"Surrogate" Constituent Models are developed at USGS streamflow gages, called Super Gages, throughout Ohio, Kentucky, and Indiana. Each Super Gage deploys a variety of in-situ continuous water-quality monitors and is intermittently sampled for water-quality constituents over the range of hydrologic and seasonal conditions. By statistically combining continuous water-quality data with intermittent samples, models are developed to continuously estimate constituents that are not easily measured in real-time. For example, after a Surrogate Constituent Model is developed, turbidity (clarity of water) may be used to estimate suspended sediment concentration. Click here for a list of Ohio-Kentucky-Indiana Water Science Center Surrogate Constituent Models.
Many states provide hourly computed concentrations and loads for sediment, nutrients, bacteria, and many additional constituents; uncertainty values and probabilities for exceeding drinking water or recreational criteria; frequency distribution curves; and all historical hourly in-stream sensor measurements.
Ohio-Kentucky-Indiana Water Science Center regression models are listed in the table below. The list of these models also is available as a Microsoft Excel spreadsheet.
|Yellow River near Oak Grove, IN (USGS Site ID: 05516665)|
|Yellow River at Knox, IN (>USGS Site ID: 05517000)|
|Yellow River near Brems, IN (USGS Site ID: 05517010)|
|White River at Hazleton, IN (USGS Site ID: 03374100)|
|Eagle Creek at Zionsville, IN (USGS Site ID: 03353200)|
|Kankakee River at Davis, IN (USGS Site ID: 05515500)|
aConstituent and unit of measurement: suspended-sediment concentration (SSC) in milligrams per liter (mg/L).
bExplanatory Variables: Turbidity (TURB, YSI 6136).
cYears regression has been available on USGS National Real-Time Water-Quality (NRTQW) web site.
dModels listed followed protocols from Rasmussen, P.P., Gray, J.R., Glysson, G.D., and Ziegler, A.Z., 2009, Guidelines and Procedures for Computing Time-Series Suspended-Sediment Concentrations and Loads from In-Stream Turbidity-Sensor and Streamflow Data: U.S. Geological Survey Techniques and Methods book 3, chap. C4, 53 p.