Milwaukee River Research Articles

Milwaukee’s Swing Park: Guerrilla Urbanism at the Intersection of Public Space, Community, and Urban Planning

Guerrilla urbanism involves citizen-led bottom-up unsanctioned temporary efforts. This kind of temporary urbanism may offer unique opportunities not possible through traditional planning approaches. This paper is a case study of the Swing Park in Milwaukee, Wisconsin, USA. It began as an effort to temporarily enliven an area at one end of a pedestrian walkway – the Marsupial Bridge – suspended under a viaduct across the Milwaukee River. What started as an illegal temporary installation of swings made of used tires was embraced physically and emotionally as part of the everyday life of the pedestrian bridge by the local community who wanted the swings to stay. The guerrilla urbanism group found itself in conflict with the City’s Department of Public Works over concerns about safety and legal liability, aside from budgetary constraints on permanently upgrading and maintaining the swings. This paper conceptualizes the case study within a three-part framework of public space, community, and urban planning. It examines how the Swing Park has been seen to have both succeeded and failed, while problematizing it within the context of the interdisciplinary literature on temporary urbanism.

Anthropogenic particle concentrations and fluxes in an urban river are temporally variable and impacted by storm events.

Anthropogenic particles (AP), which include microplastics and other synthetic, semisynthetic, and anthropogenically modified materials, are pollutants of concern in aquatic ecosystems worldwide. Rivers are important conduits and retention sites for AP, and time series data on the movement of these particles in lotic ecosystems are needed to assess the role of rivers in the global AP cycle. Much research assessing AP pollution extrapolates stream loads based on single time point measurements, but lotic ecosystems are highly variable over time (e.g., seasonality and storm events). The accuracy of models describing AP dynamics in rivers is constrained by the limited studies that examine how frequent changes in discharge drive particle retention and transport. This study addressed this knowledge gap by using automated, high-resolution sampling to track AP concentrations and fluxes during multiple storm events in an urban river (Milwaukee River) and comparing these measurements to commonly monitored water quality metrics. AP concentrations and fluxes varied significantly across four storm events, highlighting the temporal variability of AP dynamics. When data from the sampling periods were pooled, there were increases in particle concentration and flux during the early phases of the storms, suggesting that floods may flush AP into the river and/or resuspend particles from the benthic zone. AP flux was closely linked to river discharge, suggesting large loads of AP are delivered downstream during storms. Unexpectedly, AP concentrations were not correlated with other simultaneously measured water quality metrics, including total suspended solids, fecal coliforms, chloride, nitrate, and sulfate, indicating that these metrics cannot be used to estimate AP. These data will contribute to more accurate models of particle dynamics in rivers and global plastic export to oceans. PRACTITIONER POINTS: Anthropogenic particle (AP) concentrations and fluxes in an urban river varied across four storm events. AP concentrations and fluxes were the highest during the early phases of the storms. Storms increased AP transport downstream compared with baseflow. AP concentrations did not correlate with other water quality metrics during storms.

Prediction of total organic carbon and E. coli in rivers within the Milwaukee River basin using machine learning methods

Ensemble-hybrid ML models can explain and predict the variability in water quality parameters and living microorganism behavior in natural streams with satisfactory prediction accuracies based on specific physicochemical parameters.

Contaminants of emerging concern may pose prezygotic barriers to freshwater mussel recruitment

Increased detection of contaminants of emerging concern (CECs) throughout the Laurentian Great Lakes Basin has raised concern about the impact CECs may have on aquatic life. In particular, the impacts of CECs on the highly imperiled freshwater mussels (family: Unionidae) have not yet been assessed. Contaminants may alter reproductive success during either the pre- or postzygotic stages of reproduction and lead to population declines. This study sought to address possible disruption of prezygotic processes while acknowledging the complexity of CEC mixtures in nature. River waters from sites with dominant urban and agricultural land use in the Milwaukee River Basin and Lower Maumee River Basin respectively were used as treatments during 21-day exposures of adult Lampsilis cardium, Lampsilis siliquoidea, and Eurynia dilatata. At the conclusion of exposures, the development of gonad tissue was histologically examined to address deviations from expected seasonal development as a barrier to recruitment. No abnormalities in development were found compared to control waters. Sperm densities were also examined; and, though no significant differences were found among treatments, lampsiline species sperm density tended to increase along the gradient of CEC mixture complexity while E. dilatata sperm density correlated positively with a lower concentration of pharmaceuticals, especially antibiotics, despite increased pesticide detection. Given the complexity of natural occurring CEC mixtures and variable unionid response, future work may utilize these data to elucidate combinations of CECs most likely to create impacts on gametogenesis which could lead to further population declines.

