HomeMy WebLinkAbout20160225 Ver 1_Pre-Prospectus Meeting Summary_20160311Strickland, Bev
From: Jeff Keaton <jkeaton@wildlandseng.com>
Sent: Friday, March 11, 2016 4:35 PM
To: Tugwell, Todd SAW; Williams, Andrew E SAW; Haupt, Mac; Wilson, Travis W.
Cc: John Hutton; Shawn Wilkerson
Subject: Cane Creek Mitigation Bank Site Visit
Attachments: Cane Creek Pre -Prospectus Meeting Summary.docx
All — Here is the meeting summary for the site visit on February 25t". Please let me know if there are any questions or
comments. If there are no comments, we will move forward with the full prospectus. Thanks.
Jeff Keaton, PE I Senior Water Resources Engineer
0:919.851.9986 x103 M: 919.302.6919
Wildlands Engineering, Inc.
312 West Millbrook Road, Suite 225
Raleigh, NC 27609
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IRT Pre -Prospectus Field Meeting Summary — Cane Creek Umbrella Mitigation Bank
February 25, 2016
Meeting Attendees
Todd Tugwell/USACE
Andy Williams/USACE
Mac Haupt/NCDWR
Travis Wilson/NCWRC
John Hutton/Wildlands
Jeff Keaton/Wildlands
Jeff Keaton and John Hutton of Wildlands Engineering, Inc. (Wildlands) led the group on a tour of the
three sites that comprise the proposed Cane Creek Umbrella Mitigation Bank on February 25, 2016. The
purpose of the tour was to present the sites to a group of IRT members to get initial feedback on the
viability of the proposed bank before moving forward with the prospectus. During the tour, the group
openly discussed the condition of the stream channels on the sites and the design options they felt
would be most appropriate to provide uplift to the streams. Discussions related to each of the sites is
summarized below.
Bethel Branch
The tour began with the Bethel Branch site. The group walked UT1 first. The IRT members agreed that
restoration was the appropriate approach for this reach due to incision, erosion, and lack of instream
habitat. The group discussed the trees at the upstream end of UT1 and how many would need to be
removed to implement stream restoration on this portion of the reach. Travis stated that many of the
trees in the area were stressed and it would be OK to remove them. The group felt that restoration of
this portion of the reach would be the most beneficial approach if possible, even if some trees must be
removed. Another discussion topic for this reach was the culvert at the upstream end under Moon -
Lindley Road. The culvert makes Priority 1 restoration more difficult. John stated that the bed of the
channel could be raised somewhat which would back water up through the culvert. This will likely
require a non -encroachment agreement with DOT. John also said that building an incised channel would
be an option. This will reduce the number of trees that would need to be removed and cause less
impact on adjacent wetlands. The IRT members agreed that this approach makes sense. John also
added that a multi -stage channel could be constructed so that a bankfull bench could be constructed
within the incised channel. Todd asked if adjacent wetlands along the upper end of this reach would be
protected. John said that Wildlands would evaluate putting the conservation easement around them.
The group also discussed the potential for wetland rehabilitation and reestablishment on the floodplain
of UT1. Todd said that Wildlands should go ahead and install one or more wells in a potential wetland
zone on the floodplain so that data could be collected to establish the baseline conditions. A delineation
and JD would also need to be done in this area. Todd said that the plan for wetlands should be included
in the prospectus and mitigation plan.
The downstream end of UT1 is also in a wooded area. Travis stated that the trees in this area are also
stressed and that removing some of them for restoration would be OK.
John and Jeff also discussed the farmland conservation easement for this site which has been platted by
the Triangle Land Conservancy. This easement includes an envelope for the mitigation project,
however, it is not wide enough in some locations for Wildlands to develop an optimal stream design.
Jeff showed a drawing of the mitigation envelop overlaid with Wildlands' optimal mitigation easement.
