Upper Knapps Creek

PROJECT OBJECTIVES

1. Restore and maintain a stable stream channel
2. Eliminate or reduce the damage to and loss of property caused by the stream bank erosion, sedimentation and flooding problems along Upper Knapps Creek
3. Implement restoration measures and management practices throughout the watershed that reduce the need for long-term maintenance and ensure the success of this effort

ASSESSMENT

• Evaluation of Climate and USGS Gage Record Data
• GIS Mapping and Probability of Unstable Conditions and Sensitivity to Disturbance Analysis
• Evaluation of Historic Aerial Photograph Overlays for Channel Migration and Sediment Loss Analysis
• Field Reconnaissance Surveys along 35 miles of Tributaries
• Gage Calibration Surveys at U.S.G.S. gage stations in the Appalachian Plateau Region
• Geomorphic Stream Assessments along 14 miles of Upper Knapps Creek
• In-Stream Habitat Evaluation
• Biological Surveys of Fish and Macroinvertebrate Communities
• Water Quality Monitoring
• Hydrologic Modeling of the Upper Knapps Creek watershed

WATERSHED

Evaluation of regional climate data and stream gage records indicate Upper Knapps Creek watershed

• Reliably generates at or near bankfull peak flows at least once a year.
• Rain-on-snow events  historically most strongly correlated with peak flows
• Large rainstorms are occurring with greater frequency

Due to basin morphometry, impervious nature of geologic formations and soils the Upper Knapps Creek subwatersheds are naturally sensitive to land use activities that concentrate runoff and expose the soils to active weathering or erosion.

Basin slope and drainage density are two key natural features contributing to high runoff and erosion rates in Upper Knapps Creek. Measurable differences in runoff and erosion rates between the eastern and western subwatersheds.

SUBWATERSHEDS

Eastern Subwatersheds

• Moderately steep to very steep tributaries
• Narrow, V-shaped Valleys
• Flow across alluvial fans onto the wide valley floor of the mainstem Upper Knapps
  Creek.

Western Subwatersheds

• Low gradient to moderately steep tributaries
• Meander along U-shaped valleys parallel to main valley, turning to drop through
  narrow V-notches
• Flow across alluvial fans and join the mainstem Upper Knapps Creek.

Historic Impacts

• Eastern subwatersheds still recovering from instability problems caused by historic
  timber harvesting operations between the late 1870’s and early 1920’s
• Resulting erosion of slopes and sedimentation of streams was widespread and
  devastating.
• Still evidence of the impacts – large alluvial/colluvial deposits are spaced at irregular
  intervals along the valley profile
• Remnants of the old logging railroad beds are still discernable
• During large storm events the lower reaches of some tributaries are overwhelmed by
  the amount of material transported from their respective watersheds, completely
  filling in and overflowing onto the adjacent alluvial fans.

Current Impacts

• Recent clear cuts, skid trails, landing areas and haul roads increasing and
  concentrating runoff into ephemeral channels or directly over the steep, erodible
  slopes.
• Gullies and debris flow channels are developing along the slopes below a number of
  the areas that were disturbed by these logging operations.
• Western tributaries are stable and in good condition. With an abundant baseflow
  and stable habitat conditions, several of these tributaries support populations of
  trout.

UPPER KNAPPS CREEK – TRIBUTARIES

Subwatersheds were ranked relative to potential and existing problems identified during the study. Potential problems were identified using the mapped stream types from the Level I – Geomorphic Characterization and field reconnaissance and the stream response characteristics presented in Management Interpretations of Various Stream Types (Rosgen, 1994).

UPPER KNAPPS CREEK – MAINSTREAM

With exception of channelized reaches, the mainstem Upper Knapps Creek is a low gradient, meandering stream, with a well-developed floodplain. Dominant land use along the valley bottom is pasture, utilized for the grazing of cattle, sheep, and horses. Land ownership is almost totally private.

