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Steven C. Chapra
Professor and Berger Chair, Dept. of Civil and Environmental Engineering, Tufts Univ., 200 College Ave., Medford, MA 02155. ORCID:

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Preprint content
Published: 04 March 2021
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The Natural Reserve “Torbiere del Sebino” is situated on the southern bank of Lake Iseo and is one the most meaningful wet zone for extension and ecological importance of northern Italy, belonging to the Natura2000 network.

Torbiere occupies an area of 3.60 km2 within a 14 km2 watershed where almost 12000 inhabitants live and where agricultural activities, mostly vineyards, cover almost 40% of the area; this leads to a significant anthropic pressure that over the last 50 years has compromised the system and changed the equilibria between species, enhancing eutrophication.

Despite the ecological relevance of the area, one of the most important in northern Italy, very little quantitative information is available regarding its current state and evolution in terms of water quality and hydrodynamics.  Given the critical environmental condition of the habitat, it is necessary to address the consequences of human impact on the trophic state of Torbiere.

Torbiere consists of a system of shallow lakes or ponds (average depth 1.5 m) whose main affluent is a creek (called Rì) entering from the South. A secondary occasional affluent enters the system from the East and consists of a combined sewer overflow (CSO). Finally, the main effluent is an artificial channel located in the North connecting Torbiere directly with the subalpine Lake Iseo. Although originally subdivided into a set of many interconnected ponds, the separation levees have been demolished over the last decades to enhance internal circulation, under the assumption that this would decrease the residence time and improve the water quality. However, no rational argument was used to support this decision that led to a system where similar characteristics (Secchi’s depth, turbidity, specific conductivity) are found all over the study area and where the expansion of invasive species was easier; now there is some evidence that a separate set of ponds would be better manageable to contrast the eutrophication process. To understand this process, a 3D hydrodynamic model has been set up using Delft-3D, an open source, finite difference package. 

Given the great extension of the system, the inner circulation of the water is not driven by the momentum of the affluents, instead the wind plays a major role. This forcing term presents a daily pattern: it blows from the North in the mornings and shifts to the opposite direction in the late afternoon. The water mainly flows from the South to the North. However, preliminary results by Delft 3D showed that the circulation is made complex by the wind. The model shows that opposite directions of horizontal flow velocities are found at the surface and at the bottom of the water column, showing that only the upper layers follow the direction of the wind.

By comparing the actual and previous conditions of separation of the ponds, the model aims to give an answer to whether the choice of demolishing the banks was positive or negative for the water quality of Torbiere. Once the role of the banks will be clarified, the effects of their possible restoration will be addressed.

ACS Style

Stella Volpini; Marco Pilotti; Giulia Valerio; Steven C. Chapra. Modeling the hydrodynamics of a wetland under strong anthropic pressures (Torbiere del Sebino, Italy). 2021, 1 .

AMA Style

Stella Volpini, Marco Pilotti, Giulia Valerio, Steven C. Chapra. Modeling the hydrodynamics of a wetland under strong anthropic pressures (Torbiere del Sebino, Italy). . 2021; ():1.

Chicago/Turabian Style

Stella Volpini; Marco Pilotti; Giulia Valerio; Steven C. Chapra. 2021. "Modeling the hydrodynamics of a wetland under strong anthropic pressures (Torbiere del Sebino, Italy)." , no. : 1.

Journal article
Published: 01 August 2020 in Journal of Environmental Engineering
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ACS Style

J. Christopher Rutherford; Roger G. Young; John M. Quinn; Steven C. Chapra; Robert J. Wilcock. Nutrient Attenuation in Streams: A Simplified Model to Explain Field Observations. Journal of Environmental Engineering 2020, 146, 04020092 .

AMA Style

J. Christopher Rutherford, Roger G. Young, John M. Quinn, Steven C. Chapra, Robert J. Wilcock. Nutrient Attenuation in Streams: A Simplified Model to Explain Field Observations. Journal of Environmental Engineering. 2020; 146 (8):04020092.

Chicago/Turabian Style

J. Christopher Rutherford; Roger G. Young; John M. Quinn; Steven C. Chapra; Robert J. Wilcock. 2020. "Nutrient Attenuation in Streams: A Simplified Model to Explain Field Observations." Journal of Environmental Engineering 146, no. 8: 04020092.

Journal article
Published: 01 February 2020 in Ecological Modelling
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ACS Style

Anika Kuczynski; Ankita Bakshi; Martin T. Auer; Steven C. Chapra. The canopy effect in filamentous algae: Improved modeling of Cladophora growth via a mechanistic representation of self-shading. Ecological Modelling 2020, 418, 1 .

AMA Style

Anika Kuczynski, Ankita Bakshi, Martin T. Auer, Steven C. Chapra. The canopy effect in filamentous algae: Improved modeling of Cladophora growth via a mechanistic representation of self-shading. Ecological Modelling. 2020; 418 ():1.

