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At least 145 records · Page 8Linked to original sources
USGS2014

Integrated synoptic surveys of the hydrodynamics and water-quality distributions in two Lake Michigan rivermouth mixing zones using an autonomous underwater vehicle and a manned boat

The U.S. Geological Survey (USGS), in cooperation with the National Monitoring Network for U.S. Coastal Waters and Tributaries, launched a pilot project in 2010 to determine the value of integrated synoptic surveys of rivermouths using autonomous underwater vehicle technology in response to a call for rivermouth research, which includes study domains that envelop both the fluvial and lacustrine boundaries of the rivermouth mixing zone. The pilot project was implemented at two Lake Michigan rivermouths with largely different scales, hydrodynamics, and settings, but employing primarily the same survey techniques and methods. The Milwaukee River Estuary Area of Concern (AOC) survey included measurements in the lower 2 to 3 miles of the Milwaukee, Menomonee, and Kinnickinnic Rivers and inner and outer Milwaukee Harbor. This estuary is situated in downtown Milwaukee, Wisconsin, and is the most populated basin that flows directly into Lake Michigan. In contrast, the Manitowoc rivermouth has a relatively small harbor separating the rivermouth from Lake Michigan, and the Manitowoc River Watershed is primarily agricultural. Both the Milwaukee and Manitowoc rivermouths are unregulated and allow free exchange of water with Lake Michigan. This pilot study of the Milwaukee River Estuary and Manitowoc rivermouth using an autonomous underwater vehicle (AUV) paired with a manned survey boat resulted in high spatial and temporal resolution datasets of basic water-quality parameter distributions and hydrodynamics. The AUV performed well in these environments and was found primarily well-suited for harbor and nearshore surveys of three-dimensional water-quality distributions. Both case studies revealed that the use of a manned boat equipped with an acoustic Doppler current profiler (ADCP) and multiparameter sonde (and an optional flow-through water-quality sampling system) was the best option for riverine surveys. To ensure that the most accurate and highest resolution velocity data were collected concurrently with the AUV surveys, the pilot study used a manned boat equipped with an ADCP. Combining the AUV and manned boat datasets resulted in datasets that are essentially continuous from the fluvial through the lacustrine zones of a rivermouth. Whereas the pilot studies were completed during low flows on the tributaries, completion of surveys at higher flows using the same techniques is possible, but the use of the AUV would be limited to areas with relatively low velocities (less than 2 feet per second) such as the harbors and nearshore zones of Lake Michigan. Overall, this pilot study aimed at evaluation of AUV technology for integrated synoptic surveys of rivermouth mixing zones was successful, and the techniques and methods employed in this pilot study should be transferrable to other sites with similar success. The use of the AUV provided significant time savings compared to traditional sampling techniques. For example, the survey of outer Milwaukee Harbor using the AUV required less than 7 hours for approximately 600 profiles compared to the 150 hours it would have taken using traditional methods in a manned boat (a 95 percent reduction in man-hours). The integrated datasets resulting from the AUV and manned survey boat are of high value and present a picture of the mixing and hydrodynamics of these highly dynamic, highly variable rivermouth mixing zones from the relatively well-mixed fluvial environment through the rivermouth to the stratified lacustrine receiving body of Lake Michigan. Such datasets not only allow researchers to understand more about the physical processes occurring in these rivermouths, but they provide high spatial resolution data required for interpretation of relations between disparate point samples and calibration and validation of numerical models.

Wisconsin↗
USGS2011

Highway-runoff quality, and treatment efficiencies of a hydrodynamic-settling device and a stormwater-filtration device in Milwaukee, Wisconsin

The treatment efficiencies of two prefabricated stormwater-treatment devices were tested at a freeway site in a high-density urban part of Milwaukee, Wisconsin. One treatment device is categorized as a hydrodynamic-settling device (HSD), which removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater-filtration device (SFD), which removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. Efficiency-ratio and summation-of-load (SOL) calculations were used to estimate the treatment efficiency of each device. Event-mean concentrations and loads that were decreased by passing through the HSD include total suspended solids (TSS), suspended sediment (SS), total phosphorus (TP), total copper (TCu), and total zinc (TZn). The efficiency ratios for these constituents were 42, 57, 17, 33, and 23 percent, respectively. The SOL removal rates for these constituents were 25, 49, 10, 27, and 16 percent, respectively. Event-mean concentrations and loads that increased by passing through the HSD include chloride (Cl), total dissolved solids (TDS), and dissolved zinc (DZn). The efficiency ratios for these constituents were -347, -177, and 20 percent, respectively. Four constituents—dissolved phosphorus (DP), chemical oxygen demand (COD), total polycyclic aromatic hydrocarbon (PAH), and dissolved copper (DCu)—are not included in the list of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Event-mean concentrations and loads that decreased by passing through the SFD include TSS, SS, TP, DCu, TCu, DZn, TZn, and COD. The efficiency ratios for these constituents were 59, 90, 40, 21, 66, 23, 66, and 18, respectively. The SOLs for these constituents were 50, 89, 37, 19, 60, 20, 65, and 21, respectively. Two constituents—DP and PAH—are not included in the lists of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Similar to the HSD, the average efficiency ratios and SOLs for TDS and Cl were negative. Flow rates, high concentrations of SS, and particle-size distributions (PSD) can affect the treatment efficacies of the two devices. Flow rates equal to or greater than the design flow rate of the HSD had minimal or negative removal efficiencies for TSS and SS loads. Similar TSS removal efficiencies were observed at the SFD, but SS was consistently removed throughout the flow regime. Removal efficiencies were high for both devices when concentrations of SS and TSS approached 200 mg/L. A small number of runoff events were analyzed for PSD; the average sand content at the HSD was 33 percent and at the SFD was 71 percent. The 71-percent sand content may reflect the 90-percent removal efficiency of SS at the SFD. Particles retained at the bottom of both devices were largely sand-size or greater.

Wisconsin↗
USGS2016

Comparison of benthos and plankton for selected areas of concern and non-areas of concern in western Lake Michigan Rivers and Harbors in 2012

