Biological assessment
INDIRECT IMPACTS-CRITICAL HABITAT
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- CUMULATIVE IMPACTS-CRITICAL HABITAT
- CONSERVATION MEASURES AND PROPOSED MEASURES TO OFFSET IMPACTS
- Selection of Relocation Sites
- Transportation to Relocation Site
- Preparation of Relocation Site
- Fish Sampling Survey Methods
- Macroinvertebrate Sampling Methods
INDIRECT IMPACTS-CRITICAL HABITATIndirect impacts to Critical Habitat for the Appalachian elktoe (Unit 6) resulting from the proposed action include possible water quality degradation from induced changes in land use in the form of residential, commercial, and to a lesser extent industrial development projects. These water quality impacts may compromise the primary constituent element of “clean” water in localized areas within the Unit 6. The other primary constituent elements of the Designated Critical Habitat within the action areas, including stable streams and presence of fish host species, are not expected to be significantly compromised by any indirect impacts associated with the proposed projects. The construction of the Cane River and South Toe River crossings is not expected to result in significant channel instability, and thus habitat degradation, over time. The design and installation of the various culvert and pipe crossings will attempt to minimize the potential for channel instability, which could ultimately affect Critical Habitat downstream of the respective crossings in the Cane, South Toe, or North Toe rivers. Likely fish host species for the Appalachian elktoe will not be eliminated from the action area as a result of project-related indirect impacts. CUMULATIVE IMPACTS-CRITICAL HABITATThe proposed actions will directly and indirectly result in adverse impacts to the Appalachian elktoe and Designated Critical Habitat. Future land-use impacts and infrastructure projects combined with the project-related projects described above have the potential to impact the “clean water” constituent element of Critical Habitat for the Appalachian elktoe (Unit 6) to the point that conservation values are compromised in localized areas. These localized areas are expected to be small and will not extend into the majority of the areas contained within Unit 6. ASSESMENT OF IMPACTS: CONCLUSIONS The proposed widening of US 19/US19E discussed in this Biological Assessment will result in adverse impacts to the Appalachian elktoe and its Designated Critical Habitat in the Cane River, South Toe River, and North Toe River watersheds. As mentioned above, the combined total estimated impacts resulting from both bridge sites to river habitat is 9,600 ft2 (892 m2) (temporary) at the South Toe River bridge, and 750 ft2 (70 m2) (700 ft2 (65 m2) temporary, 50 ft2 (5 m2) permanent) at the Cane River bridge. Appalachian elktoe individuals have been found short distances both upstream and downstream of these impact areas, thus there is a potential for direct take of a few individuals at each site. A number of measures have been proposed to reduce these impacts. There is a moderate potential for indirect impacts in the form of water quality degradation resulting from induced land development and associated increase in impervious surface area in the Cane River, South Toe River, and North Toe River watersheds occupied by the Appalachian elktoe. However, the existing level of imperviousness in the Cane River, South Toe River and North Toe River subbasins of 4.9%, 5.2% and 5.5% respectively is below the 6% threshold recommended by NCWRC (NCWRC 2002) to maintain protected aquatic species habitats. Additionally, the amount of additional development in these watersheds needed to raise the percentage of imperviousness to the 6% threshold is not likely to occur according to land-use trend analysis of the area (Earth Tech 2007). Cumulative impacts to the species and its Critical Habitat may result in localized reduction/elimination of population numbers. Further measures can be incorporated to help offset the magnitude of these impacts to the Appalachian elktoe population. The proposed widening of US 19 and US 19E from I-26 in Madison County east to Spruce Pine in Mitchell County (R-2518 and R-2519) “may affect- likely to adversely affect” the Appalachian elktoe and its Designated Critical Habitat. CONSERVATION MEASURES AND PROPOSED MEASURES TO OFFSET IMPACTSThere are a number of prudent measures that NCDOT will implement to help conserve the Appalachian elktoe and its Critical Habitat as well as to help offset impacts to this species