Evaluating external nutrient and suspended-sediment loads to Upper Klamath Lake, Oregon, using surrogate regressions with real-time turbidity and acoustic backscatter data

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov/.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.Suggested citation: Schenk, L.N., Anderson, C.W., Diaz, Paul, and Stewart, M.A., 2016, Evaluating external nutrient and suspendedsediment loads to Upper Klamath Lake, Oregon, using surrogate regressions with real-time turbidity and acoustic backscatter data: U.S. Geological Survey Scientific Investigations Report 2016-5167, 46 p., https://doi.org/10.3133/ sir20165167. DatumsVertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88) unless otherwise noted.Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).Elevation, as used in this report, refers to distance above the vertical datum. Executive SummarySuspended-sediment and total phosphorus loads were computed for two sites in the Upper Klamath Basin on the Wood and Williamson Rivers, the two main tributaries to Upper Klamath Lake. High temporal resolution turbidity and acoustic backscatter data were used to develop surrogate regression models to compute instantaneous concentrations and loads on these rivers. Regression models for the Williamson River site showed strong correlations of turbidity with total phosphorus and suspended-sediment concentrations (adjusted coefficients of determination [Adj R 2 ]=0.73 and 0.95, respectively). Regression models for the Wood River site had relatively poor, although statistically significant, relations of turbidity with total phosphorus, and turbidity and acoustic backscatter with suspended sediment concentration, with high prediction uncertainty. Total phosphorus loads for the partial 2014 water year (excluding October and November 2013) were 39 and 28 metric tons for the Williamson and Wood Rivers, respectively. These values are within the low range of phosphorus loads computed for these rivers from prior studies using water-quality data collected by the Klamath Tribes. The 2014 partial year total phosphorus loads on the Williamson and Wood Rivers are assumed to be biased low because of the absence of data from the first 2 months of water year 2014, and the drought conditions that were prevalent during that water year. Therefore, total phosphorus and suspended-sediment loads in this report should be considered as representative of a low-water year for the two study sites. Comparing loads from the Williamson and Wood River monitoring sites for November 2013-September 2014 show...

Examining the Effect of Physicochemical and Meteorological Variables on Water Quality Indicators of Harmful Algal Blooms in a Shallow Hypereutrophic Lake Using Machine Learning Techniques

“…Hydrologic predictors included streamflow from the Williamson River, the main tributary to Upper Klamath Lake that represents 46% of the total streamflow to the lake, 37 precipitation and snow depth from Crater Lake National Park operated by the National Oceanic and Atmospheric Administration (NOAA), and publicly available Oregon Water Resources Department data, 38 including a reference site for long-term streamflow trends (site 14057500) and groundwater levels (site KLAM2145, Figure 1). 1.…”