Pebble Creek Project Maps:
The Pebble Creek watershed is a 6th field watershed covering an area of approximately 13,845 acres. It enters the Upper Nehalem River at river mile 90 southeast of the City of Vernonia. It is home to several species of salmonids, including native Coho salmon which use 24.5 miles of stream for spawning and rearing habitat. The geology is mostly sedimentary sandstone, plus 23% of the area is sandy shale and 3% basalt. Soils are mixed, but 98% are described as silt-loam configurations. These soils are moderately to highly prone to erosion. Approximately 15% of the Pebble Creek watershed is privately owned rural residential property, and the rest is managed forestland owned primarily by Weyerhaeuser Corporation, with smaller ownerships held by Longview Fibre and the State of Oregon.
The Pebble Creek watershed was initially recognized as a candidate for restoration activities by the ODFW 1994 Salmonid Habitat Restoration: Guide to Project Selection Tillamook/North Coast Region, as well as the supplemental ODFW 1997 North Coast Stream Project Guide to Restoration Site Selection Phase II. The Upper Nehalem Watershed Assessment, the 2007 Upper Nehalem Watershed Habitat Assessment and Prioritization Project prepared by Boswell Consultants (2007), the 2008 Nehalem Data Synthesis, and the UpperNehalem Rapid Bio-assessment prepared by Bio-Surveys (2009,10,11) identify Pebble Creek as a priority candidate for habitat and access enhancement for habitat and access enhancement. Some of the limiting factors within Pebble Creek identified by these assessments include:
- Lack of large woody debris to create high quality winter refuge and complex pool habitat (average well below benchmark levels)
- Reduced spawning habitat due to lack of gravel retention from incised, scoured channels with little key LWD
- Limited off-channel and slow velocity habitat
- Excessive fine sediment input
- Low recruitment potential for in-stream large woody debris
- Temperature concerns in lower portion of the watershed
In recognition of the information results provided by the above assessments, the Upper Nehalem Watershed Council (UNWC), in cooperation with the main landowner of the watershed, Weyerhaeuser Corporation (WeyCo) and Oregon Department of Fish and Wildlife (ODFW) has identified the Pebble Creek Watershed as a priority for restoration. The UNWC will be working with WeyCo, ODFW and other members of the UNWC Tech Team to develop a Work Plan specific to addressing the needs identified by these assessments. This proposed 2011 project is the beginning of that effort to address outstanding fish passage needs and road maintenance needs to reduce sediment inputs. The large wood project is also the beginning of a long-term goal to achieve Oregon benchmark, or better, levels of large wood.
This work also complements previous large wood placement projects conducted within the watershed and some harvest-related placement scattered across the watershed.