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HomeMy WebLinkAbout20130773 Ver 1_Mitigation Plans_20131104r �� �� �3 Mitigation Plan US 19E Widening Yancey & Mitchell Counties, North Carolina T.I.P. Number R-2519B WBS No. 35609.1.1 May 6, 2013 (Revised November 4, 2013) 1.0 BASELINE INFORMATION Transportation Improvement Project (TIP) R-2519B involves improvements to existing US 19 from SR 1186 (Old US 19) on the west side of Micaville in Yancey County to multi-lane sections west of Spruce Pine in Mitchell County. The proposed construction of R-2519B involves unavoidable impacts to jurisdictional resources within USGS hydrologic unit 06010108, the Nolichucky River Sub basin. The R-2519B study area is located in the Blue Ridge physiographic province of western North Carolina. The topography in the project study area is generally characterized as rolling hills with steeply sloping, deeply cut drainage ways. Elevations in the study area range from 2,600 to 3,000 feet above mean sea level (USGS 1978, 1994). The project study area consists of existing maintained right-of-way including fill slopes, rural, residential, commercial, agricultural, and forested areas. Surrounding land uses include agricultural, residential, commercial, and forested lands. The R-2519B Natural Resources Technical Report (NRTR) dated October 2004 provides further details concerning existing roadway/project study area conditions and jurisdictional resources. The mitigation site selection and mitigation work plan sections of this plan will refer to the identification labels given the affected jurisdictional resources in that NRTR. However, the site names match the associated permit impact site number. Additional information about the Nolichucky Sub basin can also be found in the NCDWR French Broad River Basinwide Water Quality Plan dated 2011. 2.0 OBJECTIVES NCDOT proposes to provide a portion of its mitigation requirements associated with the unavoidable impacts of this project, as allowable per the Federal Mitigation Rule, 33 CFR 332.3 with on-site and in-kind mitigation while acquiring the remainder through the North Carolina Ecosystem Enhancement Program's in-lieu fee program. NCDOT has been providing mitigation for road projects for more than 20. years and has established a record of acquiring, designing, and constructing successful mitigation sites with over 225 closed out sites protected in perpetuity either through fee-simple ownership or conservation easements throughout the state. Through in-kind stream relocations, removal of in-stream structures, and the use of natural channel :/ design, NCDOT proposes to offset and mitigate for a portion of its impacts adjacent to the R-2519B corridor. These mitigation sites are located within the same USGS hydrologic unit and watershed, as well as on the same reach of channel as the associated, permitted impact where it is most likely that the mitigation will replace the lost aquatic resource functions and services incurred by both the associated impact and the project as a whole. This will be achieved by: improving floodplain functions; establishing protected riparian buffers; improving water quality within the watershed by reducing sediment, nutrient, and pollutant inputs; and increasing channel stability while reducing bank erosion. The removal of perched structures at several sites will improved channel stability as well as increase habitat connectivity through improved access and passage. Additionally, many of the sites occur on multiple sections or unnamed tributaries of the same streams (Long Branch, Brushy Creek) which will provide improvements to habitat connectivity within the South Toe-North Toe and Headwater North Toe watersheds respectively as well as within the Nolichucky Sub basin as a whole and more specifically within designated trout waters. The mitigation will be performed on ten individual sites described below on a total of 2322 linear feet of relocated or adjacent streams of the R-2519B project. 3.0 SITE SELECTION Each site was evaluated both internally as well as discussed and reviewed with regulatory personnel during concurrence meetings and field visits. Many involve either the removal of perched structures or stream channel relocations due to the road project. All sites are located either within the existing or the proposed NCDOT Right-of-Way for US 19. Site SA - Long Branch � ONE ID# 100-013 This site is located on plan sheet 12 from Station 122+00 to 124+00 Lt and involves the relocation of 148 feet of Long Branch (2D). Long Branch is a tributary of the South Toe River and has a NCDWQ Best Use Classification of C and Tr. Long Branch has an USACE Stream Quality Assessment Worksheet score of 53.5 at this location where it flows between US 19 and SR 1424, Deneen Road. Relocating this portion of Long Branch prior to construction of the South Toe Bridge will avoid impacts directly to the channel as well as result in an improved tie-in further downstream from the existing confluence. The new tie-in will prevent Long Branch from discharging directly into the existing Appalachian Elktoe habitat located in the South Toe River. Existing conditions on Long Branch include