Geology topics

Guy M. Foster

Publications and source records attributed to Guy M. Foster.

At least 19 recordsLinked to original sources

USGS2025

Spatiotemporal variability of algal biomass and nitrate in Owasco and Seneca Lakes in the Finger Lakes Region, New York, in 2019

Cyanobacterial harmful algal blooms (CyanoHABs) have become increasingly common, threatening the security of water resources globally. The U.S. Geological Survey conducted high-resolution nearshore mapping surveys using boat-mounted multiparameter sondes and nitrate sensors during the summer and fall of 2019 on Owasco Lake and Seneca Lake, two lakes with documented CyanoHABs in the Finger Lakes region of New York State. Discrete sensor measurements and water-quality samples were collected at fixed points along survey routes and continuous data were generated at open-water monitoring platforms. This investigation examined whether water-quality information from nearshore surveys was representative of open-water conditions and if nearshore surveys could be used to identify areas with localized nearshore CyanoHABs and potential sources of nutrients not captured by tributary sampling. In addition to comparisons across methods, nearshore concentrations of nitrate and chlorophyll were evaluated relative to tributary outlets, cyanobacterial abundance and biovolume at discrete locations, and the locations of near-surface CyanoHABs that were designated as “confirmed with high toxins” by the New York State Department of Environmental Conservation. Nitrate and chlorophyll concentrations were comparable across methods for each lake, although concentration ranges were typically higher for nearshore mapping datasets than for nearshore discrete datasets. Nearshore surveys indicated areas of nitrate enrichment that varied temporally in both lakes. Orthophosphate was not routinely detected. Across methods, median chlorophyll concentrations were higher for the summer survey than for the fall survey in Owasco Lake. Nearshore chlorophyll concentrations varied more temporally in Owasco Lake than in Seneca Lake. Phytoplankton and cyanobacterial abundance and biovolume were about five times higher in Owasco Lake than in Seneca Lake. Cyanobacteria dominated the phytoplankton community in most samples, and Microcystis comprised the bulk of the cyanobacterial biovolume. The most abundant potential cyanotoxin-producing (specifically microcystins) genera were Microcystis , Synechococcus , Aphanocapsa , and Pseudanabaena . The cyanobacterial community composition was comparable between open-water monitoring platforms and nearshore samples. Microcystins were detected in seven survey samples from Owasco Lake, in one survey sample from Seneca Lake, and in one sample each from the open-water monitoring platforms on Owasco and Seneca Lakes that were collected about 7 days before the fall surveys. Microcystin detections were not consistently associated with high cyanobacterial cell counts or cyanotoxin-producing genera. Results from nearshore surveys were comparable to open-water monitoring platforms and discrete nearshore observations in the absence of nearshore or open-water CyanoHABs in these systems during the study. Patterns of nearshore concentrations of nitrate and chlorophyll from nearshore surveys may aid in the identification of areas with localized nitrate loading and shifts in phytoplankton abundance and community composition.

New York↗

USGS2024

Comparison of imaging flow cytometry and microscopy for freshwater algal bloom detection

Imaging flow cytometry (IFC) is an emerging tool that allows for rapid identification and enumeration of phytoplankton in freshwater systems. However, few studies have assessed the effects of preservation on IFC results or compared live IFC and microscopy results in freshwater systems. Understanding the effects of preservation and differences between IFC and microscopy will improve interpretation of these data and inform strategies to use IFC-based approaches in freshwater systems. Our study objectives were to compare IFC and phase contrast with epifluorescence microscopy as techniques for phytoplankton identification and enumeration, and the effects of sample preservation with an emphasis on taxa forming harmful cyanobacterial blooms (HCBs). During June through October 2020, samples were collected from 2 lakes in the Finger Lakes region of New York. Live and preserved samples were analyzed by laboratory-based IFC, and preserved samples were analyzed by microscopy. The IFC approach captured community dynamics while detecting potential cyanobacterial bloom-forming taxa earlier and at lower abundances than microscopy. Laboratory-based IFC allowed for an intermediate level of taxonomic information when compared to microscopy, gross techniques, such as extracted chlorophyll a or fluorescence sensors, and field-based operation of IFC approaches. The laboratory-based application of IFC in this study allowed receipt of results in 5 d or less, a substantial improvement over microscopy, which can be time-consuming to conduct. However, the laboratory-based IFC approach had some limitations. Imaging flow cytometry-estimated biovolume may be less accurate than microscopy for some taxa because of the algorithms used to calculate biovolume, particularly for chrysophytes and coccoid cyanobacteria. Colonial dissociation during preservation appeared to affect detection of Microcystis by IFC less than for other fragile bloom-forming taxa like chrysophytes. Our study results advance understanding of how IFC may translate to field-based approaches for early harmful algal bloom indicators in freshwater.

Lake and Reservoir Management↗

USGS2024

Advancing the understanding of Cyano-HABs in New York State

Most harmful algal blooms (HABs) in freshwater lakes, rivers, and streams are caused by cyanobacteria (Cyano-HABs). Under certain environmental conditions, dense concentrations (blooms) can form, which have the potential to cause aesthetic, ecological, and economic damage to afflicted waterbodies. Most importantly, Cyano-HABs can cause physical harm to people, pets, and livestock through the production of cyanotoxins.