Recent data are lacking to assess whether impairments still exist at four of Wisconsin’s largest Lake Michigan harbors that were designated as Areas of Concern (AOCs) in the late 1980s due to sediment contamination and multiple Beneficial Use Impairments (BUIs), such as those affecting benthos (macroinvertebrates) and plankton (zooplankton and phytoplankton) communities. During three seasonal sampling events (“seasons”) in May through August 2012, the U.S. Geological Survey collected sediment benthos and water plankton at the four AOCs as well as six less-degraded non-AOCs along the western Lake Michigan shoreline to assess whether AOC communities were degraded in comparison to non-AOC communities. The four AOCs are the Lower Menominee River, the Lower Green Bay and Fox River, the Sheboygan River, and the Milwaukee Estuary. Due to their size and complexity, multiple locations or “subsites” were sampled within the Lower Green Bay and Fox River AOC (Lower Green Bay, the Fox River near Allouez, and the Fox River near De Pere) and within the Milwaukee Estuary AOC (the Milwaukee River, the Menomonee River, and the Milwaukee Harbor) and single locations were sampled at the other AOCs and non-AOCs. The six non-AOCs are the Escanaba River in Michigan, and the Oconto River, Ahnapee River, Kewaunee River, Manitowoc River, and Root River in Wisconsin. Benthos samples were collected by using Hester-Dendy artificial substrates deployed for 30 days and by using a dredge sampler; zooplankton were collected by net and phytoplankton by whole-water sampler. Except for the Lower Green Bay and Milwaukee Harbor locations, communities at each AOC were compared to all non-AOCs as a group and to paired non-AOCs using taxa relative abundances and metrics, including richness, diversity, and an Index of Biotic Integrity (IBI, for Hester-Dendy samples only). Benthos samples collected during one or more seasons were rated as degraded for at least one metric at all AOCs. In the Milwaukee Estuary, benthos richness was lower in the Milwaukee River subsite spring and summer samples and in the Menomonee River subsite spring sample relative to the paired non-AOCs. Benthos diversity and IBIs at the Menomonee River subsite and IBIs at the Milwaukee River subsite and Sheboygan River were significantly lower than at all non-AOCs as a group across all seasons and therefore were rated as degraded. In addition, IBIs at the Lower Menominee River were significantly lower than those at the paired non-AOCs during all seasons and were therefore rated degraded. Benthos at both Fox River subsites and the Milwaukee River subsite were significantly different from their paired non-AOCs during all three seasons, based on a comparison of the relative abundances of taxa using multivariate testing. Metrics for plankton at AOCs were not significantly lower than those at the paired or group non-AOCs during all seasons; however, zooplankton richness in spring at the Sheboygan River and in fall at the Menomonee River subsite was rated as degraded in comparison to paired non-AOCs. Also, zooplankton richness in fall at the Fox River near Allouez subsite and in spring at the Milwaukee River subsite was rated degraded overall because values were lower than at all non-AOCs as a group and lower than at the paired non-AOCs. Zooplankton diversity in fall at the Fox River near Allouez subsite and the Lower Menominee River was rated degraded in comparison to paired non-AOC comparison sites. Zooplankton communities at the Fox River near Allouez subsite were significantly different from the paired non-AOCs when multivariate comparisons were made without rotifers other than A. priodonta . Overall, benthos and zooplankton BUIs remained at the AOCs in 2012 but no AOCs with a phytoplankton BUI were rated degraded in comparison to non-AOCs. The use of a multiple ecological measures, structural and functional, and multiple statistical analyses, biological metrics and multivariate statistics, provided assessments that defined 2012 status of communities relative to less-impaired non-AOCs in the Great Lakes area.

Michigan↗
USGS2011

Predicting lake trophic state by relating Secchi-disk transparency measurements to Landsat-satellite imagery for Michigan inland lakes, 2003-05 and 2007-08

Inland lakes are an important economic and environmental resource for Michigan. The U.S. Geological Survey and the Michigan Department of Natural Resources and Environment have been cooperatively monitoring the quality of selected lakes in Michigan through the Lake Water Quality Assessment program. Sampling for this program began in 2001; by 2010, 730 of Michigan’s 11,000 inland lakes are expected to have been sampled once. Volunteers coordinated by the Michigan Department of Natural Resources and Environment began sampling lakes in 1974 and continue to sample (in 2010) approximately 250 inland lakes each year through the Michigan Cooperative Lakes Monitoring Program. Despite these sampling efforts, it still is impossible to physically collect measurements for all Michigan inland lakes; however, Landsat-satellite imagery has been used successfully in Minnesota, Wisconsin, Michigan, and elsewhere to predict the trophic state of unsampled inland lakes greater than 20 acres by producing regression equations relating in-place Secchi-disk measurements to Landsat bands. This study tested three alternatives to methods previously used in Michigan to improve results for predicted statewide Trophic State Index (TSI) computed from Secchi-disk transparency (TSI (SDT)). The alternative methods were used on 14 Landsat-satellite scenes with statewide TSI (SDT) for two time periods (2003– 05 and 2007–08). Specifically, the methods were (1) satellitedata processing techniques to remove areas affected by clouds, cloud shadows, haze, shoreline, and dense vegetation for inland lakes greater than 20 acres in Michigan; (2) comparison of the previous method for producing a single open-water predicted TSI (SDT) value (which was based on an area of interest (AOI) and lake-average approach) to an alternative Gethist method for identifying open-water areas in inland lakes (which follows the initial satellite-data processing and targets the darkest pixels, representing the deepest water, before regression equations are created); and (3) checking to see whether the predicted TSI (SDT) values compared well between two regression equations, one previously used in Michigan and an alternative equation from the hydrologic literature. The combination of improved satellite-data processing techniques and the Gethist method to identify open-water areas in inland lakes during 2003–05 and 2007–08 provided a stronger relation and statistical significance between predicted TSI (SDT) and measured TSI than did the AOI lake-average method; differences in results for the two methods were significant at the 99-percent confidence level. With regard to the comparison of the regression equations, there were no statistically significant differences at the 95-percent confidence level between results from the two equations. The previously used equation, in combination with the Gethist method, yielded coefficient of determination (R 2 ) values of 0.71 and 0.77 for the periods 2003–05 and 2007–08, respectively. The alternative equation, in combination with the Gethist method, yielded R 2 values of 0.74 and 0.75 for 2003–05 and 2007–08, respectively. Predicted TSI (SDT) and measured TSI (SDT) values for lakes used in the regression equations compared well, with R 2 values of 0.95 and 0.96 for predicted TSI (SDT) for 2003–05 and 2007–08, respectively. The R 2 values for statewide predicted TSI (SDT) for all inland lakes with available open-water areas for 2003–05 and 2007–08 were 0.91 and 0.93, respectively. Although the two equations predicted similar trophic-state classes, the alternative equation is planned to be used for future prediction of TSI (SDT) values for Michigan inland lakes, to promote consistency in comparing predicted values between States and for potential use in trend analysis.

Michigan↗
USGS2018

Water-quality response to changes in phosphorus loading of the Winnebago Pool Lakes, Wisconsin, with special emphasis on the effects of internal loading in a chain of shallow lakes