a bankfull width of 12 feet, eroding banks ranging from two to eight feet in height, beaver dams, and lack of a wooded buffer. There is currently an overhead utility line with a 30 foot easement that crosses Long Branch near the beginning ofthe relocation and runs parallel to Long Branch at this site. t Site 6 — Long Branch ONE ID# 100-014 Located on plan sheet 12 from station 125+95 to 127+17 Lt, this site involves the removal of a perched, two-barrel, six foot by six foot, reinforced concrete box culvert (RCBC) on Long Branch (2D). NCDOT will restore 144 linear feet of Long Branch through the removal of the existing RCBC and soil path. The stress of the existing structure is evident by the presence of flow behind J one of the wing walls at the inlet as well as a blowhole at the outlet that is causing channel instability and increased sedimentation through erosion. Removal of the perched structure will prevent future sedimentation issues that could be negatively impacting the existing Appalachian elktoe habitat located 400 feet downstream in the South Toe River. Long Branch has an USACE Stream Quality Assessment Worksheet score of 62.5 at this location where it flows between US 19 and SR 1424, Deneen Road. The US 19 utility plans indicate that there are no existing utility easements at this location. Site 8 — Long Branch ONE ID# 100-015 NCDOT plans to relocate a total of 449 feet of Long Branch (2D) from station 152+50 to 155+00 Rt. and 155+98 to 157+80 Lt. to avoid additional impacts to the channel due to the road widening and associated fill slopes. Long Branch has an USACE Stream Quality Assessment Worksheet score of 59 at this location. Existing conditions include a scarcely vegetated buffer on the upstream portion, adjacent fill slope and cutover buffer conditions downstream, and a perched culvert. The upstream portion has fairly stable stream conditions, but the downstream portion has eroding, collapsing, and undercut banks. Removing the perched structure, restoring more stable channel dimensions, and planting a protected wooded riparian buffer will establish a stable channel and reduce erosion and sedimentation downstream in the watershed while improving water quality and in-stream habitat throughout this reach. Utility plans show an existing overhead utility just south of Long Branch from station 152+00 to 155+00 Rt. The current buffer is affected by mowing of this utility easement. Site 9 — Long Branch ONE ID# 100-016 NCDOT will remove a perched 36 inch corrugated metal pipe and restore 40 feet of Long Branch at this site which is located on plan sheet 15 at station 179+80. Existing channel conditions include a bankfull width of five to six feet, bank heights of two to three feet, and a narrow scrubby vegetated buffer approximately 10-15 feet wide. Long Branch at this location has an USACE Stream Quality Assessment Worksheet score of 60.5. Existing adjacent conditions include an agricultural field and a cutover. The utility plans indicate that there are no existing utility easements at this location. Removal of the perched pipe and establishment of a protected, wooded, riparian buffer will improve channel stability and reduce erosion, sedimentation and nutrient input into the channel. Site 18 — Parsnip Branch ONE ID# 100-017 Due to the installation of a new 54" pipe, NCDOT plans to relocate 70 feet of Parsnip branch instead of extending the new pipe structure at this site which is located on plan sheet 18 at station 214+00 Lt. Existing channel conditions include a varying bankfull width from two to six feet, bank heights ranging from two to ten feet and an existing 54" pipe that is perched 12-18". Parsnip Branch has a sparsely vegetated buffer on one side, a grass buffer on the other, and scored 60.5 on the USACE Stream Quality Assessment Worksheet at this location. The utility plans indicate that there are no existing utilities at this location. Removing the perched structure, restoring more stable channel dimensions, reconnecting the channel with the floodplain, and planting a protected wooded riparian buffer will establish a stable reach and reduce erosion and sedimentation 0 downstream in the watershed while improving water quality and in-stream habitat throughout this reach Site 21— UT Big Crabtree Creek ONE ID# 100-018 This site involves the relocation of 396 feet of UT Crabtree Creek (lI) due to the widening of the roadway. This site is located on plan sheets 20 and 21 from station 244+10 to 247+94 Rt. Existing conditions include a very narrow buffer with a few trees on the north side due to the proximity of the existing US 19 fill slope and a narrow buffer on the southern side due to the adjacent pasture. UT Big Crabtree Creek has an USACE Stream Quality Assessment Worksheet score of 59.5 at this location. The utility plans indicate an existing overhead utility that crosses UT Big Crabtree Creek near the confluence with Big Crabtree Creek. Through the acquisition of additional right-of-way at this site; wider, protected, riparian buffer areas can be planted with native, woody species which will decrease sedimentation and nutrient inputs from adjacent land uses while improving in-stream