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Shoreline Inventory and Assessment Project
Project Overview
 The Spokane County Conservation District (SCCD) has completed an inventory and assessment of the shorelines along the waterways in Spokane County. The work was conducted to determine the overall health of the riparian-wetland areas. SCCD and others will use the results to identify high quality areas for preservation, as well as those at-risk or non-functional areas that require restoration.
SCCD's study covers the physical
and ecological condition of the local
stream and river channels. Information on riparian plant communities and
other biological data was also collected and evaluated. An interdisciplinary team with experience in hydrology, plant taxonomy, geomorphology, soils, and fluvial systems conducted the shoreline evaluations. The SCCD's analysis utilized the Proper Functioning Condition (PFC) methodology. The PFC method utilizes a standardized set of factors indicative of shoreline health, allowing for the identification of significant attributes that may be out of balance with the natural processes necessary for the system to function properly. This methodology provides a consistent and rapid means for assessment. Attributes such as hydrology, vegetation and soils are evaluated to determine the overall physical and functional condition of a riparian-wetland area.
This work was funded by a Centennial Clean Water Fund Grant # G000029283
awarded through the Washington State Department of Ecology.
Project Goals
The timing of the Conservation District's work was coordinated with Spokane County's update of their Shoreline Master Program
(SMP). A central objective of the SCCD's assessment was to generate a product that is useful to local
decision-makers, especially within the framework of the
existing City and County Shoreline Management Plan
and Critical Areas Ordinances. A report of the SCCD's findings was completed in the summer of 2005. The study data has also been integrated into Geographic Information System (GIS) format for utilization by local governments in the designation and protection of critical areas and shorelines in the County.
Summary of Project Findings
More than 192 miles of shoreline and approximately 9,318 acres (200 feet landward of the ordinary high water mark) were included in the inventory and assessment project. The stream or river was segmented into 'reaches' based on factors such as plant community type, valley form, geology, land use, or a combination of these factors. A total of 105 different reaches were delineated for the project area. The study focused on the 88 reaches that are under current regulation by local and state shoreline management programs. Information on the additional reaches was collected in the event that the shoreline programs were extended in the future.
Shoreline Conditions
The SCCD's PFC analysis involved an assessment of seventeen hydrologic, vegetation, and soils/geology attributes related to the physical functionality of riparian systems. The PFC methodology recognizes four categories of stream functionality: proper functioning condition, functional-at-risk, nonfunctional, and unknown. Of the 88 reaches evaluated, 71 percent of the river miles were in proper functioning condition, 27 percent were functional-at-risk, and two percent were non-functional.
Properly functioning condition (PFC) is based on the physical ability of the reach to withstand a 25-30 year hydrological event. Properly functioning reaches have characteristics such as well-established riparian vegetation, an active floodplain, and stable channels. However, there are many sites considered to be functioning on a physical basis that do not provide other important ecological or biological values and functions.
Pine Creek and Deadman Creek are the only basins rated as having 100 percent of their reaches to be in proper functioning condition. The Spokane River is also in good condition, with 95 percent of its shorelines in PFC. The majority of the other systems are in fairly good condition and had most of their shoreline in PFC: the Little Spokane River at 77 percent, Dragoon Creek at 90 percent and the West Branch of the Little Spokane River at 74 percent.
Functional-at-Risk (FAR) reaches are usually a direct result of significant past or current land use influences. Residential and urban development, shoreline modifications, livestock grazing, deficient riparian communities, road encroachment, agricultural production, and moderate to severe stream bank erosion are typical in these reaches.
Hangman Creek is by far the most critical system in Spokane County, with 63 percent of its shorelines rated as FAR. Rock Creek, a major tributary of Hangman Creek, has 36 percent of its shorelines rated as FAR. The trends associated with FAR reaches are upward and downward, depending upon the site conditions and the level of current influence.
Nonfunctional (NF) conditions are fairly uncommon throughout the watersheds in Spokane County. These reaches indicate severe hydrological problems such as bank instability. Significant erosion and inadequate or absent riparian plant communities are characteristic. Hangman Creek is the only system identified with a NF rating. However, there are reaches in Hangman Creek and others that are listed at the lower end of FAR that could degrade to a NF condition in the future.
Ecological Condition and Restoration potential
Ecological condition ratings for each reach are based on the diversity, density and continuity of the vegetative community. This vegetative or ecological condition affects the ability of the shoreline to trap sediment and pollution from surface run off, provide root systems to serve as filters and minimize streambank erosion, and moderate temperatures. The ecological condition of a reach is rated as good, fair or poor.
Ecologically, the streams and river reaches evaluated exhibit a wide variety of conditions, with a considerable portion of current shoreline conditions falling short of their natural potential. Approximately 25 percent of river miles are in good condition (48 river miles). The majority of habitat communities are in fair condition (47 percent) and the remaining 28 percent are rated as poor (53.6 river miles).
