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COUNTY OF ALBEMARLE
Department of Community Development
401 McIntire Road, Room 227
Charlottesville, Virginia 22902 -4596
Phone (434) 296 -5832 Fax (434) 972 -4126
Project: Briarwood — Gas Station WPO
Plan preparer: Scott Collins; Collins Engineering [200 Garrett St., Suite K, Charlottesville, VA
22902, scott(abcollins -en in�g com]
Owner or rep.: Wendell Wood and Nena Harrell [ulcwww @embargmail.com]
Woodbriar Associates [P. O. Box 5548, Charlottesville, VA 22905]
Plan received date: 13 June 2014
Date of comments: 14 July, 2014
Reviewer: John Anderson
Stormwater Management Plan (WP0201400059)
1. Comment applies to WP0201400059 [site], WP0201400030 [underground storage amendment],
WP0201300072 [road plan WPO]): Furnish print or e -copy of state - issued Virginia Stormwater
Management Program VPDES (General) Permit for Briarwood development. WPO technical review
criteria depend upon General Permit status. We are in receipt of email explaining that project has VPDES
permit; based upon Jul -8 email assurance, it is assumed that technical criteria listed at 9VAC25- 870- 93/ -99
(Part II C) apply, but criteria listed at 9VAC25- 870- 62/ -92 (Part II B) may apply, depending upon permit
status. Further review and comment are contingent upon receipt of copy of VPDES GP. We have
requested information of VDEQ as well.
2. As follow -up to conversation 25 -June, revised design will include 3.0" (min) DIA low -flow orifice at low
point of 10' -DIA underground detention system. With this change, other system dimensions may change.
SCS routing results may change. Please revise design, and provide revised routing calculations. Also,
outfall control structure 1 should be modeled as an orifice with area equivalent to the circle segment shown
in detail, sheet 4, rather than as a weir.
3. Grading and proposed 48' -15" HDPE or CMP shown within VDOT RW require VDOT permit. Explain
maintenance plan for this outfall. VDOT will not maintain structure or riprap.
4. Provide specific depth, length, distance dimensions for Filterra -SWM detention system necessary to review,
inspect, and construct these interconnected structures (supplement Americast typical detail on sheet 5).
5. Note —ACCD is in receipt of correspondence dated 6 -Jun 2014 from Filterra to Collins Engineering. Letter
affirms design and is included with file.
6. Note - ACCD is in receipt of letters from Contech, dated 8 -Jul 2013 and 9 -Jun 2014, affirming designs of
underground detention systems proposed north (WP0201400030) and south (gas station) of Briarwood
Drive. Letters included with files.
7. Note - Further plan review revision request must be accompanied by a VSMP GP registration form, revised
application fee, and additional information listed on a new VSMP application (WPO Virginia Stormwater
Management Program Application.pdf). SWM/ESC application used as recently as Jun -30, 2014 has been
replaced. New application is listed at: http : / /www.albemarle.ora/dotforms .asp ?department= cdenaMMo; it's
the last in a list of .pdf files.
Please feel free to call 434- 296 -583, ext. 3069 to discuss comments, especially #1 or 7.
Erosion and Sediment Control Plan (WP0201400059 /plans dated 12- Jun -14)
1. Comment applies to WP0201400059 [commercial site], WP0201400030 [underground storage
amendment], WP0201300072 [road plan WPO]): MS -19 — please reference Briarwood Channel Adequacy
Engineering Review Comments
Page 2 of 2
Report, Nov -4, 2013, rev Jun -9, 2014 (Also, e -mail, Michelle Roberge, April 4, 2014, 11:19AM). For
portions of natural terrain that lie between outfalls of existing 24" CMP (MS -19 Cross Section #1) and
existing 18" concrete pipe (MS -19 Cross Section #3) beneath U.S. Rte. 29 and Herring Branch:
a. Photos indicate erosion down slope of pipe outfalls, an indication that receiving channels are
inadequate. The computations should reflect this, and appropriate measures should be specified to
correct the problem. The computations (roughness and velocities) appear to indicate conditions of
adequacy that do not exist.
2. Show SF / SAF along south edge of Briarwood Drive.
3. Furnish perimeter control at NW corner of site. If site is developed prior to road (ref. SUB201400066),
ESC is needed to prevent runoff at the NW corner.
4. Furnish sediment traps at low end of each diversion dike that ends at inlet (DI) of pipe beneath Briarwood
Drive. IP alone is insufficient. Jul -7 -14 site visit indicates DI of pipe beneath Briarwood Drive is elevated
well above existing grade, so runoff skirts this DI. Add note to modify existing grade at DI of pipe beneath
Briarwood Drive to ensure that runoff from site development and road construction reaches inlet without
bypassing onto paved surface of U.S. Rte. 29 (photos available).
5. Furnish IP at proposed relocated DI in the median of Rte. 29.
6. Show MU for areas to be mulched.
7. Show IP at existing inlet on the north side of Briarwood Drive, sheet 7.
8. Show crest of stone weir elevation, sheet 8 (detail), as 427'.
9. Land disturbance in VDOT RW requires VDOT permit.
10. Remove Stormwater Runoff Considerations note, sheet 6 (applies to WP0201300072).
File: WP0201400059- briarwood -gas station- 071414rev