Oregon Water Science Center
Hydrology of the Beaver Creek Estuary at Ona Beach State Park, Oregon
Contact: Adam Stonewall
Beaver Creek near its mouth at low tide (Photograph by Karl Lee, USGS)
The Beaver Creek estuary, at the terminus of a 34 square mile basin just south of Newport, in Lincoln County, is home to diverse native flora and fauna. It is part of Ona Beach State Park, which is administered by the Oregon Parks and Recreation Department (OPRD). The estuary extends about 3 miles upstream from the mouth. The Beaver Creek basin lies between the Yaquina River basin to the north and the Alsea River basin to the south.
OPRD has recently acquired property in the estuary, and is developing plans for restoration to a more natural condition. Federal lands in the North Fork of Beaver Creek basin (upstream of the estuary area) are designated as a Key Watershed in the Northwest Forest Plan, making it a high priority for maintenance and restoration of aquatic and terrestrial habitats and species. Lower reaches of the Beaver Creek watershed are designated as critical habitat for coho salmon. Restoration will require an understanding of the tidal and storm-surge dynamics of the Beaver Creek estuary, as well as of the salinity component of stream water and thermal regime of the estuary.
The USGS has a cooperative agreement with the OPRD to collect and analyze the data from 2010-2013 to necessary to develop wetland restoration strategies for the Beaver Creek estuary and to evaluate the results of restoration efforts. The goals of this 4-year study are to:
Measuring specific conductance and temperature (Photograph by Karl Lee, USGS)
This study measures the extent of tidal and storm-surge influence, as well as gradients of specific conductance and temperature. Two sites are instrumented with continuous water level, temperature, and specific conductance recorders. These sites are located on Beaver Creek at the Highway 101 bridge (Beaver Creek at Highway 101 near Seal Rock, Oregon, USGS site number 14306085), and just downstream of the confluence with South Beaver Creek (Beaver Creek below South Beaver Creek near Seal Rock, Oregon, USGS site number 14306080). A third site on Beaver Creek, located upstream of the State Park boundary, (Beaver Creek at NW Beaver Valley Drive, near Seal Rock, Oregon (USGS site number 14306065) monitors temperature only. In addition, about three times each year, streamflow and water-level measurements are made at the sites on Beaver Creek as well as near the mouth of South Beaver Creek (USGS site number 14306075). Direct instream specific conductance measurements were made on July 14 and November 12–13, 2012.
Measuring streamflow (Photograph by Karl Lee, USGS)
The pattern of water-level fluctuation, coupled with the specific conductance and temperature data, provides an indication of the predominant source of water to the estuary. Periodic streamflow measurements identify flow contributions to the estuary from upland sources. These measurements are made at sites upstream of tidal influence during periods of relatively stable streamflow. The sites are visited bimonthly. Each field visit consists of verifying operation of the sensors with a portable, calibrated test unit, collecting the stored data, and, when appropriate, making streamflow measurements.
USGS data from 2010–2012 has provided insight into the dynamics of the Beaver Creek estuary’s hydrology and water quality:
These exceedences of the standards could have implications for basin restoration plans.
Additional analysis of 2010–2013 baseline flow, temperature, and specific conductance data will be needed to evaluate the results of ongoing restoration efforts.
Poster: Hydrology of the Beaver Creek Estuary PDF (1.2 MB)
Data from direct measurements made July 14 and November 12–13, 2012. (SC = specific conductance.)
Water Quality in the Mid-Coast Basin (from Lincoln Soil and Water Conservation District)