Loading...
HomeMy WebLinkAbout20120396 Ver 1_Mitigation Plans_20120815Strickland, Bev From: Kulz, Eric Sent: Wednesday, August 15, 2012 2:33 PM To: Strickland, Bev Subject: FW: Moores Fork Stream Mitigation Project Creek, Surry County Draft Final Mitigation Plan Comment Responses and July 13, 2012 Meeting Minutes for Review /Approval Attachments: Moores Fork IRT comments_EEP responses and 7 -13 -2012 Meeting Minutes.docx Please include in 12 -0396 including the attached document Thanks! Eric W. Kulz Environmental Senior Specialist N.C. Division of Water Quality- Program Development Unit 1650 MSC Raleigh, NC 27699 -1650 Phone: (919) 807 -6476 Please note this is a ne,,N- phone number effective May 10, 2012 Fax: (919) 807 -6488 E -mail correspondence to and from this address may be subject to the North Carolina Public Records La,,N- and may be disclosed to third parties - - - -- Original Message---- - From: Home,, vood, Sue Sent: Mondav, Jule 30, 2012 3:58 PM To: Kulz, Eric Subject: FW: Moores Fork Stream Mitigation Project Creek, Surn- County Draft Final Mitigation Plan Comment Responses and Juh- 13, 2012 Meeting Minutes for Revie,,N- /Approval When 5vou said the5v hadn't addressed even-thing, ,vere you referring to this document or,,N -hat's on the portal? Why didn't I get notification that it's on the portal again. This document is an accurate summar�� of the meeting �� -e had in Asheville. TheSv need to follo,,v through with more details in the Mit. Plan. I didn't think they , ere going to put it back on the portal until after sending the agencies some preliminary- documents to see that they ,, ere on the right track. We can ask Todd tomorro,, . Sue Home-wood NC DENR Winston -Salem Regional Office Division of Water Quality- 585 Waughto,,Nn Street Winston - Salem, NC 27107 Voice: (336) 771 -4964 FAX: (336) 771 -4630 E -mail correspondence to and from this address may be subject to the North Carolina Public Records La-w and may be disclosed to third parties. - - - -- Original Message---- - From: Mcdonald, Mike Sent: Friday, Jule 27, 2012 11:29 AM To: Tug-well, Todd SAW, Kulz, Eric, Crumbley, Tyler SAW Cc: Cahill, Julie, Ellison, Michael, Melia, Gregory - Bro-, n, Wyatt, Matthews, Monte K SAW, Home-wood, Sue, Jurek, Jeff Subject: Moores Fork Stream Mitigation Project Creek, Surn- County Draft Final Mitigation Plan Comment Responses and July 13, 2012 Meeting Minutes for Revie- w/Approval Folks- Please see the attached responses /minutes to the IRT posted comments and the follo-wup meeting on July 13, 2012. Please revie-w and comment/approve as needed by COB Thursday August 2nd. On August 3rd EEP -will send out the final minutes as -well as a package of Tables, figures, and revised text sections for concurrence prior to reposting the Draft Final document to the portal. Thanks and -, e look fonvard to the successful implementation of this and many more projects! Michael McDonald Western Regional Supervisor NC Ecosystem Enhancement Program ANAYAY. nceep. net 5 Ravenscroft Dr. Asheville, NC 28801 (828)231 -7912 Mobile mailto: mike. mcdonald d ncdenr.goi E -mail correspondence to and from this address may be subject to the North Carolina Public Records La-'v and may be disclosed to third parties. Attn: IRT Review Committee and Moore's Fork Team Members Todd Tugwell -USACE Monte Matthews -USACE Eric Kulz -NCDWQ Sue Homewood -NCDWQ Travis Wilson -NCWRC Michael Ellison -EEP Marc Recktenwald -EEP Michael McDonald -EEP Greg Melia -EEP Jeff Jurek -EEP Wyatt Brown -EEP Ed Hajnos -EEP Andrew Bick — Confluence Engineering Re: Moore's Fork Final Draft Mitigation Plan Revision Comment Responses from July 13, 2012 meeting During the meeting it was discussed that in an effort to move the project forward and to avoid ongoing comment /responses the following will be presented to the IRT members before the document is reposted so general concurrence can be gained and then the final document posted. 1. Table 4a and 4b along with the additional text in Section 7 2. Table 11 Performance Standards /Success Criteria and proposed additional Project Goals 3. Revised figures depicting the reach breaks with management strategy (R /E /P) and the proposed credit ratio as well as the final Conservation Easement boundary. Revised Table 6 reflecting these. 4. Confluence Engineering will discuss the stream power /proposed cross sectional area with WRC via phone. 