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Shoreline Inventory and Assessment Project
Project Methodology
The Spokane County Conservation District's inventory and assessment focuses on the physical
and ecological condition of the streams and rivers. Information on riparian plant communities and
other biological data has also been collected and evaluated. An interdisciplinary team with experience in hydrology, plant taxonomy, geomorphology, soils, and fluvial systems conducted the shoreline evaluations. Several techniques and rating systems have been employed for this study.
Properly Functioning condition Methodology
The concept of Properly Functioning Condition (PFC) has its origin in hydrology and watershed management. Its methodology was originally developed for the Bureau of Land Management by a team of fifty scientists specializing in hydrology, vegetation, and soils attributes. The methodology provides a consistent and rapid means for assessment.
Several parameters are evaluated in field assessments of streams or wetlands including the adjacent riparian areas, and the contributing uplands. These parameters are: stream channel or wetland properties, flow regime, hydrology/soils, erosion/deposition, the plant community, nutrient inputs, and water quality. The attributes are considered when evaluating riparian areas to determine their physical condition. Areas are rated as “ Properly Functioning,” “at Risk,” or “Non-Functional,” depending on the observations made.
The PFC methodology recognizes four categories
of stream functionality:
- Proper Functioning Condition:
A riparian-wetland area is considered to be in proper functioning
condition when adequate vegetation, landform, or large woody
material is present to:
- Dissipate stream energy associated with high
waterflows, thereby reducing erosion and improving
water quality;
- Filter sediment, capture bedload, and aid floodplain
development;
- Improve flood-water retention and ground-water
recharge;
- Develop root masses that stabilize streambanks
against cutting action;
- Develop diverse channel characteristics
to provide the habitat and the water depth, duration,
and temperature necessary
for fish production, waterfowl breeding and other
uses;
- Support
greater biodiversity.
- Functional-At Risk:
Riparian-wetland areas that are in functional condition,
but an existing soil, water, or vegetation attribute
makes them
susceptible to degradation during a high flow event.
This rating is associated with an identified trend (upward,
downward, or
not apparent). The trend may or may not be easily identified
through current influences.
- Nonfunctional
Riparian:
Wetland areas that clearly are not providing
adequate vegetation, landform, or large woody material to
dissipate
stream energy associated with high flows and thus are
not reducing erosion, improving water quality, etc.
- Unknown:
There is insufficient information to make any form of
determination
Ecological Condition and Restoration Potential
Ecological condition ratings are based on the current structural diversity, density and continuity of native plant communities, factors that indicate the ability of the shoreline to trap sediments and pollutants from surface run-off, provide wildlife habitat, moderate water temperature, minimize erosion and perform other vital functions. The ecological condition of each area is rated as good, fair or poor based on the following criterion.
Good: Exhibits well-connected, high quality habitats that support a diverse assemblage of continuous native plant communities (discontinuity is less than 10 percent of the overall reach length).
Fair: Exhibits discontinuous habitats that supported minimum assemblages of native or non-native plant communities (discontinuity is greater than 10 percent of the reach length, but less than 70 percent).
Poor: Exhibits little to no continuity, may support monotypic communities, and/or deficient plant communities due to limiting factors such as natural conditions or human influences (discontinuity is greater than 70 percent of reach length).
The restoration potential of each reach is measured by its ability to naturally regenerate (resiliency) and reach its potential given no political, social or economic constraints. Restoration potential of a reach is given ratings of good, fair and poor based on the following criterion.
Good: Has the ability to achieve potential if limiting factors are removed or moderated. Assistance in the restoration process will accelerate recovery, but is not a necessity.
Fair: Has achieved some of the potential conditions and has a moderate probability of reaching its full potential. Limitations may be due to natural conditions or the site requires some assistance in management and restoration.
Poor: Has a minimal probability of achieving potential conditions due to present limiting factors (human and natural).
Not Applicable (N/A): The reach has either attained optimal potential conditions or the rating did not apply for other reasons.
High Quality Areas
High quality areas include terrestrial and aquatic landscapes and habitats that are important to wildlife and fisheries and human enjoyment for view or recreation. For this study, high quality areas are defined as those exhibiting a set of attributes and characteristics developed by the Shoreline Technical Advisory Committee and experts from the Washington State Departments of Ecology and Fish and Wildlife.
High Quality Wildlife Areas:
- Contain the following native plant communities of significant size or quality -
- Water birch associations (1/4 acre or larger)
- Black cottonwood associations (1/2 acre or larger)
- Quaking aspen associations (1/4 acre or larger)
- Black hawthorn associations (1/2 acre or larger)
- Common chokecherry associations (1/2 acre or larger)
- Willow/sedge associations (1/4 acre or larger)
- Contain documented rare species.
- Support multilayered galleries of 1 acre or larger.
- Support large, mature stand of Ponderosa pine forest near riparian areas (2 acres or larger).
- Contain intact stream and river confluence areas.
- Contain springs, seeps, and aquifer influence.
- Support wildlife biodiversity (as determined by the Dept of Fish and Wildlife).
High Quality Fisheries Areas: Support native interior redband trout populations or contain established salmonid spawning beds.
High Quality Recreational and Aesthetic Areas: Support enjoyable public viewsheds or provide important or unique recreational opportunities.
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