HomeMy WebLinkAboutWPO201600054 Correspondence 2016-10-03Frank,
I don't like disturbing the preserved slopes with pipes but don't think level spreaders will protect the
slopes from erosion either. They are surrounded with steep slopes. What do you think?
Max
From: Graham Murray [mailto:graham@collins-engineering.com]
Sent: Monday, October 03, 2016 8:28 AM
To: Max Greene <MGreene@albemarle.org>
Cc: Adam Long <adam@collins-engineering.com>
Subject: RE: Briarwood Phase 6 VSMP plans- WP0201600054
Good morning Max,
Thanks for your quick response and helping us get this plan approved before you leave.
The only way we can direct the two outfalls below the steep slopes is to extend each of the pipes about 50-75'.
These extensions would impact preserved steep slopes though. Perhaps the best way to protect the slopes is to
install level spreaders at the end of each riprap outfall where they are currently proposed. Do you agree this
revision, in conjunction with the flow restriction and legislation listed below, is the best way to handle runoff at
this site while still protecting the steep slopes in the most reasonable way possible? Please note, the development
of this area as a whole took into consideration the site's topography/steep slopes and the cluster development
helps protect the steep slopes as well.
Thanks,
Graham
From: Max Greene [mailto:MGreene@albemarle.orq]
Sent: Monday, October 03, 2016 7:55 AM
To: Graham Murray
Cc: Matthew Wentland; Frank Pohl
Subject: RE: Briarwood Phase 6 VSMP plans- WP0201600054
Graham,
I told Adam the concentrated flow from the basins should not be discharged over critical slopes. The
basins are supposed to discharge into adequate channels. Can you get the outlets below the critical
slopes? Or protect the slopes in some way?
Max
From: Graham Murray [mailto:graham@collins-engineering.com]
Sent: Tuesday, September 27, 2016 1:54 PM
To: Max Greene <MGreene@albemarle.org>
Cc: Adam Long <adam@collins-engineering.com>
Subject: Briarwood Phase 6 VSMP plans- WP0201600054
Good afternoon Max,
I spoke with Adam from our company a few minutes ago. He advised me you are ready to approve the Briarwood
Phase 6 VSMP plans once you can confirm the channel adequacy/energy balance calculations are sufficient. When
we submitted the plans we included the attached 15 page SWM calculations packet, I'm not sure if this was
delivered to you. On the last page, per VA legislation section 9 VAC 25-870-66, it states under section B.3.a, "Under
no condition shall Qdev be greater than Qpre-dev. nor shall Qdev. Be required to be less than that calculated in the
equation (Q forest x RV forest) / RV developed..." The last page of this report shows compliance with this,
therefore removing the requirement to provide channel adequacy calculations given the site's greatly reduced
flow rate. (FYI: This is the calculation Glenn used to call the Pocahontas equation because it compares post -
development flows to conditions when Pocahontas was alive.)
Since your days are unfortunately numbered, and this plan is so close to an approval, can you please review this
and respond to me as soon as possible.
Thanks for your final efforts on this project.
Graham
Graham Murray, P.E.
COLLINS ENGINEERING
www.collins-engineering.com
200 Garrett Street, Suite K
Charlottesville, VA 22902
Cell: (434) 566-3011
graham(d)collins-engineering.com