Basin Overview

For purpose of this assessment and analysis, the Lower Eel Basin was divided into four subbasins (Estuary, Salt River, Middle, and Upper) comprised of a total of 11 CalWater 2.2.1 Planning Watersheds (PWs). Subbasins were designated based on several attributes, including geography, geology, climate patterns, and land use. Original PW boundaries were edited to more accurately reflect the drainage patterns and watershed processes within the Lower Eel Basin when defining subbasins.

The Eel River estuary was divided into two subbasins: the Estuary Subbasin and the Salt River Subbasin.  The Salt River drainage was previously assessed separately by Downie and Lucey (2005) in order to assist key entities with impending management decisions.  Findings and recommendations from the Salt River Watershed Assessment have been incorporated into the Salt River Subbasin section.  For this Lower Eel River watershed assessment, the Estuary and Salt River subbasins are viewed as two integral parts, which describe the Eel River estuary as a whole.

General attributes of the Lower Eel River Basin
Attribute Estuary Subbasin Salt River Subbasin Middle Subbasin Upper Subbasin
Area (square miles) 24 49 24  75
% of basin 14 29 14 43
Miles of stream 43 42 40  133
Principal Communities Loleta, Fernbridge Ferndale Fortuna, Rohnerville Hydesville, Carlotta, Rio Dell 
Dominant Geology Alluvium Alluvium Unconsolidated river terrace deposits Wildcat Group 
Dominant Vegetation Grassland Grassland Conifer Conifer 
Dominant Land Use Agriculture Agriculture Urban, Agriculture, Mining Forestry, Agriculture, Mining 
Lowest Elevation (feet)
 0 0
5
 30
Highest Elevation (feet) 581
1,630
2,255
2,435
Salmon Species Coho, Chinook, Steelhead, Coastal Cuthroat
Coho, Chinook, Steelhead, Coastal Cuthroat Coho, Steelhead, Coastal Cutthroat Coho, Chinook, Steelhead 
The Lower Eel River Basin is the depositional zone for the entire Eel River catchment, and as such embodies the processes throughout. As part of this highly dynamic catchment, the Lower Eel experiences high levels of sedimentation due to natural hillslope processes including very erodible bedrock and high levels of precipitation (Reynolds et al. 1981). Additionally, the area is situated in a tectonically complex area. Landslides and erosion introduce large quantities of sediment to streams, and are exacerbated by the region’s climate, geology, topography and land use. The Eel has the highest recorded average suspended sediment yield of any U.S. river its size (Brown and Ritter 1971), and in 2002, the US Environmental Protection Agency (EPA) listed the lower portion of the Eel River as an impaired water body due to sediment and temperature.