HomeMy WebLinkAboutWPO201800020 Review Comments WPO VSMP 2018-08-07COUNTY 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 title: Keswick Hall Additions and Site Improvements
Project file number: WP0201800020
Plan preparer: Timmons Group, Craig Kotarski, P.E. craig.kotarski@timmons.com
Owner or rep.: Historic Hotels of Albemarle, LLC, John Trevenen
jrevenen@keswick.com
Plan received date: 27 March 2018
Plan received date
(Revision 1):
Date of comments:
Date of comments
(Revision 1):
Reviewer:
30 July 2018
27 April 2018
03 August 2018
WW Associates, Inc.
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. The
rationale is given in the comments 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 Section 1 — Please have the owner execute the Registration Statement Certification (Item
12) and resubmit. Delete instructions for filling out the Registration Statement from the SWPPP
documents.
Revision 1 Response: Instruction pages deleted. Registration Statement Certification will be
executed prior to final approval.
Revision 1 Comment: Acknowledged. Registration Statement Item 9 — the estimated
project start date of August 1, 2018 has passed. Please adjust accordingly.
2. SWPPP Section 2 — Please provide a copy of the DEQ coverage letter when obtained.
Revision 1 Response: Letter will be provided when obtained.
Revision 1 Comment: Acknowledged.
3. SWPPP Section 7 — Please add the verbiage from subparagraphs (b) and (c) of 9VAC25-880-70
Part I(B)(4).
Revision 1 Response: Additional notes added.
Revision 1 Comment: Comment Addressed.
4. SWPPP Section 9 — Complete and sign the certification.
Revision 1 Response: Certification will be signed prior to final approval.
Revision 1 Comment: Acknowledged.
Engineering Review Comments
Page 2 of 7
5. SWPPP Section 10 —Per 9VAC25-880-70 Part K, provide the person with the authority to sign
inspection reports or to modify the stormwater pollution prevention plan.
Revision 1 Response: Information to be added once Contractor is selected.
Revision 1 Comment: Acknowledged.
B. Pollution Prevention Plan (PPP)
The PPP content requirements can be found in County Code section 17-404.
1. SWPPP Section 6 PPP meets Albemarle County Code section 17-404 requirements.
Revision 1 Response: Acknowledged.
Revision 1 Comment: Acknowledged.
C. Stormwater Management Plan (SWMP)
VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a
SWMP. This plan is disapproved, and the reasons are provided in the comments below. The
stormwater management plan content requirements can be found in County Code section 17-403.
Please provide pre- and post -development hydrographs for Water Quantity Analysis Points 1
through 5 and place on the plans.
Revision 1 Response: The stormwater calculations packet containing hydrographs were
provided to the County with the plans. In the future, an electronic copy of these calculations
will be provided to WW Associates as well.
Revision 1 Comment: Comment addressed.
2. Please provide the pre- and post -development Tc calculation worksheets for Water Quantity
Analysis Points 1 through 5 drainage areas.
Revision 1 Response: See Sheets C6.01 and C6.03 for Tc calculation values.
Revision 1 Comment: Comment not addressed. Requested worksheets not provided to
substantiate pre -developed Tc value. Please note that no Tc path shown on Sheet No. C6.01
or Tc worksheet provided to substantiate a pre -developed Tc of 30 minutes for the 1.03-acre
pre -developed drainage shed as well as for the 0.52-acre post -developed drainage shed and
thus validate the energy balance for Water Quantity Analysis Point 3. Please provide the
Tc worksheets for the pre -developed drainage areas listed on Sheet No. C6.04 for Water
Quantity Analysis Points 1 through 5. Please provide the Tc worksheets for the post -
developed drainage areas listed on Sheet No. C6.04 for Water Quantity Analysis Points 3
and 5 as these areas do not contain pond routed flows.
Please provide complete VRRM spreadsheets for Water Quality Analysis.
Revision 1 Response: The stormwater calculations packet containing VRRM spreadsheets were
provided to the County with the plans. In the future, an electronic copy of these calculations
will be provided to WW Associates as well.