habitat and water quality along this reach as well as downstream in the watershed. Site 25 — Fox Hollow Creek ONE ID# 061-003 Located on plan sheet 24 at station 299+30 to 300+31 Rt., this site involves the relocation of 94 feet of Fox Hollow Creek (stream 2E) due to the road widening and a new 54 inch reinforced concrete pipe at this location. Existing conditions of Fox Hollow Creek include a bankfull width of six feet, bank heights of two to four feet (some of which are unstable), a slight head cut in the channel, and a wooded buffer on both sides greater than 50 feet. The stream has an USACE Stream Quality Assessment Worksheet score of 67. No current utility easements exist that neither cross nor run adjacent to the stream at this location. The stream relocation will increase channel stability through improved channel dimensions as well as the removal of the head cut feature. Site 30 — iJT Brushy Creek ONE ID# 061-004 This site involves the relocation and restoration of 635 feet of an unnamed tributary to Brushy Creek (stream 1G) into the historic, relic channel location. It is located on plan sheet 26 at station 325+00. The existing channel currently runs parallel between US 19 and a gas station/repair shop and parking lot. The channel has a narrow, maintained, grass buffer and receives direct storm water runoff from the parking lot and road. There are several areas e�chibiting severe erosion problems. Existing channel conditions include a bankfull width of four to six feet, bank heights between one and two feet, and an USACE Stream Quality Assessment Worksheet score of 22.5. There are no existing utility easements at this location. More stable channel dimensions will reduce erosion and sedimentation while a protected, planted, riparian buffer will provide for improved in-stream habitat and water quality both along the reach and downstream within the watershed. Site 33 — UT Brushy Creek ONE ID# 061-005 This site is located on plan sheet 28 at station 346+50 Rt. and involves the relocation of 300 feet of an unnamed tributary to Brushy Creek (stream 1 G). The existing channel runs parallel to US 19 i' with a narrow, fifteen foot wide, wooded buffer on both sides of the channel. It has an existing bankfull width of six feet, two foot bank heights, and an USACE Stream Quality Assessment Worksheet score of 60.5. Adjacent land uses include agricultural fields and livestock pastures. Currently, there is an overhead transmission line that both crosses as well as runs parallel to the stream at this location. There is also an existing gas line that crosses the stream at this location. Planting a protected, riparian, buffer on the relocated channel will decrease pollutant and nutrient inputs from adjacent land uses and improve in-stream habitat and water quality along the reach and downstream in the watershed. Site 35 — UT Brushy Creek • ONE ID# 061-006 On plan sheet 29 at station 358+50, NCDOT plans to relocate 46 feet of UT Brushy Creek to establish a better alignment with the new structure. An existing 24 inch reinforced concrete pipe and a 30 inch corrugated metal pipe are being removed and replaced with a 30 inch welded steel pipe which UT Brushy Creek will flow through under US -19. The existing channel has a bankfull width of two to three feet, one foot bank heights, and an USACE Stream Quality Assessment Worksheet score of 65. There are no existing utility easements at this location. Planting a protected, wooded buffer on the relocated channel will reduce nutrient and pollutant inputs from the adjacent land uses and improve in-stream habitat and water quality along the reach and downstream in the watershed. . 4.0 SITE PROTECTION INSTRUMENT The mitigation areas are within the NCDOT Right-of-Way for the project. They will be managed to prohibit all use inconsistent with their use as mitigation properties, including any activity that would materially alter the biological integrity or functional and educational value of the sites, consistent with the mitigation plan. The sites will be placed on the NCDOT-Natural Environment Section (NES) Mitigation GeoDatabase. This database is provided to all NCDOT personnel as a record of mitigation sites and their attributes, including prohibited activities. NCDOT is held by virtue of the permit associated with these mitigation sites and the associated roadway impacts to protect the sites in perpetuity. 5.0 MITIGATION WORK PLAN Each mitigation site will be constructed in conjunction with the construction of the roadway project. Following the successful completion of site grading and stabilization, each site will be reforested with a mix of bare-root tree species and live stakes as described in the Streambank Reforestation Detail in Appendix A. The stream channels will be stabilized by planting live stakes on three foot centers and matting with coir fiber on the banks as necessary. In accordance with the guidance and standard procedures of NCDOT's Roadside Environmental Unit (REU), seeding and mulching will be performed on all disturbed areas within the mitigation sites for stabilization purposes. An as-built report will be submitted within 60 days of completion of the project.