20190188 Ver 2_Pre-Filing Meeting Information_20201130

TEHERILL
ENGINEERING
WE Design Your Tomorrow . . .
Subject:
Participants:
Raleigh
Transportation
Planning
Bridge/Structural
Civil/Site
Construction Observation
Surveying
November 3, 2017
Minutes of the Interagency Hydraulic Design Review (4B) Meeting on
October 18, 2017 for W-5600, Johnston County
Team Members:
Ron Lucas, FHWA (not present)
Travis Wilson, NCWRC (not present)
Tom Steffens, USACE (present)
Chris Militscher, USEPA (not present)
Rob Ridings, DWR (present)
Gary Jordan, USFWS (not present)
Items discussed are summarized as follows:
Plan Sheet 4: No JS features impacted.
Plan Sheet 5: No JS features.
Other Attendees:
Wilmington
Surveying
Paul Atkinson, NCDOT Hydraulics
Craig Freeman, NCDOT Hydraulics
Jim Davis, Wetherill
Tommy Davis, Wetherill
Chris Rivenbark, NCDOT-EAU
Mark Staley, NCDOT-REU
John Thomas, Gannett Fleming
Chad Coggins, NCDOT-DEO
Jonathan Hefner, Wetherill
Gordon Cashin, NCDOT-EAU
Plan Sheet 6: The box culvert extension at Little Poplar Creek was discussed. Jim Davis pointed out
that the leftmost barrel (looking downstream) would convey the low flow. Question was asked
regarding how flow would be maintained to the secondary downstream channel on the left side at culvert
outlet. Jim Davis said there would need to be a"cut" through the rip rapped bank to allow flow to pass.
There was a general comment to ensure that rip rap is counted as an impact on permit drawings. There
was a comment regarding how the buffers were drafted at the inlet and outlet of the culvert. Jim Davis
said that the buffers were drawn in accordance with a DWR memorandum. It was mentioned that
Plan Sheet 7: No JS features.
Plan Sheet 8: Only JS feature is a wetland that will be impacted by rip rap pad at pipe outlet. It was
emphasized that this will be "fill in wetland".
Plan Sheet 9: It was pointed out that Stream SC (Intermittent/No Buffers) will be conveyed under SR1
by proposed 36" pipe. Stream SF is perennial but CE document stated "Not subject to buffer rules".
Jim Davis asked for clarification and was told that the CE document was correct because of stream
rating being 30.5. Discussed Stream SD (Intermittent/Buffers) that is presently conveyed under US 70
by 42" pipe that will be extended. Discussion of widened lateral ditch that "daylights" prior to entering
buffer. Resulting velocity is less than 2 fps. Rip rap protection is provided at toe of fill slope within
buffer to prevent erosion.
Plan Sheet 10: It was mentioned that there will be no impacts to Stream SE (Intermittent/No Buffers).
A question was asked regarding why two slope stake lines were shown on the plans. Jim Davis
explained that the line provided by roadway design is shown in black and the revised line by hydraulics
design is shown in red. The slope stake line shown by hydraulics will be the final construction limits
line shown in the plans and permit drawings.
Plan Sheet 11: No impacts to Stream SE (Intermittent/No Buffers) or large wetland. No JS impacts on
this sheet.
Plan Sheet 12: Discussion of existing 48" pipe that will be retained. Pipe conveys a JS stream. Jim
Davis said that the outlet velocity will be evaluated and if warranted rip rap will be placed embedded at
stream bed level at the pipe outlet. A detail will be provided.
The equalizer pipes under —SR3- at the large wetland were discussed. It was mentioned that equalizer
pipes will be installed at grade level, not buried. There will not be a headwall on equalizer pipes. The
footprint of the proposed service road across wetland was discussed. Question was asked if slopes could
be steepened to minimize impacts. This will need to be discussed with the Division.
Plan Sheet 13: Rip rap at outlet of dua148" pipes should not be shown as rip rap pads but should be
placed at stream bed level and depicted by a detaiL The note "Remove 15' +/- 48" RCP" needs to be
corrected. The subject pipe is 15" not 48". The velocity at 48" pipe outlet under —SR3- needs to be
evaluated. It was mentioned that existing pipe length is not included in stream impacts.
Plan Sheet 14: Jim Davis explained the re-routing of surface runoff due to grade constraints
caused by —Y7RPC- being in a cut. The existing cross pipe at Sta. 144+50 —L- will be retained.
A drop inlet will be installed and will intercept water which will be conveyed to a junction box placed
on the existing 36" pipe. This will allow some flow to be maintained to the wetland pocket on opposite
side of US 70.
2
Plan Sheet 15: Discussion of box culvert on Poplar Creek under US 70. The existing culvert is a 2@
10' x 6'. The inlet end will have to be extended. The outlet end will not require extension.
