HomeMy WebLinkAboutSDP201800061 Review Comments Minor Amendment 2018-09-13COUNTY 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 title:
ACSA Admin & Ops Center —Minor Amendment
Project file number:
SDP201800061
Plan preparer:
Dewberry Engineers / 4805 Lake Brook Drive, Suite 200
Glen Allen, VA 23060
Owner or rep.:
Alexander J. Morrison, PE /ACSA[aorrison(abserviceauthority.org]
Plan received date:
7 Aug 2018
Date of comments:
10 Sep 2018; rev. 13 Sep 2018
Plan Coordinator:
Andy Reitelbach
Reviewers:
John Anderson
SDP201800061
1. A separate standalone VSMP permit is required. Please remove the following from the Minor Site
Plan Amendment: C0.2; portion of C2.0 related to ESC; C5.0, C5.1, C6.2, C6.3.
2. Recommend revise title of Minor Site Plan Amendment to include `SDP201800061, Minor Site
Plan Amendment' and to delete `100% submission.' (Engineering recommendation only).
3. Title VSMP Plan: `Albemarle County Service Authority Operation Center Expansion Parking Lot
Expansion, VSMP /WP02018-XXXXX.' Note: once WPO# assigned, will provide # for final
VSMP Plan title sheet revision.
4. Ref. Albemarle County Code, Chapter 17, Sec. 17-401 thru 17-405 for VSMP Application form
and content requirements (incl. SWPPP, PPP, ESC /SWM plans + Application /fee requirements).
Link:
http://www.albemarle.or¢wload/images/Forms_Center/Departments/County Attorney/Forms/AlbemarleC
ounty_Code _Ch17 Water_Protection.pdf
5. C3.1 —Label ditch and ditchline slope on upslope side of retaining wall.
6. C3.1 — Recommend revise description of Str. 20 (in data arranged as table) to include 48" diameter.
7 C3-2 Proposed retaining wail design problematie: (Rev. 13-Sep) After further consideration of
18-30.7.5 design standards, plan review, and discussion, a combination of grade at base of wall not
to exceed 2:1 and wall height not to exceed 6' is permissible; however, revised design must
eliminate angle at top of 2:1 fill slope. Option recommendation: provide min. F wide bench, 1-2%
slope away from base of wall. ACSA to coordinate slope -grade design revision with Dewberry.
Further, Dewberry is encouraged to consider stabilization matting for existing drainage way at base
of wall /base of 2:1 slope that will likely be in proposed fill section, and susceptible to erosion.
a. Proposed design must meet each applicable standard listed at 18-30.7.5.a.1-3, b.l-4;
please call if any questions.
b. Eliminate proposed 2:1 slope at base of wall, an impeFmissible appreaeb to limiti"g
height to (3- . (Rev. 13-Sep) Comment withdrawn.
e. Provide stepped walls,, max. ht. —6', with 3' separation between walls-.
d. Consider constructability /possible need for off -site temporary construction easement.
e. Proposed design (w/ 2:1 slope at toe, to be eliminated) requires 6' horizontal space; 4.5'
is available between face of wall and property line.
f. Show property line (accurate scale) in profile view.
Engineering Review Comments
Page 2 of 2
listed a4 18 30.7.5 while still pr-evidifig 18 paF44fig spaees. Reviewer- is linawafe Of any
C4.0
8. Revise STM 24 MH-1 label (typo) -diameter should read 60".
9. Provide Note that steps are required for MH depth > 4.0'.
10. Compare inside crown of pipe elevation, 375.75 (INV IN, STM 20), with 10-31 event elevation,
376.52. Detention pipe must be sized to contain a 10-yr event without exceeding interior elevation
(of top of pipe, at lowest point). Avoid pressurized system. Recommend examine next larger pipe
diameter.
11. STM20 - Provide ref. to weir plate detail, sheet C5.3.
12. C4.1 - Conduit flex table slope and length values for Node # 25, 30 do not match profile labels,
C4.0, C4.1. Review /revise for consistency.
13. 5_2 - Recommend detail for handrail post, since detail provided assumes handrail set in retaining
wall. Proposed handrail is not on wall, but behind wall, in fill section. Also note: handrail design
must prevent easy access to top of wall. If rail slopes down with grade behind wall, ensure design
provides suitable deterrent to trespass /prevents access to top of wall.
14. C5.3 - Show MH steps schematically in top view of weir plate MH detail, to limit conflict and
guide installation during construction.
15. C5.3 - Provide VDOT ST-1 (MH step) detail.
16. C5.3 - Provide trash rack, 4" orifice.
VSMP (preview comments): additional comments likely, once VSMP Application submitted:
17. C0.2, ESC Maintenance /Note. 2: Revise to specify paved construction entrance. Provide paved
CE detail. Ref. ACDSM /p. 8 -link:
http://www.albemarle.org/upload/images/forms center/departments/community development/forms/design s
tandards_manual/Albemarle County Design Standards _Manual _2015-04-25 draft.pdf
18. C0.2, ESC Sequence item 4 must come prior to item 3; install silt fence prior to clearing /grubbing.
19. C2.0 -Revise CE label to read PCE (Incl. PCE in ESC legend).
20. Provide schematic depicting Phase 2, once retaining wall constructed and STM25 installed. See
ESC Sequence note 6 (storm structure #25). Provide phased ESC schematic.
21. In Phase 2 ESC schematic, specify VESCH blanket stabilization for ditch behind (upslope side of)
retaining wall to limit proximate effect on adjacent property, should erosion develop in this area.
22. C5.0 - Provide paved construction entrance detail -ref. p. 8, ACDSM; also, comment 17, above.
23. C6.2 - Coordinate nutrient credit purchase with Ana Kilmer, Management Analyst, CDD, prior to
purchase. Legal must review documents prior to sale. Ms. Kilmer: 434.296-5832 -x3246
/akilmer(aalbemarle.org. (Rev. 13-Sep) ACSA has purchased credits; will work with Albemarle to
address any outstanding nutrient credit purchase document (VSMP) needs or requirements.
24. C6.2 -Provide stormwater quality /quantity narrative to outline and demonstrate compliance.
25. C6.3 -Energy balance is incomplete, and confusing. Provide RV(1-yr, pre -/Post -development)•
26. C6.3 -Provide routing for 1-year event, pre -development; provide model input /hyrdrograph.
27. Use county SWPPP template.
Link:
http://www.albemarle.orgLupload/images/forms_center/departments/CommunityDevelopment/forms/Engine
eringtand _WPO_Forms/Stormwater_Pollution _ Prevention_Plan _S WPPP_template.pdf
Thank you.
J. Anderson 434.296-5832 -0069
SDP201800061 ACSA Admin Parking 091318comment-rev.docx