The purpose of this drawing is to show the overlap of the conservation easement that Wildlands would
prefer and how it would need to overlap with the farmland conservation easement. A revised version of
this drawing is attached to this meeting summary. A question was raised about the width of the buffer if
the farmland easement encroached into the conservation easement. John said that his reading of the
farmland easement was that there would be no prohibited activities resulting in improved stream
quality, that cattle would continue to be allowed in the creeks, and no restoration work was required.
Additionally, no grantee reserved rights under the farmland conservation easement would limit the
effectiveness of the overlay of a mitigation conservation easement. The overlapped easements should
work fine for the mitigation project. John said that Wildlands' attorney would work with the Corps'
attorney to ensure that there would not be a problem slightly overlapping the two easements.
Wildlands would like resolution of this issue before submitting the prospectus.
The group then walked UT2 and UT3. The group agreed that restoration is the best approach for UT2.
There are side channels in the current UT2 floodplain and it appears that this reach has been relocated.
John said that the channels could be left as vernal pools. John also discussed a "regenerative" approach
to restoration where the streams are designed as braided systems across the entire floodplain. This
approach results in a very wet floodplain that Jeff said would resemble a beaver pond. The group
agreed that this was not the best approach for this site. Wildlands agreed and indicated that the stream
would be designed as a single thread Priority 1 restoration. There is a stream crossing which John said
would be an internal, culvert crossing. An internal crossing gives Wildlands more control over how the
crossing is maintained. (Note that all crossings planned for all three sites are internal culvert crossings.)
Travis discussed options of the culvert design. He said that he would prefer a bottomless culvert which
ideally would be an arch pipe. He also suggested side culverts at the floodplain elevation for additional
capacity. Jeff said that Wildlands has been designing some projects with bottomless arch culverts and
that this would be a consideration for this project. There was also a discussion about planting on UT2
which is in a wooded area. Travis said that he didn't think planting understory species would be
beneficial to the forest community which is already well established with canopy species.
UT3 is a small tributary that originates from a pond. The group thought that restoration was the
appropriate approach for the reach as long as it is jurisdictional. Much of the discussion about this reach
focused on how to deal with the pond. Three options were discussed including:
Leaving the pond as is and putting it within the conservation easement. John suggested that
wildlands would get "straight line" enhancement II credit for the length of the pond if this
approach was agreed upon. This would not require removing the dam which at this time is in
good condition. Wildlands would stabilize the outlet from the pond to the stream. The
drawback to this approach is that the owner would not have incentive to maintain the pond and
dam.
2. Wildlands could also stabilize the outlet but leave the pond out of the easement. No mitigation
credit would be given for the pond under this scenario. However, the land owner would
continue to maintain the pond.
3. The third option discussed by the group was removing the pond and restoring the stream
channel through the pond bottom. With this method, Wildlands would receive stream
restoration credit for the length of restored channel through the pond and the conservation
easement would extend to the upper end of where the pond is currently located. Todd
suggested that a good approach would be to drain the pond, remove the dam, and see how the
stream channel forms before rebuilding the channel. One reason for taking this approach is to
see where a spring might be that hydrates the pond and would be the upstream end of the
restoration reach. John said that the problem with this is that the spring might be just upstream
of the dam and that, in that case, Wildlands would not get enough stream restoration credit to
make removing the dam feasible.
No decision was made on what approach would be used for the pond area. Wildlands' said that
each scenario would be evaluated and the proposed approach would be described in the prospectus
and mitigation plan.
South Fork
The next site that the group walked was the South Fork site. This site is immediately upstream of
the Underwood Mitigation Site which is a DMS mitigation project. The group first walked UT1. Jeff
explained that the approach for most of the reach would be restoration except for the portion
upstream of the UT11B confluence and a section beginning just downstream of UT11D and ending at
UT1E. Upstream of UT11B, the approach will be enhancement II up to the existing fence line which
will be the upstream extent of the project. Enhancement II will also be the approach for the section
between UT11D and UT1E. The downstream end of the project will also be restoration. The IRT
members agreed with these approaches. Jeff explained that restoration is proposed for the lower
end of UT11B and the upper portion of the project is proposed for enhancement II because it is more
stable and less incised than the lower reach. The group walked UT1A and Jeff explained that
Wildlands proposes a mix of restoration in sections where the stream appears unstable and
enhancement II in sections where it is not incised and the banks are stable. Rather than trying to
break out the individual reaches, Jeff stated that Wildlands will propose the whole reach as
enhancement I. The IRT members agreed that that is the best way to propose credits for this reach.
