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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 1 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 4 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.