HomeMy WebLinkAboutWPO201600012 Review Comments WPO VSMP 2016-03-13COUNTY 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
Project: Landmark Aviation Hangar (VSMP)
Plan preparer: Kent O'Donohue, L.A./Scott Kesecker, EIT / Balzer & Assoc. Inc. dodonohue(a�,balzer.cc
1561 Commerce Road, Suite 401, Verona, VA 24482; skeseckerkbalzer.cc
Owner or rep.: Charlottesville -Albemarle Airport Authority
201 Bowen Loop, Charlottesville, VA 22911
Plan received date: 19 Feb 2016 (e -plan)
Date of comments: 13 Mar 2016 e -review
Reviewer: John Anderson
WP0201600012
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 Sec. 3/Construction Sequence Notes 7, 9 to include with County ESC inspector approval.
2. Replace 11" x 17" ESC/SWM plan sheet inserts, if sheets revised.
3. Sec. 6.G.l.a. —check here/elsewhere, please remove reference to separate project.
4. Recommend coordinate with Airport Authority on any restrictions: hours of operation, site access, etc.
B. VSMP: SWPPP: Stormwater Management Plan (WP0201600012)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is
disapproved for several reasons, listed below. Stormwater management plan content requirements can be found in
County Code section 17-403.
30" Nyloplast MH inconsistent with VDOT Specifications (VDOT R&B Std., Vol. 1). If designer aware of
VDOT approval of Nyloplast as VDOT-equivalent, please notify County. (p. 50, SWM Report; 16 Feb 2016)
Nyloplast 48" DIA MH equipped with steps may be substituted* but recommend VDOT MH -1 (30" DIA
too narrow). Site plan should follow VDOT standards (ACDSM, 6.A.1.), especially since Charlottesville -
Albemarle Airport is a public use facility. County will consider Alt. to VDOT MH -1.*
* Nyloplast 48" DIA MH may be used (structures # 2, 4, 6) at Landmark Aviation Hangar, provided:
Shown equivalent to brick /concrete (VDOT MH -1)
Nyloplast Str. details w/plans (link, below)
Installation Notes w/plans (Last p.)
MH equipped with steps (reqd.)
PE -Certification: Installation per design
A. Plans: for plan requirements please refer to the review checklist at
http://www,albemarle.org/deptforms.asp?department=cdengwpo.. For purposes of this
design manual, the review checklist sets review policy, and is an integral part of the manual.
1. Design Guidelines, in general, designs must follow the VDOT Drainage Manual and the
Road and Bridge Standards, with the following additional specific points; (see
www.virginiadot.org/business/locdes)
SEE STA4DARAD SL -1 FOR APPLICABILITY OF SAFETY SLABS.
STANDARD NH -1 NOTE:
FRAME H COYER THE TOP OF M -Y E TO BE LEFT
SUFFICIENTLY LOW TO PERMIT PROPER
AONSTMENT OF COVER AND FRAME TO
GRADE BY THE USE OF MORTAR OR
BRICK AS DIRECTED BY THE ENGINEER.
B
SLAB TOP AS DETAILED
iTANOARD T -MH -2 MAY BY
:TNUTED FOR TAPERED
16M WHEN APPR6VE0 Dr
ERGINEER.
BEVEL 45'
SECTION B -B
BRIICK CONCRETE OR
CONCRETE BLOCK
DEPTH
Engineering Review Comments
Page 2 of 4
HALF PLAN VIEW
HALF SECTION A -A
(WITH FRAME AND COVER REMOVED)
BRICK CONCRETE
B
J
r��NC MANHOLE FDR 12" - 48" PIPE CULVERTS ROAD ANDURD�E STANDARDS VIRGIMA DEPARTMEHi OF TRANSPORTRT i:'• REVISION DATE SHEET 1 OF 5
D6-01
2. Pipe slopes, p. 49 (Sfo), appear identical: 0.20. Please revise LD -347 (SWM Report; 16 Feb 2016).
INLET
STATION
OUTLET
WATER
SURFACE
ELEV.
DO
NOTES:
LO
Sf6
2 4
1- QUANTITES SHOWN ARE FOR MANHOLE
15"
2.89
23.19
WNHOUT PIPES. THE AMOUNT DISPLACED
BY PIPES MUST BE DEDUCTED TO
OBT,ARj TRUE CumTITES.