Chicago/Turabian Style

Anika Kuczynski; Ankita Bakshi; Martin T. Auer; Steven C. Chapra. 2020. "The canopy effect in filamentous algae: Improved modeling of Cladophora growth via a mechanistic representation of self-shading." Ecological Modelling 418, no. : 1.

Journal article
Published: 31 January 2019 in Journal of Hydrology
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This paper investigates the residual nutrient load from a combined sewer system along the shore of a deep Italian lake, to provide data that can help explaining the contribution of combined sewers to lakes eutrophication. To this purpose, a stochastic methodology is applied to the analysis of the combined sewer overflows and pollutants, that provides reliable estimates, with related uncertainties, of the storage capacity to be supplied in order to mitigate the impact on the quality of receiving waters. The sewer is modeled by SWMM and two terminal combined sewer weirs are modeled in detail and instrumented for calibration purposes. A year-long campaign was accomplished, allowing to study the occurrence and relevance of the first flush. The calibrated model of the sewer network was used to extrapolate the results to a 10-years period, thus providing a statistically reliable estimate of the residual load delivered from this watershed to the lake. A conservative evaluation shows that up to 22 % of phosphorus and up to 41 % of nitrogen delivered to the sewer are still discharged into the environment. However, the results also show that in this case a relatively small capture volume would obtain a target pollution reduction, thus providing insights on the feasibility of this structural practice in similar watersheds along the shore of endangered lakes.

ACS Style

Laura Barone; Marco Pilotti; Giulia Valerio; Matteo Balistrocchi; Luca Milanesi; Steven C. Chapra; Daniele Nizzoli. Analysis of the residual nutrient load from a combined sewer system in a watershed of a deep Italian lake. Journal of Hydrology 2019, 571, 202 -213.

AMA Style

Laura Barone, Marco Pilotti, Giulia Valerio, Matteo Balistrocchi, Luca Milanesi, Steven C. Chapra, Daniele Nizzoli. Analysis of the residual nutrient load from a combined sewer system in a watershed of a deep Italian lake. Journal of Hydrology. 2019; 571 ():202-213.

Chicago/Turabian Style

Laura Barone; Marco Pilotti; Giulia Valerio; Matteo Balistrocchi; Luca Milanesi; Steven C. Chapra; Daniele Nizzoli. 2019. "Analysis of the residual nutrient load from a combined sewer system in a watershed of a deep Italian lake." Journal of Hydrology 571, no. : 202-213.

Review
Published: 29 January 2019 in International Journal of Environmental Research and Public Health
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Public health has always been, and remains, an interdisciplinary field, and engineering was closely aligned with public health for many years. Indeed, the branch of engineering that has been known at various times as sanitary engineering, public health engineering, or environmental engineering was integral to the emergence of public health as a distinct discipline. However, in the United States (U.S.) during the 20th century, the academic preparation and practice of this branch of engineering became largely separated from public health. Various factors contributed to this separation, including an evolution in leadership roles within public health; increasing specialization within public health; and the emerging environmental movement, which led to the creation of the U.S. Environmental Protection Agency (EPA), with its emphasis on the natural environment. In this paper, we consider these factors in turn. We also present a case study example of public health engineering in current practice in the U.S. that has had large-scale positive health impacts through improving water and sanitation services in Native American and Alaska Native communities. We also consider briefly how to educate engineers to work in public health in the modern world, and the benefits and challenges associated with that process. We close by discussing the global implications of public health engineering and the need to re-integrate engineering into public health practice and strengthen the connection between the two fields.

ACS Style

Richard J. Gelting; Steven C. Chapra; Paul E. Nevin; David E. Harvey; David M. Gute. “Back to the Future”: Time for a Renaissance of Public Health Engineering. International Journal of Environmental Research and Public Health 2019, 16, 387 .

AMA Style

Richard J. Gelting, Steven C. Chapra, Paul E. Nevin, David E. Harvey, David M. Gute. “Back to the Future”: Time for a Renaissance of Public Health Engineering. International Journal of Environmental Research and Public Health. 2019; 16 (3):387.

Chicago/Turabian Style

Richard J. Gelting; Steven C. Chapra; Paul E. Nevin; David E. Harvey; David M. Gute. 2019. "“Back to the Future”: Time for a Renaissance of Public Health Engineering." International Journal of Environmental Research and Public Health 16, no. 3: 387.