New York↗

USGS2023

Field techniques for fluorescence measurements targeting dissolved organic matter, hydrocarbons, and wastewater in environmental waters: Principles and guidelines for instrument selection, operation and maintenance, quality assurance, and data reporting

The use of field deployable fluorescence sensors by the U.S. Geological Survey has become increasingly common for a wide variety of surface water and groundwater investigations. This report addresses field deployable fluorometers that measure the fluorescence response of various substances in water exposed to incident light generated by the sensor. An introduction to the basic principles of field measurements of fluorescence is provided, as well as technical background information on sensors that target dissolved organic matter, wastewater, and hydrocarbons, including sensor selection, operating principles, key features, and design elements. General deployment, operation and maintenance protocols, quality-assurance techniques, and suggestions for data reporting are presented to facilitate and standardize the collection and accurate communication of data collected by the U.S. Geological Survey across studies, sites, and sensor types. Sensor performance issues and common interferences are also described. An appendix is included to describe sensor calibration criteria and procedures, reporting units, and specific approaches to correct for interferences for fluorescence of dissolved organic matter sensors.

Techniques and Methods↗

USGS2022

Technical note—Performance evaluation of the PhytoFind, an in-place phytoplankton classification tool

In 2019, the U.S. Geological Survey evaluated the performance of the Turner Designs, Inc. PhytoFind, an in-place phytoplankton classification tool. The sensor was tested with sample blanks, monoculture and mixed phytoplankton cultures, and turbidity challenges in a laboratory, and was tested on a 120-mile survey of the Caloosahatchee and St. Lucie Rivers in Florida, including Lake Okeechobee. Results include the following: The mixed phytoplankton group fluorescence channel (green excitation sensor) of the PhytoFind can be sensitive to interference. The PhytoFind generally overestimated chlorophyll concentration relative to laboratory-measured chlorophyll a concentrations. Turbidity interference may be less apparent in samples where green algae (chlorophytes) represent a high relative percentage of biovolume. The dissolved organic matter compensation feature was effective in the environmental waters sampled during this evaluation. The correlation between percent chlorophyll contribution per phytoplankton group measured by the PhytoFind and relative percent biovolume per phytoplankton group measured in the laboratory varied and was not explicitly determined to be related to dominant taxa, phytoplankton community composition, or environmental conditions.

Scientific Investigations Report↗

USGS2022

Field techniques for the determination of algal pigment fluorescence in environmental waters—Principles and guidelines for instrument and sensor selection, operation, quality assurance, and data reporting

The use of algal fluorometers by the U.S. Geological Survey (USGS) has become increasingly common. The basic principles of algal fluorescence, instrument calibration, interferences, data quantification, data interpretation, and quality control are given in Hambrook Berkman and Canova (2007). Much of the guidance given for instrument maintenance, data storage, and quality assurance in Wagner and others (2006) are also applicable to algal fluorometers, although they are not explicitly discussed. Algal fluorometers have advanced substantially since these guidance documents were published; so that while the basic principles remain unchanged, new guidance is needed. This techniques and methods report is intended to provide additional information on algal fluorescence-sensor calibration, maintenance, measurement, data storage, and quality assurance that meet stated objectives of USGS data-collection efforts. The operations described facilitate and standardize the collection and accurate communication of algal fluorescence data collected by the USGS across studies, sites, and instrument types. This report provides technical background information on algal fluorescence sensors; including specifications, operating principles, key features, and design elements. Maintenance and calibration protocols, quality-assurance techniques, and suggestions for data reporting are presented. Sensor performance issues, common interferences, and strategies for addressing them are also described.

Techniques and Methods↗

USGS2021

Technical note—Relative variability of selected turbidity standards and sensors in use by the U.S. Geological Survey

The challenges associated with field measurements of turbidity are well known and result primarily from differences in reported values that depend on instrument design and the resulting need for reporting units that are specific to those designs. A critical challenge for making comparable turbidity measurements is the selection and use of appropriate turbidity standards for sensor calibration. The accepted primary standards for turbidity measurements use formazin made from scratch; all others should relate back to readings obtained using standard formazin. However, because turbidity is a qualitative property of water, comparing standards is not as simple as it is for many chemical measurements. The U.S. Geological Survey “National Field Manual for the Collection of Water-Quality Data” currently allows for the use of two standards, formazin and polymer beads, for the calibration of field turbidimeters. Another challenge for making comparable turbidity measurements is selection of turbidity sensors. A turbidity sensor commonly used in the U.S. Geological Survey, the Yellow Springs Instruments (YSI) 6136, has been replaced by the manufacturer with the YSI EXO turbidity sensor. Both sensors operate on the same principles but have slight design differences that result in readings that are not directly comparable on a 1:1 basis. Differences in calibration standards and sensors are a cause of concern in ongoing studies that require switching calibration standards or sensor types, and for comparisons of data collected with sensors calibrated by using different calibration standards, different sensor types, or both. The objectives of this study were to evaluate the response of two YSI turbidity sensors in both formazin-based standards (StablCal) and polymer turbidity standards (in this case YSI brand; however, other brands are available) and to compare the performance of the YSI EXO and YSI 6136 turbidity sensors under similar laboratory and environmental (field) conditions. To quantify these differences, a series of laboratory and field side-by-side comparisons were conducted. Nine field comparisons of YSI EXO and YSI 6136 sensors were performed at site locations in Kansas and Virginia. Two field comparisons of StablCal and polymer calibration standards were performed in Kansas, both using YSI EXO turbidity sensors. Five laboratory comparisons between the YSI EXO and YSI 6136 turbidity sensors were performed, and seven laboratory comparisons between StablCal and polymer turbidity standards were performed using YSI EXO turbidity sensors. The results can help the USGS and others better understand how turbidity data can differ depending on the sensors and calibration standards used. Key findings and conclusions include the following— Regardless of the comparison, strong linear associations were typically found across all measures of turbidity under field and laboratory conditions, but linear associations were not necessarily 1:1 and varied by type of standard, type of sensor, and field and laboratory conditions. The mean relative percentage differences for all but a few comparisons were greater than 10 percent but less than 30 percent. However, differences were inconsistent across the laboratory and field conditions measured in this study, precluding the ability to formulate definitive statements of consistent directional bias depending on the type of standard or sensor used. Across all tests and a range of 0 to 1,000 formazin nephelometric units (FNU), no consistent bias between the YSI EXO and YSI 6136 turbidity sensors was observed, but either regression relations were near 1:1 or the YSI EXO turbidity readings were lower than those measured with the YSI 6136. Relative percentage differences typically exceeded the 10- and 30-percent benchmarks. However, most (about 95 percent) of the absolute differences between turbidity values measured with the YSI EXO and those measured with the YSI 6136 sensors were less than 20 FNU. In laboratory experiments, when turbidity was “constant,” the absolute difference between YSI EXO and YSI 6136-measured turbidity values ranged from near 0 FNU to nearly 400 FNU (over a range of 0 to 1,000 FNU). Substantial variability in turbidity measurements makes comparison between standards and sensor types challenging. Given the inherent variability in turbidity measurements and the lack of consistent bias between calibration standards or sensors, changing methods during an ongoing study would compromise the comparability of the data. The effect of changing methods ultimately depends on study objectives. If method changes are required, laboratory- and field-based comparisons across a range of conditions ideally would be conducted to determine whether site-specific biases can be identified.