Revision 1 Comment: Comment addressed.
4. Please provide 2-year and 10-year routing worksheets for SWM1 and SWM2. Please route the
100-year storm event for SWM1 and SWM2 and place the routed 100-year post -developed flow
water surface elevation on the SWM1 and SWM2 details on Sheet No. C6.03.
Revision 1 Response: Specified routing worksheets were included in the stormwater
calculations packet. 100-year post -developed flow water surface elevation for Bioretention
Facilities added to Sheet C6.03. SWM 1 and SWM 2 are not required to handle the 100-year
storm.
Revision 1 Comment: Comment addressed.
Engineering Review Comments
Page 3 of 7
Pretreatment of runoff entering biofilters is required. Please provide.
Revision 1 Response: Gabion basket forebay walls have been provided to pretreat all runoff
entering the proposed biofilters.
Revision 1 Comment: Please provide calculations demonstrating that pretreatment cell
volume is equivalent to 15% of the treatment volume.
6. Please provide a ratio of shortest flow path to overall length calculation, provide recalculation on
the plan, and geographically show on the plan for each biofilter.
Revision 1 Response: All nyloplast riser structures elevations shall be 0.5 feet above the bottom
of the biofilter. System short-circuiting will not occur.
Revision 1 Comment: Comment addressed.
7. A nutrient credit availability letter is shown on Sheet No. C6.03. Please provide documentation
that the Oak Grove facility is within the HUC contained in SWPPP Registration Statement.
Revision 1 Response: The Oak Grove facility is located within HUC 02080204. Nonpoint
nutrient offset generation certification will be provided for your use and review.
Revision 1 Comment: Comment addressed (letter on Sheet No. C6.05).
Please note that additional comments may be generated based on response to these comments.
Revision 1 Response: Acknowledged.
Revision 1 Comment: Additional comments were generated during review of
SDP201800016 dated 6 June 2018. A copy of the 6 June 2018 letter is enclosed. Comment 1
from the SDP201800016 review was required to be addressed. Responses to the comments
were not included in the design consultants July 27, 2018 comment response letter.
Comments 1D(i), (ii), and (iii) have been properly addressed (see information on Sheet No.
C6.09). Comments la, lb, and lc were not addressed with WP0201800016. These
comments are to be addressed with this plan.
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, and the reasons are provided in the comments below. The erosion
control plan content requirements can be found in County Code section 17-402.
Please add WP0201800020 to the cover sheet of the plans and SWPPP.
Revision 1 Response: WPO number added. See Sheet C0.0.
Revision 1 Comment: Comment addressed.
2. The County's Critical Resource Plan indicates critical slopes within the limits of clearing and
grading/disturbance. Please add the critical slopes within the limits of clearing and
grading/disturbance to the plan and label whether managed or preserved.
Revision 1 Response: Critical slopes added to Existing Conditions plan sheets as well as
Grading plan sheets. Per Albemarle County GIS data, these areas within the property are
neither managed or preserved steep slopes; they are classified as "Critical Slopes". See Sheets
C2.01-C2.05 and C5.00-05.04.
Revision 1 Comment: Comment addressed.
Please add limits of clearing and grading/disturbance to the demolition sheets.
Revision 1 Response: Limits have been added to Demolition Plan. See Sheets C2.06-C2.10.
Revision 1 Comment: Comment addressed.
4. Please provide location of construction entrance (CE) on Phase I and Phase II E&SC plans. It
Engineering Review Comments
Page 4 of 7
appears that a CE was intended to be located from SR 731 Keswick Road adjacent to the "Energy
Plant Building" and the "Laundry Building."
Revision 1 Response: Construction entrances have been added. See Sheets C3.01-C3.10.
Revision 1 Comment: Comment addressed.
5. Please add a note indicating the new retaining walls 3 feet and higher require separate building
permit. If retaining walls are within managed critical slopes, the design must comply with
Albemarle County Code Chapter 18 Section 30.7.5.
Revision 1 Response: Note added. See Note 23 on Sheet C1.00.
Revision 1 Comment: Comment addressed.