Journal article
Published: 14 December 2018 in Ecological Modelling
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Located on the same river, the degree of eutrophication in the upper and middle reaches of the Qu’Appelle River in Saskatchewan are different. While the upper Qu’Appelle is eutrophic, the middle Qu’Appelle River is hypereutrophic. To manage the river sustainably, there is a need to understand key processes governing eutrophication in both systems. In this study, a comprehensive global sensitivity analysis technique, Variogram Analysis of Response Surface (VARS), was applied to gain insights to the functioning of the two systems. Eutrophication in both systems was modelled using the Water quality Analysis Simulation Program (WASP 7.52). The performance of the model to predict key variables of eutrophication was measured using relative root mean square error. The global sensitivity analyses showed that although diffuse loading has significant influence on the systems, prevailing processes governing eutrophic state in the upper Qu’Appelle River include: nutrient and, phytoplankton cycles. Meanwhile, in the middle Qu’Appelle River a number of processes including phytoplankton cycle, nutrient cycle, diffuse loading and DO balance together sustain its hypereutrophic state.

ACS Style

Eric Akomeah; Karl-Erich Lindenschmidt; Steven C. Chapra. Comparison of aquatic ecosystem functioning between eutrophic and hypereutrophic cold-region river-lake systems. Ecological Modelling 2018, 393, 25 -36.

AMA Style

Eric Akomeah, Karl-Erich Lindenschmidt, Steven C. Chapra. Comparison of aquatic ecosystem functioning between eutrophic and hypereutrophic cold-region river-lake systems. Ecological Modelling. 2018; 393 ():25-36.

Chicago/Turabian Style

Eric Akomeah; Karl-Erich Lindenschmidt; Steven C. Chapra. 2018. "Comparison of aquatic ecosystem functioning between eutrophic and hypereutrophic cold-region river-lake systems." Ecological Modelling 393, no. : 25-36.

Journal article
Published: 01 September 2018 in Ecological Modelling
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ACS Style

Julie A. Terry; Amir Sadeghian; Helen Baulch; Steven C. Chapra; Karl-Erich Lindenschmidt. Challenges of modelling water quality in a shallow prairie lake with seasonal ice cover. Ecological Modelling 2018, 384, 43 -52.

AMA Style

Julie A. Terry, Amir Sadeghian, Helen Baulch, Steven C. Chapra, Karl-Erich Lindenschmidt. Challenges of modelling water quality in a shallow prairie lake with seasonal ice cover. Ecological Modelling. 2018; 384 ():43-52.

Chicago/Turabian Style

Julie A. Terry; Amir Sadeghian; Helen Baulch; Steven C. Chapra; Karl-Erich Lindenschmidt. 2018. "Challenges of modelling water quality in a shallow prairie lake with seasonal ice cover." Ecological Modelling 384, no. : 43-52.

Conference paper
Published: 01 September 2018 in Smart and Sustainable Planning for Cities and Regions
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The historical roots of environmental engineering and water-quality management are traced to mid-19th century London when engineers and public health workers worked to control and manage the major water-quality problems derived from urbanization. This is followed by a brief review of the field’s subsequent century-plus evolution. The talk then turns to the current state of the art and a delineation of key research issues and frontiers. These include the modelling of “black water”, scum formation, the nepheloid layer, floatables (plastics & weeds), macrophytes, zooplankton, and uncertainty analysis of large model frameworks. Beyond specific research needs, global warming and mega-urbanization mean that, in the future, water-quality management must be expanded beyond the traditional reduction of pollutant inputs with novel approaches essential to maintain acceptable water quality in a sustainable fashion. Several case studies are used to illustrate possible approaches including dissolved oxygen bubblers, pure oxygen injection, lake hypolimnetic electron acceptor injection, boom deployment to capture floatables, flushing flows for oxygen and pathogen control, and deep lake siphons. Many of these schemes will be facilitated by coupling improved observational technology such as drones, robots, and sensors with water quantity and quality models. Real time, model-based distributed control could allow the development of “smart waters” where in situ interventions could be implemented in a sustainable fashion.

ACS Style

Steven C. Chapra. Advances in River Water Quality Modelling and Management: Where We Come from, Where We Are, and Where We’re Going? Smart and Sustainable Planning for Cities and Regions 2018, 295 -301.

AMA Style

Steven C. Chapra. Advances in River Water Quality Modelling and Management: Where We Come from, Where We Are, and Where We’re Going? Smart and Sustainable Planning for Cities and Regions. 2018; ():295-301.

Chicago/Turabian Style

Steven C. Chapra. 2018. "Advances in River Water Quality Modelling and Management: Where We Come from, Where We Are, and Where We’re Going?" Smart and Sustainable Planning for Cities and Regions , no. : 295-301.

