HomeMy WebLinkAboutWPO202200050 Correspondence 2023-01-11SHIMP ENGINEERING, P.C.
Design Focused Engineering
January 10, 2023
John Anderson
County of Albemarle
Department of Community Development
401 McIntire Road, North Wing
Charlottesville, Virginia 22902
RE: Response Letter #1 for WPO2022-00050 Forest Lakes Self -Storage - VSMP
Dear John,
Thank you for your review of the VSMP request for Forest Lakes Self -Storage. This letter contains
responses to County comments dated 12/29/22.Our responses are as follows:
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.
1. Revise title pg. of SWPPP to reference WP02022-00050.
2. Once revisions complete, include I I" x 17" plan inserts, Sec 4 /5 (ESC /SWM plans).
3. Sec. 1 /Registration Statement:
a. Sec. ILF. —List `Albemarle County' since project located in Albemarle County MS4.
4. Sec. 8: List /name qualified personnel responsible for SWPPP inspections. Required for Grading
Permit, not plan approval.
5. Sec. 9: Signed Certification (is blank): Complete form with next submittal.
6. Sec. 11: Insert 26-p. 2019 VAR10 CGP. Available at this link.
RESPONSE:
1. The WPO reference is now included on the cover.
2. 11x17 plans will be included upon plan approval
3. Albemarle County is now listed.
4. This will be provided once a contractor is selected.
5. This will be provided in complete SWPPP prior to permit issuance.
6. The VAR10 CGP is now included.
B. Pollution Prevention Plan (PPP) — See above.
The PPP content requirements can be found in County Code section 17-404.
1. Sec. E: List named individual responsible for PPP (required for Grading permit, not plan
approval).
RESPONSE: The responsible person will be identified once a contractor is selected and updated
in the SWPPP prior to the grading permit being issued.
912 E. High Sr. Charlottesville, VA 22902 1434.227.5140 1 shimp-engineering.com
C. Stonnwater 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. C1
a. Revise WPO plan title and Cale. packet title to include reference to WPO2022-00050.
b. Recommend also ref. WPO2022-00049, Maplewood Development, TMP 46B4-4
/adjacent parcel
RESPONSE:
a. WPO plan title and Cale packet title now reference WPO202200050.
b. WPO202200049 is now referenced.
2. C2
a. Show EOP, Worth Crossing. EOP label provided, but not linework matching EP. It is
typical to show roads clearly w/ identifiable EP features (gray solid line). Only existing
contours and Worth Crossing and EOP labels are provided, but not distinct EP linework,
which is now requested.
b. Depict and label:
i. Existing buildings, parking, improvements, etc. on adjacent parcels that lie within
100' of TMP 46B4-3 parcel boundaries. Much detail is shown, but check image,
below:
ii. As example, show Private Road EOP along west parcel boundary on C2, as well
as C3.
RESPONSE:
a. Linework for EP is now shown in standard line type.
b. Existing buildings, parking, and additional road EP are now labeled.
3. C3
a. Show /label CG-6, rolhop, and CG-2 curbing. Note item b., below, request to revise CG-
2 to CG-6 in specific locations.
b. Wherever runoff concentrates against curbing provide CG-6 curb and gutter, not CG-2
curb alone.
RESPONSE:
4. C4
a. Curb labels are now provided.
b. CG-6 is indicated where runoff concentrates against curb.
a. Label detention pond emergency spillway dimensions, L x W x D. Alternatively, label at
C8.
b. Provide spot elevations that define earthen /grass emergency spillway cross-section.
c. Provide ( w/ C 10) emergency spillway cross-section, provide spillway geometry.
d. Label emergency spillway grass.
e. Label swale created by proposed contours. Also, ESC plan review item 3.b., below.
f. Label Str. at end of 15 LF 12" HDPE (Applies to C3, as well. Provide profile Str./15LF
pipe, C5).
g. Provide spot elevations at Str. B 1 to ensure positive drainage.
h. Provide proposed contours as needed at grate inlet, Str. BL Applies to C8, as well.
i. Items g.-h., above, apply to unlabeled structure at item f, above.
j. Provide SWM facility sign for pond that warns of risk of detained water and forbids
trespass. Sample sign follows SWM review item 10., below.
