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imap://jolin.dorney %40dwq.denr. [e-mail]:143/fe...
Subject: Re: Regarding Swansboro Isolated Wetland Issues
Froin: Ken Pohlig <[e-mail]>
Date: Mon, 05 Apr 2004 15:54:46 -0400
To: John Dorney <[e-mail]>
CC: Kim Colson <[e-mail]>, Cecil Madden <[e-mail]>, Noelle
Lutheran <[e-mail]>, Edward Schwartzman <[e-mail]>,
Tom Steffens <[e-mail]>
This is fine with me. I'll put it on my calendar unless I here otherwise. Just let
me know where I need to meet you Monday morning at 7 am (here in Raleigh... Archdail
Building I assume).
Ken Pohlig
Construction Grants & Loans Section
[phone]
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John Dorney wrote:
okay just talked to noelle and we tentatively set a date for field visit for monday
april 19th starting at 10 am on site. can everyone else (or most of everyone
else!) make that date? noelle will coordinate WiRO staff attendance. if we cannot
make the 19th, then it will be mid to late may before noelle and i are available.
please advise. if we have a majority, then i'll call the consultant to get them
there too. we'll have a vehicle leaving from raleigh that morning but will
probably need to leave around 7 am to get there on time. thankx
Ken Pohlig wrote:
John and Kim,
Cecil Madden (my boss) asked me to send an e-mail to you both regarding the
Swansboro Isolated wetlands issues, and to let you know that I'd be happy to go
along with you all to visit the Swansboro proposed spray + storage pond site, if
you all decide to visit the site. I've already visited the site, along with
Wilmington Regional Office staff (Bruce Parris, Groundwater Section - now in the
Mooresville Reg. Office, and Jim Bushardt, WQ Section). My schedule is generally
open any day, with the exception of April 7th (when I would not be able to go).
I thought I'd take this opportunity to provide some background on the proposed
project. As you well may know, currently the Swansboro WWTP discharges into
Fosters Creek in the White Oak River Basin. They were told by the WQ Section
years ago that the entire discharge into the White Oak Basin had to be eliminated;
hence the driving force behind this totally non-discharging project. The WWTP
currently is rated at 0.3 MGD, but will be increased to 0.6 MGD. The WWTP will
use oxidation ditch technology with denitrification capability, with tertiary
filters (rotating cloth filters, already installed) with W disinfection to
generate Reclaimed Water.
The proposed site is several miles west of the Swnasboro WWTP, off Rt. 24. It is
roughly a 200+ acre tract of land purchased by the Town just for this spray
irrigation project, of which about 109 acres is useable irrigation land, after you
carve out the required buffers. (Note: The 109 spray acres supplies about 0.485
MGD of spray disposal, not the full 0.6 MGD. Therefore this is how we intend to
write the permit.] Two small streams dissect the site: one is classified as SA,
the other is not.
The proposed reclaimed water holding pond originally was not to be lined, but now
will be lined with a 60-mil HDPE synthetic liner. This was based mainly on our
comment to the Engineer (Leo Green of Green Engineering) about preventing seepage
on the outside berm walls. The holding pond will hold roughly 18 MG of water, and
is roughly 6 acres at a maximum water depth of 10 feet in the holding pond. There
are two isolated wetlands in question that will be completely covered by the pond
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footprint: one about 1 acre in size, and the other about 0.06 acres. The exising
ground elevation across the proposed footprint varries from about 30.x to 40'
MSL, with the proposed pond bottom being at 30' MSL. This implies obviously that
the footprint will need to be excavated and the surface prepared for the
installation of the 60 mil HDPE liner. The larger isolated wetland ground
elevation is about at 31' MSL, and the smaller one at about 32' MSL. Several
subsurface drainpipes are proposed to be placed under the liner to ensure that
groundwater hydrostatic pressure will not cause liner installation problems, in
addition to operational problems with the liner in the future.
With this current pond design, the berm walls are at a maximum of about 10 feet
tall. If the pond bottom were not placed at 30' MSL but rather the bottom were
placed at a higher elevation, then this obviously shoves up the berm walls
higher. At some point, Dam Safety will get involved (at the 15' mark) which
obviously they would like to avoid. The other problem, however, is that this land
is not flat, and in order to practically install a liner, a flat bottom is
required. Therefore, either cutting and leveling is required, or filling and
leveling is required. They obviously prefer to cut and level, and we here at CG&L
would agree with them.
There are several other isolated wetlands dotted throughout the site, which are
buffered out from the spray irrigation wetted area.
Hopes this gives you some useful background information.
Ken Pohlig
Construction Grants & Loans Section
715-6221
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