6. There are numerous trees along the east and southeast side of the project within the limits of
clearing and grading that are to remain (not be demolished) but not indicated to be protected with
tree protection measures. Please provide tree protection for existing trees to remain. Further,
trees shown as being demolished are to be removed from the Phase I and 1I Erosion and Sediment
Control Plans.
Revision 1 Response: Additional tree protection has been added and demolished trees have
been removed from E&SC Plans. See Sheets C3.01-C3.10.
Revision 1 Comment: Comment addressed.
7. Sheet No. C3.03 — SSF shown to be constructed across Club Drive approximately 150 feet south
of SR 731 Keswick Road. Is Club Drive intended to be closed? Please advise. If not, remove
SSF from across the road.
Revision 1 Response: SSF across Club Drive has been removed from Sheet C3.03.
Revision 1 Comment: Comment addressed.
Sheet No. C3.00 — The E&SC narrative section "Off Site Areas" references that some utility
connections will require offsite connections. These will need to be shown on the plans if ground
is to be disturbed to include erosion and sediment control measures.
Revision 1 Response: Note has been updated. See Sheet C3.00.
Revision 1 Comment: Comment not properly addressed. What does "significantly
impacted" mean? Either ground "offsite" is to be disturbed or not and, if so, must note that
it is subject to separate E&SC plan. Please resolve.
9. Please show stockpile locations on plan.
Revision 1 Response: Stockpile locations have been added. See Sheets C3.01-C3.05.
Revision 1 Comment: Comment addressed.
10. Please verify that cut or fill balances have a deficit of 10,000 C.Y. or less.
Revision 1 Response: Earthwork balances will not exceed 10,000 C.Y.
Revision 1 Comment: Comment addressed.
11. Please identify on the plan the contractor staging/laydown area and parking area.
Revision 1 Response: Staging/laydown area have been shown on Sheet C3.02. Parking will
occur on paved surfaces, particularly within existing parking bays as construction allows.
Revision 1 Comment: Comment addressed.
12. Silt fence in numerous locations is shown running perpendicular to the contour. Silt fence is to
be installed on contour, not across contour. Please place silt fence tangents parallel to contour or
provide other measures to contain E&S.
Revision 1 Response: Silt fence has been modified to be shown parallel with contours.
Engineering Review Comments
Page 5 of 7
Revision 1 Comment: Comment not properly addressed. On Sheet No. C3.02, from the
bend in the rubberized asphalt cart path northward approximately 130 feet, the super silt
fence is still perpendicular to contour. Please place super silt fence in tangents parallel to
the contour or provide other measures to provide perimeter containment.
13. Sheet No. C3.05 — Silt fence appears to traverse across the existing driveway to existing house/to
proposed laundry building. Please remove silt fence from across existing driveway.
Revision 1 Response: Silt fence removed from driveway. See Sheets C3.05 and C3.10.
Revision 1 Comment: Comment addressed.
14. Sheet No. C3.00 — Silt Fence Break (SFB) measure not found on Phase I and II drawings. Please
delete detail from this sheet. Also note that SFD is not an approved VE&SCH control measure
unless a variance is requested and subsequently approved by the program authority.
Revision 1 Response: SFB detail has been removed. See Sheet C3.00.
Revision 1 Comment: Comment addressed.
15. In accord with VE&SCH Standards and Specifications 3.13 Sediment Traps, the maximum height
of the sediment embankment shall be 5 feet as measured from the base of the store outlet (see
VE&SCH page III-73 Embankment Cross -Section and page III-74 plate 3.13-1). Sediment trap
ST-1 (on Sheet No. C3.02) embankment height exceeds this requirement by approximately 5 feet.
Please provide an erosion and sediment control measure that meets the VE&SCH requirements
for this drainage area. Further, this trap should be labeled as ST-2 per calculations shown on
Sheet No. C3.00.
Revision 1 Response: Sediment Trap #1 has been revised accordingly. See Sheet C3.02.
Revision 1 Comment: Comment addressed.
