19970616 Ver 1_Mitigation Information_20010417

p?pATFgPG Michael F. Easley
Governor
63 X, 7? William G. Ross, Jr., Secretary
Department of Environment and Natural Resources
Q y '+ C Kerr T. Stevens
s!r Division of Water Quality
A -
April 17, 2001
Memorandum To: Cynthia Van der W i e l
From: Todd St. John
Subject: Bare Site Stream Mitigation Proposal
Ashe County
I would like to start out by saying that this appears to be a very good stream enhancement proposal
for 3:1 credit. The approach seems to be valid for an enhancement project. The applicant indicated
that pattern will not be changed, but that a flood plain bench would be constructed to allow the stream
to access a flood plain. Also, instream structures are proposed. Such structures should be placed to
help reestablish a proper profile. As such, dimension and profile should be adjusted and riparian
vegetation is proposed to be reestablished. The riparian area and streams are proposed to be
preserved with a conservation easement. As such, the project should qualify to obtain 3:1 credit.
Additional information should be obtained to establish these facts:
1) Width and location of the conservation easement should be shown on the site plan. We should
obtain a copy or draft copy for our files.
2) Typicals are not specific to the size of rock to be used in the structures. Rock sizes and footer
depths should be appropriate for the amount of scour predicted to occur behind the structures. I
recommend that the applicant indicate the rock sizes for evaluation.
3) The site plan indicates the potential use of rootwads, rock vanes, rock weirs and step pools.
However, the applicant is not specific as to exactly what would be used at certain locations or
why. More detail or explanation should be provided to describe what structures are anticipated at
which locations and why. Also, no typical was provided for the step pool. Rock sizes should be
specified.
4) A specific biological monitoring plan may be required. Mr. Penrose should be consulted regarding
this matter.
Also, I think we should provide specific approval language if and when a 401 WQC is issued to
ensure that the project will be built and maintained properly (below).
"The stream mitigation plan shall be built according to the approved plans before any mitigation credit
is given. If this Office determines that the stream restoration or associated riparian area has become
unstable, the stream shall be repaired or stabilized using only natural channel design techniques. Rip
rap and other hard structures may only be used as temporary repairs if required by the Division of
Land Resources or Delegated Local Program. Additionally, all repair designs must be submitted to
and receive written approval from this Office before the repair work is performed. Because the
restored stream is proposed as compensatory mitigation for stream impacts, the restored portion shall
be preserved in perpetuity through a preservation easement or some other legally binding mechanism
or agreement. The above easement or other legally binding mechanism or agreement must be in
place before any mitigation credit shall be given. Additionally, the stream physical and biological
monitoring plan shall be followed and reports shall be submitted to this Office after the first year and
every other y
North Carolina Division of Water Quality, 401 Wetlands Certification Unit,
1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address)
2321 Crabtree Blvd., Raleigh, NC 27604-2260 (location)
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Joseph H. Mickey; Jr
From: Cynthia Van Der Wiele [[e-mail]]
Sent: Wednesday, June 13, 2001 10:27 AM
To: Joseph H Mickey Jr
Subject: Bare Site
Hi Joe,
Dave Penrose reviewed the plan for the Bare Site. Everything is ok. No benthos monitoring is
required. You can go to work.
Cynthia