Geology topics

David R. Piatt

Publications and source records attributed to David R. Piatt.

4 recordsLinked to original sources

USGS2018

Water temperature in tributaries, off-channel features, and main channel of the lower Willamette River, northwestern Oregon, summers 2016 and 2017

The U.S. Geological Survey collected continuous water-temperature data in select tributaries of the lowermost 80 kilometers (50 miles) of the Willamette River in northwestern Oregon, during summers 2016 and 2017. Point measurements of water temperature and water quality (dissolved oxygen, specific conductance, and pH) also were collected at multiple locations and depths within the river and in the lower reaches of three major tributaries (Clackamas and Molalla Rivers, and Johnson Creek). These datasets were collected to identify potential locations of cold-water refuges for sensitive fish species, and to characterize daily, seasonal, and spatial variability in water conditions. These datasets may be useful for local municipalities that are required to identify cold-water refuges (as defined in State of Oregon water-quality standards) and determine approaches for protecting and enhancing these features as part of their Willamette River water-temperature Total Maximum Daily Load implementation plans. This report documents the data collection methods, provides summary graphs and maps of the water-temperature data, and outlines steps for accessing the data.

Oregon↗

USGS2011

Water-quality in the North Santiam River Basin, Oregon— Comparison of water-quality data for water year 2007 with the preceding period of record

Water-quality data have been collected in the North Santiam River basin since 1998. During water year 2007, eight monitoring stations were operated throughout the basin. Streamflow data were collected at all but one of these sites. This report presents a comparison of the water-quality and streamflow data collected at each monitoring station from monitor installation through water year 2006 with the data for water year 2007. Data were compiled monthly and annually to identify extreme values by season and for entire periods of study.

Oregon↗

USGS2008

Analysis of Geomorphic and Hydrologic Characteristics of Mount Jefferson Debris Flow, Oregon, November 6, 2006

On November 6, 2006, a rocky debris flow surged off the western slopes of Mount Jefferson into the drainage basins of Milk and Pamelia Creeks in Oregon. This debris flow was not a singular event, but rather a series of surges of both debris and flooding throughout the day. The event began during a severe storm that brought warm temperatures and heavy rainfall to the Pacific Northwest. Precipitation measurements near Mount Jefferson at Marion Forks and Santiam Junction showed that more than 16.1 centimeters of precipitation fell the week leading up to the event, including an additional 20.1 centimeters falling during the 2 days afterward. The flooding associated with the debris flow sent an estimated 15,500 to 21,000 metric tons, or 9,800 to 13,000 cubic meters, of suspended sediment downstream, increasing turbidity in the North Santiam River above Detroit Lake to an estimated 35,000 to 55,000 Formazin Nephelometric Units. The debris flow started small as rock and ice calved off an upper valley snowfield, but added volume as it eroded weakly consolidated deposits from previous debris flows, pyroclastic flows, and glacial moraines. Mud run-up markings on trees indicated that the flood stage of this event reached depths of at least 2.4 meters. Velocity calculations indicate that different surges of debris flow and flooding reached 3.9 meters per second. The debris flow reworked and deposited material ranging in size from sand to coarse boulders over a 0.1 square kilometer area, while flooding and scouring as much as 0.45 square kilometer. Based on cross-sectional transect measurements recreating pre-event topography and other field measurements, the total volume of the deposit ranged from 100,000 to 240,000 cubic meters.

Scientific Investigations Report↗

USGS2007

Suspended-Sediment Loads and Yields in the North Santiam River Basin, Oregon, Water Years 1999-2004

The North Santiam River provides drinking water to the residents and businesses of the city of Salem, Oregon, and many surrounding communities. Since 1998, water-quality data, including turbidity, were collected continuously at monitoring stations throughout the basin as part of the North Santiam River Basin Turbidity and Suspended Sediment Study. In addition, sediment samples have been collected over a range of turbidity and streamflow values. Regression models were developed between the instream turbidity and suspended-sediment concentration from the samples collected from each monitoring station. The models were then used to estimate the daily and annual suspended-sediment loads and yields. For water years 1999-2004, suspended-sediment loads and yields were estimated for each station. Annual suspended-sediment loads and yields were highest during water years 1999 and 2000. A drought during water year 2001 resulted in the lowest suspended-sediment loads and yields for all monitoring stations. High-turbidity events that were unrelated or disproportional to increased streamflow occurred at several of the monitoring stations during the period of study. These events highlight the advantage of estimating suspended-sediment loads and yields from instream turbidity rather than from streamflow alone.

Scientific Investigations Report↗