20060385 Ver 1_Email_20060825

Green Valley South review status report
Subject: Green Valley South review status report
From: Ken Pickle <[e-mail]>
Date: Fri, 25 Aug 2006 13:07:08 -0400
To: Cyndi Karoly <[e-mail]>.
CC: Boyd Devane <[e-mail]>, Bradley Bennett <[e-mail]>,
Amanda Boone <[e-mail]>
Cyndi,
I've passed verbal comments on to Amanda Boone at Duane K. Stewart & Assoc this
morning. So far, our review comments as of this afternoon are as follows. Our
review is progressing, but is not yet complete.
MINOR CORRECTIONS - easily and quickly remedied by Amanda
- Sheet 1: add one missing leg of piping, left off inadvertently; label CB466A;
General Note 5. to be expanded to highlight the potential for an interference at
CB44, 464, and #65 with other piping.
- Sheet 5: re-label the detail called "Plunge Pool" to clarify that it is intended to
be the level spreader detail.
- Check the calcs on the drain down time for both wet ponds to be sure that the
volume from the 1" rain is drained within 2 - 5 days. This probably will require a
new assumption on the head over the orifice and a new orifice size. A new orifice
size would require minor changes at several places on the drawings.
CORRECTIONS WITH POTENTIAL IMPACT ON THE DESIGN, and consequently our approval of the
proposed stormwater control system.
- As previously communicated, we are concerned about the runoff from the properties
adjacent to the connector road. Both before development of that property and after
development of that property. Amanda is aware that we have a problem with that part
of the site.
- Similarly, the control of run-on from other parcels surrounding the project is not
well documented on the submittal documents, and we Are concerned about how that
control will be accomplished to prevent run-on.
- The actual runoff volume for the design storm is not shown in the calcs. We need
that in order to continue to evaluate the sufficiency of the wet pond designs.
our review is being guided by the design provisions of 15A NCAC 2H .1000, some of
which are:
a) .1008(e) - 1" rain, 2-5day drawdown, forebay, vegetative shelf, sediment storage
provisions.
b) .1008(c) - sized for the ultimate build-out potential, 3:1 vegetated slopes, 30'
vegetative filter.
c) .1008(f) -vegetative filter with non-erosive velocity for the 10-yr flow, 5%
slope.
Ken
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