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Home My WebLink About20090734 Ver 1_Year 5 Monitoring Report_20141218 Buckhorn Generating Facility Removal and Stream Restoration Monitoring (YR) Chatham County, North Carolina December 201 FINAL Submitted By: Stantec Consulting Services Inc. 801 Jones Franklin Rd, Suite 300 Raleigh, NC 27606 Table of Contents 1Introduction and Background .............................................................................................3 2Visual Assessment ..............................................................................................................3 2.1Stream ..........................................................................................................................3 2.2Vegetation ....................................................................................................................4 3Summary ............................................................................................................................5 4References ..........................................................................................................................6 Appendix A. Photos ....................................................................................................................7 Appendix B. Figures ..................................................................................................................25 Figure 1. Vicinity..........................................................................................................................27 Figure 2. Monitoring Plan View & Current Condition................................................................29 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCPage i This page intentionally left blank. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCPage ii 1INTRODUCTIONAND BACKGROUND Progress Energy Carolinas (PEC)hired Stantec Consulting Services, Inc. (Stantec) to provide engineering work related to the demolition of the Buckhorn Generating Facility and subsequent stream restoration of Buckhorn Creek. As per direction from Monte Matthews (USACE)and Eric Kulz (NCDW)on March 10, 2009, the project is tobe visually monitored for 5 years to prove stability. Monitoring consistsof visualinspections of channel and structure stability, photo points and a qualitative assessment of the survival of planted vegetation. All monitoring activities will be completed for Buckhorn Creek and the two redesigned tributaries. A brief report will be prepared and submitted to USACE and NCDW annually for 5 years following completion of the project. This report documents the fifth and final year of monitoring. 2VISUALASSESSMENT Stantec staff visited the siteon October 1, 2014to perform a visual assessment of post- construction conditions at the end of the fifthgrowing season. 2.1Stream Approximately 1575linear feet (LF) along Buckhorn Creek(Reach 1)and two unnamed tributaries(Reach 2and Reach 3) wererestored in conjunction with the of the removal of the Buckhorn Power Generating Facility. Restoration techniques included channel relocation, placement of in-stream structures, and floodplain grading. The approximately 900LF of restoration along Buckhorn Creek is stablewith only acute minor changes in banks resulting from natural adjustments(Appendix A2 Photo 14). Riffles are maintaining constructed dimensions and continue to exhibit desired substrate characteristics. The innerberm features continue to adjust to the proper dimension, but show no significant signs of degradation. Pools have maintained theirdimension and depth. The three brush layeringsutilized in the outside meander bends are maintaining protection to the banks as intended. The additional rock vane constructed in the Spring of 2011 has stabilized a section (Sta. 4+54 to Sta. 5+20) of the right bank where excessive erosion was observed in 2010 (Appendix A2 Photos 1 and 2). Stantec observed 10 beaver dams during the site assessment; twodams along Reach 1,three along Reach 2, and five along Reach 3. The first dam (BD 1) was located near Sta. 6+80 just downstream of the confluence with Reach 2, and the seconddam (BD 2) was located near Sta. 6+30 just upstream of the confluence with Reach 2(Appendix A2 Photo 6and 7). Thethird dam (BD3)was located near Sta. 1+70 just upstream of Photo Point 2, and dams (BD4 and 5) were located near Sta. 0+40 and 0+30 just upstream of Photo Point 3 (Appendix A2 Photos 8 and 9). Reach 2beaver dams were comprised of mud and planted livestakes from Reach 2, leaving a large section of Reach 2 streambanks with no vegetation.The remaining five beaver dams were located along Reach 3 from ~Sta. 1+40 to ~Sta. 3+60 (Appendix A2 Photo 10). Reach 3 dams were comprised of mostly sediment with some vegetative material and are smaller in size relative to the other dams. The vegetation, including livestakes, along Reach 3 has only minor beaver damage and should recover during the following growing season. Stantec staff was unable to remove any of the beaver dams at the time of the visual assessment. Stantec observed no beaver activityon Reach 1 upstream of the confluence with Reach 3. Buckhorn Generating Facility Removal & Stream Restoration – Monitoring YR5 December 2014 Chatham County, NCAppendix These beaver dams can severely compromise the stability of the stream, and lead to major problem areas.However, a consistent stand of riparian vegetation will maintainthegeomorphic stability of the streams. Currently the planted vegetation on-site has excellent vigor and is supported by a healthy stand of native volunteer species. Livestakes previouslydamaged by beaver foraging have regeneratedand livestakes throughout the project area are thriving. Beaver dams and foragingobserved along Reaches 1, 2, and 3 have not affected geomorphic stabilityand are unlikely to affect long-term stability. The approximately 200LF of restoration along Reach 2 is stable. The banks exhibit no signs of erosion and the bed shows no downcutting. All drop structures are holding grade as intended. Some of the livetakes damaged by beaver activity in 2012 have resprouted, but severalof the damagedlivestakes remain inundated by a beaver impoundment. A consistent standof herbaceous and woody vegetationin the surrounding area will maintainthe geomorphic stability. Currently there is no evidence of erosion along the banks. The approximately 475LF of restoration along Reach 3 is stable. The banks exhibit no signs of erosion and the bed shows no downcutting. All drop structures are holding grade as intended. The five beaver dams along this reach are mainly comprised of sediment and herbaceous vegetation. The result of the beaver activity in this area is minor damage to woody vegetation and small stands of cattails (Typha latifolia) along the beaver dams. 2.2Vegetation After final grading was completein December 2009, the riparian zone was planted with native woody species