Open-File Report↗

USGS2021

Spatial and temporal variability of nutrients and algae in the Republican River and Milford Lake, Kansas, June through November 2017 and May through November 2018

Milford Lake has been listed as impaired and designated hypereutrophic because of excessive nutrient loading, specifically biologically available orthophosphate. It is the largest lake by surface area in Kansas and is a reservoir built for purposes including water supply and recreation. In 2015, the Kansas Department of Health and Environment (KDHE) divided the lake into three zones (Zones A, B, and C) for recreational monitoring of harmful algal blooms (HABs). Upstream Zone C has historically been more affected by HABs than Zones B and A, and Zone C has historically had the highest phosphorus concentrations. The U.S. Geological Survey, in cooperation with the KDHE, completed a study in 2017–18 to assess the spatial and temporal variability of nutrients and algae in the Republican River (the primary inflow to Milford Lake) and Milford Lake using spatially and temporally dense data. During the study period, discrete water-quality samples were collected at 36 lake sites, 21 river sites, and 1 pond. All samples were analyzed for nutrients; some samples were also analyzed for chlorophyll, phycocyanin, microcystin, and (or) phytoplankton community composition and abundance. Results from this study provide perspective for understanding the potential role nutrient and algal conditions have in facilitating the formation of HABs and may inform future actions to prevent and mitigate HABs and their potential effects on human and environmental health. In 2017, one low-flow floating synoptic on the Republican River into Zone C of Milford Lake and one 24-hour synoptic in Zone C of Milford Lake were completed. Results from the low-flow floating synoptic on July 17, 2017, at 21 river sites, 8 lake sites, and 1 pond site indicated that the Republican River was not contributing dissolved orthophosphate or total phosphorus concentrations higher than those in the main body of Milford Lake. No patterns in nutrient or total microcystin concentrations were evident from the 24-hour synoptic at two sites on August 24–25, 2017. Total nitrogen was dominated by total Kjeldahl nitrogen (TKN) at both sites. Different oscillation activity in algal biomass and chlorophyll at the two sites demonstrated the variable nature of algal accumulations and their effects on nutrient and dissolved oxygen concentrations. Different patterns in chlorophyll and microcystin concentrations indicate that the relation between algal biomass and cyanotoxin concentrations were different at the two sites, possibly because of differences among algal communities present at each site. Three whole-lake synoptics through Zones A, B, and C in Milford Lake were completed on July 10, August 9, and October 16–17, 2018, at 30 lake sites. Orthophosphate was consistently at least 77 percent of total phosphorus at all sites except the two most uplake sites. At the two most uplake sites, orthophosphate was between 52 and 72 percent of the total phosphorus present at the site. Concentrations of TKN were not consistently increasing or decreasing during 2018. Total nitrogen was dominated by TKN in July and August. Very low concentrations of dissolved nitrate plus nitrite indicate that the nutrient was likely tied up in algal biomass. By October, total nitrogen was approximately one-half TKN and one-half dissolved nitrate plus nitrite. Higher concentrations of dissolved orthophosphate and dissolved nitrate plus nitrite in October than in July and August were likely caused by reduced biological activity (less uptake of nutrients) and lower air and water temperatures. Multiple inflow events (streamflow greater than median daily value) between August and October also may have moved nutrients through the lake. Chlorophyll, phycocyanin, microcystin, and phytoplankton samples were collected at eight sites in 2018. Most sites had their highest chlorophyll concentrations in August. The three most uplake sites had their highest phycocyanin concentrations in July, whereas the other five sites had their highest phycocyanin concentrations in August. Two of 23 samples had detections of total microcystin (0.11 and 0.12 microgram per liter). Phytoplankton community composition mainly consisted of Bacillariophyta, Chlorophyta, Cryptophyta, and Cyanobacteria. Phytoplankton community composition and abundance data described broad seasonal patterns and did not capture the full range of possible conditions at each site.

