ORCID Profile
0000-0001-6799-0596
Current Organisation
US Geological Survey
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Surfacewater Hydrology | Environmental Science and Management | Environmental Management | Environmental Engineering Modelling
Ecosystem Adaptation to Climate Change | Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments |
Publisher: US Geological Survey
Date: 2017
DOI: 10.3133/OFR20161131
Publisher: Elsevier BV
Date: 06-2008
Publisher: Springer Science and Business Media LLC
Date: 08-1992
DOI: 10.1007/BF00141379
Publisher: Informa UK Limited
Date: 20-06-2016
Publisher: US Geological Survey
Date: 2007
DOI: 10.3133/OFR20071173
Publisher: Copernicus GmbH
Date: 03-05-2016
DOI: 10.5194/HESS-20-1681-2016
Abstract: Abstract. The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911–2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s−1 before 1994 to 3.74 m s−1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (−1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911–1980, 1981–1993, and 1994–2014) delineated by abrupt changes in air temperature and wind speed. Average summer hypolimnetic temperature and fall turnover date exhibit significant differences between the third period and the first two periods. Changes in ice cover (ice-on and ice-off dates, ice cover duration, and maximum ice thickness) exhibit an abrupt change after 1994, which was related in part to the warm El Niño winter of 1997–1998. Under-ice water temperature, freeze-over water temperature, hypolimnetic temperature, fall turnover date, and stratification duration demonstrate a significant difference in the third period (1994–2014), when air temperature was warmest and wind speeds decreased rather abruptly. The trends in ice cover and water temperature demonstrate responses to both long-term and abrupt changes in meteorological conditions that can be complemented with numerical modeling to better understand how these variables will respond in a future climate.
Publisher: US Geological Survey
Date: 2004
DOI: 10.3133/OFR20041087
Publisher: Springer Science and Business Media LLC
Date: 29-11-2006
DOI: 10.1007/S00267-005-0022-8
Abstract: Various approaches are used to sub ide large areas into regions containing streams that have similar reference or background water quality and that respond similarly to different factors. For many applications, such as establishing reference conditions, it is preferable to use physical characteristics that are not affected by human activities to delineate these regions. However, most approaches, such as ecoregion classifications, rely on land use to delineate regions or have difficulties compensating for the effects of land use. Land use not only directly affects water quality, but it is often correlated with the factors used to define the regions. In this article, we describe modifications to SPARTA (spatial regression-tree analysis), a relatively new approach applied to water-quality and environmental characteristic data to delineate zones with similar factors affecting water quality. In this modified approach, land-use-adjusted (residualized) water quality and environmental characteristics are computed for each site. Regression-tree analysis is applied to the residualized data to determine the most statistically important environmental characteristics describing the distribution of a specific water-quality constituent. Geographic information for small basins throughout the study area is then used to sub ide the area into relatively homogeneous environmental water-quality zones. For each zone, commonly used approaches are subsequently used to define its reference water quality and how its water quality responds to changes in land use. SPARTA is used to delineate zones of similar reference concentrations of total phosphorus and suspended sediment throughout the upper Midwestern part of the United States.
