Yadkin Project (FERC No. 2197)

Reservoir Fish and Aquatic Habitat Assessment

Final Study Plan

June, 2003

Background  

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.

Issues  

The following issue was raised during initial consultation regarding reservoir fisheries and aquatic habitat at the Yadkin Project:  

• Evaluate the effects of Yadkin Project reservoir operations on fish and aquatic habitat

Study Objectives  

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

• Map the existing aquatic habitat in the existing and potential drawdown zones of High Rock and Narrows reservoirs and the littoral zones of Tuckertown and Falls reservoirs for inclusion in a GIS based (ARC View) database.

• Evaluate the impacts of fluctuating water levels under existing Project operations on the existing fishery and aquatic habitats in the four impoundments.

A draft study plan for the Yadkin Reservoir Fish and Aquatic Habitat Assessment was prepared by Normandeau Associates and distributed electronically to the Fish and Aquatics IAG on April 4, 2003 for review prior to the April 9, 2003 IAG meeting held in Badin , NC .  Comments from the April 9 meeting have been incorporated into this final study plan.  Comments at the meeting included discussions on the difficulties of doing the proposed habitat assessment by boat on High Rock during low water because of the shallow water encountered, especially in the tributary arms.  Another comment was that the draft habitat study plan lacked sufficient detail on the habitat types that would be mapped and what the final report and Arc View file would contain.  Comments on the proposed mapping of significant erosion along the reservoir were also discussed at the April 9^th IAG meeting, including what constituted significant erosion and the impacts of potential erosion on affected resources.  It was agreed that those Participants that were not familiar with Normandeau Associates Santeetlah Reservoir Aquatic Habitat Study would be given a copy as an example of the type of habitat survey and the work product (Arc View) that Normandeau Associates will provide for the proposed Yadkin Reservoirs Habitat surveys.  

A revised draft study plan was distributed to the IAG in May, 2003 and IAG members and no additional comments were received.  

Methods-Habitat surveys  

The habitat mapping portion of the study will be conducted by Normandeau Associates Inc. (NAI) and will entail the following:  

• Significant aquatic habitat will be mapped in the drawdown zones of High Rock and Narrows in one foot contour intervals during the fall/early winter of 2003 after the reservoirs have been drawn down.  In order to document habitat conditions in the typical 10-15 foot drawdown zone within High Rock Reservoir, Normandeau will attempt to map habitat in High Rock with at least a 10 ft drawdown.  A drawdown greater than these may be possible to achieve for study purposes, but it is important to recognize that factors such as weather and incoming flows that are beyond the control of Yadkin can create conditions under which significant drawdowns of the two reservoirs are not possible.  At Narrows , Normandeau will attempt to map habitat to a depth of 15 ft in order to evaluate the potential resource impacts associated with increasing the annual drawdown of Narrows Reservoir, similar to that currently done at High Rock.

• At High Rock, Normandeau Associates plans to conduct the habitat survey in two parts – the first effort will focus on the shallow tributary arms when the drawdown is approximately 5 ft below full pond in late summer or early fall (depending on the bathymetry in the various coves/tributary arms).  This will enable the field crew to work mostly from a boat in the shallower areas, which would not be possible during a full 10 to 15 ft drawdown.  The second effort will occur after High Rock is drawn down at least 10 ft, and at this time the remaining habitat in the main body of the reservoir and in the deeper areas of the tributary arms will be mapped.  Field crews may also conduct the Narrows habitat survey in two trips, but this may not be necessary because the reservoir is generally deeper than High Rock and the area exposed at a 15 ft drawdown is expected to be significantly less than at High Rock. 

• Habitat will be mapped in the littoral zones of Tuckertown and Falls Reservoirs (using the same methods cited above) during the fall/early winter of 2004.  Because these two reservoirs have limited storage capability and do not have significant seasonal drawdowns, attempts will be made to coordinate and conduct these surveys when the reservoirs are down approximately 2 to 3 ft below high water (if feasible).

• Habitat surveys at all four reservoirs will be conducted using a Trimble GPS unit coupled with a laser scope, digital movie camera, laptop computer and Hydro Pro software. The laser scope will enable a crew to pinpoint and outline important habitat features to sub-meter accuracy so that habitat area can be calculated. Habitat types will include, but not be limited to stream confluences, aquatic vegetation, woody debris (natural and cut), structures (piers, docks, marinas, etc.), rock habitat – gravel, cobble, boulder and ledge, and sand/clay habitat.  Stream confluences will be filmed at drawdown to document access between the tributaries and the reservoir and any blockage will be pinpointed with the Trimble GPS. 

• Aquatic vegetation will be mostly lacking during the fall/winter period when this habitat work is planned, therefore most of the mapping of aquatic vegetation habitat types will be done during the proposed wetland and terrestrial studies during spring and summer, using a combination of stereo overflights and ground truthing. This effort will quantify the major water willow beds and other aquatic plants present.  Once this data is collected and mapped, it will be imported into the Arc View habitat data file for each reservoir. 