as a result of project construction. Potential opportunities for these prudent measures have been discussed between the USFWS, NCWRC and the Project Development & Environmental Analysis Branch of NCDOT. Mussel surveys have confirmed that individual Appalachian elktoe mussels occur within the action area at the crossing of the Cane River and South Toe River. In addition, the wavy-rayed lampmussel has also been documented in these river reaches. It is anticipated that up to 10,350 ft2 (962 m2) of potentially occupied substrate will be impacted at the two bridges sites, combined. Individual mussels occurring in these footprints are unlikely to survive during the construction activities, and would thus be lost from the overall population. In order to minimize the “take” of these individuals, NCDOT is proposing to remove all individual mussels from the impact sites (as determined by NCDOT and approved by USFWS and NCWRC) and relocate them to suitable locations in the river outside of the potential impacted area (approved by USFWS and NCWRC). The Catena Group (TCG) and the NCDOT Natural Environment Unit (NEU) have successfully relocated other protected mussel species from NCDOT project impact areas in North Carolina, and TCG has relocated the Appalachian elktoe from other impact areas in the Nolichucky River subbasin (TCG 2006). The relocation plan provided below details collection methods, tagging and recapture, selection of relocation sites, handling and transportation of individuals, and monitoring protocols. The relocation plan was developed with input from the USFWS and NCWRC and requires the approval of all parties prior to implementation. Mussel surveys have confirmed that individual Appalachian elktoe mussels occur within the construction footprints of action area for both of these projects. In addition, the state Special Concern wavy-rayed lampmussel (Lampsilis fasciola) has also been documented at these sites. NCDOT is proposing to remove all individual mussels from the impact sites (as determined by NCDOT and approved by USFWS and NCWRC) and relocate them to suitable locations in the river outside of the potential impacted area (approved by USFWS and NCWRC). Freshwater mussels have often been relocated to mitigate impacts from in-stream construction activities with varying degrees of success (Dunn et al. 2000, Cope and Waller 1995). Cope and Waller (1995) revealed that mortality of relocated mussels was >70% in 30% of the relocation studies reported in the literature, with mortality exceeding 90% in some projects. Several factors can be attributed to the successful relocation of freshwater mussels. The most important stream attributes to consider include size, substrate stability, hydrology and riparian vegetation (Cope et al. 2003, Morris and Corkum 1996, DiMaio and Corkum 1995, Lewis and Riebel 1984, Strayer 1983, Vannote and Minshall 1982). Vaughn (1997) suggested that most riverine unionids are located in areas with stable substrate but with current substantial enough to keep fine silts and sand from depositing. This observation is consistent with the conditions in which mussels were found in the Nolichucky River Subbasin by TCG in June and July 2005. Relocation methods must be developed to minimize stress caused by handling and movement of the mussels (Cope et al. 2003, Cope and Waller 1995). Dunn et al. (2000) noted that the use of personnel experienced in handling mussels is crucial to ensure the proper placement of mussels back in the substrate. In addition, avoiding extreme temperatures and keeping the mussels moist are also critical considerations for a successful relocation (Dunn 1994). Minimizing the amount of aerial exposure increases the chance of survival of relocated mussels (Dunn et al. 2000). Waller et al. (1995) reported a decreasing trend of survival of relocated mussels with increased duration of exposure. Carefully planned and implemented relocation plans can lead to success. For instance, Watson (2002) reported that only three Elliptio Complex mussels out of 334 relocated in North Carolina were found dead on the two week monitoring date. The small amount of mortality observed was attributed to predation and it was surmised that this mortality did not result from stress. TCG relocated 36 individual Appalachian elktoe and 3 wavy-rayed lampmussel individuals collectively from 4 sites (1 in Cane River, 1 in South Toe River, 2 in North Toe River) in the Nolichucky River Basin with no observed mortality and 84.6% recovery after 2-months monitoring (TCG 2006).