Conference paper
Published: 01 September 2018 in Smart and Sustainable Planning for Cities and Regions
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The research is motivated by the need to understand the nutrient pollution dynamics in combined sewer overflows (CSOs) contributing to the eutrophication of Lake Iseo, the fifth largest Italian lake in terms of volume. To this end, the effectiveness of the combined sewer system along the lake’s eastern shore is assessed. The sewer’s efficiency is quantified with regard to the residual nutrients load from CSOs, which was originally reckoned at no more than 3% of the overall sewer load. A hydrodynamic model of the sewer system was developed by SWMM and calibrated by a long time series of measurements collected at two selected CSOs. This data allowed to investigate in detail the occurrence of first flush and to estimate the pollutant loads discharged during wet weather periods. The calibrated model then allowed to extrapolate the results of the year-long campaign to a 10-year simulation period providing, for the first time, quantitative information on the total residual loads to the lake. Such loads are at least 5 times larger than the design value. This research provides important insight into the potential impact of CSOs on the other deep lakes of the pre-alpine chain (e.g., lakes Como, Maggiore, and Garda in Italy), that are struggling with growing environmental stressors, opening the way to important technical and management considerations regarding remedial actions.

ACS Style

Laura Barone; Marco Pilotti; Manuel Murgioni; Giulia Valerio; Steven C. Chapra; Matteo Balistrocchi; Luca Milanesi. Measuring and Modelling the Nutrients Residual Load from the Combined Sewer of the Eastern Shore of Lake Iseo. Smart and Sustainable Planning for Cities and Regions 2018, 349 -354.

AMA Style

Laura Barone, Marco Pilotti, Manuel Murgioni, Giulia Valerio, Steven C. Chapra, Matteo Balistrocchi, Luca Milanesi. Measuring and Modelling the Nutrients Residual Load from the Combined Sewer of the Eastern Shore of Lake Iseo. Smart and Sustainable Planning for Cities and Regions. 2018; ():349-354.

Chicago/Turabian Style

Laura Barone; Marco Pilotti; Manuel Murgioni; Giulia Valerio; Steven C. Chapra; Matteo Balistrocchi; Luca Milanesi. 2018. "Measuring and Modelling the Nutrients Residual Load from the Combined Sewer of the Eastern Shore of Lake Iseo." Smart and Sustainable Planning for Cities and Regions , no. : 349-354.

Journal article
Published: 07 August 2018 in Aquatic Botany
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The attenuation of photosynthetically active radiation (PAR) through the filamentous alga Cladophora glomerata was investigated both in situ and in an experimental flow tank under both natural and artificial lighting using a fiber-optic sensor. Over 35 separate experiments were completed to characterize downward light attenuation and water velocity effects. Measured extinction coefficients ranged from 4.3–150.7 m−1 for biomass samples ranging from 40–253 mg chlorophyll-a m−2 (41–381 g ash free dry weight m−2) at shear velocities from 0–51.8 cm s−1. An exponential relationship between light attenuation coefficient (Kalg) and algal biomass thickness (δ) was found (lnKalg = −1.1831 lnδ + 8.3789; r2 = 0.41, p < 0.001). Unexpectedly, chlorophyll-a (Chla) and ash free dry weight (AFDW) areal density were poor predictors of Kalg. No significant correlations (p > 0.01) were found amongst any of the other experimental variables (e.g., shear velocity, Reynolds number, etc.). Cladophora mat thickness (δ ) and volumetric biomass (Chla m−3) provided the greatest explanation of downward light attenuation in flowing water, reducing irradiance in proportion to how closely the filaments are pressed together. Observed δ generally decreased with increasing shear velocity, albeit not predictably. Results have important implications on aquatic systems where macroalgae movements generate variable light regimes on understory aquatic species.

ACS Style

Kyle F. Flynn; Wayne Chudyk; Vicki Watson; Steven C. Chapra; Michael W. Suplee. Influence of biomass and water velocity on light attenuation of Cladophora glomerata L. (Kuetzing) in rivers. Aquatic Botany 2018, 151, 62 -70.

AMA Style

Kyle F. Flynn, Wayne Chudyk, Vicki Watson, Steven C. Chapra, Michael W. Suplee. Influence of biomass and water velocity on light attenuation of Cladophora glomerata L. (Kuetzing) in rivers. Aquatic Botany. 2018; 151 ():62-70.

Chicago/Turabian Style

Kyle F. Flynn; Wayne Chudyk; Vicki Watson; Steven C. Chapra; Michael W. Suplee. 2018. "Influence of biomass and water velocity on light attenuation of Cladophora glomerata L. (Kuetzing) in rivers." Aquatic Botany 151, no. : 62-70.