Publisher: US Geological Survey
Date: 1996
DOI: 10.3133/FS20896
Publisher: Wiley
Date: 03-09-2019
Publisher: US Geological Survey
Date: 2018
DOI: 10.3133/SIR20185078
Publisher: Wiley
Date: 08-08-2011
Publisher: Springer Science and Business Media LLC
Date: 18-07-2007
DOI: 10.1007/S00267-006-0452-Y
Abstract: We s led 41 sites on 34 nonwadeable rivers that represent the types of rivers in Wisconsin, and the kinds and intensities of nutrient and other anthropogenic stressors upon each river type. Sites covered much of United States Environmental Protection Agency national nutrient ecoregions VII--Mostly Glaciated Dairy Region, and VIII--Nutrient Poor, Largely Glaciated upper Midwest. Fish, macroinvertebrates, and three categories of environmental variables including nutrients, other water chemistry, and watershed features were collected using standard protocols. We summarized fish assemblages by index of biotic integrity (IBI) and its 10 component measures, and macroinvertebrates by 2 organic pollution tolerance and 12 proportional richness measures. All biotic and environmental variables represented a wide range of conditions, with biotic measures ranging from poor to excellent status, despite nutrient concentrations being consistently higher than reference concentrations reported for the regions. Regression tree analyses of nutrients on a suite of biotic measures identified breakpoints in total phosphorus (approximately 0.06 mg/l) and total nitrogen (approximately 0.64 mg/l) concentrations at which biotic assemblages were consistently impaired. Redundancy analyses (RDA) were used to identify the most important variables within each of the three environmental variable categories, which were then used to determine the relative influence of each variable category on the biota. Nutrient measures, suspended chlorophyll a, water clarity, and watershed land cover type (forest or row-crop agriculture) were the most important variables and they explained significant amounts of variation within the macroinvertebrate (R(2) = 60.6%) and fish (R(2) = 43.6%) assemblages. The environmental variables selected in the macroinvertebrate model were correlated to such an extent that partial RDA analyses could not attribute variation explained to in idual environmental categories, assigning 89% of the explained variation to interactions among the categories. In contrast, partial RDA attributed much of the explained variation to the nutrient (25%) and other water chemistry (38%) categories for the fish model. Our analyses suggest that it would be beneficial to develop criteria based upon a suite of biotic and nutrient variables simultaneously to deem waters as not meeting their designated uses.
Publisher: Canadian Science Publishing
Date: 03-2015
Abstract: Little St. Germain Lake (LSG), a relatively pristine multibasin lake in Wisconsin, USA, was examined to determine how morphologic (internal), climatic (external), anthropogenic (winter aeration), and natural (beaver activity) factors affect the trophic state (phosphorus, P chlorophyll, CHL and Secchi depth, SD) of each of its basins. Basins intercepting the main flow and external P sources had highest P and CHL and shallowest SD. Internal loading in shallow, polymictic basins caused P and CHL to increase and SD to decrease as summer progressed. Winter aeration used to eliminate winterkill increased summer internal P loading and decreased water quality, while reductions in upstream beaver impoundments had little effect on water quality. Variations in air temperature and precipitation affected each basin differently. Warmer air temperatures increased productivity throughout the lake and decreased clarity in less eutrophic basins. Increased precipitation increased P in the basins intercepting the main flow but had little effect on the isolated deep West Bay. These relations are used to project effects of future climatic changes on LSG and other temperate lakes.
Publisher: Springer Science and Business Media LLC
Date: 22-11-2007
DOI: 10.1007/S00267-006-0135-8
Abstract: We s led 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera in iduals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables.
Publisher: US Geological Survey
Date: 2008
DOI: 10.3133/SIR20085053
Publisher: Springer Science and Business Media LLC
Date: 30-10-2015
Publisher: Wiley
Date: 20-07-2021
DOI: 10.1111/GCB.15797
Abstract: Winter conditions, such as ice cover and snow accumulation, are changing rapidly at northern latitudes and can have important implications for lake processes. For ex le, snowmelt in the watershed—a defining feature of lake hydrology because it delivers a large portion of annual nutrient inputs—is becoming earlier. Consequently, earlier and a shorter duration of snowmelt are expected to affect annual phytoplankton biomass. To test this hypothesis, we developed an index of runoff timing based on the date when 50% of cumulative runoff between January 1 and May 31 had occurred. The runoff index was computed using stream discharge for inflows, outflows, or for flows from nearby streams for 41 lakes in Europe and North America. The runoff index was then compared with summer chlorophyll‐ a (Chl‐ a ) concentration (a proxy for phytoplankton biomass) across 5–53 years for each lake. Earlier runoff generally corresponded to lower summer Chl‐ a . Furthermore, years with earlier runoff also had lower winter/spring runoff magnitude, more protracted runoff, and earlier ice‐out. We examined several lake characteristics that may regulate the strength of the relationship between runoff timing and summer Chl‐ a concentrations however, our tested covariates had little effect on the relationship. Date of ice‐out was not clearly related to summer Chl‐ a concentrations. Our results indicate that ongoing changes in winter conditions may have important consequences for summer phytoplankton biomass and production.