Relocation MethodsNCDOT proposes the following plan to relocate all mussels, including the Appalachian elktoe, from the footprints and extending downstream 262 feet (80 meters) and upstream 66 feet (20 meters) of the both the Cane River and South Toe River bridge crossings described in this BA. The following methods were developed based on recommendations outlined by Dunn et al (2000), from procedures developed by the NCWRC (Watson 2002), and from experience with other freshwater mussel relocation efforts (TCG). These procedures were developed in order to relocate freshwater mussels to reduce stress and minimize the risk of injury while the species are in transit. If at any time during the relocation it is determined that these procedures are not meeting the stated objectives, then, in cooperation with the NCWRC and the USFWS, methods that are more stringent may be developed. Relocation efforts will be carried out under the supervision of NCDOT biologists. Suitable relocation sites exist within one hundred meters upstream of both bridge sites. Mussels will be salvaged from the construction footprint and moved to the suitable habitat upstream. Collection of Mussels at Impact SiteAll individual Appalachian elktoe found in the project footprints will be relocated to the relocation site approved for each relocation project. The salvage area will consist of the section of the river that will be directly disturbed by construction procedures and extend 66 feet (20 meters) upstream of the project area and 262 feet (80 meters) downstream. In addition to the Appalachian elktoe, the wavy-rayed lampmussel may also occur in the project areas. All freshwater mussels found at the impact site will be relocated to the sites chosen. It is proposed that two visual-survey sweeps of each impact site, as previously defined, be conducted to salvage freshwater mussels from the anticipated impact area(s). The type of visual method used (mask/snorkel, batiscope, SCUBA, etc.) will be determined during the salvage effort and will be based on depth, flow, visibility and temperature. A minimum of a 6-person crew will perform the relocation. Dunn et al. (2000) stressed the importance of personnel experienced with handling freshwater mussels in successful relocation projects. The relocation crew will be supervised by one lead technical specialist and all of the personnel used will be experienced with handling freshwater mussels. A review/training session will be conducted prior to beginning the relocation efforts to ensure each member of the relocation team is properly briefed and understands their respective roles in the operation. Hand collection of mussels will be performed by the surveyors, who will spread out across the river starting at the downstream end of the salvage area and proceeding upstream. Each crew member will carry a mesh dive bag in which any found mussels will be placed. After the sweep of the salvage area has been performed, collected mussels will be carried to the banks for data processing. A final preconstruction survey will be conducted at the respective salvage areas for the two bridge sites. The pre construction survey will occur one month prior to initiation of in-stream construction activities. If any mussels are found during this survey, they will be relocated to the selected relocation site, and processed as described above. Data ProcessingAll mussels will be measured (mm) and tagged and then placed in a mesh dive bag and kept submerged in a shaded portion of the river until ready for transport to the relocation site. All mussel species will be tagged on both valves. Numerous relocation projects report scrubbing mussels with burlap to remove any algae, mud, or other debris and then drying to apply tags. This creates additional stress on the mussels, and does not appear to be necessary. Tags have been successfully applied to un-cleaned, moist mussels in other areas of North Carolina (Personal observation). Mussels will be kept as moist as possible while measuring and affixing the tags to avoid unnecessary stress. The tags (Hallprint Tags) are made of polyethylene, oval in shape and approximately 0.35 in long by 0.16 in wide (9 mm by 4 mm). Each tag is colored (e.g., green) and has a unique 4-character code, which begins with a letter followed by three numbers. The tags will be applied to the mussels using Instant Krazy Glue© or another quick dry epoxy. Once the adhesive is dry, the mussels will