Kansas↗

USGS2020

Cyanotoxin occurrence in large rivers of the United States

Cyanotoxins occur in rivers worldwide but are understudied in lotic ecosystems relative to lakes and reservoirs. Eleven large river sites located throughout the United States were sampled during June–September 2017 to determine the occurrence of cyanobacteria with known cyanotoxin-producing strains, cyanotoxin synthetase genes, and cyanotoxins. Chlorophyll-a concentrations spanned the range from oligotrophic to eutrophic (0.5–64.4 µg L-1). Cyanobacteria were present in the algal communities of all rivers (82% of samples, n=50), but did not dominate the phytoplankton (0 to 52% of total abundance; mean=8.8%). Pseudanabaena and Planktothrix occurred most often and many (64%) of the cyanobacterial genera identified (n=25) have known cyanotoxin-producing strains. Cyanotoxin synthetase genes occurred in all but one river. The mcyE and sxtA genes were most common, present in 73% of rivers and 44% and 40% of samples, respectively. The cyrA gene was less common (22% of samples) but occurred in 64% of rivers. The anaC gene was detected in one river (4% of samples). Anatoxin-a and microcystins were detected at low levels (0.10–0.38 µg L-1) in two midcontinent rivers. Cylindrospermopsins and saxitoxins were not detected. Cyanobacteria, cyanotoxin synthetase genes, and cyanotoxins were present at low concentrations throughout this subset of US rivers. Eutrophic rivers located in the midcontinent region of the US had the highest algal biomass, abundance of cyanotoxin synthetase genes, and cyanotoxin occurrence.

Inland Waters↗

USGS2019

Spatial and temporal variability of harmful algal blooms in Milford Lake, Kansas, May through November 2016

The U.S. Geological Survey, in cooperation with the Kansas Department of Health and Environment (KDHE), completed a study to quantify the spatial and temporal variability of cyanobacterial blooms in Milford Lake, Kansas, over a range of environmental conditions at various time scales (hours to months). A better understanding of the spatial and temporal variability of cyanobacteria and microcystin will inform sampling and management strategies for Milford Lake and for other lakes with cyanobacterial harmful algal bloom (CyanoHAB) issues throughout the Nation. Spatial and temporal variability were assessed in the upstream one-third of Milford Lake (designated as “Zone C” by KDHE) during May through November 2016 using a combination of time-lapse photography, continuous water-quality monitors, discrete phytoplankton, chlorophyll, and microcystin samples, and spatially dense near-surface data. Combined, these data were used to characterize variability of cyanobacterial abundance, algal biomass, and microcystin concentrations in Zone C of Milford Lake before, during, and after cyanobacterial blooms in 2016. Temporal patterns were evaluated during May through November 2016 using time-lapse photography at six locations in Zone C and at a single point location (the Wakefield site) using a combination of discrete and continuously measured water-quality data (including the cyanobacterial pigment phycocyanin). Based on time-lapse photography, CyanoHABs developed in Zone C of Milford Lake in early July and persisted through the end of November. Bloom accumulations at individual sites were dependent on wind direction. After a change in wind direction, it would take about 1 day for accumulations to become visible at different locations. During periods with low wind, accumulations were widespread and visible at all sites. Cyanobacteria were absent from the algal community at the Wakefield site in late May and were a minor component of the community in June; however, by mid-July the cyanobacteria were dominant and remained dominant until early November. Chlorophyll and microcystin concentrations at the Wakefield site were estimated using sensor-measured phycocyanin based on regression models developed for Zone C. Regression-estimated concentrations likely are more indicative of seasonal patterns in algal biomass (as indicated by chlorophyll concentrations) and microcystin than discretely collected samples because regression-estimated data have a much higher temporal resolution. Based on regression estimates, algal biomass and microcystin concentrations at the Wakefield site steadily increased from May through August. After August, concentrations decreased but remained relatively high compared to May and June. Daily chlorophyll maxima were as much as 400 times higher than daily minima, and daily microcystin maxima were as many as several orders of magnitude higher than daily minima. The extreme variability in algal biomass and microcystin concentrations at the Wakefield site reflects the development and dissipation of blooms, as indicated by the time-lapse cameras. Based on regression-estimated microcystin concentrations, the KDHE watch and warning thresholds for microcystin were exceeded during mid-June through late November. Exceedance of KDHE advisory thresholds often changed from no advisory to watch or warning over the course of the day because of the variability in algal biomass and microcystin concentrations caused by bloom development and dissipation. Continuous water-quality monitors may be useful in informing public-health decisions in lakes with variable CyanoHAB conditions; however, site-specific models need to be developed, and best practices for using continuous water-quality monitors to inform CyanoHAB management strategies need to be established. Spatial data were collected on May 26, July 21, and September 15, 2016, using a combination of a boat-mounted array and discrete water-quality samples analyzed for phytoplankton community composition and chlorophyll and microcystin concentrations. Spatial patterns were described using regression-estimated chlorophyll and microcystin concentrations. During the May 26, 2016, spatial surveys, cyanobacterial abundances were relatively low throughout Zone C and did not exceed KDHE guidance values compared to spatial surveys on July 21 and September 15. Regression-estimated chlorophyll concentrations were indicative of higher algal biomass uplake in Zone C, and decreases in the downlake direction towards Zone B. Regression-estimated chlorophyll concentrations also were more variable uplake than downlake. Based on regression estimates, microcystin concentrations did not exceed KDHE guidance values anywhere in Zone C on May 26. Spatial patterns in microcystin throughout Zone C did not match patterns in regression-estimated chlorophyll concentrations, likely because the algal community was not dominated by cyanobacteria at most locations in May. During the July 21, 2016, spatial surveys, cyanobacterial abundances in Zone C exceeded KDHE guidance values in 50 percent of samples. The algal community in Zone C was dominated by cyanobacteria at all locations except two, where cyanobacteria codominated with diatoms. Both locations where cyanobacteria and diatoms codominated were north of the causeway. Regression-estimated chlorophyll concentrations were indicative of higher algal biomass north of the causeway and on the eastern shore of Zone C. On July 21, algal biomass did not always decrease in the downlake direction. There was a decrease just south of the causeway but an increase shortly after with higher concentrations into Zone B. Spatial maps indicated changes in algal distribution at a 0.5-meter depth, with algae moving to the central part of the lake north of the causeway and along the eastern shore south of the causeway. Most regression-estimated microcystin concentrations on July 21 exceeded KDHE guidance values, reflecting the pervasive bloom conditions in Zone C during this period. Spatial patterns in regression-estimated microcystin concentrations throughout Zone C were similar to patterns seen in discrete samples and regression-estimated chlorophyll concentrations, with higher concentrations north of the causeway and on the east shore of Zone C. During the September 15, 2016, spatial surveys, cyanobacterial abundances did not exceed KDHE guidance values. The algal community north of the causeway was dominated by diatoms. The algal community throughout the rest of Zone C was dominated by cyanobacteria. Of regression-estimated microcystin concentrations on September 15, 80 percent did not exceed KDHE guidance values. Spatial patterns indicated northward movement of the cyanobacterial bloom consistent with a wind shift noted the previous day. On September 14, winds were generally from the north to northwest, shifting to the south by September 15. There was a northward progression of chlorophyll and microcystin during the spatial surveys. These data, along with the camera data and spatial and wind data from May and July, indicate that wind can be a major driver of the spatial and temporal variability of cyanobacterial blooms in Milford Lake and likely plays a role in the extent and duration of near-shore accumulations.