The Winnebago Pool is a chain of four shallow lakes (Lake Poygan, Lake Winneconne, Lake Butte des Morts, and Lake Winnebago) that are fed primarily by the Fox and Wolf Rivers, two large agriculturally dominated rivers in Wisconsin, United States. Because the lakes have received extensive phosphorus inputs from their watershed, they have become highly eutrophic with much phosphorus in the water column as well as trapped in their sediments. Each of the four Winnebago Pool lakes has been included on the Wisconsin Department of Natural Resources impaired waters list because of their high total phosphorus concentrations, water-quality use restrictions, and excess algal growth. The study described in this report is part of a Total Maximum Daily Load investigation to determine what actions are needed to improve the water quality (trophic status) of these lakes and thus be able to be removed from the impaired waters list and restore their designated uses. As part of this study, data were collected to describe the existing water quality of the lakes, detailed phosphorus budgets were developed for each of the lakes to describe the different sources of the phosphorus, and two eutrophication models (BATHTUB and Jensen models) were used to determine how much of the phosphorus being input to the lakes needs to be reduced for the lakes to be removed from the impaired waters list and restore their designated uses. In-lake water-quality data indicated that each of the lakes had extensive vertical mixing that resulted in their water quality deteriorating throughout summer. Each of the lakes had mean summer total phosphorus concentrations exceeding 0.088 milligram per liter (mg/L), well above the 0.040 mg/L criterion for the lakes. Detailed phosphorus budgets for the lakes indicated that the primary sources of phosphorus were from their tributaries (for the most upstream lake in the Winnebago Pool–Lake Poygan) or from a combination of input from the upstream lakes and phosphorus release from the bottom sediment when only the summer months were considered (for the other three lakes). Model simulations with the BATHTUB and Jensen models indicated that (1) the lakes should have almost linear response in their total phosphorus concentrations to changes in their phosphorus inputs; (2) phosphorus inputs need to be reduced by about 60 percent to the Upper Pool Lakes and 69–73 percent to Lake Winnebago to reduce their mean summer total phosphorus concentrations to 0.040 mg/L; and (3) if all the anthropogenic phosphorus inputs to the lakes could be eliminated, their best possible mean summer total phosphorus concentrations should decrease to about 0.022–0.028 mg/L in the Upper Pool Lakes and to 0.032–0.033 mg/L in Lake Winnebago. The effects of any reduction in phosphorus loading will take many years (50 to more than 75 years) to be fully realized in lake water quality because of phosphorus release from the lake sediments. The effects of nutrient reductions in the watershed of a chain of lakes, such as the Winnebago Pool, gradually cascades down the chain, which has beneficial and detrimental effects. Any action made in the watershed of upstream lakes to reduce phosphorus inputs should improve the water quality of all downstream lakes; however, the upstream lakes delay the response in the downstream lakes, especially in lakes where internal phosphorus loading is important.

Wisconsin↗
USGS2021

Assessment of groundwater trends near Crex Meadows, Wisconsin

Crex Meadows Wildlife Area (Crex) is a 30,000-acre property in Burnett County, Wisconsin. Crex is managed by the Wisconsin Department of Natural Resources (WDNR) with the goal of providing public recreation opportunities while also protecting the quality of native ecological communities and species on the property. The WDNR’s management strategy includes controlling water levels at flowages in Crex using a system of dikes, water control structures, ditches, and a diversion pump. For the past several decades there has been concern among nearby landowners that the water manage-ment strategy at Crex may be contributing to groundwater flooding in adjacent, privately held properties. This issue has been particularly contentious during periods when regional groundwater elevations are already high. This study was conducted in response to those concerns. For the study, a network of 12 monitoring wells was installed in and to the west of Crex. Groundwater elevations were recorded in the wells before, during, and after water-level changes in the western Crex flowages to assess if groundwater elevations to the west of Crex are detectably affected by the flowage water levels. This study successfully collected groundwater elevations in 11 study wells during a 3-month period in 2019 when water elevations in the Dike 6 flowage and Erickson flowage were lowered and then raised. The data logger at a 12th location failed and no data were recorded. The groundwater elevation trends in these study wells were compared with groundwater elevation trends at a regional U.S. Geological Survey well to provide information for determining if changing the flowage elevations had a noticeable response in the study wells west of Crex Meadows. This analysis was done by (1) evaluating study well groundwater elevation trends compared to the regional well, (2) using a scatter plot of study well and regional well data during raising and lowering periods, (3) assessing horizontal hydraulic gradient data during the study period, and (4) assessing the cumulative departure from the mean groundwater elevation for each well. Overall, regional groundwater elevations had a down-ward trend before and during the flowage lowering period and then had an upward trend during the flowage raising period. This pattern was observed in the regional well and in all the study wells adjacent to and several miles from the flowages. The similarity in patterns indicates that precipitation and regional groundwater flow conditions were the dominant drivers of the system during the study period. The scatter plot and cumulative departure from the mean analysis showed that in addition to regional trends, wells 1, 6, and 7 were likely affected by the changes in the flowage water levels. Overall, at least on the timescale of this study, water management at Crex likely did not have detectable effects on wells outside the Crex property. Wells installed on the Crex property including the wells in the lakebeds of the flowages (wells 1 and 7) and possibly well 6 east of the flowages showed what seems to be minor affects due to water management at Crex.

Wisconsin↗
USGS2007

Lithostratigraphic and Hydrogeologic Characteristics of the Ordovician Sinnipee Group in the Vicinity of Waupun, Fond du Lac County, Wisconsin, 1995-96

Three boreholes were drilled at a farm site near Waupun, Wis., to improve the understanding of regional hydrogeology of the Ordovician Sinnipee Group. At the site the Sinnipee Group is the uppermost bedrock unit and is found to be about 183 ft thick. On the basis of core descriptions by the Illinois State Geological Survey, the Sinnipee Group at the site comprises (stratigraphically lowest to highest) the Platteville Formation (about 51 ft thick), the Decorah Formation (about 14 ft thick), and the Galena Dolomite (about 119 ft thick). The Illinois State Geological Survey noted that hardgrounds were common in the rock core, some having stratigraphic significance. Four very well developed hardgrounds were identified, three of which were used as formation or member contacts. The hardground at about 797 ft NGVD 29 represents the top of the Platteville Formation, the hardground at about 754 ft represents the top of the Pecatonica Member of the Platteville Formation, and the hardground at about 746 ft represents the top of the Glenwood Formation. On the basis of samples collected from one borehole, the ground water at the site is of the calcium-magnesium bicarbonate type. Trichloroethene was detected in one sample at a concentration of 1 ?g/L, and the concentration of antimony in one sample exceeded the U.S. Environmental Protection Agency (USEPA) Primary Drinking Water Standard. Other water samples contained aluminum and sodium in concentrations that exceeded the USEPA Secondary Drinking Water Standard and the USEPA Drinking Water Equivalent Level, respectively. Samples from various depths contained concentrations of iron, manganese, or dissolved manganese that were near or exceeded the USEPA Secondary Drinking Water Standard. The cross-borehole radar tomography data show differences in velocity and attenuation among the three major units in the Sinnipee Group. Matrix porosity measured in rock-core samples correlates well with these velocity and attenuation tomograms. The Galena Dolomite has the lowest mean porosity at 2.4 percent (7 samples) and is represented in the tomograms as generally having the lowest attenuation and greatest velocity. Below the Galena Dolomite is a transition to a zone with the greatest attenuation and lowest velocity on the tomograms. The rock core shows this interval to be the shaley dolomite of the Decorah Formation which has a mean porosity of 8.3 percent (2 samples). Below the Decorah Formation, the Platteville Formation has a mean porosity of 3.6 percent (6 samples) and is represented in the tomograms as having velocity and attenuation generally intermediate between the Galena Dolomite and the Decorah Formation. The evaluation of the single-hole directional ground-penetrating radar reflection survey in FL-800 identified 15 reflectors (secondary permeability features). Some of the reflectors do correlate with fractures and partings noted on geophysical logs and rock core; however, many additional fractures and partings identified by the televiewer log and/or core description were not measured by the borehole radar survey. Horizontal or sub-horizontal reflectors (bedding-plane partings) which do correlate with indications of bedding-plane partings on the acoustic televiewer intersect the borehole at about 917 ft, 907 ft, 870 ft, 805 ft, and 797 ft. The flowmeter profiles indicate that water entering and exiting the boreholes at seven bedding-plane partings accounts for most of the total borehole transmissivity. The flowmeter profiles in all three boreholes show that more than 90 percent of the total borehole transmissivity is provided by bedding-plane partings found at 870 ft and higher stratigraphically within the Galena Dolomite. Static water levels were measured in selected intervals of the three boreholes, and vertical hydraulic gradients were estimated by comparing levels in adjacent intervals. Gradients were found to be almost uniformly downward, ranging from -0.040 to -1.251 ft/ft. On th

