Yadkin Project (FERC No. 2197)

Tailwater Fish and Aquatic Biota Assessment


Final Study Plan

June, 2003


Alcoa Power Generating Inc. (APGI) is the licensee for the Yadkin Hydroelectric Project.  The Yadkin Project is currently licensed by the Federal Energy Regulatory Commission (FERC) as Project No. 2197.  This license expires in 2008 and APGI must file a new license application with FERC on or before April 30, 2006 to continue operation of the Project.   

The Yadkin Project consists of four reservoirs, dams, and powerhouses (High Rock, Tuckertown, Narrows, and Falls) located on a 38-mile stretch of the Yadkin River in central North Carolina.  The Project generates electricity to support the power needs of Alcoa’s Badin Works, to support its other aluminum operations, or is sold on the open market.  

As part of the relicensing process, APGI prepared and distributed, in September 2002, an Initial Consultation Document (ICD), which provides a general overview of the Project.  Agencies, municipalities, non-governmental organizations and members of the public were given an opportunity to review the ICD and identify information and studies that are needed to address relicensing issues.   To further assist in the identification of issues and data/study needs, APGI has formed several Issue Advisory Groups (IAGs) to advise APGI on resource issues throughout the relicensing process.  IAGs will also have the opportunity to review and comment on Draft Study Plans.  This Draft Study Plan has been developed in response to comments on the ICD and through discussions with the Fish and Aquatics IAG, to provide additional necessary information for consideration in the relicensing process.


The following issues were raised during initial consultation regarding tailwater fish and aquatic biota at the Yadkin Project:  

§         Effects of Yadkin Project reservoir releases on tailwater fish, macroinvertebrates and aquatic habitat  

§         Current status of rare, threatened and endangered (RTE) aquatic species at the Yadkin Project that could be impacted by Project operations  


On March 12, 2003 the Fish and Aquatics IAG met and discussed objectives for the tailwater fish and aquatic biota study.  Over the course of those discussions the following objectives were identified for the study.  

§         Describe tailwater habitats in all four Yadkin development tailwater areas.

§         Inventory and assess the resident fish community in the Project tailwaters on a seasonal basis (spring, summer & fall) to develop baseline data that can be used to detect changes over time. Evaluate the impacts of existing Project operations on the tailwater fish community, such as impacts associated with generation schedules (generation on/off), and impacts due to the low dissolved oxygen (DO) found in the tailwaters during certain times of the year. 

§         Inventory and assess the macroinvertebrate and mussel species in the Project tailwaters on a seasonal basis to develop baseline data that can be used to detect changes in these communities over time. Evaluate impacts of existing Project operations on the tailwater macroinvertebrate community and describe tailwater habitats.

§         Search for RTE mussel species in Project tailwaters. 

§         Search for RTE fish species, including the Robust and Carolina Redhorse species, in the Project tailwaters during the spring (spawning period) and during the summer and fall fish surveys.  

Following the March 12, 2003 IAG meeting, Normandeau prepared a draft study plan for the Yadkin Project Tailwater Fish and Aquatic Biota Assessment.  This draft study plan was distributed electronically to the Fish and Aquatics IAG on April 4, 2003 for review prior to the next IAG meeting scheduled for April 9, 2003 in Badin, NC.  Comments on the Draft Tailwater Fish and Aquatic Biota Assessment at the meeting included discussions on modifying the fish sampling plan in the Project tailwaters so that sampling would occur during generation and during no generation periods to see if it effects fish movement in and out of the tailwaters.  It was also requested that more detail be provided in the study plan, including particulars on the sampling design and other parameters that will be collected during tailwater fish surveys, such as water quality sampling.  Discussions also focused on sampling in the tailwaters during low DO and normal DO periods each season.  It was requested that the extent of the low DO “plume” be determined, as well as its impacts to fish movements into and out of the tailwaters.  Other comments included determining the change in the amount and quality of habitat in the tailwaters between peaking and non-peaking operations, especially if there is stranding due to fluctuating tailwater elevations.  It was requested that the mussel searches in the tailwaters be expanded beyond the two transects proposed for each tailwater so that good mussel habitat that does not fall along a transect line would get searched.  It was also requested that the mussel searches include walking the banks on both sides of each tailrace to identify fresh mussel shells/middens.  It was agreed upon by the IAG participants that interested parties would meet during the summer, 2003 for a site visit to the four tailwaters to assist in establishing the permanent fish and mussel sampling stations (transects) proposed for each tailwater.   

A revised draft study plan was distributed to the IAG in May, 2002.  Minor comments received on the revised draft have been incorporated into this final study plan.  