2. A BASE THCIA NE95 OF 9" WAS USED IN
COMPUTING CONCRETE QUANTITE5,
TABLE OF gUPNTITES
CONCRETE
BRICK
MANHOLE
MANHOLE
3, INCREMENTS TO BE ADDED FOR EACH
AO0ITIONAL FOOT OF OEPTH-
4. MATERIALS MAY BE BRICK, CONCRETE OR
APPROVED CONCRETE MANHOLE BLOCK.
5. IF BLOCKS ARE USED THE MINIMUM
THICKN:$5 OF $AME IS TO BE 5".
OTHER THICKNESSES ARE TO COWORM
TO WALL TWKNESS SHOWN FOR
CONCRETE.
6.ALL CONCRETE TO BE CLASS A3.
7. WHEN SPECIFED ON PLANS THE
INVERT K TO BE SHAPED N
ACCCPLANCE WITH STANDARD IS -1.
�I NG
ALL THE 1 ATERIAALS IOF NCIDENTAL TO THE
SHAPW 15 TO BE INCLUDED IN THE BID
PRICE F9R THE STRUCTUPE.
BRICK "KKCRETE CONGRETE
'HOUSANDS CU. YARDS CV.7AR05
0.5 0.785 1.437
0.7 0.785 1-599
0.9 0.785 1961.
t0 0.785 2.223
L2 0.7953.{85
1.4 0.785 2.747
te. 0.795 3-009
1.9 1 0.970 3.455
2.2 0.970 3.617
23 0.970 4.174
2.8 0.970 4,541
3.1 0.470 4.905
3.4 0.970 5265
r��NC MANHOLE FDR 12" - 48" PIPE CULVERTS ROAD ANDURD�E STANDARDS VIRGIMA DEPARTMEHi OF TRANSPORTRT i:'• REVISION DATE SHEET 1 OF 5
D6-01
2. Pipe slopes, p. 49 (Sfo), appear identical: 0.20. Please revise LD -347 (SWM Report; 16 Feb 2016).
INLET
STATION
OUTLET
WATER
SURFACE
ELEV.
DO
00
LO
Sf6
2 4
601.00
15"
2.89
23.19
0.20
4 6
604.57
15"
2.89
209.44 0.20
6
606.46
15"
2.89
47.39
0.20
2 71N
601.00
15"
2.89
23.19
0.20
71N
604.60
15"
1.63
54.76
0.06
0.00
9
596.00
15"
0.78
33.20
0.01
0.00
Engineering Review Comments
Page 3 of 4
3. Bioretention /Level 2 (No request for revision):
a. BMP surface elev. =600.00'
b. 6" orifice elev. =600.50'
c. 24" riser elev. =601.50'
d. 1 -yr event peak elev. =600.60' @ 24.03 hrs
e. 10 -yr event peak elev. =601.43 @ 12.68 hrs
f. Ponded depth; time to peak, Acceptable.
g. Bottom of sediment trap elev. =595.5'
h. Bottom of bioretention stone elev. =594.67' (0.83' /Acceptable)
Energy balance QDeveloped, Allowable'_5 0.8 x (QPre-Developed x RVPre-Developed)/RVDeveloped (9VAC25-870-66.B.3)
(No request for revision; one recommendation)
16 -Feb SWM Report (HydroCAD); 1 -yr event for DA A only evaluated.
Typically, would evaluate all developed areas: A, B, C.
`A'/pre- (0.87 Ac./No impervious); `A'/post- (1.39 Ac./ 0.76 Ac. impervious)
`B'/pre- (0.29 Ac./ 0.11 Ac. impervious); `B'/post- (0.13 Ac./ 0.09 Ac. impervious)
`C'/pre- (0.82 Ac./ 0.16 Ac. impervious); `C'/post- (0.45 Ac./ 0.16 Ac. impervious)
Recommend confirm DA `C' Developed Imp =0.16 Ac. (ref. DA maps)
a. Qpre-D /A, B, C (cfs): 0.14 x x = ?
b. RVpre-D /A, B, C (af): 0.026 x x = ?
C. RVDeveloped /A, B, C (af): 0.012 x x = ? (DAs B, C: 1 -yr not evaluated)
d• QDeveloped, proposed /A, B, C (cfs): 0.03 x x = ? (DA A: routed)
e• QDeveloped, Allowable = ?
i. May drop DAB C from Energy balance Eq. (runoff Vol/peak discharge for DA B, C
developed < existing). Portions of impervious currently uncontrolled will be routed.
ii. QDeveloped, Allowable <_ 0.8(0.14)(0.026)/0.012
iii. QDeveloped, Allowable :S 0.24 cfs
1V. QDeveloped, Allowable > QDeveloped, proposed
v. YES: 0.24 > 0.03; Acceptable
f Please Advise if QAllowable =0.24 cfs appears an error. SWM Report lists Q. =0.05 cfs.