Kansas↗

USGS2018

Water-quality conditions with an emphasis on cyanobacteria and associated toxins and taste-and-odor compounds in the Kansas River, Kansas, July 2012 through September 2016

Cyanobacteria cause a multitude of water-quality concerns, including the potential to produce toxins and taste-and-odor compounds that may cause substantial economic and public health concerns, and are of particular interest in lakes, reservoirs, and rivers that are used for drinking-water supply. Extensive cyanobacterial blooms typically do not develop in the Kansas River; however, reservoirs in the lower Kansas River Basin occasionally develop blooms that may affect downstream water quality. During July 2012 through September 2016, continuous and (or) discrete water-quality data were collected at several sites (Wamego, De Soto, and three main reservoir-fed tributaries) on the Kansas River to characterize the sources, frequency and magnitude of occurrence, and causes of cyanobacteria, cyanobacterial toxins, and taste-and-odor compounds and to develop a real-time notification system of changing water-quality conditions that may affect drinking-water treatment. Algal biomass, as estimated by chlorophyll, was consistently higher at the downstream De Soto site than the upstream Wamego site. Higher algal biomass at the De Soto site likely was caused by algal growth during downstream transport without major losses due to grazing by aquatic organisms or other processes. Algal biomass at the Wamego and De Soto sites was negatively correlated with streamflow and total and bioavailable nutrient concentrations. The negative association between algal biomass and nutrients in the Kansas River likely reflects the relatively strong positive association between nutrient concentrations and streamflows. Cyanobacteria were relatively common in the Kansas River but rarely dominated the algal community. Like overall algal biomass, cyanobacterial abundances typically were higher at the De Soto site than the Wamego site. Cyanobacterial abundances generally peaked in late summer or early fall (July through October), with smaller peaks occasionally observed in spring (April through May). Cyanobacteria in the Kansas River rarely exceeded 20,000 cells per milliliter, the abundance at which cyanobacteria may become a concern for drinking-water treatment. Relations between cyanobacterial abundance and streamflow, turbidity, and nutrients in the Kansas River were similar to those between chlorophyll and total phytoplankton abundance, indicating the same processes that influence overall algal biomass and dynamics also are influencing cyanobacteria. The cyanotoxin microcystin was detected in about 27 percent of the samples collected from Kansas River tributary and main-stem sites. Cylindrospermopsin was detected in one sample from the De Soto site. Microcystin occurrence and concentration were similar between the Wamego and De Soto sites. Concentrations exceeded the U.S. Environmental Protection Agency health advisory guidance values for finished drinking water of 0.3 (for bottle-fed infants and pre-school children) and 1.6 micrograms per liter (μg/L; for school-age children and adults) in 6 percent or less of samples collected. These guidance values are for finished drinking water and are not directly applicable to observed environmental concentrations but do provide a benchmark for comparison. Microcystin was detected most often and had the highest concentrations during summer. Though seasonal patterns in microcystin occurrence were generally consistent, seasonal maxima varied by an order of magnitude across years. The taste-and-odor compounds geosmin and 2-methylisoborneol (MIB) were detected in about 78 and 43 percent of samples, respectively, collected across all sites (main stem and tributaries). Geosmin and MIB occurrence and concentration varied considerably between the Wamego and De Soto sites. Geosmin was detected in about 67 percent of Wamego samples and 81 percent of De Soto samples. The human detection threshold of 5 nanograms per liter (ng/L) was exceeded for geosmin in about 11 and 17 percent of the samples collected at the Wamego and De Soto sites, respectively. Geosmin was detected during all months of the year at both sites, and there were no clear seasonal patterns. MIB was detected less frequently in the Kansas River than geosmin and was observed in about 42 percent of Wamego samples and 33 percent of De Soto samples. Concentrations exceeded 5 ng/L in about 7 and 5 percent of samples from the Wamego and De Soto sites, respectively. As observed for geosmin, there were no clear seasonal patterns in MIB occurrence or concentration. There seems to be a connection between microcystin detections in the Kansas River and occurrence of microcystin in upstream reservoirs (and tributary streams). Microcystin concentrations greater than 0.3 μg/L may be likely during the summer when streamflow is less than 3,000 cubic feet per second (ft 3 /s) and contributions from Milford Lake exceed about 30 percent of total flow in the Kansas River. Observed microcystin concentrations typically were higher at the De Soto site than the Wamego or tributary sites during 2012 through 2016, indicating cyanobacteria may continue to grow and produce microcystin once introduced to the Kansas River. The spatial and temporal patterns in geosmin and MIB occurrence and concentration were more complex than microcystin. There were no clear connections between geosmin and MIB occurrence in the Kansas River and potential upstream reservoir (or tributary stream) sources. Likewise, there was not a clear relation between algal biomass, cyanobacteria, or actinomycetes bacteria and taste-and-odor events in the Kansas River. Geosmin and MIB were not strongly correlated with any measured environmental variable at either Kansas River site. Continuous water-quality data may be used independently or in combination with regression models to provide information on changing water-quality conditions that may affect drinking-water treatment processes or recreational activities on the Kansas River. For example, logistic regression model outputs and continuous water-quality data may both be indicative of the potential for microcystin events. Logistic regression models that are estimating a high probability of microcystin occurrence at concentrations above 0.1 μg/L can be used as one indicator. Streamflows less than 3,000 ft 3 /s during upstream reservoir releases during periods with low turbidity and increased chlorophyll fluorescence, specific conductance, and pH values may also be indicative of microcystin events. Advanced or near-real-time notification may inform proactive, rather than reactive, management strategies when water-quality conditions are changing rapidly or are likely to cause cyanobacteria-related events.