Journal article
Published: 01 March 2018 in Environmental Modelling & Software
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Algal simulations in many water quality models perform poorly because of oversimplifications in the process descriptions of the algae growth mechanisms. In this study, algae simulations were improved by implementing variable chlorophyll a/algal biomass ratios in the CE-QUAL-W2 model, a sophisticated two-dimensional laterally-averaged water quality model. Originally a constant in the model, the chlorophyll a/algal biomass ratio was reprogrammed to vary according to the nutrient and light limiting conditions in the water column. The modified model was tested on Lake Diefenbaker, a prairie reservoir in Saskatchewan, Canada, where, similar to many other lakes in the world, field observations confirm variable spatiotemporal ratios between chlorophyll a and algal biomass. The modified version yielded more accurate simulations compared to the standard version and provides a promising algorithm to improve results for many lakes and reservoirs globally.

ACS Style

Amir Sadeghian; Steven C. Chapra; Jeff Hudson; Howard Wheater; Karl-Erich Lindenschmidt. Improving in-lake water quality modeling using variable chlorophyll a/algal biomass ratios. Environmental Modelling & Software 2018, 101, 73 -85.

AMA Style

Amir Sadeghian, Steven C. Chapra, Jeff Hudson, Howard Wheater, Karl-Erich Lindenschmidt. Improving in-lake water quality modeling using variable chlorophyll a/algal biomass ratios. Environmental Modelling & Software. 2018; 101 ():73-85.

Chicago/Turabian Style

Amir Sadeghian; Steven C. Chapra; Jeff Hudson; Howard Wheater; Karl-Erich Lindenschmidt. 2018. "Improving in-lake water quality modeling using variable chlorophyll a/algal biomass ratios." Environmental Modelling & Software 101, no. : 73-85.

Journal article
Published: 01 February 2018 in Journal of Great Lakes Research
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During an initial field survey in 2012, we observed an unexpected asymmetry of dissolved oxygen distribution between the western and eastern side in northern Lake Iseo. Motivated by this apparent anomaly, we conducted a detailed field investigation, and we used a physical model of the northern part of the lake to understand the influences that might affect the distribution of material in the northern section of the lake. These investigations suggested that the Earth's rotation has significant influence on the inflow of the lake's two main tributaries. In order to further crosscheck the validity of these results, we conducted a careful analysis at a synoptic scale using images acquired during thermally unstratified periods by Landsat-8 and Sentinel-2 satellites. We retrieved and post-processed a large set of images, providing conclusive evidence of the role exerted by the Earth's rotation on pollutant transport in Lake Iseo and of the greater environmental vulnerability of the north-west shore of this lake, where important settlements are located. Our study confirms the necessity for three-dimensional hydrodynamic models including Coriolis effect in order to effectively predict local impacts of inflows on nearshore water quality of medium-sized elongated lakes of similar scale to Lake Iseo.

ACS Style

Marco Pilotti; Giulia Valerio; Claudia Giardino; Mariano Bresciani; Steven C. Chapra. Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry. Journal of Great Lakes Research 2018, 44, 14 -25.

AMA Style

Marco Pilotti, Giulia Valerio, Claudia Giardino, Mariano Bresciani, Steven C. Chapra. Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry. Journal of Great Lakes Research. 2018; 44 (1):14-25.

Chicago/Turabian Style

Marco Pilotti; Giulia Valerio; Claudia Giardino; Mariano Bresciani; Steven C. Chapra. 2018. "Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry." Journal of Great Lakes Research 44, no. 1: 14-25.

Journal article
Published: 14 July 2017 in Water
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Dissolved oxygen (DO) depression in urban rivers appears to be increasing in developing countries, which causes severe aquatic ecosystem stresses. One urban river which suffers DO depression under low flow conditions and requires systematic research for effective mitigation strategies is the Nanfei River (Hefei, China). We investigated its longitudinal profiles of DO and other related water constituents with high spatial resolution monitoring at low flow. A mechanistic DO model for the reach was customized and calibrated with the data obtained. We found that the daily average DO levels within the 11 km study reach shifted from supersaturation (11.5 mg L−1) upstream of the Wangtang Wastewater Treatment Plant (WWTP) to serious depletion (3.6 mg L−1) downstream. Process analysis indicated that DO production via strong algal photosynthesis overwhelmed the DO consumptions upstream from the WWTP. In contrast, DO sources could not compensate for DO consumptions, wherein carbonaceous deoxygenation was the largest consumer of the DO (approximately 70%) downstream the WWTP. Rather than directly contributing labile organics, the WWTP effluent affected the DO balance by shifting the metabolism from upstream autotrophy to downstream heterotrophy. Finally, mitigation strategies for DO depression in rivers in rapidly-urbanizing regions were suggested accordingly.

ACS Style

Jingshui Huang; Hailong Yin; Steven C. Chapra; Qi Zhou. Modelling Dissolved Oxygen Depression in an Urban River in China. Water 2017, 9, 520 .

AMA Style

Jingshui Huang, Hailong Yin, Steven C. Chapra, Qi Zhou. Modelling Dissolved Oxygen Depression in an Urban River in China. Water. 2017; 9 (7):520.

