 Ongoing Research
During 2001-03, the U.S. Geological Survey, in cooperation with the city of Wichita,
Kansas, conducted a study to develop reliable tools to estimate the onset of
cyanobacterial-related taste-and-odor occurrences in Cheney Reservoir,
one of Wichita’s primary drinking-water supplies. The study combined discrete sampling
with real-time continuous water-quality monitoring in an effort to relate the
concentration of the taste-and-odor compound geosmin to environmental variables
measured in real time (specific conductance, pH, temperature, turbidity, dissolved oxygen,
and chlorophyll). Geosmin was detected in 92 percent of discrete water-quality samples
(n=25), and concentrations ranged from < 3 to 113 nanograms per liter (median = 6 ng/L).
Multiple regression was used to develop a relation between geosmin concentrations in discrete water samples and the real-time
variables turbidity and specific conductance (r2=0.71, p<0.01, n=18), and the resulting
model was used to provide hourly estimates of geosmin concentration.
The model consistently indicated when geosmin concentrations would exceed the human
detection limit of 10 ng/L. Real-time estimates of geosmin and the probability that
concentrations will meet or exceed the human detection limit are available on the World
Wide Web at http://ks.water.usgs.gov/rtqw/index.shtml. Ongoing studies at Cheney
Reservoir will refine the relations between reservoir and inflow conditions and
taste-and-odor occurrences. The city of Wichita plans to use these models, along with
other variables measured in real time, to aid the management of the resource and decrease
water-treatment costs.
 Photo Courtesy of KDHE
Current Research
A diverse range of physical, chemical, and biological factors may potentially limit algal growth, and no single variable stands out
as an unequivocal link to cyanobacterial bloom formation. As a result, the relations
between environmental variables and cyanobacterial by-products, such as taste-and-odor
compounds and toxins, are invariably complex and may vary considerably over time
(hours-weeks). Understanding the factors driving algal community dynamics is critical to
the development of reliable models predicting the occurrence of taste-and-odor episodes.
Current research in Cheney Reservoir is focused on characterizing the physicochemical,
hydrological, and biological processes in Cheney Reservoir with respect to both watershed
inputs and in-reservoir processes. Specific objectives include:
- Assessment of annual and seasonal water-quality conditions and description of
taste-and-odor and other algal-related by-products that occur in Cheney Reservoir
- Description of the water-quality dynamics in the photosynthetic zone of the
water column to provide an understanding of algal growth, diurnal movement, and
production of taste-and-odor compounds associated with algae in Cheney Reservoir
- Use of the latest technology in water-quality instrumentation to
continuously monitor variability and potentially relate that information to observed
algal-population dynamics and taste-and-odor episodes
- Determination of relations between algal community structure dynamics and
the production of taste-and-odor producing algal compounds (geosmin/MIB) and potential
algal toxins such as microcystin
- Providing a long-term data base with which to verify and refine previously
determined relations between easily monitored water-quality variables and constituents
related to the use of Cheney Reservoir as a water-supply source for the city of Wichita.
Benefits
The current Cheney Reservoir and watershed study will have immediate and long-standing
impacts for the city of Wichita, state of Kansas, and the USGS.
Study results will provide information on taste-and-odor and toxin-producing blue-green
algae as well as a broad understanding of the general structure and function of the
Cheney Reservoir ecosystem. In addition, the seasonal assessment of factors driving
algal growth will increase understanding of reservoir processes.
Knowledge gained will assist in the development, implementation, maintenance,
and assessment of watershed-management goals and plans to maintain Cheney Reservoir
as a public water supply and recreational resource. Understanding the biological,
physicochemical, and hydrological factors associated with proliferation of nuisance
cyanobacterial blooms in a eutrophic, Central Plains reservoir will provide insight
into how to assess and manage problems experienced in other lakes regionally,
nationally, and globally.
Publications
- Water Quality and Relation to Taste-And-Odor Compounds in the North Fork Ninnescah River and Cheney Reservoir,
South-Central Kansas, 1997 - 2003. Chistensen V.G., Graham, J.L., Milligan, C.R., Pope L. M., and Ziegler, A.C., 2006, U.S. Geological Survey Scientific Investigations Report 2006-5095, 49p.
- Sediment Deposition and Trends and Transport of Phosphorus and Other Chemical Constituents, Cheney
Reservoir Watershed, South-Central Kansas, Mau, D.P., 2001, U.S. Geological Water-Resources Investigations Report 01-4085, 29 p.
- Watershed Trend Analysis and Water-Quality Assessment Using Bottom-Sediment Cores from Cheney Reservoir,
South-Central Kansas, Pope, L.M., 1998, U.S. Geological Survey Water-Resources Investigations Report 98-4227, 24 p.
 Photo Courtesy of KDHE
Water-Quality Data
Current water temperature, specific conductance, pH, turbidity, and dissolved oxygen data
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WATER DATA & STUDIES
U.S. Department of the Interior |
U.S. Geological Survey
