Estuary Subbasin Overview

The Eel River estuary is located approximately 13 miles south of the town of Eureka in Humboldt County. The Estuary Subbasin includes approximately 24 square miles of delta wetlands lands, pastures and hillsides that form the Hawk Slough and portions of the Salt River and Palmer Creek CalWater 2.2 Planning Watersheds. Mean annual discharge from the Eel River Basin to the estuary is approximately 5.4 million acre-feet. The highest recorded annual discharge into the estuary was 12.6 million acre feet in 1983 and the lowest was 410,000 acre feet in the drought of 1977. The peak flow into the estuary was on December, 1964 when 750,000 cubic feet per second was recorded at the USGS gauging station at Scotia. Beginning in the 1850s, the high winter flows have been noted to make changes to the delta lands and estuarine channels, by eroding banks and redirecting flows.

Elevations in the subbasin range from sea level at the river mouth to approximately 700 feet in upland areas near Table Bluff. Most of the delta lands are relatively flat. The town of Loleta is located at the base of rolling hills at an elevation of approximately 50 feet above sea level. The elevation of Loleta prevents the town from flooding during large winter storms that periodically inundate the delta lands. The Estuary Subbasin does not include the Salt River or its tributaries. The Salt River watershed, although hydrologically connected to the Eel River estuary, is treated as a distinct assessment subbasin in this report.
Attributes of the Lower Eel River Estuary Subbasin
Area (square miles) 24
Percent of Basin 14
Miles of Stream (permanent + intermittent) 43 miles
Principal Communities Loleta, Fernbridge
Predominant Geology Alluvium 
Predominant Vegetation Grassland
Predominant Land Use Agriculture
Lowest Elevation (feet) 0
Highest Elevation (feet) 581
Salmonid Species Coho, Chinook, Steelhead, Coastal Cutthroat
Roper Slough entrance (approximately RM 1).  Photo taken from Cock Robin bridge looking upstream.
Humboldt Bay
Tidegate on McNulty Slough (approximately 1.25 miles upstream of the estuary).
Juvenile Dungeness crabs collected during a seining effort in the North Bay.  Photo taken in 1993.