• Woody habitat types that will be mapped include downed trees (natural fall or cut), brush piles, stumps, standing timber and man-made fish habitat such as Christmas trees. Downed trees will be further broken down by their size and the amount of branches remaining on them, such as bare tree trunk, medium branched and heavily branched trees.  Also, trees that were cut by agencies and cabled together to provide fish habitat will be differentiated from those that fell naturally or were cut illegally. 

• Docks and piers will also be layered into the Arc View data file for each reservoir and this work (including the area of the docks in square feet) has already be completed by PB Power on High Rock using overflight pictures from a 2002 survey.

• All substrate types within the drawdown zone will be delineated and mapped, including sand/clay (or mud), gravel, cobble, boulder, ledge and rip-rap.  Substrate that does not provide good habitat, such as heavily imbedded gravel (imbedded >75%) will not be measured.  The predominant substrate type (mud or sand/clay) will not be mapped by the field crew, but will instead become the “default substrate”.  All habitat types except this category will be mapped, and all other habitat of lower value that is not mapped will fall into this category.

• All habitat data from the four reservoirs will be imported into an ARC View data file after it’s collected, so the amount of aquatic habitat (acres and ft²) can be calculated.  Bathymetry in all four reservoirs will be presented in 1 ft contour intervals.

• During the habitat surveys, the entire shoreline of all four reservoirs will be filmed with a digital movie camera connected to the Trimble GPS unit.  Areas of significant erosion and their extent will be located with the GPS system (latitude/longitude), filmed during this survey and their locations included in the Arc View data file for each reservoir.  Significant erosion will include areas that are observed to have active and ongoing erosion and observable impacts to important aquatic and terrestrial resources.  Such areas will include but are not necessarily limited to:
• areas where eroding shoreline has resulted in localized sediment deposits that are noticeably affecting water quality or aquatic habitats
• areas where eroding shoreline has resulted in the loss of vegetation from a significant  plant community or habitat type.
• areas where eroding shoreline are impacting public recreation facilities

 Methods – Reservoir level fluctuation evaluation

 The reservoir fluctuation evaluation portion of the study will also be conducted by Normandeau and will entail the following:  

• Evaluate effects of current Project operations and water level fluctuations on existing fishery and aquatic habitats, including impacts to fish species of management concern during the spawning season and impacts due to daily and seasonal drawdowns.  Fish species evaluated will primarily include all those that spawn in the littoral zone, such as largemouth bass, sunfish species (bluegill, pumpkinseed etc).  Other fish, such as the forage species that are pelagic spawners (threadfin and gizzard shad, blueback herring) will also be evaluated.  The habitat surveys discussed above will be used to quantify impacts of fluctuations on fish and aquatic habitats.  Other Project operations that could affect aquatic biota such as stranding (after generation ceases) and water quality (especially dissolved oxygen and temperature) will also be evaluated as part of this study.

• Evaluate effects of alternative reservoir fluctuations, such as reduced drawdown zone, seasonal changes to rule curve (fill reservoir sooner or hold full longer, etc.)
• Assess existing water level fluctuation and drawdown data for the reservoirs, calculate median, mean low and mean high water levels from long term data sets and prepare a graph for a 12-month cycle to assess impacts (this data will also be used for wetlands evaluation).
• Use existing fishery data (species lists) collected by NCWRC, Yadkin consultants (recent Progress Energy fish sampling in four reservoirs) and fisheries data that will be collected during the proposed tailwater fisheries sampling beginning in August 2003 to conduct this evaluation.

 Data Collection and Reporting Schedule

 Data collection for the habitat surveys on High Rock and Narrows Reservoirs are planned for the  fall and early winter in 2003 and the habitat data collection for the Tuckertown and Falls Reservoirs is planned for the fall/early winter in 2004.  Results of the habitat surveys and reservoir fluctuation evaluations for the four impoundments will be reported in draft and final study reports.  A draft study report of the habitat surveys on High Rock and Narrows Reservoirs will be prepared and distributed to the Fish and Aquatics IAG for review and comment by the 1st quarter of 2004, approximately two to three months after the completion of data collection.  A draft study report for the Tuckertown and Falls Habitat survey will be prepared and distributed to the Fish and Aquatics IAG by the 1^st quarter of 2005, approximately 2 months after data collection.  IAG comments will be addressed in a final habitat study report for all four reservoirs that will be distributed to the IAG in March 2005.  Interim results, such as draft habitat maps of the reservoirs, may be shared with the IAG as such information becomes available, prior to completion of the draft study report.  The draft Reservoir Level Fluctuation report for High Rock and Narrows will be prepared and distributed to the IAG for review and comment by the 2^nd quarter of 2004, about three months after the draft Habitat survey report for these two reservoirs is turned in.  The draft Reservoir Level Fluctuation report for Tuckertown and Falls Reservoirs will be distributed to the IAG for review and comment by the 2^nd quarter of 2005, about two months after the draft habitat survey for these reservoirs is turned in (draft habitat survey reports are needed in order to complete the draft reservoir fluctuation reports).  Final Reservoir Level Fluctuation reports for the four reservoirs will be distributed to the IAG for review and comment by the 2^nd quarter of 2005.