Kansas↗

USGS2017

Twenty years of water-quality studies in the Cheney Reservoir Watershed, Kansas, 1996-2016

Since 1996, the U.S. Geological Survey (USGS), in cooperation with the City of Wichita, has done studies in the Cheney Reservoir watershed to understand environmental effects on water-quality conditions. Early studies (1996–2001) determined subwatershed sources of contaminants, nutrient and sediment loading to Cheney Reservoir, changes in reservoir sediment quality over time, and watershed sources of phosphorus. Later studies (2001–present) focused on nutrient and sediment concentrations and mass transport from the watershed; the presence of cyanobacteria, cyanotoxins, and taste-and-odor compounds in the reservoir; and development of regression models for real-time computations of water-quality constituents of interest that may affect drinking-water treatment. This fact sheet summarizes key results from studies done by the USGS during 1996–2016 in the Cheney Reservoir watershed and Cheney Reservoir.

Kansas↗

USGS2017

Occurrence of cyanobacteria, microcystin, and taste-and-odor compounds in Cheney Reservoir, Kansas, 2001-16

Cheney Reservoir, located in south-central Kansas, is one of the primary drinking-water supplies for the city of Wichita and an important recreational resource. Since 1990, cyanobacterial blooms have been present occasionally in Cheney Reservoir, resulting in increased treatment costs and decreased recreational use. Cyanobacteria, the cyanotoxin microcystin, and the taste-and-odor compounds geosmin and 2-methylisoborneol have been measured in Cheney Reservoir by the U.S. Geological Survey, in cooperation with the city of Wichita, for about 16 years. The purpose of this report is to describe the occurrence of cyanobacteria, microcystin, and taste-and-odor compounds in Cheney Reservoir during May 2001 through June 2016 and to update previously published logistic regression models that used continuous water-quality data to estimate the probability of microcystin and geosmin occurrence above relevant thresholds. Cyanobacteria, microcystin, and geosmin were detected in about 84, 52, and 31 percent of samples collected in Cheney Reservoir during May 2001 through June 2016, respectively. 2-methylisoborneol was less common, detected in only 3 percent of samples. Microcystin and geosmin concentrations exceeded advisory values of concern more frequently than cyanobacterial abundance; therefore, cyanobacteria are not a good indicator of the presence of these taste-and-odor compounds in Cheney Reservoir. Broad seasonal patterns in cyanobacteria and microcystin were evident, though abundance and concentration varied by orders of magnitude across years. Cyanobacterial abundances generally peaked in late summer or early fall (August through October), and smaller peaks were observed in winter (January through February). In a typical year, microcystin was first detected in June or July, increased to its seasonal maxima in the summer (July through September), and then decreased. Seasonal patterns in geosmin were less consistent than cyanobacteria and microcystin, but geosmin typically had a small peak during winter (January through March) during most years and a large peak during summer (July through September) during some years. Though the relation between cyanobacterial abundance and microcystin and geosmin concentrations was positive, overall correlations were weak, likely because production is strain-specific and cyanobacterial strain composition may vary substantially over time. Microcystin often was present without taste-and-odor compounds. By comparison, where taste-and-odor compounds were present, microcystin frequently was detected. Taste-and-odor compounds, therefore, may be used as indicators that microcystin may be present; however, microcystin was present without taste-and-odor compounds, so taste or odor alone does not provide sufficient warning to ensure human-health protection. Logistic regression models that estimate the probability of microcystin occurrence at concentrations greater than or equal to 0.1 micrograms per liter and geosmin occurrence at concentrations greater than or equal to 5 nanograms per liter were developed. Models were developed using the complete dataset (January 2003 through June 2016 for microcystin [14-year dataset]; May 2001 through June 2016 for geosmin [16-year dataset]) and an abbreviated 4-year dataset (January 2013 through June 2016 for microcystin and geosmin). Performance of the newly developed models was compared with previously published models that were developed using data collected during May 2001 through December 2009. A seasonal component and chlorophyll fluorescence (a surrogate for algal biomass) were the explanatory variables for microcystin occurrence at concentrations greater than or equal to 0.1 micrograms per liter in all models. All models were relatively robust, though the previously published and 14-year models performed better over time; however, as a tool to estimate microcystin occurrence at concentrations greater than or equal to 0.1 micrograms per liter in a real-time notification system near the Cheney Dam, the 4-year model is most representative of recent (2013 through 2016) conditions. All models for geosmin occurrence at concentrations greater than or equal to 5 nanograms per liter had different explanatory variables and model forms. The previously published and 16-year models were not robust over time, likely because of changing environmental conditions and seasonal patterns in geosmin occurrence. By comparison, the abbreviated 4-year model may be a useful tool to estimate geosmin occurrence at concentrations greater than or equal to 5 nanograms per liter in a real-time notification system near the Cheney Dam. The better performance of the abbreviated 4-year geosmin model during 2013 through 2016 relative to the previously published and 16-year models demonstrates the need for continuous reevaluation of models estimating the probability of occurrence.

