RE_ Comments for M-0540 (NC 24, Living Shoreline)

From:Dilday, Jason L
To:Brittingham, Cathy; Rivenbark, Chris
Cc:Lane, Stephen; Sprinkle, Hannah H; Tom Steffens; Stanton, Tyler P
Subject:RE: Comments for M-0540 (NC 24, Living Shoreline)
Date:Thursday, July 7, 2022 1:17:16 PM
Attachments:image001.png
Cathy,

As for the comments that were received from WRC and DMF, DOT has the following responses.

For Design revisions requested from WRC, Chris Rivenbark had provided the following to Stephen
Lane on 6/14.

“As noted below, the long-term intention is for this area to silt in and vegetate naturally to create a
living shoreline marsh. The gaps will allow fish access until this occurs and afterwards there will still
be tidal exchange with the marsh during the high part of the tidal cycle.

Natural accretion behind the sills to eventually expand the marsh is expected and a wanted
result.
Shortening the closure sills is not an option as doing so wouldn’t allow overlap between the
sills in the deepest areas. Doing so would likely result in unwanted erosion through increased
velocities directed at the roadway embankment.
Spacing between the sills have been designed to allow hydraulic connectivity between the
marsh area and the open water outside of the sills, allowing flushing of the water during tidal
cycles to prevent stagnant water in the marsh.
Increasing spacing between the main sill and the closure sill is not recommended as doing so
would increase the hydraulic cross-sectional opening thus reducing the velocity of water flow
between the sills. Decreasing the velocity in this location could allow sediment to accumulate
between the sills which is not wanted. It is recommended to leave the spacing narrow
between the sills so that sedimentation doesn’t occur at this location, and the flushing action
can occur.”

As for DMF’s request for a 1.77:1 ratio for mitigation of the SAV impacts, DOT believes the ratio is
excessive. The nature of the project is to create a biological uplift to the system that should replace
if not enhance the current situation. The SAV found on the project site had not been previously seen
in past years and maybe ephemeral in nature. DOT would prefer to monitor site to access the true
impact and determine the appropriate mitigation ratio after monitoring has concluded. The 5-year
monitoring request has not been discussed at length, but it should not be an issue.

Let me know if you have any questions.

Jason

From: Brittingham, Cathy <[e-mail]>
Sent: Wednesday, July 6, 2022 2:40 PM
To: Rivenbark, Chris <[e-mail]>; Dilday, Jason L <[e-mail]>
Cc: Lane, Stephen <[e-mail]>; Sprinkle, Hannah H <[e-mail]>;
Tom Steffens <[e-mail]>
Subject: Comments for M-0540 (NC 24, Living Shoreline)

Hello,

As requested below, please see the attached comments received by DCM on the CAMA major
permit application.

Please let me or Stephen Lane know if you have any questions or concerns.

Sincerely,

Cathy

From: Rivenbark, Chris <[e-mail]>
Sent: Friday, June 3, 2022 1:14 PM
To: [e-mail]; Ward, Garcy <[e-mail]>; Lane, Stephen
<[e-mail]>
Cc: Dilday, Jason L <[e-mail]>; Cashin, Gordon E <[e-mail]>
Subject: Status for several projects

Good afternoon gentlemen,

We’ve been asked about a few projects and I wanted to check in with the three of you.
Minor request for R-1015 (DWR & DCM approved)
Minor request for U-5713/R-5777 A&B
Any comments received from public notices for M-0540 (NC 24, Living Shoreline)

Any updates would be greatly appreciated.

Chris Rivenbark
Environmental Coordination & Permitting-Eastern Team Lead
North Carolina Department of Transportation

919 707 6152 office
[e-mail]

1598 Mail Service Center
Raleigh, NC 27699-1598

1000 Birch Ridge Drive
Raleigh, NC 27610

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