16. Sheet No C3.03 — a wedge drainage area to the west of the Energy Plant Building and drainage
area east of sediment trap #1 is uncontained and drains directly to Keswick Road. Please provide
erosion and sediment control measures to provide containment for this portion of the site and add
to the respective Phase II plan sheet.
Revision 1 Response: Silt fence added along Keswick Road. See Sheet C3.03.
Revision 1 Comment: Comment addressed.
17. Please add check dam detail to Sheet No. C3.00.
Revision 1 Response: Detail added. See Sheet C3.00.
Revision 1 Comment: Comment addressed.
18. Sheet No. C3.07 — no erosion and sediment controls shown between the new hotel addition and
Fairway Drive. Please provide appropriate controls for this area.
Revision 1 Response: Silt fence added here. See Sheet C3.07.
Revision 1 Comment: Comment addressed.
19. Sheet No. C3. I O/C5.09 — the parking area to the northeast of the new laundry building depicts the
427 closing on itself resulting in ponding of water. No soil type is shown on Sheet No. C3.05.
The area enclosed by the 427 contour is substantial and water will remain/stagnate until it
evaporates/infiltrates. Further, a good portion is within the new paved parking lot in front of the
building. It is recommended that drainage be relieved overland, or by an area drain with outfall.
Revision 1 Response: Soil data updated to include the limits of work on Sheet C3.05. The
proposed laundry facility has been relocated and grades adjusted accordingly.
Revision 1 Comment: Comment addressed.
Engineering Review Comments
Page 6 of 7
20. Sheet No C3.09 — The inlet and outlet of the culvert under Club Drive are to be equipped with
inlet protection and outlet protection to include outlet protection calculations for the drainage area
directed to this culvert.
Revision 1 Response: Culvert inlet protection added. See Sheet C3.09.
Revision 1 Comment: Comment addressed.
21. Sheet No. C3.08 — Please provide outlet protection calculations for storm drain structure 100.
Revision 1 Response: Outlet protection has been provided accordingly.
Revision 1 Comment: Comment partially addressed. Please provide outlet protection
riprap class and blanket thickness based on 2 x d50 of riprap specified (see VESC Standard
and Practice 3.19).
22. Sheet No. C6.04 — Please provide drainage area to culvert C3/C 1 and provide which drainage
structure will receive the existing hotel roof drainage.
Revision 1 Response: Drainage area information added to Sheet C6.06. Additional stormwater
infrastructure has been provided to collect existing hotel roof drainage.
Revision 1 Comment: Comment addressed (see Sheet No. C6.06).
23. Please demonstrate that the drainage from the new parking lot area does not exceed the existing
capacity of the existing culvert under Keswick Drive located just to the east of Club Drive.
Provide appropriate culvert hydraulic calculations for the VDOT-required storm event for a state
route.
Revision 1 Response: Energy balance and flood protection requirements are being met at
analysis point 4, prior to entering the existing culvert. A note has been provided on Sheet C5.02
calling for Contractor to clean out and maintain proper drainage through existing culvert. See
Sheet C6.04 for stormwater calculations.
Revision 1 Comment: Comment addressed.
24. Please provide closed conduit storm drain pipe and drop inlet/curb drop inlet calculations and
provide culvert calculations for the culvert under the hotel entrance from Club Drive. Provide
LD204, LD229, and LD269 worksheets (See VDOT Drainage Manual).
Revision 1 Response: Drainage computations for the closed conduit storm drain system can be
found on separate documents titled "Design Calculations & Narrative" submitted separately to
the County for review. A digital copy shall be provided for your use and review.
Revision 1 Comment: Comment addressed.
25. Please add TP tree protection symbol to the legend on E&SC Phase I and Phase II plan sheets.
Revision 1 Response: TP tree protection symbol has been added. See Sheets C3.01-C3.10.
Revision 1 Comment: Comment addressed.
The VSMP permit application and all plans may be resubmitted for approval when all comments have
been satisfactorily addressed. For re -submittals please provide 2 copies of the complete permit package
with a completed application form.
Engineering plan review staff are available from 2-4 PM on Thursdays, should you require a meeting to
discuss this review.
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
Engineering Review Comments
Page 7 of 7
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.