The approach for UT1E is proposed as restoration for the lower half of the reach and enhancement
II for the upper half. The IRT members agreed with this approach as well.
There was some discussion about the restoration portion at the downstream end of UT1. There is a
side channel off of this reach and some other indications that the channel has been moved. A
question was asked if Wildlands would re -rout the stream through this channel. Jeff said that
Wildlands would evaluate that option and added that another way to incorporate the side channel
might be to keep it connected so that the system functions like a multi -thread channel through this
reach. No decision was made on this during the meeting but Wildlands will evaluate these options
during design. Andy said that the side channel may be jurisdictional but that any impacts would not
likely be considered to require mitigation. He said that Wildlands would just note the impacts with
the 404 application.
Another discussion that arose while walking this reach is the need to consider habitat for the
northern long-eared bat due to the woods on the sites. The Corps representatives indicated that
the Corps would make the determination if bat habitat is present but that Wildlands should consult
the U.S. Fish and Wildlife Service about the potential for bat habitat before submitting the 404
permit application. This would help expedite the process of dealing with the potential for bat
habitat.
The last reach walked on this site was UT11F. This is a small channel through a cattle pasture. Jeff
explained that Wildlands had not done an intermittent/ephemeral determination yet and did not
know where the intermittent stream might begin. He stated that Wildlands' plan is to implement an
enhancement II approach up the point where the channel becomes ephemeral and to install a BMP
above that point. Some members of the group speculated that the reach might be entirely
ephemeral and Jeff said that if that ends up being the case that a BMP would be installed lower on
the reach and no enhancement II credit would be proposed. Jeff said that this decision would be
made before submittal of the mitigation plan.
Pine Hill Rranch
The final site visited was Pine Hill Branch. Multiple members of the group indicated that they
needed to leave at mid-afternoon for another commitment. Therefore, the visit to the Pine Hill
Branch site was very brief. The only reaches the group walked were UT1E, part of the enhancement
II section of UT1, and part of the restoration section of UT1 upstream of the old dam.
The first section walked was UT1E. Jeff explained that the tributary is spring fed and that a BMP at
the upstream end might not work due to the fact that it is very possible that there is not an
ephemeral reach. Andy said that Wildlands could probably install a BMP on the northern fork at the
upstream end of the reach because it is badly eroding and incised. He said that, even if the reach is
determined to be jurisdictional, the Corps would allow a BMP due to the poor habitat value of the
existing reach. Todd added that the location seems ideal for a regenerative stormwater conveyance
(RSC). Jeff agreed and indicated that wildlands would evaluate that option.
While walking the enhancement II section of UT1, Jeff explained that Wildlands had debated
internally what the best approach for this reach would be between enhancement II and restoration
but had decided on Ell. The group members mostly agreed that either approach was not straight
forward because the stream is badly incised and has sections that are eroding. Jeff said that, while
this was true, there are also sections with stable banks and the bed form is mostly in good shape.
Jeff explained that, with an Ell approach, Wildlands would repair areas of significant and ongoing
bank erosion. Todd indicated that would help justify the Ell credit ratio because he did not think the
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cows (even though the clearly have access) are significantly impacting the reach. The group agreed
that the reach of UT1 upstream of the old dam was in need of restoration.
Mac voiced some concerns about the jurisdictional nature of some of the tributaries at the
upstream end of the project. The group did not look at those tributaries during the site walk but Jeff
indicated that intermittent/ephemeral determinations would be made prior to design of the project.
The group agreed that the other tributaries on this site would be walked during the prospectus site
visit.
Jeff mentioned that this site drains to the Holman Mill project site which is a DMS full delivery site
and that the site captures an entire watershed. The group agreed that these aspects of the project
help make the site a good mitigation project overall.