Publisher: US Geological Survey
Date: 2006
DOI: 10.3133/SIR20065066
Publisher: American Chemical Society (ACS)
Date: 21-06-2016
Abstract: Despite progress in the implementation of conservation practices, related improvements in water quality have been challenging to measure in larger river systems. In this paper we quantify these downstream effects by applying the empirical U.S. Geological Survey water-quality model SPARROW to investigate whether spatial differences in conservation intensity were statistically correlated with variations in nutrient loads. In contrast to other forms of water quality data analysis, the application of SPARROW controls for confounding factors such as hydrologic variability, multiple sources and environmental processes. A measure of conservation intensity was derived from the USDA-CEAP regional assessment of the Upper Mississippi River and used as an explanatory variable in a model of the Upper Midwest. The spatial pattern of conservation intensity was negatively correlated (p = 0.003) with the total nitrogen loads in streams in the basin. Total phosphorus loads were weakly negatively correlated with conservation (p = 0.25). Regional nitrogen reductions were estimated to range from 5 to 34% and phosphorus reductions from 1 to 10% in major river basins of the Upper Mississippi region. The statistical associations between conservation and nutrient loads are consistent with hydrological and biogeochemical processes such as denitrification. The results provide empirical evidence at the regional scale that conservation practices have had a larger statistically detectable effect on nitrogen than on phosphorus loadings in streams and rivers of the Upper Mississippi Basin.
Publisher: Wiley
Date: 19-04-2018
DOI: 10.1002/RRA.3278
Publisher: US Geological Survey
Date: 2009
DOI: 10.3133/SIR20085213
Publisher: US Geological Survey
Date: 2006
DOI: 10.3133/OFR20061080
Publisher: Wiley
Date: 04-2017
DOI: 10.1002/FEE.1472
Publisher: US Geological Survey
Date: 1998
DOI: 10.3133/FS06698
Publisher: Wiley
Date: 16-01-2014
DOI: 10.1111/JAWR.12153
Publisher: US Geological Survey
Date: 2012
DOI: 10.3133/OFR20121238
Publisher: US Geological Survey
Date: 2012
DOI: 10.3133/SIR20125064
Publisher: Wiley
Date: 13-05-2013
DOI: 10.1111/JAWR.12060
Publisher: US Geological Survey
Date: 2023
DOI: 10.3133/SIR20235073
Publisher: Elsevier BV
Date: 02-2018
Publisher: US Geological Survey
Date: 2004
DOI: 10.3133/SIR20045141
Publisher: Wiley
Date: 13-05-2020
DOI: 10.1111/FWB.13515
Publisher: US Geological Survey
Date: 2018
DOI: 10.3133/SIR20185051
Publisher: US Geological Survey
Date: 2001
DOI: 10.3133/OFR02135
Publisher: US Geological Survey
Date: 1998
DOI: 10.3133/CIR1156
Publisher: Wiley
Date: 05-11-2013
DOI: 10.1002/HYP.10083
Publisher: National Research Council of Canada
Date: 2018
DOI: 10.4224/23004810
Publisher: Wiley
Date: 09-2013
Abstract: Quantifying the effectiveness of perceived best management practices (BMPs) at the field and landscape-scale is difficult, so paired watershed studies are used to detect water quality improvements. We evaluated concentrations of NO-N discharged from three tiled Iowa watersheds during a 4-yr period to assess their suitability for a paired watershed approach. Our objectives were to evaluate similarities in physical characteristics, concentration patterns, and correlation among the three paired sites and perform a minimum detectable change (MDC) analysis on paired site configurations. The study results demonstrate that concentration variability within and between s le sites affected correlation among the paired basins, even though the physical characteristics of the basins are quite similar. Restricting comparisons to the active tile drainage period (March-July) improved correlations. The lack of a suitable correlation will impair the ability to detect changes expected to result from BMP implementation. The MDC for NO-N concentration change detection varied from 6.9 to 12.9% and averaged 8% for the best control-treatment pair. To ensure that conservation resources are being used effectively, implemented BMPs should focus on practices capable of achieving at least this magnitude of change. These practices may include reduced fertilizer applications, adoption of cover crops, and land use change.