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USGS2017

Spatial variability of harmful algal blooms in Milford Lake, Kansas, July and August 2015

Cyanobacterial harmful algal blooms (CyanoHABs) tend to be spatially variable vertically in the water column and horizontally across the lake surface because of in-lake and weather-driven processes and can vary by orders of magnitude in concentration across relatively short distances (meters or less). Extreme spatial variability in cyanobacteria and associated compounds poses unique challenges to collecting representative samples for scientific study and public-health protection. The objective of this study was to assess the spatial variability of cyanobacteria and microcystin in Milford Lake, Kansas, using data collected on July 27 and August 31, 2015. Spatially dense near-surface data were collected by the U.S. Geological Survey, nearshore data were collected by the Kansas Department of Health and Environment, and open-water data were collected by U.S. Army Corps of Engineers. CyanoHABs are known to be spatially variable, but that variability is rarely quantified. A better understanding of the spatial variability of cyanobacteria and microcystin will inform sampling and management strategies for Milford Lake and for other lakes with CyanoHAB issues throughout the Nation. The CyanoHABs in Milford Lake during July and August 2015 displayed the extreme spatial variability characteristic of cyanobacterial blooms. The phytoplankton community was almost exclusively cyanobacteria (greater than 90 percent) during July and August. Cyanobacteria (measured directly by cell counts and indirectly by regression-estimated chlorophyll) and microcystin (measured directly by enzyme-linked immunosorbent assay [ELISA] and indirectly by regression estimates) concentrations varied by orders of magnitude throughout the lake. During July and August 2015, cyanobacteria and microcystin concentrations decreased in the downlake (towards the outlet) direction. Nearshore and open-water surface grabs were collected and analyzed for microcystin as part of this study. Samples were collected in the uplake (Zone C), midlake (Zone B), and downlake (Zone A) parts of the lake. Overall, no consistent pattern was indicated as to which sample location (nearshore or open water) had the highest microcystin concentrations. In July, the maximum microcystin concentration observed in each zone was detected at a nearshore site, and in August, maximum microcystin concentrations in each zone were detected at an open-water site. The Kansas Department of Health and Environment uses two guidance levels (a watch and a warning level) to issue recreational public-health advisories for CyanoHABs in Kansas lakes. The levels are based on concentrations of microcystin and numbers of cyanobacteria. In July and August, discrete water-quality samples were predominantly indicative of warning status in Zone C, watch status in Zone B, and no advisories in Zone A. Regression-estimated microcystin concentrations, which provided more thorough coverage of Milford Lake ( n =683–720) than discrete samples ( n =21–24), generally indicated the same overall pattern. Regardless of the individual agencies sampling approach, the overall public-health advisory status of each zone in Milford Lake was similar according to the Kansas Department of Health and Environment guidance levels.

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USGS2016

Spatiotemporal variability of inorganic nutrients during wastewater effluent dominated streamflow conditions in Indian Creek, Johnson County, Kansas, 2012–15

Nutrients, particularly nitrogen and phosphorus, are a leading cause of water-quality impairment in Kansas and the Nation. Indian Creek is one of the most urban drainage basins in Johnson County, Kansas, and environmental and biological conditions are affected by contaminants from point and other urban sources. The Johnson County Douglas L. Smith Middle Basin (hereinafter Middle Basin) wastewater treatment facility (WWTF) is the largest point-source discharge on Indian Creek. A second facility, the Tomahawk Creek WWTF, discharges into Indian Creek approximately 11.6 kilometers downstream from the Middle Basin WWTF. To better characterize the spatiotemporal variability of nutrients in Indian Creek, the U.S. Geological Survey, in cooperation with the Kansas Department of Health and Environment and Johnson County Wastewater, collected high-resolution spatial and temporal (a large number of samples collected over the entire reach or at single locations over a long period of time) inorganic nutrient (nitrate plus nitrite and orthophosphorus) data using a combination of discrete samples and sensor-measured data during 2012 through 2015. Nutrient patterns observed in Indian Creek along the upstream-downstream gradient during wastewater effluent dominated streamflow conditions were largely affected by the WWTFs and by travel time of the parcels of water. Nitrate plus nitrite concentrations in the Middle Basin WWTF effluent and at downstream sites varied by as much as 6 milligrams per liter over a 24-hour period. The cyclical variability in the Middle Basin WWTF effluent generated a nitrate plus nitrite pulse that could be tracked for approximately 11.5 kilometers downstream in Indian Creek, until the effect was masked by the Tomahawk Creek WWTF effluent discharge. All longitudinal surveys showed the same general patterns along the upstream-downstream gradient, though streamflows, wastewater effluent contributions to streamflow, and nutrient concentrations spanned a wide range. Differences in orthophosphorus and nitrate plus nitrite patterns were clear along the upstream-downstream gradient in Indian Creek, and orthophosphorus concentrations were not as variable as nitrate plus nitrite concentrations. In general, nitrate plus nitrite concentrations decreased downstream from the Middle Basin WWTF to minima near the confluence with Tomahawk Creek, increased downstream from the Tomahawk Creek WWTF, and then varied little within the study reach. Orthophosphorus concentrations generally decreased downstream from the Middle Basin WWTF. Despite the marked variability in nitrate plus nitrite concentrations caused by the Middle Basin WWTF effluent discharges, decreases in nitrate plus nitrite concentrations were discernable along the study reach between the two WWTFs. Decreases in nitrate plus nitrite concentrations along study reach were less variable than the cyclical variability typically measured, reiterating the effect of the Middle Basin WWTF effluent discharges on the spatiotemporal variability of nitrate plus nitrite in Indian Creek. Although decreases and rates of change in nitrate plus nitrite concentration were similar between the upper and lower reaches of Indian Creek, relations with initial nitrate plus nitrite concentrations and seasonal patterns were different between the upper (from College to the Marty study sites) and lower reaches (from Marty to the Mission Farms study sites) and did not reflect patterns observed for the overall reach. Quantifying the decreases in nitrate plus nitrite concentration caused by dilution and other in-stream processes were beyond the scope of this study, and were limited by available data. The data that are available suggest that dilution and other in-stream processes play a role in decreasing nitrate plus nitrite concentrations downstream from the Middle Basin WWTF in Indian Creek. Analysis of the spatiotemporal variability of nutrients focused on below-normal and normal streamflow conditions, when streamflow and nutrient conditions in Indian Creek were largely controlled by WWTF effluent flows and nutrient removal processes. Spatial and temporal data indicate there are decreases in nutrient concentrations along the upstream-downstream gradient in Indian Creek, but quantifying decreases is complicated by the variability in nutrient concentrations caused by the WWTFs. During below-normal and normal streamflow conditions, Indian Creek nutrient concentrations downstream from the Middle Basin WWTF primarily reflect effluent concentrations in the hours or days before depending on relative distance downstream.