Please coordinate Nutrient Credit Purchase with the County's Management Analyst prior to purchase.
Evidence of purchase of required level of nutrient credits is required prior to Applicant receiving a
grading permit.
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 nutrient purchase, ideally) 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 complete the request for a pre -construction conference 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.orLy/del)tfonns.asD?dei)artment--cdenpwDo
File: WPO201800020 Keswick Hall Additions and Site Improvements 08-03-18 Revl.doc
COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902-4596
Phone (434) 296-5832 Fax (434) 972-4126
Site Plan review
Project: Keswick Hall Additions and Site Improvements — Major Site Plan Amendment
Plan preparer: Craig Kotarski, PE, Timmons Group — 608 Preston Ave, Suite 200,
Charlottesville, VA 22903 [craig.kotarskigtimmons.com ]
Owner or rep.: Historic Hotels of Albemarle, LLC; 701 Club Drive, Keswick, VA 22947
Plan received date: 4 May 2018
Date of comments: 6 June 2018
Reviewer: John Anderson
Project Coordinator: Megan Nedostup
SDP2018-00016
Required prior to Major Site Plan Amendment Approval
1. Permeable Pavers (in certain respects, several comments relate to VSMP plan and will be shared with
Applicant as follow-up to VSMP Engineering plan review comments):
a. Provide design consistent with VDEQ Design Spec. #7, 6.6, Conveyance and Overflow
6.6. Conveyance and Overflow
Permeable pavement designs should include methods to convey larger storms (e.g., 2-yr, 10-yr)
to the storm drain system_ The following is a list of methods that can be used to accomplish this:
• Place a perforated pipe horizontally near the top of the reservoir layer to pass excess flows
after water has filled the base. The placement and/or design should be such that the incoming
runoff is not captured (e_g., placing the perforations on the underside only).
• Increase the thickness of the top of the reservoir layer by as much as 6 inches (i.e., create
freeboard). The design computations used to size the reservoir layer often assume that no
freeboard is present.
• Create underground detention within the reservoir layer of the permeable pavement system.
Reservoir storage may be augmented by corrugated metal pipes, plastic or concrete arch
structures, etc.
• Route excess flows to another detention or conveyance system that is designed for the
management of extreme event flows.
• Set the storm drain inlets flush with the elevation of the permeable pavement surface to
effectively convey excess stormwater runoff past the system (typically in remote areas). The
design should also make allowances for relief of unacceptable ponding depths during larger
rainfall events.
i. Provide storm drain inlets flush with elevation of the permeable pavement.
ii. Route excess flows to another detention or conveyance system.
iii. Provide curb and gutter in parking areas and along travelways, per 18-4.12.15.g.
iv. Label curb and gutter type on site plan sheets, C4.00-4.04.
b. Ensure planting plan is consistent with VA DEQ Stormwater Design Specification No. 7.
From Spec. #7, Sec. 5 —Physical Feasibility and Design Applications:
Engineering Review Comments
Page 2 of 4
External Drainage Area. Any external drainage area contributing runoff to permeable pavement
should generally not exceed twice the surface area of the permeable pavement, and it should be
as close to l00% impervious as possible. Some field experience has shown that an upgradient
drainage area (even if it is impervious) can contribute particulates to the permeable pavement
and lead to clogging (Hirschman, et al., 2009). Therefore, careful sediment source control and/or
a pre-treatment strip or sump (e.g., stone or gravel) should be used to control sediment run-on to
the permeable pavement section-
c. Evaluate proposed tree species in parking areas (upgradient drainage) and consider replacing
species that shed pods, fronds, filaments, needles, cones, or tiny leaves that tend to blind
openings between permeable pavers.