Publisher: US Geological Survey
Date: 2000
DOI: 10.3133/FS12100
Publisher: Informa UK Limited
Date: 02-10-2019
Publisher: Elsevier BV
Date: 04-2014
Publisher: US Geological Survey
Date: 1995
DOI: 10.3133/OFR95190
Publisher: Wiley
Date: 25-03-2009
Publisher: Springer Science and Business Media LLC
Date: 18-03-2008
Publisher: Wiley
Date: 26-05-2017
DOI: 10.1002/LNO.10557
Publisher: Elsevier BV
Date: 2022
Publisher: US Geological Survey
Date: 2000
DOI: 10.3133/OFR0089
Publisher: American Geophysical Union (AGU)
Date: 12-1999
DOI: 10.1029/1999WR900277
Publisher: US Geological Survey
Date: 2010
DOI: 10.3133/SIR20105196
Publisher: Springer Science and Business Media LLC
Date: 03-06-2009
DOI: 10.1007/S00267-008-9139-X
Abstract: Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction that should be achievable following the implementation of riparian buffers then we estimated load reduction potential for a set of 1598 watersheds (average 54 km(2)) in Wisconsin. Our results indicate that land cover is generally the most important driver of constituent loads in Wisconsin streams, but its influence varies among pollutants and according to the scale at which it is measured. Physiographic (drainage density) variation also influenced sediment and phosphorus loads. The effect of historical land use on present-day channel erosion and variation in soil texture are the most important sources of phosphorus and sediment that riparian buffers cannot attenuate. However, in most watersheds, a large proportion (approximately 70%) of these pollutants can be eliminated from streams with buffers. Cumulative frequency distributions of load reduction potential indicate that targeting pollution reduction in the highest 10% of Wisconsin watersheds would reduce total phosphorus and sediment loads in the entire state by approximately 20%. These results support our approach of geographically targeting nonpoint source pollution reduction at multiple scales, including the watershed scale.
Publisher: US Geological Survey
Date: 2019
DOI: 10.3133/SIR20195114
Publisher: US Geological Survey
Date: 2004
DOI: 10.3133/SIR20045085
Publisher: US Geological Survey
Date: 2017
DOI: 10.3133/OFR20161050
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.SCITOTENV.2016.06.202
Abstract: Complex watershed simulation models are powerful tools that can help scientists and policy-makers address challenging topics, such as land use management and water security. In the Western Lake Erie Basin (WLEB), complex hydrological models have been applied at various scales to help describe relationships between land use and water, nutrient, and sediment dynamics. This manuscript evaluated the capacity of the current Soil and Water Assessment Tool (SWAT) to predict hydrological and water quality processes within WLEB at the finest resolution watershed boundary unit (NHDPlus) along with the current conditions and conservation scenarios. The process based SWAT model was capable of the fine-scale computation and complex routing used in this project, as indicated by measured data at five gaging stations. The level of detail required for fine-scale spatial simulation made the use of both hard and soft data necessary in model calibration, alongside other model adaptations. Limitations to the model's predictive capacity were due to a paucity of data in the region at the NHDPlus scale rather than due to SWAT functionality. Results of treatment scenarios demonstrate variable effects of structural practices and nutrient management on sediment and nutrient loss dynamics. Targeting treatment to acres with critical outstanding conservation needs provides the largest return on investment in terms of nutrient loss reduction per dollar spent, relative to treating acres with lower inherent nutrient loss vulnerabilities. Importantly, this research raises considerations about use of models to guide land management decisions at very fine spatial scales. Decision makers using these results should be aware of data limitations that hinder fine-scale model interpretation.