Scientific Investigations Report↗
USGS2011

Precipitation-runoff relations and water-quality characteristics at edge-of-field stations, Discovery Farms and Pioneer Farm, Wisconsin, 2003-8

A cooperative study between the U.S. Geological Survey, the University of Wisconsin (UW)-Madison Discovery Farms program (Discovery Farms), and the UW-Platteville Pioneer Farm program (Pioneer Farm) was developed to identify typical ranges and magnitudes, temporal distributions, and principal factors affecting concentrations and yields of sediment, nutrients, and other selected constituents in runoff from agricultural fields. Hydrologic and water-quality data were collected year-round at 23 edge-of-field monitoring stations on 5 privately owned Discovery Farms and on Pioneer Farm during water years 2003-8. The studied farms represented landscapes, soils, and farming systems typical of livestock farms throughout southern Wisconsin. Each farm employed a variety of soil, nutrient, and water-conservation practices to help minimize sediment and nutrient losses from fields and to improve crop productivity. This report summarizes the precipitation-runoff relations and water-quality characteristics measured in edge-of-field runoff for 26 "farm years" (aggregate years of averaged station data from all 6 farms for varying monitoring periods). A relatively wide range of constituents typically found in agricultural runoff were measured: suspended sediment, phosphorus (total, particulate, dissolved reactive, and total dissolved), and nitrogen (total, nitrate plus nitrite, organic, ammonium, total Kjeldahl and total Kjeldahl-dissolved), chloride, total solids, total suspended solids, total volatile suspended solids, and total dissolved solids. Mean annual precipitation was 32.8 inches for the study period, about 3 percent less than the 30-year mean. Overall mean annual runoff was 2.55 inches per year (about 8 percent of precipitation) and the distribution was nearly equal between periods of frozen ground (54 percent) and unfrozen ground (46 percent). Mean monthly runoff was highest during two periods: February to March and May to June. Ninety percent of annual runoff occurred between January and the end of June. Event mean concentrations of suspended sediment in runoff during unfrozen-ground periods were significantly higher (p<0.05) than those during frozen-ground periods. Mean annual suspended-sediment yields ranged from about 3 to nearly 5,000 pounds per acre (lb/acre), with a mean yield of 667 lb/acre. Ninety percent of suspended sediment was yielded in runoff during unfrozen-ground periods. May and June alone contributed more than 80 percent of the overall yield. Phosphorus concentrations and yields were also affected by the ground conditions at the time of runoff; however, unlike suspended sediment, phosphorus was usually available for transport in runoff regardless of ground condition. Mean annual total-phosphorus yields ranged from 0.03 to 7.0 lb/acre, with a mean yield of about 2.0 lb/acre. Nitrogen in runoff followed similar patterns to phosphorus in that concentrations were highest during unfrozen-ground periods, yields were highest during months of highest runoff, and speciation was affected by the ground conditions at the time of runoff. Mean annual total-nitrogen yields ranged from 0.11 to 19.2 lb/acre, and the mean was 7.2 lb/acre. Mean monthly total-nitrogen yields were strongly correlated with mean monthly total-phosphorus yields (r 2 = 0.92), indicating that the sources of nitrogen and phosphorus in runoff were likely similar. Analysis of runoff, concentration, and yield data on annual, monthly, and seasonal time scales, when combined with precipitation, soil moisture, soil temperature, and on-farm field-activity information, revealed conditions in which runoff was most likely. The analysis also revealed the effects that field conditions and the timing of field-management activities-most notably, manure applications and tillage-had on the quantity and quality of surface runoff from agricultural fields.

Scientific Investigations Report↗
USGS2018

Simulation of hydrodynamics, water quality, and lake sturgeon habitat volumes in Lake St. Croix, Wisconsin and Minnesota, 2013

Lake St. Croix is a naturally impounded, riverine lake that makes up the last 40 kilometers of the St. Croix River. Substantial land-use changes during the past 150 years, including increased agriculture and urban development, have reduced Lake St. Croix water-quality and increased nutrient loads delivered to Lake St. Croix. A recent (2012–13) total maximum daily load phosphorus-reduction plan set the goal to reduce total phosphorus loads to Lake St. Croix by 20 percent by 2020 and reduce Lake St. Croix algal bloom frequencies. The U.S. Geological Survey, in cooperation with the National Park Service, developed a two-dimensional, carbon-based, laterally averaged, hydrodynamic and water-quality model, CE–QUAL–W2, that addresses the interaction between nutrient cycling, primary production, and trophic dynamics to predict responses in the distribution of water temperature, oxygen, and chlorophyll a. Distribution is evaluated in the context of habitat for lake sturgeon, including a combination of temperature and dissolved oxygen conditions termed oxy-thermal habitat. The Lake St. Croix CE–QUAL–W2 model successfully reproduced temperature and dissolved oxygen in the lake longitudinally (from upstream to downstream), vertically, and temporally over the seasons. The simulated water temperature profiles closely matched the measured water temperature profiles throughout the year, including the prediction of thermocline transition depths (often within 1 meter), the absolute temperature of the thermocline transitions (often within 1.0 degree Celsius), and profiles without a strong thermocline transition. Simulated dissolved oxygen profiles matched the trajectories of the measured dissolved oxygen concentrations at multiple depths over time, and the simulated concentrations matched the depth and slope of the measured concentrations. Additionally, trends in the measured water-quality data were captured by the model simulation, gaining some potential insights into the underlying mechanisms of critical Lake St. Croix metabolic processes. The CE–QUAL–W2 model tracked nitrate plus nitrite, total nitrogen, and total phosphorus throughout the year. Inflow nutrient contributions (loads), largely dominated by upstream St. Croix River loads, were the most important controls on Lake St. Croix water quality. Close to 60 percent of total phosphorus to the lake was from phosphorus derived from organic matter, and about 89 percent of phosphorus to Lake St. Croix was delivered by St. Croix River inflows. The Lake St. Croix CE–QUAL–W2 model offered potential mechanisms for the effect of external and internal loadings on the biotic response regarding the modeled algal community types of diatoms, green algae, and blue-green algae. The model also suggested the seasonal dominance of blue-green algae in all four pools of the lake. A sensitivity analysis was completed to test the total maximum daily load phosphorus-reduction scenario responses of total phosphorus and chlorophyll a. The modeling indicates that phosphorus reductions would result in similar Lake St. Croix reduced concentrations, although chlorophyll a concentrations did not decrease in the same proportional amounts as the total phosphorus concentrations had decreased. The smaller than expected reduction in algal growth rates highlighted that although inflow phosphorus loads are important, other constituents also can affect the algal response of the lake, such as changes in light penetration and the breakdown of organic matter releasing nutrients. The available habitat suitable for lake sturgeon was evaluated using the modeling results to determine the total volume of good-growth habitat, optimal growth habitat, and lethal temperature habitat. Overall, with the calibrated model, the fish habitat volume in general contained a large proportion of good-growth habitat and a sustained period of optimal growth habitat in the summer. Only brief periods of lethal oxy-thermal habitat were present in Lake St. Croix during the model simulation.