912 E. High St.. Charlottesville, VA 22902 1434.227.51401 shlmp-engineenrig.rom
RESPONSE:
a. Emergency spillway dimensions are now shown.
b. Spot elevations are now shown to better define the emergency spillway.
c. A cross section is now provided on sheet C10.
d. The emergency spillway is now labeled as grass.
e. The swale is now labeled.
f. The 12" HDPE pipe is now labeled and profiled.
g. Spot elevation is now shown at structure B 1.
h. Contours are now shown around structure B 1.
i. Contours are now shown for 12" HDPE pipe.
j. Signage will be provided as specified. Location of sign is now shown in plan. A detail is
provided on sheet C 11.
5. C5
a. Show /label detention pond principal riser base in storm profile AO-A5 (riser = Sir. Al).
b. Label riser base, concrete/steel. Label base dimensions (Lx W x D).
c. Provide buoyancy calculations for riser /base.
d. Label detention pond floor elevation (513').
e. Coordinate sediment basin dewatering device, elev. 514.5', with mid -flow 4" orifice,
elev. 514'. Coordinate dewatering and 4" permanent orifice in separate vertical planes
(offset locations).
RESPONSE:
a. Standpipe riser base is now shown in profile.
b. The riser base type and dimensions are now shown.
c. A buoyancy calculation has been provided with this resubmittal.
d. Detention pond floor elevation is now labeled.
e. A standpipe detail is now provided showing the dewatering device orifice and permanent
4" orifice in separate vertical planes.
6. Sheet C 12/Calc Packet p. 2 propose purchase of 3.37 lb. nutrient credits to meet 9VAC25-870-65
requirements. Incl. letter of nutrient credit availability for project from Ivy Creek Nutrient bank
on the plan. Project discharges to Powell's Creek /S. Fork Rivanna River, impaired streams. Ivy
Creek is the only nutrient bank that meets DEQ eligibility criteria for impaired streams in project
HUC. Please coordinate with Ana Kilmer, 434.296-5832 -x3246 (akilmer@albemarle.org) prior
to purchase to ensure bill of sale /Affidavit include requisite project data. Nutrient purchase not
required for plan approval but is required to receive a Grading Permit.
RESPONSE: Letter of availability for nutrient credit purchase is now included in this submittal.
Purchase will be coordinated with Ana Kilmer.
7. Check LD-229 table, p. 61, Calcs: Provide design for `A' series storm line. Additional comments
possible.
RESPONSE: Missing stone line is now included in the LD-229 table.
8. SWM /public drainage easement plat (and off -site temporary construction) easement plat
recordation is required for WPO plan approval.
RESPONSE: Acknowledged, an easement plat will be submitted for review and recorded.
9. A recorded Maintenance Agreement is required for WPO plan approval.
RESPONSE: Acknowledged, a maintenance agreement will be signed and recorded.
10. Proof of nutrient credit purchase, state VAR10 CGP (LOD =3.29 Ac.), SWPPP update (Sec.
912 E. High St.. Charlottesville, VA 22902 1434.227.51401 shlmp-engineenrig.rom
6E/8), and WPO plan bond required prior to receiving a Grading ' nit.
RESPONSE: Proof of nutrient credit purchase, complete SWPPP, and bond will be provided.
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. C10
a. Provide Contech StormRax or similar storm rack /riser cover detail for detention basin.
RESPONSE: A detail is now provided on C 10.
2. C9
a. Include paved wash rack detail, see p. 8, ACDSM.
RESPONSE: The ACDSM paved wash rack detail is now included.
3. C8
a. Although Maplewood Development (parcel to N) final site plan (SDP202200067) and
WPO plan (WPO202200049) appear to suggest near -term development, should these
plans fall through:
i. Provide offsite grading easement on TMP 046134-00-00-00400, Maplewood
Investments LLC. Grading easement are shown on C3, C4. Furnish copy of
recorded off -site easement (required for WPO plan approval).
ii. Provide ROE (Right of Entry) Letter Agreement, between TMP 046B4-00-00-
00400 owner and County of Albemarle that allows ESC inspector entry to TMP
46B4-4.
iii. Note: Once a WPO plan is approved, SWM Agreement is recorded, and Grading
Permit issued for Maplewood Development (TMP 46B4-4), Albemarle will have
right to enter adjacent parcel, but development plans often change, so i./ii. are
required, unless iii.