Publisher: Elsevier BV
Date: 02-2021
Publisher: IWA Publishing
Date: 03-2011
DOI: 10.2166/WCC.2011.026
Abstract: To determine how climate-induced changes in hydrology and water level may affect the trophic state (productivity) of stratified lakes, two relatively pristine dimictic temperate lakes in Wisconsin, USA, were examined. Both are closed-basin lakes that experience changes in water level and degradation in water quality during periods of high water. One, a seepage lake with no inlets or outlets, has a small drainage basin and hydrology dominated by precipitation and groundwater exchange causing small changes in water and phosphorus (P) loading, which resulted in small changes in water level, P concentrations, and productivity. The other, a terminal lake with inlets but no outlets, has a large drainage basin and hydrology dominated by runoff causing large changes in water and P loading, which resulted in large changes in water level, P concentrations, and productivity. Eutrophication models accurately predicted the effects of changes in hydrology, P loading, and water level on their trophic state. If climate changes, larger changes in hydrology and water levels than previously observed could occur. If this causes increased water and P loading, stratified (dimictic and monomictic) lakes are expected to experience higher water levels and become more eutrophic, especially those with large developed drainage basins.
Publisher: US Geological Survey
Date: 2003
DOI: 10.3133/FS06303
Publisher: US Geological Survey
Date: 2008
DOI: 10.3133/OFR20081182
Publisher: US Geological Survey
Date: 2000
DOI: 10.3133/FS06700
Publisher: Springer Science and Business Media LLC
Date: 1990
DOI: 10.1007/BF00879763
Publisher: Wiley
Date: 15-10-2015
DOI: 10.1111/JAWR.12246
Publisher: US Geological Survey
Date: 2012
DOI: 10.3133/SIR20125135
Publisher: US Geological Survey
Date: 2012
DOI: 10.3133/SIR20125134
Publisher: US Geological Survey
Date: 2019
DOI: 10.3133/SIR20195069
Publisher: Informa UK Limited
Date: 22-01-2018
Publisher: US Geological Survey
Date: 2013
DOI: 10.3133/SIR20135174
Publisher: US Geological Survey
Date: 1995
DOI: 10.3133/FS22095
Publisher: Springer Science and Business Media LLC
Date: 03-09-2016
Publisher: US Geological Survey
Date: 2008
DOI: 10.3133/PP1754
Publisher: Springer Science and Business Media LLC
Date: 18-03-2008
Publisher: US Geological Survey
Date: 1999
DOI: 10.3133/OFR9998
Publisher: Informa UK Limited
Date: 13-05-2022
Publisher: Wiley
Date: 14-09-0014
Publisher: US Geological Survey
Date: 2009
DOI: 10.3133/SIR20095089
Publisher: US Geological Survey
Date: 2006
DOI: 10.3133/SIR20065273
Publisher: US Geological Survey
Date: 2013
DOI: 10.3133/SIR20135224
Publisher: US Geological Survey
Date: 2011
DOI: 10.3133/OFR20111130
Publisher: Springer Science and Business Media LLC
Date: 05-2003
DOI: 10.1007/S00267-002-2955-5
Abstract: Various approaches have been used to classify large geographical areas into smaller regions of similar water quality or extrapolate water-quality data from a few streams to other unmonitored streams. A combination of some of the strengths of existing techniques is used to develop a new approach for these purposes. In this new approach, referred to here as SPARTA (SPAtial Regression-Tree Analysis), environmental characteristics for each monitored stream are first quantified using a Geographic Information System (GIS) and then regression-tree analysis is used to determine which characteristics are most statistically important in describing the distribution of a specific water-quality constituent. GIS coverages of only the most statistically significant environmental characteristics are then used to sub ide the area of interest into relatively homogeneous environmental water-quality zones. Results from the regression-tree analysis not only define the most important environmental characteristics, but also describe how to sub ide the coverage of the specific characteristic (for ex le, areas with or=26% soil clay content). The resulting regionalization scheme is customized for each water-quality constituent based on the environmental characteristics most statistically related to that constituent. SPARTA was used to delineate areas of similar phosphorus, nitrogen, and sediment concentrations (by including land-use characteristics) and areas of similar potential water quality (by excluding land-use characteristics). The SPARTA approach reduced the variability in water-quality concentrations (phosphorus, total nitrogen, Kjeldahl nitrogen, and suspended sediment) within similarly classified zones from that obtained using the US Environmental Protection Agency's nutrient ecoregions.