be placed back into the appropriate mesh bag in the stream. This procedure will be repeated until all the collected mussels are tagged, measured, and ready for transport. Each individual mussel will be kept out of the water for a period less than five minutes for data recording and tagging. Transportation to Relocation SiteAfter the mussels are collected from their source area and processed, they will be transported to the selected relocation site. To minimize stress, the mussels will be transported to the relocation site in 10-gallon coolers, or other appropriate containers. Pieces of burlap or towels soaked in the stream will be placed in the coolers. The tagged mussels will then be placed on top of the damp burlap so no mussels are stacked directly on top of each other. A maximum of 50 mussels will be placed in each cooler with approximately 3 to 4 layers per cooler. Preparation of Relocation SiteMonitoring the survival of relocated mussels is a crucial component of any mussel relocation plan in order to gauge the success of the relocation as a conservation measure. Therefore, it is necessary to monitor the survival of resident mussels at the relocation site and compare their survival rates to those of the relocated mussels. After the relocated mussels are brought to the relocation site, resident mussels in the site will be collected in the following manner (the relocated mussels will be kept submerged in the river while this is being done): Square plots measuring 3.28 ft (1 m) on a side, will be placed across the downstream boundary of the relocation site. All mussels will be collected (surface visual collection) from within the square plots, measured, and tagged. Relocated and resident mussels will then be placed by hand into the substrate within the numbered plots. The number (resident and relocated) of each mussel species placed in each plot will be recorded. Density of each species within the plots will not be increased by more than three times. Cope et al. (2003) demonstrated that increasing the density of mussels 2-3 times did not adversely affect survival rates. The number of mussels placed into each plot will be dependent on the number of mussels collected at the salvage sites. This method of collecting and tagging resident mussels and placing relocated mussels into the plots will continue upstream until all plots (except for three control plots) within the grid are sampled. Three randomly selected plots will serve as controls to assess natural mortality. Resident mussels will not be disturbed in these plots. MonitoringThe relocation sites will be monitored for recovery, survival (of recovered mussels), and movement one month after all mussels have been removed from the defined salvage areas. One month after relocating the mussels, visual surveys will be conducted at each relocation site. Mussels observed at the surface will be removed from the substrate, their tag numbers recorded, and placed back into the plots from which they were taken. This initial survey will be conducted to record any mortality that could have resulted from handling of mussels. Excavation of the grid will not be performed to avoid additional stress on the mussels and to maintain substrate stability. Visual surveys will also be conducted in a 33ft x 33ft (10m x 10m) area downstream of the relocation grid to record any mussels that may have moved out of the relocation site. The relocation sites will be monitored for recovery, survival (of recovered mussels), movement, and growth for a period of 5 years. All tagged mussels recovered during the yearly monitoring surveys will be collected, measured, and returned to the plot from which it was collected. Data will be recorded as above. WATER QUALITY INDICATOR MONITORING As discussed in Section 3.3.2, fish community and benthic macroinvertebrate community monitoring are effective ways to monitor changes in water quality over a period of time. NCDOT will be monitoring these parameters at 10 locations (Table 17) along the project corridor. These studies are intended to determine if there are currently any differences in the two fauna communities above and below the project and to provide information on possible effects on the communities due to construction of the project. Baseline data has been gathered and will be compared to the data that will be collected after completion of the project. Table 17. NCDOT Fish Community and Benthic Macroinvertebrate Sample Locations.
