
Project Manager