HomeMy WebLinkAboutWPO201300018 Review Comments Stormwater Management Plan 2013-03-29�pF A
vt�r�1Q
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 Underground Detention
Plan preparer: Collins Engineering [293 -3719]
Owner or rep.: Woodbriar Associates
Plan received date: 4 Mar 2013
Date of comments: 29 Mar 2013
Reviewer: Michelle Roberge
A. SWM (WP0201300018)
1. Please include in the title "Amendment to WP0200600066."
2. The " Stormwater Management Narrative" states that plans will not incorporate SWM quality
treatment. Please provide the treatment for Briarwood Drive and the future impervious area that is
assumed to be 20,000 sf. Please include the reduction rate calcs.
3. Please provide the sub -areas on drainage area maps to match the calculations. For example, since
20,000 sf of future impervious area is assumed, please show as a sub area so that it is clearly
documented in the plans. If the future impervious area is amended, we have a reference point to
begin with.
4. Please show the SWM easement and access easement for the detention facility. Unobstructed
access easements to the manholes and the facility shall be clearly shown.
5. Briarwood Drive has a steep slope and it is important to know the efficiency of the curb inlets (at
grade) for the 10 year storm. Please show your calculations to verify the actual flow into the
underground detention facility and to verify if additional DI are necessary upslope.
6. Please provide a 48" diameter manhole at the junction of the 15" pipe and the detention facility so
that a step ladder can be installed to the bottom of the facility. Please provide the same for the
outlet of the detention facility. Label all structures with 48" diameter manhole.
7. Please provide a 48" diameter manhole access at both sides of junction. For STR 1, the 5" low
flow orifice can easily clog up and having an additional manhole at the upstream pipe will provide
access for maintenance.
8. Please submit a written approval of any manufactured facility from the manufacturer.
9. The pipe layout of the underground detention basin is not like the pipe that is used in the program
for routing. The stormwater routing needs to provide accurate volumes. Please provide the volume
model generated either by the applicant or by the manufacturer for the routing calcs.
10. Please show the note "All excavation for underground pipe installation must comply with OSHA
Standards for Construction Industry (29 CFR Part 1926)," from the Albemarle County general
construction notes.
11. Please replace the notes on sheet 3 from "break existing ... pipe" to "saw cut at manhole or
replace to the joint."
12. Please address MS -19 per state requirements.
13. Erosion and sediment control plan is required.
Sincerely,
r&q6de__
Michelle Roberge
File: E1_rp,esc,swm,fsp_GEB _ template.doc