Table 3: Pre- to Post -Developed Storm Rates after Detention
5. Please label bioretention basin width, sheet C3 (W =22.4').
6. Please include VA DEQ Design Spec No. 9 / Sec. 8.2 / Installation notes to aid construction and inspection.
C. VSMP: SWPPP: Erosion Control Plan (WP0201600012)
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESOP. This plan is approved, but
with recommendations for revisions. Welcome .PDF preview of ESCP revisions.
1. Label OP dimensions, sheet C5 (L =9', Wl =3.75', W2 =10.25', D =?)
2. SWM Report, p. 51 SCC #1, 2 -yr Vel. (4.63 ft/s) appears > 10 -yr Vel./p. 52 (1.71 ft/s) -please clarify.
3. Plan LOD =1.97 Ac.; SWPPP General VPDES Permit Registration Statement =1.80 Ac. Please reconcile.
4. Recommend a second CE at Dickerson Road if construction access is via existing non -paved travel way, via
Dickerson Rd (visible in image, below). If existing travel way is paved, please disregard comment.
Storm Event
Flowrate cfs
Pre Energy Post
Balance Max
Ql =
0.14 0.05 0.03
]0=
1.04 - 0.78
5. Please label bioretention basin width, sheet C3 (W =22.4').
6. Please include VA DEQ Design Spec No. 9 / Sec. 8.2 / Installation notes to aid construction and inspection.
C. VSMP: SWPPP: Erosion Control Plan (WP0201600012)
Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESOP. This plan is approved, but
with recommendations for revisions. Welcome .PDF preview of ESCP revisions.
1. Label OP dimensions, sheet C5 (L =9', Wl =3.75', W2 =10.25', D =?)
2. SWM Report, p. 51 SCC #1, 2 -yr Vel. (4.63 ft/s) appears > 10 -yr Vel./p. 52 (1.71 ft/s) -please clarify.
3. Plan LOD =1.97 Ac.; SWPPP General VPDES Permit Registration Statement =1.80 Ac. Please reconcile.
4. Recommend a second CE at Dickerson Road if construction access is via existing non -paved travel way, via
Dickerson Rd (visible in image, below). If existing travel way is paved, please disregard comment.
Engineering Review Comments
Page 4 of 4
Engineering review staff are available 2-4 PM on Thursdays if you wish to discuss project, comments, or design.
Plan review staff available at 434.296-5832 -0069, should you have any questions.
Process:
After approval, plans will need to be bonded. The bonding process is begun by submitting a bond estimate request
form and fee to the Department of Community Development. One of the plan reviewers will prepare estimates and
check parcel and easement information based on the approved plans. The County's Management Analyst will
prepare bond agreement forms, which will need to be completed by the owner and submitted along with cash,
certificates or sureties for the amounts specified. The agreements will need to be approved and signed by the County
Attorney and County Engineer. This may take 2-4 weeks to obtain all the correct signatures and forms.
Stormwater Management Facilities Maintenance agreements will also need to be completed and recorded. The
County's Management Analyst or other staff will prepare the forms and check for ownership and signature
information. The completed forms will need to be submitted along with court recording fees.
After bonding and agreements are complete, county staff will need to enter project information in a DEQ database
for state application processing. DEQ will review the application information based on local VSMP authority
approval. At this time, the DEQ portion of the application fees will need to be paid directly to the state. For fastest
processing, this is done electronically with the emails provided on the application. DEQ should notify applicants
with instructions on how to pay fees. When DEQ approves the application, they will issue a permit coverage letter.
This should be copied to the county.
After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants
will need to request a pre -construction conference by completing a form, and pay the remainder of the application
fee. The form identifies the contractor and responsible land disturber, and the fee remaining to be paid. This will be
checked by county staff, and upon approval, a pre -construction conference will be scheduled with the County
inspector. At the pre -construction conference, should everything proceed satisfactorily, a joint VSMP and grading
permit will be issued by the County so that work may begin.
County forms can be found on the county website forms center under engineering;
httD://www.albemarle.ori!/deDtforms.ast)?deDarttnent=cdent!wr)o
Thank you / 434.296-5832 —x3069
File: WP0201600012_LandmarkAviation Hangar VSMP-031316