iv. Regardless of status of Maplewood Development, if Forest Lakes Self -Storage
receives plan approval, then, absent ROE (ii., above), Maplewood (Owner, TMP
46B44) must be party to ESC plan bond, since ESC measures for TMP 46134-3
(Self -Storage) are located on 46B44 (Maplewood). This requirement is
inflexible until such time development of TMP 461344 advances to point that no
self -storage ESC measures are located on TMP 4613-4. All of this (item. 3.a.i.-
iv.) may be avoided if Forest Lakes coordinates WPO plan design with
Maplewood Development design (Collins Engineering) to show no grading and
no ESC measures on TMP 46B4-4. Either option is acceptable: 3.a.i.-iii, or
3.a.iv.
b. Label swale between contours 520' and 515' /grate inlet created by proposed contours
east of detention pond. Also, SWM plan item 4.e., above.
c. Provide and label EC2 for swale, item b., above.
d. Relocate B2, B1 structure labels or 520', 524' contour labels so structure labels are
readable. Comment applies to sheet C4, as well.
e. Label ditch -lining for ditch between multi -use path and Worth Crossing (EC-3, or EC-2).
f Provide cross -sections for swale /ditch, items b., e., above.
g. Relocate IP label at Str. A3 since this label obscures A3 label.
h. Provide ESC Ph 1-A plan that depicts mass grade of site, perimeter controls, and
diversions, incl. RWD at PCE at Worth Crossing.
912 E. High St.. Charlottesville, VA 22902 1434.227.51401 shlmp-engineenrig.rom
i. Ph 2 ESC plan Sequence of Construction references RWD; depict RWD at Worth
Crossing on Ph 1-A plan.
j. Revise Ph 2 Sequence to require removal of all sediment and saturated material from
sediment basin floor to at least detention pond floor elevation prior to converting SB to
detention pond. Specify adequate disposal of saturated SB excavate.
k. Provide silt fence at Worth Crossing.
1. Provide and label safety fence between 10' multiuse path and construction site once
multi -use path is constructed. Furnish notes /labels to guide installation of safety fence.
in. Provide /label SWM facility access
i. At access, replace CG6 with roll-top curb.
ii. Recommend SWM access be opposite 22.33' opening, south face of building.
iii. Ref. design at ACDSM, p. 12 — adequate vehicle access, 10' width graded at <
20%.
iv. SWM facility access must not conflict with DI A3.
v. Comment applies to additional sheets.
RESPONSE:
a.
i. An offsite grading easement will be shown on the easement plat which will be
submitted prior to plan approval.
ii. Please provide template for ROE agreement.
iii. Acknowledged, access will be provided by way of easement/ROE agreement.
iv. The grading easement has been agreed to by both parties to make the
connection easier so an ROE agreement will be provided.
b. The swale is now labeled.
c. EC-2 is now specified.
Cl. Structure labels have been moved to be more legible.
e. Ditch lining is now specified for ditch between path and Worth Crossing.
f. Cross sections for ditches are now provided on sheet C 10.
g. IP label has been moved to be more legible.
It. An additional E&S phase is now provided to show grading with E&S controls in place
prior to permanent stabilization and conversion of sediment basin to detention pond.
i. E&S phasing has been revised to specify installation of 12" HDPE at entrance on Worth
Crossing.
j. E&S sequence has been updated. Conversion of sediment basin to detention pond is
specified and indicates removal of sediment and saturated material and adequate disposal.
k. Silt fence is now provided along Worth Crossing.
I. Safety fence is now shown between path and construction once path is complete. Fence
shall remain until sediment basin is converted to detention pond.
in. SWM facility access easement is now shown.
4. CT Provide silt fence at Worth Crossing.
RESPONSE: Silt fence is now shown along Worth Crossing.
5. C4: Label riprap outfall dimensions (BO x 2, A2). L x W x D. Alternatively, label dimensions at
C8. Detail 6, C9, provides dimensions, but please label dimensions in plan view, as well.
RESPONSE: Riprap outfall dimensions are now labeled in plan.
912 E. High St.. Charlottesville, VA 22902 1434.227.51401 shlmp-engineenrig.rom
If you have any questions or concerns about these revisions, please feel free to contact me at
chris@shimp-en ine eerine com or by phone at 434-227-5140.
Regards,
Chris Marshall, EIT
Staff Engineer
Shimp Engineering, P.C.
912 E. High St.. Charlottesville, VA 22902 1434.227.51401 shlmp-engineenrig.rom