Chicago/Turabian Style

Jingshui Huang; Hailong Yin; Steven C. Chapra; Qi Zhou. 2017. "Modelling Dissolved Oxygen Depression in an Urban River in China." Water 9, no. 7: 520.

Research article
Published: 26 June 2017 in Environmental Science & Technology
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Cyanobacterial harmful algal blooms (CyanoHABs) have serious adverse effects on human and environmental health. Herein, we developed a modeling framework that predicts the effect of climate change on cyanobacteria concentrations in large reservoirs in the contiguous U.S. The framework, which uses climate change projections from five global circulation models, two greenhouse gas emission scenarios, and two cyanobacterial growth scenarios, is unique in coupling climate projections with a hydrologic/water quality network model of the contiguous United States. Thus, it generates both regional and nationwide projections useful as a screening-level assessment of climate impacts on CyanoHAB prevalence as well as potential lost recreation days and associated economic value. Our projections indicate that CyanoHAB concentrations are likely to increase primarily due to water temperature increases tempered by increased nutrient levels resulting from changing demographics and climatic impacts on hydrology that drive nutrient transport. The combination of these factors results in the mean number of days of CyanoHAB occurrence ranging from about 7 days per year per waterbody under current conditions, to 16–23 days in 2050 and 18–39 days in 2090. From a regional perspective, we find the largest increases in CyanoHAB occurrence in the Northeast U.S., while the greatest impacts to recreation, in terms of costs, are in the Southeast.

ACS Style

Steven C. Chapra; Brent Boehlert; Charles Fant; Jr. Victor J. Bierman; Jim Henderson; David Mills; Diane M. L. Mas; Lisa Rennels; Lesley Jantarasami; Jeremy Martinich; Kenneth M. Strzepek; Hans W. Paerl. Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment. Environmental Science & Technology 2017, 51, 8933 -8943.

AMA Style

Steven C. Chapra, Brent Boehlert, Charles Fant, Jr. Victor J. Bierman, Jim Henderson, David Mills, Diane M. L. Mas, Lisa Rennels, Lesley Jantarasami, Jeremy Martinich, Kenneth M. Strzepek, Hans W. Paerl. Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment. Environmental Science & Technology. 2017; 51 (16):8933-8943.

Chicago/Turabian Style

Steven C. Chapra; Brent Boehlert; Charles Fant; Jr. Victor J. Bierman; Jim Henderson; David Mills; Diane M. L. Mas; Lisa Rennels; Lesley Jantarasami; Jeremy Martinich; Kenneth M. Strzepek; Hans W. Paerl. 2017. "Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment." Environmental Science & Technology 51, no. 16: 8933-8943.

Journal article
Published: 14 February 2017 in Water
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Climate change and freshwater quality are well-linked. Changes in climate result in changes in streamflow and rising water temperatures, which impact biochemical reaction rates and increase stratification in lakes and reservoirs. Using two water quality modeling systems (the Hydrologic and Water Quality System; HAWQS and US Basins), five climate models, and two greenhouse gas (GHG) mitigation policies, we assess future water quality in the continental U.S. to 2100 considering four water quality parameters: water temperature, dissolved oxygen, total nitrogen, and total phosphorus. Once these parameters are aggregated into a water quality index, we find that, while the water quality models differ under the baseline, there is more agreement between future projections. In addition, we find that the difference in national-scale economic benefits across climate models is generally larger than the difference between the two water quality models. Both water quality models find that water quality will more likely worsen in the East than in the West. Under the business-as-usual emissions scenario, we find that climate change is likely to cause economic impacts ranging from 1.2 to 2.3 (2005 billion USD/year) in 2050 and 2.7 to 4.8 in 2090 across all climate and water quality models.

ACS Style

Charles Fant; Raghavan Srinivasan; Brent Boehlert; Lisa Rennels; Steven C. Chapra; Kenneth M. Strzepek; Joel Corona; Ashley Allen; Jeremy Martinich. Climate Change Impacts on US Water Quality Using Two Models: HAWQS and US Basins. Water 2017, 9, 118 .

AMA Style

Charles Fant, Raghavan Srinivasan, Brent Boehlert, Lisa Rennels, Steven C. Chapra, Kenneth M. Strzepek, Joel Corona, Ashley Allen, Jeremy Martinich. Climate Change Impacts on US Water Quality Using Two Models: HAWQS and US Basins. Water. 2017; 9 (2):118.

Chicago/Turabian Style

Charles Fant; Raghavan Srinivasan; Brent Boehlert; Lisa Rennels; Steven C. Chapra; Kenneth M. Strzepek; Joel Corona; Ashley Allen; Jeremy Martinich. 2017. "Climate Change Impacts on US Water Quality Using Two Models: HAWQS and US Basins." Water 9, no. 2: 118.

