Elwha Watershed Information Resource

The Salt Creek Watershed is a 19 sq.mi. area just west of the Elwha River Watershed. This watershed is within Clallam County land use jurisdiction and has been zoned as predominately commercial forest and rural residential. As such, it contains approximately 200 miles of constructed roads of varying types from State Highway 112 to rural access roads to logging roads. These were constructed crossing various tributaries and hundreds of culverts were installed to allow for drainage. However, allowing fish passage was not a primary consideration during culvert installation. As a result, these culverts either partially or completely blocked fish passage to approximately 26 miles of fish habitat. Since the Salt Creek Watershed is within the Lower Elwha Klallam Tribe's usual and accustomed fishing area, the Tribe's Fisheries Department has looked to restore fish access to any and all habitable stream segments currently inaccessible or partially inaccessible to adult fish migrating upstream to spawn or juveniles migrating downstream to the Strait of Juan de Fuca. To do this, an inventory and assessment needed to be performed to determine which streams can provide fish habitat and which culverts needed to be replaced. Additionally, a means by which to prioritize which culverts should to be replaced first was also needed.

The existing hydrologic stream layers were considered inadequate due to the fact that some fish habitable streams were absent from the dataset. Additionally, prior geographic information systems (GIS) work had been performed by the Tribal GIS Department in assisting the Point No Point Treaty Council (PNPTC) with the Salmon and Steelhead Habitat Inventory Assessment Project (SSHIAP) since early 2000. Also, the watershed was completely included within the February, 2001 Light Detection and Ranging (LiDaR) flyover performed by the Puget Sound LiDaR Consortium (PSLC). This provided an opportunity to attempt a means by which to use LiDaR to more accurately remap the stream network within this watershed. Thus the Tribal Fish Habitat Biologist teamed up with the Tribal GIS Analyst to perform a culvert and fish habitat assessment using field crews in conjunction with recent remotely sensed data (2001 LiDaR).

Maps have been created depicting information useful for determining a means to prioritize culvert replacement, namely:

• Where fish passage culverts were inventoried
• Where numerous non mapped but existing drainage culverts exist
• A more current and accurate hydrologic stream dataset
• Stream habitat characteristics such as gradient and confinement
• Quantified stream lengths and catchment areas of fish habitat accessible or inaccessible due to partial or complete culvert blockages (global and local)
• Quantified vegetation characteristics
• Quantified zoning areas
• A methodology for modifying LiDaR to more accurately map drainage flow paths (LiDaR can’t see culverts or bridges), etc.