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USGS2016

Sediment oxygen demand in eastern Kansas streams, 2014 and 2015

Dissolved oxygen concentrations in streams are affected by physical, chemical, and biological factors in the water column and streambed, and are an important factor for the survival of aquatic organisms. Sediment oxygen demand (SOD) rates in Kansas streams are not well understood. During 2014 and 2015, the U.S. Geological Survey, in cooperation with the Kansas Department of Health and Environment, measured SOD at eight stream sites in eastern Kansas to quantify SOD rates and variability with respect to season, land use, and bottom-sediment characteristics. Sediment oxygen demand rates (SOD T ) ranged from 0.01 to 3.15 grams per square meter per day at the ambient temperature of the measurements. The summer mean SOD rate was 3.0-times larger than the late fall mean rate, likely because of increased biological activity at warm water temperatures. Given the substantial amount of variability in SOD rates possible within sites, heterogeneity of substrate type is an important consideration when designing SOD studies and interpreting the results. Sediment oxygen demand in eastern Kansas streams was correlated with land use and streambed-sediment characteristics, though the strength of relations varied seasonally. The small number of study sites precluded a more detailed analysis. The effect of basin land use and streambed sediment characteristics on SOD is currently (2016) not well understood, and there may be many contributing factors including basin influences on water quality that affect biogeochemical cycles and the biological communities supported by the stream.

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USGS2016

May through July 2015 storm event effects on suspended-sediment loads, sediment trapping efficiency, and storage capacity of John Redmond Reservoir

The Neosho River and its primary tributary, the Cottonwood River, are the main sources of inflow to John Redmond Reservoir in east-central Kansas. Storm events during May through July 2015 caused large inflows of water and sediment into the reservoir. The U.S. Geological Survey, in cooperation with the Kansas Water Office, and funded in part through the Kansas State Water Plan Fund, computed the suspended-sediment inflows to, and trapping efficiency of, John Redmond Reservoir during May through July 2015. This fact sheet summarizes the quantification of suspended-sediment loads to and from the reservoir during May through July 2015 storm events and describes reservoir sediment trapping efficiency and effects on water-storage capacity.

Kansas↗

USGS2016

Effects of May through July 2015 storm events on suspended sediment loads, sediment trapping efficiency, and storage capacity of John Redmond Reservoir, east-central Kansas

The Neosho River and its primary tributary, the Cottonwood River, are the main sources of inflow to John Redmond Reservoir in east-central Kansas. Storage loss in the reservoir resulting from sedimentation has been estimated to be 765 acre-feet per year for 1964–2014. The 1964–2014 sedimentation rate was almost 90 percent larger than the projected design sedimentation rate of 404 acre-feet per year, and resulted in a loss of about 40 percent of the original (1964) conservation (multi-purpose) pool storage capacity. To help maintain storage in the reservoir, the Kansas Water Office has implemented more than two dozen stream bank erosion control projects to reduce the annual sediment load entering the reservoir and initiated a dredging project to restore nearly 2,000 acre-feet of storage near the dam to provide additional water supply to downstream water users. Storm events during May through July 2015 caused large inflows of water and sediment into the reservoir. Initially, flood waters were held back in the reservoir in order to decrease downstream flooding in Oklahoma. Later, retained reservoir flood waters were released at high rates (up to 25,400 acre-feet per day, the maximum allowed for the reservoir) for extended periods. The U.S. Geological Survey, in cooperation with the Kansas Water Office, computed the suspended-sediment inflows and retention in John Redmond Reservoir during May through July 2015. Computations relied upon previously published turbidity-suspended sediment relations at water-quality monitoring sites located upstream and downstream from the reservoir. During the 3-month period, approximately 872,000 tons of sediment entered the reservoir, and 57,000 tons were released through the reservoir outlet. The average monthly trapping efficiency during this period was 93 percent, and monthly averages ranged from 83 to 97 percent. During the study period, an estimated 980 acre-feet of storage was lost, over 2.4 times the design annual sedimentation rate of the reservoir. Storm inflows during the 3-month analysis period reduced reservoir storage in the conservation pool approximately 1.6 percent. This indicates that large inflows, coupled with minimal releases, can have substantial effects on reservoir storage and lifespan.

Kansas↗