The tailwater fish and aquatic biota assessment will be conducted by Normandeau Associates Inc. (NAI) with assistance from Pennington and Associates, Inc. and will entail the following:  

Tailwater Fish Sampling  

Normandeau Associates will conduct intensive electrofishing, trap netting, seine netting and gill netting in the four tailwaters of the Yadkin Project during spring, summer and fall seasons.  Spring sampling will be conducted in late April/May 2004 to document resident fish use of tailwater areas and to search for RTE redhorse species.  Summer sampling will occur in August 2003 and fall sampling will be performed in November 2003.  Permanent fish sampling stations (and electrofishing transects) will be established in each of the four Project tailwaters in June 2003 by agencies and interested participants from the Fish and Aquatics IAG.   

The primary objective during the seasonal fish sampling in each of the four tailwaters will be to capture as many fish species as possible.  This will be accomplished by intensive boat electrofishing, gill netting, seine netting and trap netting over a 3 to 4 day period in each tailwater per season.  Many fish are habitat specialists, therefore efforts will be made to sample all habitats present in the tailwaters, including deeper runs, pools, undercut banks and shallow shoals.  Other objectives will include sampling during generation on and generation off (or reduced generation – this will depend on the season and flows) in each tailwater and sampling during low DO compared to normal DO time periods each season to see if these project operations effects fish movement.   DO levels are more apt to be low and fluctuate more each day during the summer sampling period, therefore sampling in the spring period may only focus on peaking generation (no generation/generation) if daily DO fluctuations are small.   

During all tailwater fish sampling, temperature and DO profiles will be collected at selected stations in each tailrace under each operating scenario, such as during generation on, generation off (or reduced generation if higher flows) and low DO or not low DO time periods.  Normandeau also plans on fishing each tailwater during daytime and nighttime periods over the four days of sampling planned for each tailwater during each season.  Fishing at night can be very effective and at times can produce the largest catches and the most species.   

In addition to the water quality data collection during fish sampling, Normandeau has installed YSI continuous DO/temperature water quality monitors in all four tailwaters in late April 2003 that will remain in place through November 2003.  This data will also be analyzed to confirm changes in DO and temperature that will occur during each seasonal fish sampling period and to review seasonal conditions prior to sampling so that collections can be designed around daily changes in DO, temperature and flows (flow data will be provided by Yadkin).  To evaluate the longitudinal and lateral extent of DO conditions in the tailwaters, in August and September 2003, beginning at each YSI continuous tailwater monitor, temperature and DO profiles will be taken at ¼ points along transects that will be spaced ¼ mile apart (going downstream from the monitor).  Transects will be added until temperature and DO conditions at consecutive transects are mixed (this effort is included within the Yadkin Water Quality study plan).   

Fish sampling methods for each tailwater (and each season) will be similar.  The shock boat will be used to sample the shoreline (where water depth permits) and channel sections of the tailwaters traveling in a downstream direction.  The shock boat uses Smith-Root electronics and will be set to pulsed DC current, >500v, 4 amps.  Shocking runs will continue along chosen transects until two consecutive shocking runs fail to capture any new species for a given habitat (i.e. shoreline or channel habitat).  The time for each boat shocking run will be recorded on the data sheets along with the number and species of fish collected.  Total length (mm) and weight (gm) of fish captured will also be recorded on the field data sheets – a sub-sample of 50 randomly chosen individuals will be measured and weighted for abundant fish species captured.   

Gill nets will also be fished at the same time the boat shocking is being conducted.  Experimental gill nets measuring 30.5 m long and 2.4 m deep, and constructed with four 7.6 m panels with mesh sizes of 2.54 cm, 5.08 cm, 7.62 cm and 10.16 cm of stretch monofilament will be used – these are the same sized gill nets recently used in 2000 by Progress Energy to sample for fish in the Yadkin Project reservoirs.  These gill nets will be set prior to electrofishing in various locations/habitat types in the tailwater and their location (GPS), depth and habitat type will be recorded for each station.  It has been our experience that the boat shocker can be used to effectively “drive” fish into the gill nets, especially in deeper tailraces where the boat shocker may not be entirely effective.  Our intent is to keep the gill nets mobile, moving them to different locations or habitat types frequently, in an effort to capture as many species as possible during each operational scenario (gen. on/ gen. off, etc).  Some gill nets will be moved around to sample in concert with the shock boat, and others will be used to fish deeper areas that the shock boat cannot effectively fish.  Gill nets will be fished at least every 4 to 6 hours and will not be left unattended or fished overnight.   

Trap nets may also be used, but their use and number of traps deployed will depend on their success at capturing fish species not collected via the shock boat and gill net.  If it is determined that this gear type does not help capture additional fish species, at least one net will be set-up in each tailwater as a holding pen to keep alive redhorse species or other uncommon species that may need to have their identity verified by other experts.  Seine nets will also be used in all four tailwaters to try to collect smaller fish species that may be present.   