The leftmost barrel (looking in downstream direction) will convey low flow. The box culvert under
Swift Creek Road will be replaced due to re-alignment of the roadway. Photos of the inlet and outlet
channels at each culvert were shown.
Jim Davis discussed the proposed steepening of fill slopes on the right side of —L- just downstream of
the Swift Creek Road culvert. The slopes will be 1.5:1 with rock plating and will minimize
encroachment into the stream buffers. Question was asked if storm water would receive any treatment
prior to discharge into Poplar Creek. Jim Davis explained that proposed roadside ditches adjacent to US
70 will provide treatment.
Discussion of Stream SM (Intermittent/Buffers) at top of sheet. Will be conveyed by 72" pipe (buried
1.0') under —Y7RPA-.
Plan Sheet 16: Discussion of the proposed 42" pipe that will convey flow under —Y7RPA-. A rip
rapped ditch will be required to convey flow through Stream SM buffers.
Discussion of the existing 72" pipe under US 70 that will have to be extended at inlet end. Talked about
the existing 60" and 54"metal pipes downstream under Twin Creek Drive. Jim Davis said a pre-/post-
construction discharge analysis will be performed at this location.
Plan Sheet 17: No JS features.
Plan Sheet 18: Discussion of Stream SP (Ephemeral/Buffers). Stream is conveyed under US 70 by a
36" pipe that will be retained and supplemented with a 42" pipe. It was decided that this stream should
not be considered jurisdictional and buffered due to the low stream rating of 14.5. It was stated that
some follow-up paperwork would be required to formalize this determination.
Jim Davis questioned if the stream impacts shown in the CE document for stream SR were correct or
should the impacts be shown for Stream SN. He was told that it did not make any difference if impacts
were on Stream SR or Stream SN.
There was discussion regarding Stream SR (perenniaUbuffers) being blocked by the proposed field
slope. The drainage design will need to be adjusted to address this. The stream will have to be re-routed
adjacent to fill slope and tied back into Stream SN just downstream of the 72" pipe outlet.
Jim Davis explained that the big ditch shown at top of sheet is necessary to maintain existing flow
pattern and avoid a flow diversion into another watershed. He asked if the 72" pipe at ditch outlet would
have to be buried. Stream SN (Intermittent/Buffers) will flow into the ditch opposite —L- Sta. 201+50.
He was told that the section of ditch between junction with Stream SN and the 72" pipe would be
considered jurisdictional and treated as such. This section will have to be lined with coir fiber matting.
The 72" pipe at ditch outlet will have to be buried 1.0 foot.
Plan Sheet 19: Discussion about how Stream SN would be coming into ditch at 90 degrees.
Jim Davis suggested that the stream could be intercepted in a more gradual manner at a flatter angle. Rip
rap will be shown on both banks at the confluence location to prevent erosion.
Plan Sheet 20: No JS features
Plan Sheet 21: Stream SO (Intermittent/No Buffers) is presently conveyed under US 70 by 36" pipe.
Does not have a JS line style. Existing 36" pipe will be replaced with a 48" pipe. Pipe outlets into
wetlands. Outlet velocity will be evaluated and rip rap protection added if velocity warrants it. Stream
identifier changes to ST downstream of pipe. Discussion about whether or not stream should be
classified as jurisdictional. Chad Coggins will re-verify in field.
Plan Sheet 22: No JS features
Plan Sheet 23: Stream SQ (Intermittent/Buffers). Discussion of 36" pipe that will be retained and
extended. Existing pipe will be supplemented with 2@ 58" x 36" CSPA. The supplemental pipes will
be conveying overflow and the outlet ditch will not be considered as JS.
Discussed the proposed dual 30" pipes under SR7. Also discussed the proposed 36" pipe crossing at
Sta. 252+00 —L- and the associated channel work. It was suggested that the pipe alignment could be
straightened and channel realignment reduced or eliminated if pipe does not have to be trenchless
installation.
Plan Sheet 24: Further discussion regarding Stream SQ (Intermittent/Buffers). It is presently being
conveyed under US 70 by a 36" pipe. This pipe will be retained and supplemented with a 60" pipe. A
proposed 4' base lateral ditch, lined with rip rap, will have to pass through the stream buffers.
Plan Sheet 25: No JS features
Plan Sheet 26: No JS features
At the close of the meeting Chad Coggins suggested that it would be worthwhile to make a field visit to
re-verify some of the jurisdictional determinations and anticipated impacts.
Jim Davis, PE
Wetherill Engineering Inc
E -H E. 4!L
Er41'F IPf
559 Jones Franklin Road 4 Phone: [phone]
Suite 164 Fax: [phone]
Raleigh, North Carolina 27606 [e-mail]