d. Include (with VSMP 1 ): permeable paver construction installation and maintenance notes
(Spec. #7), third -party construction inspection checklist, and periodic inspection checklist:
i. Include VA DEQ Stormwater Design Specification No. 7 (Spec. #7), Section 9.3
Maintenance Inspections, in its entirety, on plans. (Link to Spec. 7:
hllp://vwrrc.vt,edu/swc/documents/2013/DEQ%20BMP%2OSpec%2ONo%207 PERME
ABLE%20PAVEMENT_Final%20Draft vl-8 03012011.pdf)
ii. Include Attached 2-p. (periodic /Annual) inspection checklist on plans. (Link to source:
htWs://www.harrisonburava.gov/sites/default/files/CommunityDevelopment/files/En ig'nee
ring/BMP%20Maint%20%26%20Insp%2OChecklists_Final _Jul, 2�pdf )
iii. Include on plans 2-p. third -party construction inspection checklist and certification
(Permeable Pavement) located at:
htWs://www.fairfaxcoiM ov/publicworks/sites/publicworks/files/assets/documents/pdf/
publications/spec-7-permeable-pavement.pdf.
Revise proposed parking aisle grade north of bioretention facility #3 (see contours 446'-452') to 5% or
less, per 18-4.12.15.c.
Ensure dumpster pad, if proposed, is shown, and meets minimum design standards at 18-4.12.19.
Provide detail for dumpster pad, if proposed, and ensure design limits storm runoff through the
dumpster enclosure to reduce potential for storm runoff contamination.
C4.00-C4.04:
4. Show managed steep slopes.
5. Label curb type. If curb is flush with sidewalks, provide labels to clarify this is the case (in addition to
spot elevations).
6. At pedestrian crossings, provide CG-12 ramps (required, as needed). Ensure walks are ADA-
compliant.
a. C4.00 —Provide pedestrian pavement markings at 6' and 10' sidewalk /travelway crossings.
b. C4.01 —Provide pedestrian pavement markings at 6' sidewalk /travelway crossings.
c. Provide pedestrian pavement markings at other sidewalk /travelway crossings.
7. Provide stop bars /pavement marking and/or stop /yield signs to establish principal and secondary
traffic movement for all intersections between internal travelways and Club Drive, and between
internal travelways and internal parking aisles.
C4.01
8. Provide wheel stops for the four (4) 18' L parking spaces fronting the 6' walk. See C4.04 for
compliant design; also ACDSM, Sec. 7.C.6.
9. Provide radii for stub turnaround for reinforced turf emergency access.
10. Specify emergency access radius at Club Drive.
11. Revise 4' walk width to 5' minimum.
12. Recommend minimum curb radius of 3'.
13. Provide tick marks that define tangent (or curve -curve) endpoints for all radii >10'.
Engineering Review Comments
Page 3 of 4
14. If proposed roof runoff connects with proposed or existing storm drain systems, show and label
connections in both plan and profile view (C4.00-C4.04; C7.00-7.03).
15. L3.40: Clarify whether planting plan proposes landscaping vegetation hardier than grass for slopes
steeper than 3:1. Example, Guest Wing, C5.01. Ref, ACDSM, Sec. 8, Grading, A.2 (p. 22 of .PDF; link:
http://www.albemarle.orgLupload/images/forms center/departments/community development/forms/design standards
manual/Albemarle County Design Standards Manual 2015-04-25 draft.pdf ).
16. C5.05-5.09: Provide top and bottom of wall (TW /BW) elevations at frequent intervals for all retaining
walls (RW).
17. If RW is proposed on managed slopes, design must meet standards at 18-30.7.5.
18. State building code requires building permits when a wall retains three (3) or more feet of unbalanced
fill. Albemarle County Building Inspections Division requires engineered design when wall is four (4)
or more feet in height, in addition to a building permit. Please submit engineered design /building
permit application, if needed.
Drainage
19. C5.00-5.04: Provide drainage design tables on plans, not only in SWM calculations booklet. Include:
structure descriptions table; spread at curb /grate inlets (4" rain); pipe design tables (design for 10-yr.
event: slope, material, diameter, length); inlet data; HGL. Additional comments possible.
20. C5.00-5.04: Show and label (with alphanumeric identifiers) all permeable paver underdrain
connections to proposed drainage system in profile view. For example: two permeable paver 6"
underdrains connect to Str. 316. Provide invert data for all permeable paver underdrains. Account for
all underdrains.
