Surrogate regression models for computation of time series chloride concentrations, Chester County, Pennsylvania (2023)

In cooperation with state and county agencies, including the Chester County Water Resources Authority (CCWRA), the U.S. Geological Survey (USGS) has collected discrete stream samples for analysis of chloride concentrations at three real-time streamflow and water-quality monitoring (specific conductance) stations located in Chester County, Pennsylvania. Data were collected from 2010-2023 at these stations for the application of predicting chloride concentrations using real-time continuous specific conductance and streamflow data. Regression equations were developed by relating discrete-sample chloride and discrete specific conductance data, as well as continuous streamflow data. Regression equations included possible explanatory variables of discrete specific conductance and continuous streamflow and the response variable of chloride concentration with base-10 logarithmic (log) transformations. Data files in .CSV format include the variables of datetime, specific conductance (microsiemens per centimeter at 25 degrees Celsius, uS/cm), streamflow (Q, cubic feet per second), chloride concentrations (milligrams per liter, mg/L), and calculated or transformed variables of log specific conductance, log streamflow, and log chloride concentrations.

Data are included for 3 stream sites:
Valley Creek at PA Turnpike Bridge near Valley Forge, PA (USGS station 01473169) with discrete Cl and SC data from nearby downstream site Valley Creek at Wilson Road near Valley Forge, PA (USGS station 01473170)
White Clay Creek near Strickersville, PA (USGS station 01478245)
Brandywine Creek at Chadds Ford, PA (USGS station 01481000)

For the model developed for station 01473169, discrete Cl and SC data come from station 01473170, and continuous Q data comes from station 01473169.
For the model developed for station 01478245, discrete Cl and SC data and continuous Q data come from station 01478245.
For the model developed for station 01481000, discrete Cl and SC data and continuous Q data come from station 01481000.