Yadkin Project (FERC No. 2197)

Wetland and Riparian Habitat 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 Wetlands, Wildlife and Botanical IAG, to provide additional necessary information for consideration in the relicensing process.


In this study, wetlands and riparian habitats will be inventoried and characterized and the effects of existing Project operations, including reservoir fluctuations and tailwater flows, will be assessed.  In addition, at Narrows Reservoir, the impacts of piers on water willow[1] is of particular concern to the North Carolina Wildlife Resources Commission (NCWRC).  Narrows Reservoir has both an abundance of Water willow and piers whereas the other three reservoirs may have an abundance of one or the other but not both.  In a study conducted for Yadkin by NC State University in 1999, data on Water willow growing under and adjacent to piers was collected for one growing season.  The purpose of the present study will be to conduct a follow-up investigation, building on the information previously collected, to assess the relationship between piers and water willow.


The following issues were raised during initial consultation regarding wetlands and riparian habitat at the Yadkin Project:  

§         Effects of reservoir operations and fluctuations on wetlands and riparian habitats

§         Effects of piers on water willow at Narrows Reservoir


On March 13, and April 25, 2003 the Wetlands, Wildlife and Botanical IAG met and discussed objectives for the wetlands and riparian habitat study.  Over the course of those discussions the following objectives were identified for the study.  

§         Identify and map vegetated wetlands and riparian habitats within the influence of reservoir water levels, including aquatic beds, emergent and shrub-wetlands and some forested wetlands.

§         Evaluate effects of current Project operations, including reservoir water level fluctuations on these wetlands and riparian habitats.

§         Evaluate how significant changes in Project operations, including both increasing and decreasing short-term and long-term reservoir drawdowns would impact existing wetlands, or would allow for additional wetland development.

§         Qualitatively assess the effects of reservoir facilities (such as piers, boat ramps, beaches, bulkheads and other forms or shoreline hardening) on wetlands and riparian habitats, with a particular emphasis on the potential impact of piers on water willow at Narrows Reservoir.

Geographic Extent

§         The shorelines of all four reservoirs including all wetlands and riparian habitats within the zone of influence of reservoir operations and including wetlands to the upstream boundary of the Project, which extends above High Rock Reservoir and includes some free-flowing river (see Project boundary map in the ICD).

§         Riparian habitats adjacent to remnant mainstem riverine habitats (upper end of High Rock) and tailwater habitats (below the dams)

§         Narrows Reservoir for assessment of the effects of piers on water willow


§         Transfer National Wetlands Inventory (NWI), hydric soils, Shoreline Management Initiative (SMI), and other existing information onto orthophoto base maps of the reservoirs.

§         Delineate emergent wetlands and aquatic beds on stereo pairs of true color aerial photos taken in July 2003.  Delineate non-wetland shoreline cover types in general land use categories.  Use black and white aerial photos taken after leaf fall to confirm identifications for shrub swamps and bottomland hardwoods.  Wetland cover types will be classified according to these four designations, which are readily distinguished on aerial photos and which fulfill the needs of this study.

§         Conduct a quality control check on approximately twenty percent of the photos.

§         Ground truth and photograph questionable areas and a representative sample of wetland types, including aquatic beds, and record hydrologic, soils and vegetation conditions.

§         Transfer images on the stereo photos onto base maps, digitize into ARCView GIS and prepare maps of wetlands and riparian habitats.

§         Finalize the bathymetry for High Rock Reservoir and Narrows Reservoir to include coverage of the arms.

§         Characterize composition, functions and values of wetland types.

§         Assess water level fluctuation and drawdown data for the four reservoirs, calculate median, mean low and mean high water levels from long-term means and prepare a graph for a 12-month cycle to assess impacts.

§         Determine the portion of existing wetlands affected by current, typical Project operation and resulting water level fluctuations.

§         Assess the effects of erosion due to boat wakes on bordering wetlands in coves.

§         Assess the impacts of an existing sand and gravel dredging operation at the upper end of High Rock Reservoir in the free flowing section on nearby wetland and riparian habitat areas.

§         Evaluate how wetland configuration, structure and composition might change under altered Project operations.  Provide semi-quantitative estimates of wetland increases and decreases anticipated at High Rock and Narrows reservoirs (within 4 foot contours), and qualitative estimates at Tuckertown and Falls reservoirs under the following conditions:

a.       High Rock Reservoir (if water levels were more stable, limited seasonal drawdown)

b.       Narrows Reservoir (if water levels were less stable, more seasonal drawdown)

c.       Minor changes in operations (short-term reservoir water level fluctuations) for Tuckertown Reservoir

d.       No changes in the operation of Falls Reservoir.

§         Evaluate the impacts of existing reservoir facilities such as piers, boat ramps, beaches, bulkheads, rip-rap and other recreational facilities on wetland and riparian habitats and potential future facilities should development on each reservoir continue.

§         Evaluate the impact of piers on water willow at Narrows .

a.       Review data from previous investigations and maps showing previous sampling locations; prepare a plan for field data collection.

b.       Identify new piers built since the last study (1999) using the 2002 orthophotos (according to Alcoa there are approximately 57 new piers on Narrows ).

c.       Visit a subset of 15 piers surveyed previously and an equal number of new piers.

d.       Qualitatively assess the impact of piers on water willow relative to change in areal coverage and health of the plants.  Take photos to document water willow coverage beneath and adjacent to piers.


A draft study report will be prepared that will contain the following information:

§         Review of existing studies and information on the Project area.

§         Description of approach and methods.

§         Characterization of wetland and riparian cover types including composition and functions, a general description of upland shoreline cover types in general land use categories and maps showing wetland, riparian and upland cover types.

§         Assessment of water level fluctuation and drawdown data for the four reservoirs, including graphs for a 12-month cycle.

§         Assessment of the effects of current Project operations, including reservoir fluctuations and tailwater flows, on wetlands and riparian habitats, and including effects of the existing dredging operation.

§         Assessment of the effects of existing and potential future reservoir facilities on wetland and riparian habitats, including impacts of piers on water willow at Narrows Reservoir.

§         Assessment of how significant changes in reservoir operations would effect existing wetlands or allow for additional wetland development.

The draft report will be distributed to the IAG for review and comment, the comments addressed, and a final report prepared.  


§         Transfer NWI, hydric soils, SMI and other existing wetland and riparian habitat data onto orthophoto base maps of the reservoirs.

June 2003

§         Aerial overflight conducted to obtain stereo pairs

July 2003

§         Delineate wetland and upland cover types on stereo pairs, transfer boundaries to orthophoto base map, digitize boundaries, and prepare maps of wetlands and riparian habitats.

August–December 2003

§         Assess water level fluctuation and drawdown data

August–December 2003

§         Review previous water willow study, transfer previous pier sampling locations and new piers to base map, prepare a plan for field reconnaissance.

October–December 2003

§         Ground truth wetlands and riparian habitats, characterize wetland types, assess functions; correct photos and maps.

June–July 2004

§         Visit piers and assess impacts on water willow

June–July 2004

§         Assess impacts of existing and proposed Project operations and facilities on wetlands and riparian habitats.

August–September 2004

§         Draft report

October 31, 2004

§         Final report

December 31, 2004

[1]   Water willow is a term that is used to generically describe submerged aquatic vegetation that occurs at the Yadkin Project.  At Narrows Reservoir, submerged aquatic vegetation beds are generally dominated by the species Justicia americana , which is commonly called “water willow”.