Minnesota, Wisconsin↗
USGS2005

Water quality, hydrology, and phosphorus loading to Little St. Germain Lake, Wisconsin, with special emphasis on the effects of winter aeration and ground-water inputs

Little St. Germain Lake is a 978-acre, multibasin lake in Vilas County, Wisconsin. In the interest of protecting and improving the water quality of the lake, the Little St. Germain Lake District initiated several cooperative studies with the U.S. Geological Survey between 1991 and 2004 to (1) document the water quality and the extent of winter anoxia in the lake, (2) evaluate the success of aerators at eliminating winter anoxia, (3) develop water and nutrient budgets for the lake, and (4) assess how the water quality of the lake should respond to changes in phosphorus loading. This report presents the results of these cooperative studies with special emphasis on the water quality in the lake since 2000, including the effects of winter aeration and the importance of ground-water contributions of phosphorus to the productivity of the lake. Measurements collected during these studies indicate that the water quality in Little St. Germain Lake was consistently different among basins. The West Bay consistently had the best water quality, the South Bay had intermediate water quality, and the East and Upper East Bays consistently had the worst water quality. The water quality in each of the basins was relatively stable from 1991 to 2000; however, since 2001, the West Bay has changed from oligotrophic to mesotrophic, the South Bay has changed from mesotrophic to eutrophic, and the East and Upper East Bays have changed from eutrophic to eutrophic/hypereutrophic. Winter anoxia frequently occurred throughout most of the lake, except in the West Bay and just below the ice in the East Bay. To eliminate winter anoxia, coarse-bubble line aerators were installed and operated in the Upper East, East, and South Bays. The aerators in the Upper East and South Bays were very successful at eliminating winter anoxia; however, the aerator in the East Bay had little impact on the dissolved oxygen concentrations throughout its basin. Detailed water and phosphorus budgets computed for the lake indicated that inflow from Muskellunge Creek was the major source of phosphorus to the lake and that ground water was the secondary source. Results from a detailed ground-water-flow model indicated that ground water flows into the lake from all sides, except the south sides of the West and Second South Bays. Most of the phosphorus appears to come from natural sources, such as ground water and surface water flowing through relatively undeveloped areas surrounding Little St. Germain Lake and Muskellunge Lake. Several empirical water-quality models were used to simulate how the East and Upper East Bays of the lake should respond to reductions in phosphorus loading from Muskellunge Creek. Simulation results indicated that reductions in tributary loading could improve the water quality of the East and Upper East Bays. Improving the water quality of these bays would also improve the water quality of the South and Second South Bays because of the flow of water through the lake. However, even with phosphorus loading from Muskellunge Creek completely eliminated, most of the lake would remain borderline mesotrophic/eutrophic because of the contributions of phosphorus from ground water.

Wisconsin↗
USGS2007

Water-quality characteristics for selected sites within the Milwaukee Metropolitan Sewerage District planning area, Wisconsin, February 2004-September 2005

The Milwaukee Metropolitan Sewerage District (MMSD) Corridor Study is a three-phase project designed to improve the understanding of water resources in the MMSD planning area to assist managers and policy makers in their decisions. Phase I of the Study involved the compilation of existing data from multiple agencies into a single database. These data were analyzed to identify spatial, temporal, and technological gaps in the planning area, and were used to develop Phase II of the Study. Phase II, the subject of this report, involved an intensive data-collection effort by the U.S. Geological Survey (USGS) in cooperation with MMSD (from February, 2004, through September, 2005). This phase addressed the data gaps identified in Phase I and completed a baseline assessment of water quality for selected stream and harbor sites in the MMSD planning area. This baseline assessment included evaluations of surface-water chemistry and microbial concentrations in the streams and harbor sites; additionally, stream sites were evaluated for discharge, sediment chemistry, fish-tissue chemistry, habitat, and the quality of biological communities (including fish, macroinvertebrates, and algae). In all, data were collected at 15 stream and 6 harbor sites within the MMSD planning area, including manual sampling and analysis for more than 220 water-quality properties and constituents at all 21 sites, stream-discharge data for 14 stream sites, and automated water-quality sampling at 4 stream sites. A bioassessment during autumn 2004 included collection of biologic-community data and stream-habitat data at wadeable streams. Quartiles of Phase II aggregate bioassessment rankings were used to divide the 14 wadeable stream sites into four groups to investigate relations between bioassessment data and site characteristic and water-quality data. Quartile numbers reflect relative water quality: quartile 1 contained sites where the bioassessment data indicated the least-degraded water quality among those sampled, and quartile 4 contained sites that indicated the most-degraded water quality. Quartiles contained the following stream sites: Quartile 1: Milwaukee River near Cedarburg, Milwaukee River at Milwaukee, Jewel Creek, and Menomonee River at Menomonee Falls; Quartile 2: Willow Creek, Root River near Franklin, and Root River at Grange Avenue; Quartile 3: Menomonee River at Wauwatosa, Oak Creek, and Little Menomonee River; and Quartile 4: Honey Creek, Underwood Creek, Lincoln Creek, and Kinnickinnic River. Site characteristics (in this case, drainage area and land use) and selected water-quality data were summarized based on the four bioassessment quartiles to determine if there were relations with the aggregate bioassessment rankings. In general, sites having the largest drainage basins with the lowest proportion of urban land use were in quartile 1, and the smallest drainage basins with the highest proportion of urban land use were in quartile 4. Major ions, indicator organisms, and wastewater compounds generally had the lowest overall results in quartile 1 and highest overall results in quartile 4, with intermediate results in quartiles 2 and 3. Results for other constituent types (nutrients, mercury, pathogenic organisms, and bed sediment) were mixed, with results for some constituents decreasing from quartile 1 to quartile 4. Where sufficient Phase I data were available, summary statistics (including medians) for chemical and biological data were calculated, allowing some comparisons to be made between Phase I and Phase II data. Comparisons between Phase I and Phase II results indicated a variety of changes with respect to water quality. Concentrations of chloride, nitrate, chlorophyll a, total phosphorus in water; arsenic in bed sediment; and fish Index of Biotic Integrity ratings generally indicated declines in water quality. However, concentrations of total nitrogen, suspended sediment, and fecal coliform in water; some trace eleme

Wisconsin↗
USGS2006

Development and application of a screening model for simulating regional ground-water flow in the St. Croix River basin, Minnesota and Wisconsin