*A subset of sites were sampled more than once in order to evaluate between year variations in the fish communities. Fish Sampling Survey Methods:The collection method for all fish community surveys with this project employs a variety of collection techniques. Riffle areas were sampled by passive seining. This technique consists of using backpack electrofishing units to shock downstream to the stationary seine. The electrofishing units were also used to sample the bank habitat in run and pool areas. All fish not collected in the seine were collected with dip nets. All fish collected were temporarily placed in 5-gallon buckets. All the fish collected were identified and released onsite. All habitat types present at the various fish collection sites (rocks, logs, undercut banks, root mats, etc.) and flow regimes (riffle, run, pool) were sampled. Macroinvertebrate Sampling MethodsBenthic macroinvertebrates were collected at all stations using the Qual 5 method developed by the NC Division of Water Quality. This method is intended to assess between-station differences in water quality in streams. The benthic communities can be compared in upstream/downstream situations or site to site comparisons in similar streams. A composite of five samples was taken at each site: 1 kick, 1 sweep, 1 leafpack, 1 rock/log wash and visual collections. All macroinvertebrate groups were collected and identified. The primary output was a taxa list, with some indication of relative abundance for each taxon. Organisms were classified as Rare (1-2 specimens), Common (3-9 specimens), or Abundant (>10 specimens). Several data-analysis summaries (metrics) can be produced from such samples to evaluate stream community conditions. These metrics are based on the idea that unstressed streams and rivers have many invertebrate taxa and are dominated by intolerant species. Conversely, polluted or otherwise stressed streams have fewer numbers of invertebrate taxa and are dominated by tolerant species. The diversity of the invertebrate fauna is evaluated using taxa richness counts; the tolerance of the stream community is evaluated using a biotic index. Total taxa, EPT (Ephemeroptera + Plecoptera + Trichoptera) taxa richness, and the Biotic Index values were compared between sites. In general, higher EPT taxa richness values and lower Biotic Index values usually indicate better stream quality. Kick Net. A kick net is an easily constructed and versatile sampling device. It consists of a double layer of flexible nylon door or window screening between two poles. The screening is reinforced with denim along the edges and has lead weights sewn into the bottom edge. The net is positioned upright on the stream bed, while the area upstream is physically disrupted. The debris and organisms in the kick net are then washed down into a sieve bucket with a US Standard No. 30 mesh (0.600 mm opening) bottom, and larger leaves and debris are removed. In very small streams, or in sandy areas lacking riffles, kicks should be taken from root masses, "snags", or bank areas. All types of benthic macroinvertebrates can be collected by this sampling device, but emphasis is placed on Ephemeroptera, Plecoptera and Trichoptera. Sweep Net. A long-handled triangular sweep net is another versatile sampling device. Three samples are taken by physically disrupting an area and then vigorously sweeping through the disturbed area. Sweeps are usually taken from bank areas, including mud banks and root masses, and macrophyte beds. Bank samples are particularly important for the collection of "edge" species, which prefer low current environments. Look for Chironomini (red chironomids), Oligochaeta, Odonata, mobile cased Trichoptera, Sialis, Crustacea, and certain Ephemeroptera. A sweep net also can be used to sample gravel riffle areas where stone-cased Trichoptera may be abundant Fine-Mesh Sampler. Since the kick and sweep nets utilize a relatively coarse mesh size, an alternate sampling technique was devised to sample the smaller invertebrates (especially the Chironomidae). The resulting sampler is known as a "chironomid-getter". A cylinder is cut from four-inch PVC pipe. Fine nitex mesh (200 microns) is placed between PVC pipefittings that are designed to screw together. The exact dimensions are not critical, but the cylinder should fit inside another container, usually a one-quart plastic container. This device can be used in a variety of ways. The simplest technique is to wash down rocks or logs in a large plastic tub partially filled with water. Rocks are selected which have visible growths of periphyton, Podostemum, or moss. Any large particulate material (leaves, etc.) is washed down and discarded. A single composite sample can be made from several rocks and/or logs. The material remaining in the basin is poured through the fine mesh sampler and the water allowed to drain out completely. The residue is preserved in 95% ethanol. This is accomplished by placing the fine mesh sampler into another container which is half filled with alcohol. Leaf-Pack Samples. Leaf-packs, sticks and small logs are washed down in a sieve bucket with a U.S. Standard No. 30 sieve (0.600 mm openings) bottom, and then discarded. Generally, three to four leaf packs are collected from rocks or snags in fast current areas. The best leaf packs consist of older leaves (not freshly fallen) that have begun to decay. Piles of leaves in pool areas should not be collected. Visual Search. Visual inspection of large rocks and logs (the larger, the better) often adds to the species list. Large rocks and logs are a preferred microhabitat because of their stability during floods. Always look in a number of different areas (not just riffles). Rocks and logs in pools often yield additional species, as this habitat is not well sampled by either kicks or sweeps. Physical/Chemical Parameters. Water temperature, conductivity, and dissolved oxygen were measured at each site with hand held YSI meters. 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