Article
Published: 27 October 2016 in Water, Air, & Soil Pollution
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Phosphorus (P) associated with minerogenic particles delivered from watersheds can interfere with the common use of total P (TP) concentration as a trophic state metric in lacustrine systems, particularly proximate to tributary entries, because of its limited bioavailability. The concentration of unavailable minerogenic particulate P (PPm/u), where it is noteworthy, should be subtracted from TP in considering primary production potential and trophic state levels. A first mass balance model for PPm/u is developed and tested here for Cayuga Lake, New York. This is supported by a rare combination of detailed information for minerogenic particle level dynamics for the tributaries and lake, the bioavailability of tributary particulate P (PP), and previously tested hydrothermal/transport and minerogenic particle concentration submodels. The central roles of major runoff events and localized tributary loading at one end of the lake in driving patterns of PPm/u in time and space are well simulated, including (1) the higher PPm/u concentrations in a shallow area (“shelf”) adjoining the inputs, relative to pelagic waters, following runoff events, and (2) the positive dependence of the shelf increases on the magnitude of the event. The PPm/u component of P was largely responsible for the higher summer average TP on the shelf vs. pelagic waters and the exceedance of a TP water quality limit on the shelf. The effective simulation of PPm/u allows an appropriate adjustment of TP values to avoid overrepresentation of potential primary production levels.

ACS Style

Rakesh K. Gelda; Steven W. Effler; Anthony R. Prestigiacomo; Feng Peng; Martin T. Auer; Anika Kuczynski; Steven C. Chapra. Simulation of the Contribution of Phosphorus-Containing Minerogenic Particles to Particulate Phosphorus Concentration in Cayuga Lake, New York. Water, Air, & Soil Pollution 2016, 227, 421 .

AMA Style

Rakesh K. Gelda, Steven W. Effler, Anthony R. Prestigiacomo, Feng Peng, Martin T. Auer, Anika Kuczynski, Steven C. Chapra. Simulation of the Contribution of Phosphorus-Containing Minerogenic Particles to Particulate Phosphorus Concentration in Cayuga Lake, New York. Water, Air, & Soil Pollution. 2016; 227 (11):421.

Chicago/Turabian Style

Rakesh K. Gelda; Steven W. Effler; Anthony R. Prestigiacomo; Feng Peng; Martin T. Auer; Anika Kuczynski; Steven C. Chapra. 2016. "Simulation of the Contribution of Phosphorus-Containing Minerogenic Particles to Particulate Phosphorus Concentration in Cayuga Lake, New York." Water, Air, & Soil Pollution 227, no. 11: 421.

Journal article
Published: 01 October 2016 in Journal of Environmental Engineering
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Managers and regulators need to determine the feasibility of expanding aquaculture in freshwater and marine systems without endangering the environment or compromising water-quality goals. Models for various aquaculture operations and receiving water responses have been developed and applied by previous researchers. However, these models should be combined into a single, unified framework prior to management applications. This paper demonstrates for the first time how various submodels can be integrated and used to calculate the impacts of aquaculture on river water quality. A fish bioenergetics submodel simulates fish growth, production, and by-product nutrient loading as a function of fish numbers, feeding rate, food composition, and temperature. A receiving water submodel simulates water-quality impacts as a function of the aquaculture by-product nutrient loading and the physical, chemical, and biological characteristics of the stream or river. The utility of the approach and proof of concept is demonstrated by examining the impacts of a hypothetical aquaculture operation on one of the United States’ most renowned, high-quality recreational trout fisheries, the Au Sable River (Michigan). This framework is used to evaluate the water-quality impacts of alternative fish production levels and quantify how careful control of ration and low phosphorus-content feed can reduce by-product nutrient loads. The model can also calculate how wastewater treatment can be used to increase the probability of attaining compliance when conscientious aquaculture management practices alone are insufficient to meet water-quality goals. Issues related to model reliability and validation are discussed and recommendations for future research and development are suggested.

ACS Style

Raymond P. Canale; Steven C. Chapra. Decision Support Models for Assessing the Impact of Aquaculture on River Water Quality. Journal of Environmental Engineering 2016, 142, 03116001 .

AMA Style

Raymond P. Canale, Steven C. Chapra. Decision Support Models for Assessing the Impact of Aquaculture on River Water Quality. Journal of Environmental Engineering. 2016; 142 (10):03116001.

Chicago/Turabian Style

Raymond P. Canale; Steven C. Chapra. 2016. "Decision Support Models for Assessing the Impact of Aquaculture on River Water Quality." Journal of Environmental Engineering 142, no. 10: 03116001.