along the entire project. Bareroot trees were planted on the floodplain and adjacent slopes while livestake shrubs were planted along the streambanks. Overall,the planted vegetation onsite is doingwellwith the exception of the beaver foraging along the banksof Reach 2and 3.Desirable volunteers includingwater oak, sycamore,and eastern cottonwood are prevalent throughout the site(Appendix A2 Photo3and 13). A significant area between BD4andBD5is bare (~Sta. 0+29 -~Sta. 1+40), the planted livestakes were used by beavers to create dams along Reach 2 (Appendix A2 Photos 8 through 9). Some of the livestakes haveresprouted from initial beaver activityin 2012.Minor issues includeone bare area located along the right bank of Reach 2. This area can be seen at Photo Station 2 in Appendix A1 is due toa bedrock outcrop. This bedrock area is natural and will not be planted. The riparian buffer is greater than 100 feet in this area and this bare area will not affect water quality. Threeinvasive plant species are also present onsite. The most prevalent includes Japanese stiltgrass (Microstegium vimineum). The stiltgrass waspresent onsite before restoration, is currently present in the forest outside the disturbed areas and is also present in the watershed upstream(Appendix A2 Photos 4 and 5). Currently it is located on the northwestern half of the site. Japanese stiltgrassis difficult to eradicate since the seeds are transported by water and it is already prolific in the surrounding area. Due to the low-growing herbaceous nature of the plant it is not negatively affect the woody plant community. The invasive Asiaticdayflower (Murdannia keisak) is present along the banks of Reach 2,the downstream end of Reach 3, and two locations along the left bank of Reach 1 (~Sta. 6+00 and ~6+50).The native, yet invasive, cattail (Typha latifolia) is also present in the beaver dams and lower half of Reach 3. Theseplantscan form dense stands within the stream potentially affecting function. These species have expanded minimally during the monitoring period and will not affect the long-term success of the woody plant community.Currently these species are not affecting the stability of the streams. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix 3SUMMARY At the conclusion of the five year visual monitoring period the project has proven to be stable. Structures along all three reaches have remained intact and are functioning as designed. The structures are providing stability, grade control, and wildlife habitat within all three reaches. The project streams have experienced severalout of bank events,which indicate the streams are well connected to the floodplain. The planted vegetation within the project area has performed well and will facilitate the succession towards a climax forestedcommunity. Additionally, several volunteer woody species (oaks, sycamores, and eastern cottonwoods) have helped contribute to the successful revegetation of the project area. The invasive species listed in the report (Cattails, Japanese stiltgrass, and Asiatic dayflower) are found in small colonies and do not currently affect the stability of the stream or the viability of planted vegetation. As the vegetation in the project area matures it will likely shade out these invasive species. Beaver foraging has affected some of the planted vegetation, but the volunteer woody species will provide the quantities needed to keep the project vegetation stable. After the fifth and final year of monitoring Stantec considers the monitoring period complete as the project area streams and vegetation are stable. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix 4REFERENCES USACE 2003.US Army Corps of Engineers, Wilmington District; NC Division of Water Quality; US Environmental Protection Agency, Region IV; Natural Resource Conservation Service; and NC Wildlife Resources Commission. Stream Mitigation Guidelines. Raleigh, NC.April 2003 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix APPENDIX A. PHOTOS Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix This page intentionally left blank. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix A1. PHOTO STATIONS PhotoPoint 1-Downstream PhotoPoint 1-Upstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 2-Upstream Photo Point 2-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 3-Upstream Photo Point 3-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 4-Upstream Photo Point 4-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 5-Upstream Photo Point 5-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 6-Upstream Photo Point 6-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 7-Upstream Photo Point 7-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 8-Upstream Photo Point 8-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo Point 9-Upstream Photo Point 9-Downstream Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix A2. ADDITIONAL PHOTOS Photo 1-Bank erosionarea Right Bank(~Sta.5+00)and new rock vane Photo 2–Bank erosion area Right Bank (~Sta.5+00) and new rock vane Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 3-Eastern Cottonwood volunteers alongRight and Left Bank atlower end of Reach 1 Photo 4–Pocket Wetland and Japanese Stilt Grass extending into forest Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 5–Japanese Stilt Grass extending into forest Photo 6 –Beaver Dam 1 (~Sta.6+80) along Reach 1, immediately downstream of confluence between Reach 1 and Reach 2 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 7 –Beaver Dam 2 (~Sta.6+30)along Reach 1, immediately upstream of confluence between Reach 1 and Reach 2 Photo 8 –Beaver Dam 3(~Sta.1+70) along Reach 2 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 9 –Reach 2 livestakedamage caused by beaver foraging Photo 10 –Typical Beaver Dam found on Reach 3 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 11–Bank Scour on Left Bank (~Sta.4+10) from 2012, improvedafter removal of beaver dam Photo 12–Evidence of a bankfull event, debrisline Left Bank ofReach1 (~Sta. 7+10) Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix Photo 13–Volunteer oak and sycamore species growing along the left bank near the lower section of Reach 1 Photo 14–Minorbank slumping along the left bank of Reach 1 near Sta.2+25 Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix APPENDIX B.FIGURES Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix This page intentionally left blank. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix B.EverettJodanak rLe ¯ £ ¤ 1 Moncure SearonHriseeroir harRsv Holly Springs " 42 Figure 1. Vicinity Map Project Area Buckhorn Generating Facility Removal Railroad County boundaries US Highways NC Highways Roads Streams Lake/pond 0241Miles City Limits This page intentionally left blank. Buckhorn Generating Facility Removal & Stream Restoration –Monitoring YR5December 2014 Chatham County, NCAppendix E P A C 5 5 1 0 6 1 5 0 0 4 4 5 1 1 1 5 4 1