5. The details depicting the revised strategy for the eroding gully's (formerly proposed with level spreaders) 6. Not pertaining to this particular project but in the near future it was discussed EEP propose the use of a functional pyramid to the IRT for adoption and determination of its appropriate use (i.e. credit ratio determination etc...) The following are the revisions that have been made in the Moore's Fork Draft Final Mitigation Plan document. This document is revised and ready to be re- posted to the IRT portal with your approval. Please feel free to contact me directly if you have any questions. Todd's comments 1. Stream preservation ratios are proposed at 5:1, which appear to be high for some of the proposed streams where buffers are not mature or have been logged recently, such as much of Barn Trib. El and Ell are proposed for the Barn Tribe — Ell activities in addition to in- stream work for El and extensive buffer planting, invasive management, and cattle exclusion for Ell. A complete explanation /justification by reach that relates the existing conditions to the desired functional uplift will be added to the text and summarized in Table 4a. The description of the approach to each tributary needs to be further clarified so that each reach is addressed separately to describe the conditions, objectives, and activities proposed to correct the conditions. These descriptions should provide a justification for the credit ratios, since the ratios for several of the streams appear higher than justified by the proposed activities, with Enhancement I ratios of 1:1 and Enhancement II ratios of 1.5:1. The justification for these ratios, which should be based on the proposed ecological uplift, needs to be explicitly explained in the mitigation plan under the description for the proposed actions to be taken on the associated reach. In particular, the reaches listed below do not appear to justify the proposed credit ratio: Moore's Reach 1 is listed as El with a ratio of 1:1, yet much of the upstream portion of this reach has vegetation on both sides and during the site visit, no cattle access to this section was noted. In general, the wooded portion of this reach was in decent condition, with enhancement potential limited to providing breaks in the berm along the north side of the channel and planting /preserving a full buffer. Moore's Reach 3 is listed as E1 with a ratio of 1:1, but several long stretches of the channel do not appear to be proposed for any modification. Credit ratios are proposed based on the level of uplift expected, not so much on whether it's classified as R, El, Ell or P. Additional justification for each proposed ratio will be included in the text. Table 4a and 4b will be revised. 2. The planting plan includes Juglans nigra, which can have an allelopathic effect on surrounding vegetation. We recommend this species be removed from the planting list. This species has been removed from the planting list. 3. The design discharge for the proposed channels is substantially higher than the regional curve predicts. Justification for this was provided in the mitigation plan, which stated that "As noted in the previous section, the design cross sections will accommodate sediment storage within the channel on point bars and /or in lateral bars upstream of vane structures. This stored sediment is available for transport during large flow events, which promotes long -term stability and sediment transport equilibrium." (Section 7.3.3, Page 26) We are concerned that constructing a larger channel cross section than is appropriate for the drainage area just to make room for sediment could restrict the access of the channel to the floodplain and lead to channel instability. Also, if the source of excess sediment is not address, sediment inputs to the system will continue even once the additional cross sectional space has been filled with sediment. Please provide additional justification to address these concerns. Section 7 will be revised to include more detailed explanation /justification. 4. The plan states "For practical purposes based on available stone and log sizes, the step height was capped at 16 inches." (Section 7.3.4, Page 27) We believe that 16 -inch steps will potentially cause both aquatic passage limitations and structural instability. Please consider revising or provide more detail to explain why this is not possible. This will be revised to 12" max, or 6" max if fish passage is a concern (which it isn't for the Silage Tribe). 