A series of databases and an accompanying screening model were constructed by the U.S. Geological Survey, in cooperation with the National Park Service, to better understand the regional ground-water-flow system and its relation to stream drainage in the St. Croix River Basin. The St. Croix River and its tributaries drain about 8,000 square miles in northeastern Minnesota and northwestern Wisconsin. The databases contain information for the entire St. Croix River Basin pertaining to well logs, lithology, thickness of lithologic groups, ground-water levels, streamflow, and well pumpage. Maps and generalized cross sections created from the compiled data show the lithologic groups, extending from the water table to the crystalline bedrock, through which ground water flows. These lithologic groups are: fine-grained unconsolidated deposits; coarse-grained unconsolidated deposits; sandstone bedrock; carbonate bedrock; and other bedrock lithologies including shale, siltstone, conglomerate, and igneous intrusions. The steady-state screening model treats the ground-water-flow system as a single layer with transmissivity zones that reflect the distribution of lithologic groups, and with recharge zones that correspond to general areas of high or low evapotranspiration. The model includes representation of second- and higher-order streams and municipal and other high-capacity production wells. The analytic-element model code GFLOW was used to simulate the regional ground-water flow, the water-table surface across the St. Croix River Basin, and base-flow contributions from ground water to streams. In addition, the model routes tributary base flow through the stream network to the St. Croix River. The parameter-estimation inverse model UCODE was linked to the GFLOW model to select the combination of parameter values best able to match over 5,000 water-level measurements and base-flow estimates at 22 streamflow-gaging stations. Results from the calibrated screening model show ground-water contributing areas for selected stream reaches within the basin. The delineation of these areas is useful to water-resource managers concerned with protection of fisheries and other resources. The model results also identify the areas of the basin where ground-water travel time from the water table to streams and wells is relatively short (less than 50 years). Ninety percent of the simulated ground-water pathlines require travel times between 3 and 260 years. The median pathline distance traversed and the median pathline velocity were 1.7 mi and 177 ft/y, respectively. It is important to recognize the limitations of this screening model. Heterogeneities in subsurface properties and in recharge rates are considered only at a very broad scale (miles to tens of miles). No account is taken of vertical variations in properties or pumping rates, and no provision is made to account for stacked ground-water-flow systems that have different flow patterns at different depths. Small-scale (hundreds to thousands of feet) flow systems associated with minor water bodies are neglected, and as a result, the model is not useful for simulating typical site-specific problems. Despite its limitations, the model serves as a framework for understanding the regional pattern of ground-water flow and as a starting point for a generation of more targeted and detailed ground-water models that would be needed to address emerging water-supply and water-quality concerns in the St. Croix River Basin.

Scientific Investigations Report↗
USGS2010

Evaluation of Turf-Grass and Prairie-Vegetated Rain Gardens in a Clay and Sand Soil, Madison, Wisconsin, Water Years 2004-08

The U.S. Geological Survey, in cooperation with a consortium of 19 cities, towns, and villages in Dane County, Wis., undertook a study to compare the capability of rain gardens with different vegetative species and soil types to infiltrate stormwater runoff from the roof of an adjacent structure. Two rain gardens, one planted with turf grass and the other with native prairie species, were constructed side-by-side in 2003 at two locations with different dominant soil types, either sand or clay. Each rain garden was sized to a ratio of approximately 5:1 contributing area to receiving area and to a depth of 0.5 foot. Each rain garden, regardless of vegetation or soil type, was capable of storing and infiltrating most of the runoff over the 5-year study period. Both rain gardens in sand, as well as the prairie rain garden in clay, retained and infiltrated 100 percent of all precipitation and snowmelt events during water years 2004-07. The turf rain garden in clay occasionally had runoff exceed its confining boundaries, but was still able to retain 96 percent of all precipitation and snowmelt events during the same time period. Precipitation intensity and number of antecedent dry days were important variables that influenced when the storage capacity of underlying soils would become saturated, which resulted in pooled water in the rain gardens. Because the rooftop area that drained runoff to each rain garden was approximately five times larger than the area of the rain garden itself, evapotranspiration was a small percentage of the annual water budget. For example, during water year 2005, the maximum evapotranspiration of total influent volume ranged from 21 percent for the turf rain garden in clay to 25 percent for the turf rain garden in sand, and the minimum ranged from 12 percent for the prairie rain garden in clay to 19 percent for the prairie rain garden in sand. Little to no runoff left each rain garden as effluent and a small percentage of runoff returned to the atmosphere through evapotranspiration; therefore, the remainder was considered recharge. During water year 2005, recharge was 81 to 75 percent of total influent volume for the prairie- and turf-rain gardens in sand and 87 to 78 percent for the prairie- and turf-rain gardens in clay, respectively. Maximum recharge volumes ranged from 90 to 94 percent of the total influent volume in the turf and prairie rain gardens in sand and occurred during water year 2004. Maximum recharge in the turf and prairie rain gardens in clay ranged from 89 percent during water year 2007 to 98 percent during water year 2004. Median infiltration rates were an order of magnitude greater for rain gardens planted in sand than for those in clay, regardless of vegetation type. Under similar soil conditions, rain gardens planted with turf grass had lower median infiltration rates than those planted with prairie species. Median infiltration rates were 0.28 and 0.88 inches per hour in the turf and prairie rain gardens in clay, respectively, and 2.5 and 4.2 inches per hour in the turf and prairie rain gardens in sand, respectively. In general, infiltration rates were greater during spring (April and May) and summer (June through August) months. Of the six observed exceedences of the storage capacity of the turf rain garden in clay between April-November during 2004-07, five were predicted by use of a combination of the normalized surface storage volume, the median infiltration rate, and an estimate of specific yield for soils under the rain garden to a depth equal to the uppermost limiting layer. By use of the same criteria, in water year 2008, when the contributing drainage area to the prairie rain garden in clay was doubled, all four observed exceedences of the total storage capacity were predicted. The accuracy of the predictions of when the total storage capacity of the rain gardens would be exceeded indicates that by applying measurements of the appropriate soil properties to rain g

Scientific Investigations Report↗
USGS2012

Development and application of a groundwater/surface-water flow model using MODFLOW-NWT for the Upper Fox River Basin, southeastern Wisconsin

The Fox River is a 199-mile-long tributary to the Illinois River within the Mississippi River Basin in the states of Wisconsin and Illinois. For the purposes of this study the Upper Fox River Basin is defined as the topographic basin that extends from the upstream boundary of the Fox River Basin to a large wetland complex in south-central Waukesha County called the Vernon Marsh. The objectives for the study are to (1) develop a baseline study of groundwater conditions and groundwater/surface-water interactions in the shallow aquifer system of the Upper Fox River Basin, (2) develop a tool for evaluating possible alternative water-supply options for communities in Waukesha County, and (3) contribute to the methodology of groundwater-flow modeling by applying the recently published U.S. Geological Survey MODFLOW-NWT computer code, (a Newton formulation of MODFLOW-2005 intended for solving difficulties involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation) to overcome computational problems connected with fine-scaled simulation of shallow aquifer systems by means of thin model layers. To simulate groundwater conditions, a MODFLOW grid is constructed with thin layers and small cell dimensions (125 feet per side). This nonlinear unconfined problem incorporates the streamflow/lake (SFR/LAK) packages to represent groundwater/surface-water interactions, which yields an unstable solution sensitive to initial conditions when solved using the Picard-based preconditioned-gradient (PCG2) solver. A particular problem is the presence of many isolated wet water-table cells over dry cells, causing the simulated water table to assume unrealistically high values. Attempts to work around the problem by converting to confined conditions or converting active to inactive cells introduce unacceptable bias. Application of MODFLOW-NWT overcomes numerical problem by smoothing the transition from wet to dry cells and keeps all cells active. The simulation is insensitive to initial conditions and the water-table trend is smooth across layers. The MODFLOW-NWT code permits rigorous calibration and also robust application of the model to transient scenarios. Runtimes on a 64-bit computer are kept reasonably short by use of updated initial conditions and informed choices of solver parameters. The shallow aquifer system consists of unconsolidated material of varying thickness over Silurian dolomite. The unconsolidated material, largely of glacial origin, contains fine-textured and coarse-textured deposits that vary in permeability over short distances. This study at least partly encompasses the inevitable uncertainty in the hydraulic conductivity zones by developing two models&mdash;one favors the continuity of fine-grained deposits and a second favors the continuity of coarse-grained deposits. The separate calibration processes for the fine-favored and coarse-favored models using MODFLOW-NWT and the nonlinear regression algorithms in the parameter estimation (PEST) code produce distinct parameter values for hydraulic conductivity zones, storage parameters, and streambed conductance zones. Both models are applied to a hypothetical scenario involving 27 "riparian" wells completed adjacent to the river channel and open to the shallow aquifer systems along a 10-mile stretch of the Fox River. The results suggest that a riparian well system withdrawing about 9 million gallons per day would induce about one-third to one-half its total discharge from the river, and that this riverbank inducement would appreciably limit drawdown around the hypothetical wells.