Current Conditions and Contributing Factors:

• Heavy sediment loads are contributed from eroding banks and beds, hillslope failures
  along mainstem and unstable subwatersheds. This is contributing to widespread
  aggradation. So severe along some reaches, braiding and rapid lateral migration are
  occurring. Some aggradation is also occurring upstream of beaver dams.
• Major portions of the mainstem exhibit width/depth ratios much higher than
  normally observed along stable reaches. These over-wide conditions are likely the
  result of historic and recent post-flood channelization work and trampling of stream
  banks by livestock .
• There is a general lack of woody vegetation along significant lengths of stream banks
  resulting in a loss of lateral control. Annual channel migration rates of 12.5 – 44.5
  feet were measured in some segments utilizing overlays of historic aerial
  photographs. More stable , well vegetated reaches showed migration rates of 1.5 –
  2.5 feet per year.
• The most obvious departure from a stable form is altered meander geometry.
  Historic channelization and straightening is evident on the USGS Topographic Maps
  dated 1905 and 1929. This trend has continued throughout the years with periodic
  post-flood channel work. The effects of these channel activities are clearly visible on
  the 1948 – 1997 historic aerial photograph overlays.
• Land management practices along the mainstem are probably the most significant
  factors contributing to the current unstable conditions.
  • Unrestricted livestock grazing along the mainstem has directly impacted
    channel morphology by trampling of the banks, widening of the channel, and
    reducing sediment transport capacity.
  • Past vegetation control practices such as spraying and mechanical removal of
    undesirable vegetation eliminated much of the woody vegetation from the
    banks and riparian zone.
  • Current lack of woody vegetation and the subsequent loss of lateral control
    for the banks is a direct result of the unrestricted grazing activities.
• The reaches along Upper Knapps Creek were ranked relative to potential and existing
  problems identified during the study. Potential problems were identified using the
  mapped stream types from the Level II – Morphologic Description and the stream
  response characteristics presented in Management Interpretations of Various Stream
  Types (Rosgen, 1994).

RESTORATION AND MANAGEMENT PLAN

 The Plan employs two basic objectives:

1.  Management of resources by preventing or minimizing alteration of the slopes and ridges in the eastern and western subwatersheds and of the stream/floodplain corridor along the mainstem using all practical means.
2. Restoration of resources by reestablishing natural characteristics and hydrologic and geomorphic functions of the slopes and ridges in the eastern and western subwatersheds and stream/floodplain corridor along the mainstem.

Management Strategies for the Subwatersheds

Given the findings of this study, the management strategies identified for the subwatersheds focus on reversing the effects historic land use activities have had, as well as minimizing the effects future land use activities could have on basin runoff characteristics.

•  Forest Management Prescriptions for the Eastern Subwatersheds
• Land Use Management Zones
• Timber Harvest Permits and Best Management Practices

Management Strategies for the Upper Knapps Creek Mainstem

The unstable conditions in certain subwatersheds are exerting considerable influence on mainstem channel morphology and fluvial processes.  However, as pointed out, land management practices along the mainstem are probably the most significant factors contributing to the current unstable conditions along the mainstem Upper Knapps Creek.

Given the findings of this study, the management strategies identified for the mainstem Upper Knapps Creek focus on limiting livestock access, reestablishing lateral control with woody vegetation on the stream banks and adjacent riparian areas, modifying channel maintenance practices, and utilizing beavers as a management tool for maintaining stream channel stability.

• Land Management Plans and Best Management Practices
• Channel Maintenance Procedures
• Beaver Management
• Watershed/Stream/Floodplain Corridor -Land Use Covenants
• Conservation Easements
• Land Acquisition

Restoration Strategies for the Upper Knapps Creek Mainstem and Tributaries

• Identifying Areas in Need of Restoration and Determining the Level of Intervention Required
• Stream Restoration utilizing a Geomorphic Approach
• Floodplain Restoration
• Stream Bank and Riparian Vegetation

Recommended Restoration and Management Projects

• Identified, Mapped and Prioritized Stream Restoration Projects
  • Ninety (90) restoration projects along tributaries
  • Twenty five (25) restoration projects along the mainstem

• Identified Agricultural and Forest Management Best Management Practices (BMPs)
• Developed Preliminary Cost Estimates for All Restoration Projects

Preliminary Design Plans, Construction Specifications, and Preliminary Cost Estimates were developed for Four Demonstration Stream Restoration Projects.