5. Table 11 on Page 30 identifies the proposed success criteria (performance standards) for the project. The proposed standards are much more comprehensive than what is required by the 2003 Stream Mitigation Guidelines. Many of the standards do not appear to be enforceable or able to demonstrate the proposed ecological service enhancement. Additionally, many of proposed standards are not supported by any monitoring requirement. In particular, the stated success criteria are of concern: For the riparian buffer habitat density and diversity states " <20% non - native species at year 5, based on measurements of aerial extent ", which can be interpreted to mean that up to 20% aerial coverage of an invasive species is acceptable. For the maintenance of stable channel bed and banks, the standards allows up to a 20% change in both cross sectional area and width -depth ratio in single year, which may be a substantial change, particularly on a large stream. For thermal regulations, the project is unlikely to result in a change to water temperature, so any standard for thermal regulation is likely to fail. Additionally, taking two temperature measurements over the course of 5 years is not sufficient to make a determination that the project has reduced water temperature. Table 11 has been revised to closely mimic the latest draft Corps monitoring guidance. 6. For filtration of runoff, "evidence of floating debris or fine sediment on buffer vegetation at least twice by year 5" is more a measurement of overbank occurrence than runoff. This has been removed from Table 11. 7. The use of level spreaders is proposed in the plans and is briefly discussed on page 27, but no explanation is provided to demonstrate the need or benefit of these structures. See additional comments by NCDWQ. Level spreaders will be replaced with diversions (half berm, half channel), straw bale structures, and or regenerative storm water practices that will direct runoff away from gully stabilization areas. These can be permanent or temporary— we will decide during final design. 8. The site vicinity map (Figure 1) appears to show Barn Tribe as a restoration reach, while Table 4 shows Barn Tribe as an enhancement I reach. It would also be helpful if the plan set and Figure 1 would identify the proposed type of work for each reach. This has been corrected. 9. Please provide information on the potential impact (fill, drainage, etc.) to existing wetlands located adjacent to Moore's Fork. Wetlands will be protected by fencing during construction. Minor impacts (less than 0.1 acre) may occur as a result of stream restoration /enhancement and if so, these impacts will be noted in the PCN. Additional wetlands will be generated in the restoration reaches where the new channel departs from the old channel. See additional comments by NCDWQ. Sue Homewood: 1. The Division will need more detailed justification for credit ratios that are proposed for the highest end of the typical ranges. The Division would like to see the proposed credit ratios called out on the plan sheets for each reach /tributary. Same as Todd's #1 comment 2. The Division requests details on whether work on Moore's Fork 2 at Station 33 +00 and MF3 at Stat 44 +00 can be done with minimal disturbance to adjacent wetlands. See response to #9 a bone. 3. The Division will need a detailed construction sequence on how work will be accomplished on the Silage Trib. The Division is concerned about efforts to restore the Silage Tribe without addressing the nutrients entering the channel from the adjacent Silage runoff. The document discusses moving the silage pits away from the stream. A construction sequence will be provided in the design plans. 4. The Division does not recommend use of a concave level spreader, and strongly recommends against the use of a level spreader across swales, draws or channels that will re- concentrate the stormwater. See response to #7 above. 5. The Division is not comfortable with 20% invasive coverage by aerial extent as a performance standard. This Performance standard has been removed. Travis Wilson: Over sizing channel dimensions to promote sediment deposition in the channel is risky and often leads to buried channel features and habitat. If appropriate, assess the potential to promote sediment deposition in the floodplain by lowering the bankfull elevation. Please see more detailed discussion in Section 7. Several success criteria are problematic: 20% variance for stability is generous and could identity instability, temperature measurements are inconclusive and unnecessary, and 20% allowance for non - native vegetation is too high specifically since removal of these species is a design objective. Table 11 Performance standards have been revised. 3. Furthermore we concur with comments provide by NCDWQ and USACE. Sincerely, Julie Cahill NCEEP Project Manager