Wisconsin↗
USGS2010

Relation of urbanization to stream habitat and geomorphic characteristics in nine metropolitan areas of the United States

The relation of urbanization to stream habitat and geomorphic characteristics was examined collectively and individually for nine metropolitan areas of the United States?Portland, Oregon; Salt Lake City, Utah; Denver, Colorado; Dallas?Forth Worth, Texas; Milwaukee?Green Bay, Wisconsin; Birmingham, Alabama; Atlanta, Georgia; Raleigh, North Carolina; and Boston, Massachusetts. The study was part of a larger study conducted by the U.S. Geological Survey from 1999 to 2004 to examine the effects of urbanization on the physical, chemical, and biological components of stream ecosystems. The objectives of the current study were to determine how stream habitat and geomorphic characteristics relate to different aspects of urbanization across a variety of diverse environmental settings and spatial scales. A space-for-time rural-to-urban land-cover gradient approach was used. Reach-scale habitat data and geomorphic characteristic data were collected once during low flow and included indicators of potential habitat degradation such as measures of channel geometry and hydraulics, streambed substrate, low-flow reach volume (an estimate of base-flow conditions), habitat complexity, and riparian/bank conditions. Hydrologic metrics included in the analyses were those expected to be altered by increases in impervious surfaces, such as high-flow frequency and duration, flashiness, and low-flow duration. Other natural and human features, such as reach-scale channel engineering, geologic setting, and slope, were quantified to identify their possible confounding influences on habitat relations with watershed-scale urbanization indicators. Habitat and geomorphic characteristics were compared to several watershed-scale indicators of urbanization, natural landscape characteristics, and hydrologic metrics by use of correlation analyses and stepwise linear regression. Habitat and geomorphic characteristics were related to percentages of impervious surfaces only in some metropolitan areas and environmental settings. The relations between watershed-scale indicators of urbanization and stream habitat depended on physiography and climate, hydrology, pre-urban channel alterations, reach-scale slope and presence of bedrock, and amount of bank stabilization and grade control. Channels increased in size with increasing percentages of impervious surfaces in southeastern and midwestern metropolitan areas regardless of whether the pre-existing land use was forest or agriculture. The amount of enlargement depended on annual precipitation and frequency of high-flow events. The lack of a relation between channel enlargement and increasing impervious surfaces in other metropolitan areas was thought to be confounded by pre-urbanization hydrologic and channel alterations. Direct relations of channel shape and streambed substrate to urbanization were variable or lacking, probably because the type, amount, and source of sediment are dependent on the phase of urbanization. Reach-scale slope also was important for determining variations in streambed substrate and habitat complexity (percentage of riffles and runs). Urbanization-associated changes in reach-scale riparian vegetation varied geographically, partially depending on pre-existing riparian vegetation characteristics. Bank erosion increased in Milwaukee?Green Bay and Boston urban streams, and bank erosion also increased with an increase in a streamflow flashiness index. However, potential relations likely were confounded by the frequent use of channel stabilization and bank protection in urban settings. Low-flow reach volume did not decrease with increasing urbanization, but instead was related to natural landscape characteristics and possibly other unmeasured factors. The presence of intermittent bedrock in some sampled reaches likely limited some geomorphic responses to urbanization, such as channel bed erosion. Results from this study emphasize the importance of including a wide range of landscape variables at m

Scientific Investigations Report↗
USGS2007

Response of Stream Chemistry During Base Flow to Gradients of Urbanization in Selected Locations Across the Conterminous United States, 2002-04

During 2002-2004, the U.S. Geological Survey's National Water-Quality Assessment Program conducted a study to determine the effects of urbanization on stream water quality and aquatic communities in six environmentally heterogeneous areas of the conterminous United States--Atlanta, Georgia; Raleigh-Durham, North Carolina; Milwaukee-Green Bay, Wisconsin; Dallas-Fort Worth, Texas; Denver, Colorado; and Portland, Oregon. This report compares and contrasts the response of stream chemistry during base flow to urbanization in different environmental settings and examines the relation between the exceedance of water-quality benchmarks and the level of urbanization in these areas. Chemical characteristics studied included concentrations of nutrients, dissolved pesticides, suspended sediment, sulfate, and chloride in base flow. In three study areas where the background land cover in minimally urbanized basins was predominantly forested (Atlanta, Raleigh-Durham, and Portland), urban development was associated with increased concentrations of nitrogen and total herbicides in streams. In Portland, there was evidence of mixed agricultural and urban influences at sites with 20 to 50 percent urban land cover. In two study areas where agriculture was the predominant background land cover (Milwaukee-Green Bay and Dallas-Fort Worth), concentrations of nitrogen and herbicides were flat or decreasing as urbanization increased. In Denver, which had predominantly shrub/grass as background land cover, nitrogen concentrations were only weakly related to urbanization, and total herbicide concentrations did not show any clear pattern relative to land cover - perhaps because of extensive water management in the study area. In contrast, total insecticide concentrations increased with increasing urbanization in all six study areas, likely due to high use of insecticides in urban applications and, for some study areas, the proximity of urban land cover to the sampling sites. Phosphorus concentrations increased with urbanization only in Portland; in Atlanta and Raleigh-Durham, leachate from septic tanks may have increased phosphorus concentrations in basins with minimal urban development. Concentrations of suspended sediment were only weakly associated with urbanization, probably because this study analyzed only base-flow samples, and the bulk of sediment loads to streams is transported in storm runoff rather than base flow. Sulfate and chloride concentrations increased with increasing urbanization in four study areas (Atlanta, Raleigh-Durham, Milwaukee-Green Bay, and Portland), likely due to increasing contributions from urban sources of these constituents. The weak relation between sulfate and chloride concentrations and urbanization in Dallas-Fort Worth and Denver was likely due in part to high sulfate and chloride concentrations in ground-water inflow, which would have obscured any pattern of increasing concentration with urbanization. Pesticides often were detected at multiple sites within a study area, so that the pesticide 'signature' for a given study area - the mixtures of pesticides detected, and their relative concentrations, at streams within the study area - tended to show some pesticides as dominant. The type and concentrations of the dominant pesticides varied markedly among sites within a study area. There were differences between pesticide signatures during high and low base-flow conditions in five of the six study areas. Normalization of absolute pesticide concentrations by the pesticide toxicity index (a relative index indicating potential toxicity to aquatic organisms) dramatically changed the pesticide signatures, indicating that the pesticides with the greatest potential to adversely affect cladocerans or fish were not necessarily the pesticides detected at the highest concentrations. In a screening-level assessment, measured contaminant concentrations in individual base-flow water samples were compared with various water-qual