21. Str. 328 — Str. 316 profile caption does not match profile structure labels. Revise (C7.01).
22. Storm conveyance system minimum pipe diameter is 12". Ensure all pipe is minimum diameter. (pipe
# 429, 437, 509, 511, etc.)
23. Str. 512 design is problematic: 6" cleanout is inadequate access to storm pipe at 10.42' depth. Revise.
24. Show existing downstream pipe outlet from Ex. Str. 204 (C5.01).
25. Ensure storm pipes do not exceed 16% max. grade (pipe # 511).
26. C5.02: Provide alphanumeric labels to identify (permeable paver) underdrain pipe/s that outfall to
bioretention facility #3. Provide profile of this system —see item #20, above.
27. Provide table to depict /check design of pipe clearance beneath permeable pavers, wherever pipes
(other than underdrains) pass beneath pavers. List pipes, minimum clearance required to permit
permeable paver installation at proposed grade, and clearance provided.
28. Engineering relies on VDOT storm system collection (curb /gutter; R&B Std.) and conveyance (inlets
/pipes /MHs, etc.; Drainage Manual) standards. Albemarle County Design Standards Manual
(ACDSM), Sec. 6 —Drainage:
G. Drainage systems (collection and conveyance)
Drainage systems, or storm sewers, are reviewed by engineering reviewers at the county as
part of the Site Review Committee. Refer to the Zoning Ordinance section 18-32 (which
refers to a department of engineering and public works, now part of Community
Development), and the Subdivision Ordinance sections 14-311, 14417 and 14431.
A. Plans: for plan requirements please refer to the review checklist at
http://www.albemarle.orgldeptfortns.asp?department=cden,Qwvo.. 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)
Engineering Review Comments
Page 4 of 4
Also, from ACDSM, Sec. 7:
7. Streets, Alleys, Travetways, Parking, Sidewalks and Trails
Streets, Alleys, Sidewalks, Travelways and Parking are reviewed by the county engineer as
required by the Zoning and Subdivision Ordinances.
A. Design Plans, for plan requirements please refer to the review checklist, found at
httn:l/www. albemarle.oraidentforms.asn? denartment—eden awn o.
B. Traffic studies: traffic studies (typically for rezoning applications) are to be prepared
according to the VDOT Land Development Manual. For larger studies, applicants should
schedule a scoping meeting with VDOT and the county.
C. Parking lots and travelways: These are subject to county engineer approval per 18-
32.7.2.7. All design elements are expected to be to VDOT standards, including curb, gutter,
pavement, striping, etc., unless an alternative is approved.
Delete Nloplast as principal inlet, riser, and pipe material. At times, Nyloplast products may be
acceptable; for example, limited collection of residential runoff from lawns, or in biofilter design, but
overall this design proposes near -exclusive reliance on a non-VDOT/proprietary product. Nyloplast is
not equivalent to VDOT standards, and is inappropriate for this site /use, for travel /parking areas, and
appears inaccessible (for example: Str. 446 =14'; pipe 511). Revise drainage per VDOT standards and
ACDSM, above. Address Spec. #7, 6.6, Conveyance and Overflow specifications /requirements.
29. Recommend min. storm pipe slope of 0.55%. Frequent use of 0.50% minimum slope invites
installation error, storm system analysis to ensure As -built hydraulic capacity is adequate, and, in
certain cases, replacement. Ensure min. slope of 0.50% (note instance of 0.49% slope (pipe 103)).
30. SWM Facility Deed of Dedication, and SWM Facility Maintenance Agreement must be recorded.
31. Provide SWM facility easements for SWM facilities. Record SWM easements with Deed of
Dedication prior to Site Plan approval.
32. Provide permanent drainage easements for storm collection and conveyance to include all pipes
outside Public RW, from point of collection to ultimate outfall point of release. Record drainage
easements prior to Site Plan approval.
33. VSMP Plan approval is required for Site Plan approval.
Please feel free to call if any questions: 434.296-5832 —x3069
Thank you
SDP201800016-Keswick Hall Additions Site Improvements Maj_060618.doc