Tailwater Macroinvertebrate Sampling  

Normandeau and Pennington and Associates, Inc. will search for mussels and collect macroinvertebrates at permanent stations and transects set-up in the Project tailwaters during summer (August, 2003), fall (November, 2003), and spring (May, 2004).  These permanent macroinvertebrate stations and mussel transects in each of the four tailraces will be located in early June, 2003 by agency personnel and interested participants from the Fish and Aquatics IAG.  Once a station or transect location is picked by the IAG, its position will be pinpointed with GPS and all future macroinvertebrate sampling or mussel searches will be taken from the same locations.  

Normandeau and Pennington propose to set-up 2 transects in each of the developments tailwaters – one transect near each powerhouse and the other located downstream in the lower tailrace (to be determined in field by Normandeau and the IAG members).  Three 2 m² macroinvertebrate samples will be collected from each transect at 25%, 50% and 75% of the distance along each transect (six samples from each tailwater per each sample period).  However, these station locations will ultimately depend on the consensus from participants that attend the early June 2003 field trip to locate the stations.  Mussel searches will also be conducted along these same transect lines.  

In deep water (>4 ft), an underwater airlift will be used to collect macroinvertebrate samples (2 m² sample size) at each station along the transect line (in shoal water, a kick net will be used to collect the samples).  Macroinvertebrates collected will be preserved on-site and returned to PAI’s lab for sorting and identification of species.  Mussel searches will also be conducted each season by divers swimming along the length of each transect line (length dependent on the wetted width of each tailwater at time of sampling).  Divers will search at least one meter upstream and downstream of each transect line (2 m wide band along the entire transect), but this will greatly depend on visibility at the time of the search.  Additionally, mussel searches will done by walking along the shoreline of each tailrace looking for mussel shells and by having divers search in areas identified by participants as good mussel habitat that is not located along a transect line.  Any live RTE mussel species located during these searches will be identified, returned to where it was found (if it was removed from the water), and its location recorded with GPS.  The location of any relic mussel shells found will also be recorded and the shells collected and identified.  

During the fisheries and macroinvertebrate sampling and mussel searches planned for August 2003, the divers will also describe the habitat types found in each tailwater area.  Depending on visibility, divers will take representative U/W pictures of the habitat found along each transect line and also pictures of the chosen macroinvertebrate sampling stations.  

Carolina and Robust Redhorse Searches

 During the seasonal tailwater fish sampling, Normandeau will attempt to capture the Carolina and Robust redhorse species that are known to occupy habitat in the Pee Dee River downstream of the Falls development and the Progress Energy dams.  Normandeau will specifically target these fish in the Yadkin tailwaters during their spring spawning period in late April-early May, 2004, which is when the spring tailwater sampling begins.  Electrofishing and gill nets will be used to try to capture these fish (see methods above in Tailwater Fish Sampling).  Most of the available spawning habitat for the robust redhorse exists in the Project tailwaters.  The shoal areas at each development will be targeted for spawning redhorse species when water temperatures are between 18º C and 24º C.  The spring tailwater fish survey will begin at the Falls tailrace, and gradually (over a 2 week period) move up the river ending the spring fish sampling at the High Rock tailwater.  Any robust or Carolina redhorse captured will be identified, measured, weighted and released unharmed.  If identification is difficult, the fish will be safely held in a trap net until it can be properly identified by experts (Progress Energy personnel are willing to help with identification of these fish).  

Data Collection and Reporting Schedule  

Normandeau proposes to conduct the tailwater fish, macroinvertebrate and mussel field evaluations in each of the four Project tailwaters during spring (April/May 2004), summer (August 2003) and late fall (November 2003) sample periods.  Searches for the Carolina and robust redhorse’s will be conducted seasonally during the tailwater fish assessments. Locations of the proposed permanent fish, mussel and macroinvertebrate stations and transects will be selected in June 2003 by interested members of the Fish and Aquatics IAG.   Results of the fish, macroinvertebrate and mussel evaluations will be reported in draft and final study reports.  A draft study report for the Tailwater fish sampling will be prepared and distributed to the Fish and Aquatics IAG for review and comment by August 31, 2004, approximately three months after the completion of data collection.  IAG comments will be addressed in a final study report that will be completed by November 30, 2004.  A draft study report for the Tailwater macroinvertebrate and mussel evaluations will be prepared and distributed to the Fish and Aquatics IAG by the 3rd quarter of 2004 and after IAG comments are addressed, the final report will be distributed by the 4th quarter of 2004.  Interim results, such as results of seasonal tailwater fish sampling, and mussel searches, may be shared with the IAG as such information becomes available, prior to completion of the draft study report.