Scientific Investigations Report↗
USGS2010

Effects of urbanization on stream ecosystems along an agriculture-to-urban land-use gradient, Milwaukee to Green Bay, Wisconsin, 2003-2004

In 2003 and 2004, 30 streams near Milwaukee and Green Bay, Wisconsin, were part of a national study by the U.S. Geological Survey to assess urbanization effects on physical, chemical, and biological characteristics along an agriculture-to-urban land-use gradient. A geographic information system was used to characterize natural landscape features that define the environmental setting and the degree of urbanization within each stream watershed. A combination of land cover, socioeconomic, and infrastructure variables were integrated into a multi-metric urban intensity index, scaled from 0 to 100, and assigned to each stream site to identify a gradient of urbanization within relatively homogeneous environmental settings. The 35 variables used to develop the final urban intensity index characterized the degree of urbanization and included road infrastructure (road area and road traffic index), 100-meter riparian land cover (percentage of impervious surface, shrubland, and agriculture), watershed land cover (percentage of impervious surface, developed/urban land, shrubland, and agriculture), and 26 socioeconomic variables (U.S. Census Bureau, 2001). Characteristics examined as part of this study included: habitat, hydrology, stream temperature, water chemistry (chloride, sulfate, nutrients, dissolved and particulate organic and inorganic carbon, pesticides, and suspended sediment), benthic algae, benthic invertebrates, and fish. Semipermeable membrane devices (SPMDs) were used to assess the potential for bioconcentration of hydrophobic organic contaminants (specifically polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine and pyrethroid insecticides) in biological membranes, such as the gills of fish. Physical habitat measurements reflective of channel enlargement, including bankfull channel size and bank erosion, increased with increasing urbanization within the watershed. In this study, percentage of riffles and streambed substrate size were more strongly related to local geologic setting, slope, watershed topography, and river-engineering practices than to urbanization. Historical local river-engineering features such as channelization, bank stabilization, and grade controls may have confounded relations among habitat characteristics and urbanization. A number of hydrologic-condition metrics (including flashiness and duration of high flow during pre- or post-ice periods) showed strong relations to the urban intensity index. Hydrologic-condition metrics cannot be used alone to predict habitat or geomorphic change. Chloride and SPMD measures of potential toxicity and polycyclic aromatic hydrocarbon concentrations showed the strongest positive correlations to urbanization including increases in road infrastructure, percentage of impervious surface in the watershed, urban land cover, and land-distribution related to urban land cover. This suggests that automobiles and the infrastructure required to support automobiles are a significant source of these compounds in this study area. Chloride in spring and summer showed a significant positive correlation with the urban intensity index; concentrations increased with increasing road infrastructure, urban land cover, and a number of landscape variables related to urbanization. Spring concentrations of sulfate, prometon, and diazinon correlated to fewer urban characteristics than chloride, including increases in road infrastructure, percentage of impervious surface, and urban land cover. Changes in biological communities correlated to the urban intensity index or individual urban-associated variables. Decreased percentages of pollution-sensitive diatoms and diatoms requiring high dissolved-oxygen saturation correlated to increases in the percentage of developed urban land, total impervious surface, stream flashiness, population density, road-area density, and decreases in the percentage of wetland in the watershed. Invertebrate taxa richness and Coleop

Scientific Investigations Report↗
USGS2010

Biological water-quality assessment of selected streams in the Milwaukee Metropolitan Sewerage District Planning Area of Wisconsin, 2007

Changes in the water quality of stream ecosystems in an urban area may manifest in conspicuous ways, such as in murky or smelly streamwater, or in less conspicuous ways, such as fewer native or pollution-sensitive organisms. In 2004, and again in 2007, the U.S. Geological Survey sampled stream organisms—algae, invertebrates, and fish—in 14 Milwaukee area streams to assess water quality as part of the ongoing Milwaukee Metropolitan Sewerage District (MMSD) Corridor Study. In addition, passive-sampling devices (SPMDs, “semipermeable membrane devices”) were deployed at a subset of sites in order to evaluate the potential exposure of stream organisms to certain toxic chemicals. Results of the 2007 sampling effort are the focus of this report. Results of sampling from 2007 are compared with results from 2004. The water quality of sampled streams was assessed by evaluating biological-assemblage data, metrics computed from assemblage data, and an aggregate bioassessment ranking method that combined data for algae, invertebrates, and fish. These data contain information about the abundance (number) of different species in each group of stream organisms and the balance between species that can or cannot tolerate polluted or disturbed conditions. In 2007, the highest numbers of algal, invertebrate, and fish species were found at the Milwaukee River at Milwaukee, the largest sampled site. Algal results indicated water quality concerns at 10 of the 14 sampled sites due to the occurrence of nuisance algae or low percentages of pollution-sensitive algae. When compared to 2004, total algal biovolume was higher in 2007 at 12 of 14 sites, due mostly to more nuisance green algae from unknown causes. Results of several metrics, including the Hilsenhoff Biotic Index (HBI-10), suggest that invertebrate assemblages in the Little Menomonee River, Underwood Creek, and Honey Creek were poorer quality in 2007 compared to 2004. Six sites received “very poor” quality ratings for fish in 2007, mostly because inadequate numbers of fish were collected at five sites to allow computation of an Index of Biotic Integrity (IBI); this resulted in three additional sites receiving “very poor” ratings compared to 2004. Some signs of potential improvement in the fish assemblage were evident at Lincoln Creek, possibly reflecting delayed effects of the restoration of stream habitat, completed in 2002; however, algae and invertebrates did not show signs of improvement. Aggregate bioassessment rankings across all groups of organisms for 2004 and 2007 indicated that water quality at the two Milwaukee River main stem sites (at Milwaukee and near Cedarburg), Jewel Creek, and the Menomonee River at Menomonee Falls was the least-degraded among all sampled sites. Rankings for Oak Creek and Little Menomonee suggested water quality was worse in 2007 compared to 2004 and placed these two sites together with Kinnickinnic River and Underwood Creek, two concrete-line sites, indicating the most-degraded water quality among all sampled sites. The aggregate ranking for Lincoln Creek in 2007 would have placed it in the most-degraded category but for the positive influence of the fish ranking when compared to poor algal and invertebrate rankings. Potential toxicity due to certain manmade chemicals, such as polycyclic aromatic hydrocarbons (PAHs), was found at all six sites where SPMDs were deployed. As was found in 2004, the highest potential toxicity in 2007 was observed at Lincoln Creek where chemical screening in 2007 also showed the highest total PAHs of all six sites; however, potential toxicity at Little Menomonee River, Honey Creek, and Kinnickinnic River was relatively high compared to Milwaukee River near Cedarburg. Although toxicity and chemical results in 2007 did not agree with aggregate rankings for Lincoln Creek because of fish, nor for Honey Creek, the results did agree with aggregate rankings at four of the six sites. In addition to toxicological and chemical influences, the more urbanized sites have high percentages of impervious surface area, resulting in frequent high stream flows that can adversely affect algal, invertebrate, and fish assemblages. Assessments of the ecological status of different groups of organisms and of potential chemical and physical stressors to organisms are important tools in evaluating streamwater quality.

Wisconsin↗