Publisher: US Geological Survey
Date: 2005
DOI: 10.3133/OFR20051147
Publisher: US Geological Survey
Date: 2013
DOI: 10.3133/SIR20135181
Publisher: US Geological Survey
Date: 2005
DOI: 10.3133/SIR20055071
Publisher: Elsevier BV
Date: 06-2016
Publisher: Springer Science and Business Media LLC
Date: 18-03-2008
Publisher: US Geological Survey
Date: 2006
DOI: 10.3133/PP1722
Publisher: US Geological Survey
Date: 1998
DOI: 10.3133/OFR9878W
Publisher: US Geological Survey
Date: 2018
DOI: 10.3133/SIR20185099
Publisher: Canadian Science Publishing
Date: 04-2002
DOI: 10.1139/F02-044
Abstract: Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea l rey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea l rey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin (Myoxocephalus thompsoni), yellow perch (Perca flavescens), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia, oligochaetes, and sphaeriids, during the 1980s in nearshore waters ([Formula: see text]50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel (Dreissena polymorpha) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.
Publisher: Wiley
Date: 14-07-2015
Publisher: US Geological Survey
Date: 2015
DOI: 10.3133/TM9A10
Publisher: US Geological Survey
Date: 2009
DOI: 10.3133/SIR20095077
Publisher: US Geological Survey
Date: 2023
DOI: 10.3133/SIR20235043
Publisher: Wiley
Date: 2011
DOI: 10.2134/JEQ2010.0257
Abstract: A combination of above-normal precipitation during the winter and spring of 2007-2008 and extensive rainfall during June 2008 led to severe flooding in many parts of the midwestern United States. This resulted in transport of substantial amounts of nutrients and sediment from Iowa basins into the Mississippi River. Water s les were collected from 31 sites on six large Iowa tributaries to the Mississippi River to characterize water quality and to quantify nutrient and sediment loads during this extreme discharge event. Each s le was analyzed for total nitrogen, dissolved nitrate plus nitrite nitrogen, dissolved ammonia as nitrogen, total phosphorus, orthophosphate, and suspended sediment. Concentrations measured near peak flow in June 2008 were compared with the corresponding mean concentrations from June 1979 to 2007 using a paired t test. While there was no consistent pattern in concentrations between historical s les and those from the 2008 flood, increased flow during the flood resulted in near-peak June 2008 flood daily loads that were statistically greater (p < 0.05) than the median June 1979 to 2007 daily loads for all constituents. Estimates of loads for the 16-d period during the flood were calculated for four major tributaries and totaled 4.95 x 10(7) kg of nitrogen (N) and 2.9 x 10(6) kg of phosphorus (P) leaving Iowa, which accounted for about 22 and 46% of the total average annual nutrient yield, respectively. This study demonstrates the importance of large flood events to the total annual nutrient load in both small streams and large rivers.
Publisher: Springer Science and Business Media LLC
Date: 05-2015
Publisher: US Geological Survey
Date: 2022
DOI: 10.3133/SIR20225003
Publisher: Springer New York
Date: 1992
Publisher: US Geological Survey
Date: 2011
DOI: 10.3133/SIR20115111
Publisher: Informa UK Limited
Date: 27-07-2020
Publisher: Springer International Publishing
Date: 2018
Start Date: 04-2021
End Date: 04-2024
Amount: $390,000.00
Funder: Australian Research Council
View Funded Activity