The Little Spokane River has more river miles in good ecological condition than any other system in Spokane County (10.5 river miles). Deadman and Dragoon Creeks, both tributaries to the Little Spokane River, are largely considered to be in fair condition. This is due in large part to human influences.
The Spokane River has only 12 percent (6.9 river miles) of its plant communities rated as good ecological condition and more than half of the shoreline is rated in fair condition.
Hangman Creek exhibits the most damaged ecological condition, with approximately 45 percent (22.9 river miles) characterized as poor condition. However, Rock Creek, a tributary to Hangman Creek, had the highest percentage of its system rated as good ecological condition (63 percent or 9.8 river miles). The Little Spokane and Spokane Rivers also contain large contiguous areas of poor condition, and the entirety of Pine Creek is listed in poor condition.
Restoration potential measures the ability of a shoreline area to naturally regenerate and reach its potential given no political, social or economic constraints. Human influences and land use management practices have disturbed some riparian and wetland areas. If these limiting factors were removed, a site could exhibit natural resiliency through time or it may require restoration assistance. Restoration potential ratings range from good (has the ability to achieve potential if limiting factors are removed), to poor (minimal probability of achieving potential conditions due to present human or natural limiting factors.
The majority of Spokane County streams are rated as fair (48 percent). Pine Creek, Dragoon Creek, and Deadman Creek each have significant portions rated as fair. The rural character and small farm tract character of the areas mean that fewer environmental and social barriers to restoration efforts exist.
In contrast, the Hangman Creek watershed has more difficult restoration conditions due to soil conditions, severity of erosion, dry weather, the establishment of invasive canarygrass, the lack of riparian buffers and the farming of annual crops on large farm tracts. The Spokane River and other waterways with residential or urbanized environments are also considered as having fair and poor restoration potential due to the desire of residents to maintain views, access to the water and established bulkheads.
Reaches of good restoration potential include Rock Creek, the Little Spokane River, and the West Branch of the Little Spokane River. These streams provide superior natural environments for restoration efforts or have the potential for significant benefits from simple changes in land use practices.
A significant portion of streams (32 percent) require no restoration efforts. These reaches were rated as not applicable (N/A), indicating that the current shoreline environment is either in good ecological state or could not be improved due to existing conditions such as a rock wall, steep banks or impoundment.
High Quality Areas
High Quality Areas include terrestrial and aquatic areas that are important to local wildlife and fisheries, support human enjoyment of views, or provide important or unique recreational opportunities. There are many existing high quality areas along the streams and rivers in Spokane County. These include spawning areas for salmonds, significant wildlife areas, intact riparian communities, and natural areas. Overall, the Spokane River and the Little Spokane River have the largest contiguous high quality areas. This is due to large natural areas and state parks that currently protect the areas from certain impacts. Pine Creek is the only stream that has no existing high quality areas.
The Spokane River provides the majority of high quality areas identified for recreational use, aesthetic enjoyment and spawning areas for fish. Even the highly urbanized settings provide aesthetic and economic value to the region. The waterways in the Little Spokane River watershed provide many high quality sites of excellent wildlife and fisheries habitat, typically located on private land. While the areas are protected from access by the general public, their protection and maintenance is subject to the individual landowner.
Hangman and Rock Creeks contain large contiguous segments of quality habitat, particularly in the deep basalt canyons. The Hangman Creek canyon provides valuable water recreation, while the Rock Creek canyon has a diversity of plant communities that support many types of wildlife species.
The high quality areas throughout the County will benefit from minimal disturbance and time for natural restoration. Many sites will require extensive protective efforts and expensive restoration.
Development Risk Potential
The potential for impacts to stream reaches from future development has been evaluated based on housing density. Reaches with housing densities of one house on 40 acres or more received a rating of low. Reaches with housing densities of one house on a minimum of 10 to 40 acres are rated as medium. Reaches with housing densities of more than one house per 10 acres are rated as high. A reach may receive a medium or high risk rating, but this rating alone does not imply that future development will cause problems. Shoreline impacts could be minimized by following recommended guidelines and setbacks, maintaining natural riparian areas, routine enforcement, and applying proper management practices.
Most watersheds are rated as high for future development impacts. Only the upper reaches in Hangman, Rock and Pine Creeks and the lower reaches of the Little Spokane River are rated as low. Although several reaches throughout the watersheds are already significantly developed, they were rated as high due to the cumulative impacts that will be experiences with any future development. The Spokane River has the most river miles (37 miles) rated at high risk for development impacts, mainly due to the current level of development. Deadman Creek has the highest percentage of the creek rated at high risk (71 percent). Several areas of other water systems are rated as medium or low risk: Pine Creek, West Branch Little Spokane River, Rock Creek, and the Little Spokane River.
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