Water-Quality Monitoring in the Lower Kansas River Basin

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The Kansas River is a primary source of drinking water for about 800,000 people in northeastern Kansas. Water-quality concerns related to excessive nutrient, bacteria, and sediment concentrations have been identified by the Kansas Department of Health and Environment. Additionally, the occurrence and transport of cyanobacteria (also called blue-green algae), associated toxins, and taste-and-odor compounds have recently become focal points of interest for ongoing research in the lower Kansas River basin.

Since 1999, the USGS has conducted studies related to describing hydrology and water-quality in the lower Kansas River basin. Analysis of continuous water-quality monitor and discrete water-quality sample data has led to the development of statistical models that estimate water-quality constituent concentrations, as well as the probability of occurrence for cyanobacteria and associated toxins and taste-and-odor compounds. The data collected throughout these studies are useful for characterizing changes in water-quality conditions through time, characterizing potentially harmful cyanobacterial events, and indicating changes in water-quality conditions that may affect drinking-water treatment processes.

Fate and Transport of Cyanobacteria and Associated Toxins and Taste-and-odor Compounds from Upstream Reservoir Releases:

  • Describe the extent and duration of the transport of cyanobacteria and associated toxins and taste-and-odor compounds from upstream reservoirs to the Kansas River during September through October 2011.
  • Evaluate strengths and weaknesses of discrete sampling techniques for cyanobacteria and associated toxins and taste-and-odor compounds and develop robust plans to monitor future cyanobacteria related events.

Continuous Water-Quality Monitoring:

  • Install, operate, and maintain a real-time network of water-quality monitors at 4 existing USGS streamflow-gaging sites on the Kansas River
    • Kansas River at Wamego, KS (USGS station # 06887500)
    • Kansas River at De Soto, KS (USGS station # 06892350)
    • Kansas River near Lake Quivira, KS (USGS station # 06892518)
    • Kansas River at Topeka Water Plant, KS (USGS station # 06888990)

Discrete Water-Quality Sample Collection:

  • Collect routine samples at the Kansas River at Wamego, Topeka, and De Soto sites over the range of hydrologic conditions.
  • Collect event-based samples at Kansas River at Wamego, Topeka, and De Soto sites, as well as at three reservoir outflow sites from Milford Lake (Republican River at Junction City, Kansas; USGS station identifier # 06857100), Tuttle Creek Lake (Big Blue River near Manhattan, Kansas; USGS station identifier # 06887000), and Perry Lake (Delaware River at Perry, Kansas; USGS station identifier # 06890900); all tributaries to the Kansas River.

Evaluation of Water-Quality Data:

  • Use the real-time water-quality monitor and discrete sample data to characterize and describe the overall water-quality conditions related to:
    • Water temperature, specific conductance, pH, dissolved oxygen, turbidity, and chlorophyll fluorescence response
    • Major ions and dissolved solids
    • Alkalinity
    • Nutrients (nitrogen and phosphorous species)
    • Suspended sediment
    • Indicator and actinomycetes bacteria
    • Phytoplankton community composition and abundance
    • Cyanotoxins microcystin and cylindrospermopsin
    • Taste-and-odor compounds geosmin and 2-methylisoborneol (MIB)

 Surrogate Model Update and Development:

  • Document regression models that establish relations between continuous and discrete water-quality data collected at the Kansas River at Wamego, Topeka, and De Soto sites. These regression models provide near real-time computations water-quality constituent concentrations or densities that are not easily measured in real-time. Models will be developed and maintained for total dissolved solids, major ions, bromide, hardness as calcium carbonate, nutrients (nitrogen and phosphorus species), chlorophyll a, total suspended solids, suspended sediment, and fecal indicator bacteria.
  • Develop logistic regression models that estimate the probability of occurrence above selected thresholds for cyanobacteria, associated toxins, and taste-and-odor compounds for the Kansas River at Wamego, Topeka, and De Soto sites.
  • Assess surrogate regression model performance over time.

Long-Term Analysis of Water-Quality Trends

  • Retrospective analysis of water-quality conditions over a period spanning 5 decades.
  • Use Weighted Regressions on Time, Discharge, and Season (WRTDS) to characterize and compare trends in water-quality conditions since the inception of the Clean Water Act in Kansas.

Fate and transport of Cyanobacteria and Associated Toxins and Taste-and-odor Compounds from Upstream Reservoir Releases (Graham and others, 2012):

  • Milford Lake, an upstream reservoir with outflow into the lower Kansas River, had an ongoing cyanobacterial bloom during September and October 2011.
  • The cyanobacterial toxin microcystin was 650 to 7,500 times higher than the Kansas Department of Health and Environment guidance level for a public health warning during the Milford Lake bloom.
  • The Republican River, downstream of Milford Lake, was the only Kansas River tributary with notable microcystin concentrations (> 1 microgram per liter) during the study period.
  • Taste-and-odor compounds were detected in all tributaries located immediately downstream of reservoirs in the study area and total concentrations generally exceeded the human detection limit threshold (5 to 10 nanograms per liter).
  • Following Milford Lake outflow releases, microcystin, geosmin, and MIB were detected throughout a 173-mile reach of the Kansas River. These compounds remained detectable throughout the study reach until mid-October and indications of co-occurrence were common.
  • There was generally less variability in cyanobacteria results from depth- and width-integrated samples compared to surface dip samples at the centroid of flow. Microcystin, geosmin, and MIB were less variable in relation to discrete sample collection technique.

 

Surrogate Model Development (Williams, 2021; Foster and Graham, 2016):

  • Continuous and discrete water-quality data collected since July 2012 were used to develop statistical models for constituents of interest at the Wamego and De Soto sites.
  • Logistic models that continuously estimate the probability of occurrence above selected thresholds were developed for cyanobacteria, microcystin, and geosmin.
  • Linear regression models that continuously estimate constituent concentrations or densities were developed total dissolved solids, major ions, hardness as calcium carbonate, nutrients (nitrogen and phosphorus species), chlorophyll a, total suspended solids, suspended sediment, and fecal indicator bacteria.
  • These models will be used to provide real-time estimates of the probability that cyanobacteria and associated compounds exceed thresholds and of the concentrations of other water-quality constituents in the Kansas River.
  • The models will be useful for characterizing changes in water-quality conditions through time, characterizing potentially harmful cyanobacterial events, and indicating changes in water-quality conditions that may affect drinking-water treatment processes.

 

Evaluation of Water-Quality Data (Graham and others, 2018):

  • Continuous and discrete data collected during July 2012 through September 2018 were used to:
    • Characterize the overall water-quality conditions in the lower Kansas River at the Kansas River at Wamego and De Soto sites.
    • Describe the occurrence and co-occurrence of cyanobacteria, cyanotoxins, and taste-and-odor compounds in the lower Kansas River basin
    • Identify factors associated with occurrence of cyanobacteria, cyanotoxins, and taste-and-odor compounds.
    • Evaluate performance of previously published surrogate logistic regression models that estimate the probability of cyanobacterial abundance and microcystin and geosmin concentrations above thresholds of concern at the Kansas River at Wamego and De Soto sites during July 2015 through September 2016.

Long-Term Analysis of Water-Quality Trends

  • This report is currently in progress and will be available in during Summer 2022. Long-term trends in water-quality conditions at the Wamego and De Soto sites since the inception of the Clean Water Act in Kansas will be characterized for:
    • Total dissolved solids and chloride
    • Dissolved inorganic nitrogen
    • Total nitrogen and total phosphorus
    • Orthophosphate
    • Total suspended solids
    • Suspended sediment concentration
    • Fecal indicator bacteria