Journal article
Published: 12 September 2015 in Journal of Advances in Modeling Earth Systems
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Climate change will have potentially significant effects on freshwater quality due to increases in river and lake temperatures, changes in the magnitude and seasonality of river runoff, and more frequent and severe extreme events. These physical impacts will in turn have economic consequences through effects on riparian development, river and reservoir recreation, water treatment, harmful aquatic blooms, and a range of other sectors. In this paper, we analyze the physical and economic effects of changes in freshwater quality across the contiguous U.S. in futures with and without global‐scale greenhouse gas mitigation. Using a water allocation and quality model of 2,119 river basins, we estimate the impacts of various projected emissions outcomes on several key water quality indicators, and monetize these impacts with a water quality index approach. Under mitigation, we find that water temperatures decrease considerably and that dissolved oxygen levels rise in response. We find that the annual economic impacts on water quality of a high emissions scenario rise from $1.4 billion in 2050 to $4 billion in 2100, leading to present value mitigation benefits, discounted at 3%, of approximately $17.5 billion over the 2015 to 2100 period. This article is protected by copyright. All rights reserved.

ACS Style

Brent Boehlert; Kenneth M. Strzepek; Steven C. Chapra; Charles Fant; Yohannes Gebretsadik; Megan Lickley; Richard Swanson; Alyssa McCluskey; James E. Neumann; Jeremy Martinich. Climate change impacts and greenhouse gas mitigation effects on U.S. water quality. Journal of Advances in Modeling Earth Systems 2015, 7, 1326 -1338.

AMA Style

Brent Boehlert, Kenneth M. Strzepek, Steven C. Chapra, Charles Fant, Yohannes Gebretsadik, Megan Lickley, Richard Swanson, Alyssa McCluskey, James E. Neumann, Jeremy Martinich. Climate change impacts and greenhouse gas mitigation effects on U.S. water quality. Journal of Advances in Modeling Earth Systems. 2015; 7 (3):1326-1338.

Chicago/Turabian Style

Brent Boehlert; Kenneth M. Strzepek; Steven C. Chapra; Charles Fant; Yohannes Gebretsadik; Megan Lickley; Richard Swanson; Alyssa McCluskey; James E. Neumann; Jeremy Martinich. 2015. "Climate change impacts and greenhouse gas mitigation effects on U.S. water quality." Journal of Advances in Modeling Earth Systems 7, no. 3: 1326-1338.

Journal article
Published: 01 March 2015 in Journal of Environmental Engineering
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ACS Style

Steven C. Chapra; Rasika K. Gawde; Martin T. Auer; Rakesh K. Gelda; Noel Urban. Sed2K: Modeling Lake Sediment Diagenesis in a Management Context. Journal of Environmental Engineering 2015, 141, 04014070 .

AMA Style

Steven C. Chapra, Rasika K. Gawde, Martin T. Auer, Rakesh K. Gelda, Noel Urban. Sed2K: Modeling Lake Sediment Diagenesis in a Management Context. Journal of Environmental Engineering. 2015; 141 (3):04014070.

Chicago/Turabian Style

Steven C. Chapra; Rasika K. Gawde; Martin T. Auer; Rakesh K. Gelda; Noel Urban. 2015. "Sed2K: Modeling Lake Sediment Diagenesis in a Management Context." Journal of Environmental Engineering 141, no. 3: 04014070.

Journal article
Published: 11 February 2015 in Limnology and Oceanography
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Based primarily on data collected over the past four decades by Environment Canada, long‐term trends of eutrophication‐related variables are developed for the offshore waters of the Laurentian Great Lakes. Trends of spring concentration are reported for the major nutrient species: phosphorus [total phosphorus (TP), and soluble reactive phosphorus (SRP)]; nitrogen [total oxidized nitrogen (NO3 + NO2), and ammonia nitrogen (NH3)]; and silica [soluble reactive silica (SiO2)]. Summer trends of surface chlorophyll a and Secchi depth are developed as indicators of lake trophic response. The results show that phosphorus has declined significantly in all the lakes, whereas nitrogen and silica have both increased. Along with documenting the impacts of the 1978 Great Lakes Water Quality Agreement phosphorus controls and the introduction of dreissenids, the results demonstrate conclusively that the offshore waters are now overwhelmingly phosphorus limited, which supports the conclusion that controlling phosphorus remains the only viable option for managing the trophic status of the Great Lakes offshore waters.

ACS Style

Alice Dove; Steven C. Chapra. Long-term trends of nutrients and trophic response variables for the Great Lakes. Limnology and Oceanography 2015, 60, 696 -721.

AMA Style

Alice Dove, Steven C. Chapra. Long-term trends of nutrients and trophic response variables for the Great Lakes. Limnology and Oceanography. 2015; 60 (2):696-721.

Chicago/Turabian Style

Alice Dove; Steven C. Chapra. 2015. "Long-term trends of nutrients and trophic response variables for the Great Lakes." Limnology and Oceanography 60, no. 2: 696-721.