20030426 Ver 1_More Info Received_20030709 (2)

Dewberry
July 9, 2003
Mr. Todd St. John
NC Division of Water Quality
2321 Crabtree Blvd., Suite 250
Raleigh, NC 27607
Reference: City of Raleigh, North Carolina
Kyle DriveBeaverdam Creek Sewer Line
Stream Restoration Plan Revisions
Dewberry Project No. 02052
Dear Mr. St. John:
NTtANDS/4U1 GAO?II°
U6 .3
a ..
NATER QUALITY SECTION
On July 7, 2003, We spoke about the Kyle DriveBeaverdam Creek Restoration Plan. During that
conversation, you requested additional information to complete the review of the project plans. These
additional items were to provide typical riffle and pool cross-sections showing minimum bench widths,
longitudinal profiles of reference reaches as well as designed reaches, and a statement about sediment
transport. Dewberry has prepared these additions and enclosed the appropriate addendum to the
r --- r storation plan as well as 2 revision sheets for the plan-set. This additional information should provide
all items requested to complete your review of the project. The City of Raleigh would like to begin work
on this project as soon as possible. If any additional information is required, please contact me at 881-
9939 so that we can resolve any issues promptly.
Enclosed for your review is the following:
• Two (2) copies of the Stream Restoration Plan Addendum 1
• Two (2) copies of the Wetland and Stream Restoration Plan Revised Sheets - 2 drawings
If there are any questions concerning this Stream Restoration Plan, please contact us.
Sincerely,
Dewberry & Davis, Inc.
Brian M. Smith, PWS
Environmental Professional
Attachments
cc: Chris H. Brown
File Copy
PA02052.01\Permits\Kyle Drive Stream Restoration Revision Cover Letter DWQ.doc
5505 Creedmoor Road 919 881 9939
Suite 150 919 881 9923 fax
Raleigh, North Carolina 27612-6352 www.dewberry.com
Dewberry & Davis, Inc.
VETLMDS1401 GROUP City of Raleigh WETLODS1401
®ur
??03 Kyle Drive/Beaverdam Creek JUL 4 200,
NATERQUAVYSECT'ION Stream Restoration PladATERQUALITYSECTIp,
Addendum 1
Sediment Transport Assessment
The cause of this restoration effort was direct mechanical impacts to the streams and was not due to
systemic watershed alterations. It is not possible to directly know if these impact areas were stable prior to
disturbance. Since the impacts being restored were localized in nature and not from watershed changes, it
was determined that a reference stream reach downstream of each stream impact area would be
to disturbance. Since these
sizes and the
restoration design was based on the reference site dimensions; the reference sites were used as a primary
tool in determining the likely stream stability within the restoration areas. During the reference reach
investigation, the reference areas were found to be stable with no appreciable degradation or aggradation.
The strum impact area #1 is experiencing aggradation due to eroding banks fro road
crossing directly upstream of the restoration area. This aggradation is very localized in stream impact area
#1 and Xes not persist ownstream to reference reach 1. Once the roadside banks are stabilized, it
appears that stream impact area #1 should be as stable as reference reach 1.
Reference reach 2 is directly downstream of stream impact #3. Reference reach 2 is very stable with an
active connection to its floodplain. The sediment passing through stream impact area #3 is the same as
that passing through reference reach 2. However, some undercutting of the unprotected bank in stream
impact area #3 is occurring. The in-stream structures placed within stream impact area #3 will serve to
keep stream pressure off of the bank. This should eliminate any bank instability and should make the
restoration area as stable as reference reach 2.
Since the direct upstream development and any future development will need to comply with the Neuse
Buffer Rules, it is anticipated that future stormwater inputs will be appropriately buffered. The
implementation of buffer protection should ensure the long term stability of the restoration reaches as
well as the reference reaches.
Dewberry