Application of Deep Learning for Imaging‐Based Stream Gaging

AbstractStream gages are critically important for measuring stream flow in water resources management. Stream gages monitor and record flow and water stage within some water body. The United States Geological Survey maintains a network of stream gages across the country. Many of these sites are also equipped with webcams to gather real‐time river information, especially in flood flows. Remotely measuring flow discharge using particle image tracking has been researched intensively. This study demonstrates a process for training a deep neural network that will utilize the webcam and stream gage data to generate a water stage prediction based on webcam captured river images. This study presents the experiments on stream gages located at the Clear Creek in Iowa, Auglaize River in Ohio, and Milwaukee River in Wisconsin. The process outlined utilizes transfer learning and well‐known image classification models as a basis for a generalized river stage regression model. Across the training, validation, and deployment experiments, the developed process shows success in creating an accurate model for these testing sites of different perspective settings. The results of this study show confidence in future studies utilizing ground‐level remote stream gaging with Machine Learning‐enabled image regression.

Human Fecal Contamination Corresponds to Changes in the Freshwater Bacterial Communities of a Large River Basin.

ABSTRACTMicrobial water quality is generally monitored by culturable fecal indicator bacteria (FIB), which are intended to signal human health risk due to fecal pollution. However, FIB have limited utility in most urbanized watersheds as they do not discriminate among fecal pollution sources, tend to make up a small fraction of the total microbial community, and do not inform on pollution impacts on the native ecosystem. To move beyond these limitations, we assessed entire bacterial communities and investigated how bacterial diversity relates to traditional ecological and human health-relevant water quality indicators throughout the Milwaukee River Basin. Samples were collected from 16 sites on 5 days during the summer, including both wet and dry weather events, and were processed by 16S rRNA gene amplicon sequencing. Historical water quality at each sampling location, as opposed to upstream land use, was associated significantly with bacterial community alpha diversity. Source partitioning the sequence data was important for determining water quality relationships. Sewage-associated bacterial sequences were detected in all samples, and the relative abundance of sewage sequences was strongly associated with the human Bacteroides fecal marker. From this relationship, we developed a preliminary threshold for human sewage pollution when using bacterial community sequence data. Certain abundant freshwater bacterial sequences were also associated with human fecal pollution, suggesting their possible utility in water quality monitoring. This study sheds light on how bacterial community analysis can be used to supplement current water quality monitoring techniques to better understand interactions between ecological water quality and human health indicators.IMPORTANCE Surface waters in highly developed mixed-use watersheds are frequently impacted by a wide variety of pollutants, leading to a range of impairments that must be monitored and remediated. With advancing technologies, microbial community sequencing may soon become a feasible method for routine evaluation of the ecological quality and human health risk of a water body. In this study, we partnered with a local citizen science organization to evaluate the utility of microbial community sequencing for identifying pollution sources and ecological impairments in a large mixed-use watershed. We show that changes in microbial community diversity and composition are indicative of both long-term ecological impairments and short-term fecal pollution impacts. By source partitioning the sequence data, we also estimate a threshold target for human sewage pollution, which may be useful as a starting point for future development of sequencing-based water quality monitoring techniques.

Projected lake sturgeon recovery in the Milwaukee River, Wisconsin, USA

Using a forward projecting population model, the timing and scale of Lake Sturgeon Acipenser fulvescens (LS) recovery and natural reproduction was estimated for the Milwaukee River in Wisconsin, USA for the years 2004–2048. LS, a widely distributed potamodromous Acipenseridae species in North America, have, like other sturgeon species, suffered population declines due to overharvest and other factors since the 1800s. LS recovery efforts were initiated in the early 1980s following the successful development of LS propagation techniques and stocking has become a widely utilized tool in LS recovery programs. Sturgeon recovery programs are long-term endeavors, with annual stocking usually planned for 25 plus years, along with population assessments and habitat improvements conducted over decades before project success can be verified. LS recovery activities on the Milwaukee River, a Lake Michigan tributary in southeast Wisconsin, began with barrier mitigation in 1997 and stocking in 2003. The modest size of the Milwaukee River, along with habitat improvements, and 17 years of stocking, provided an opportunity to model and predict LS population recovery trends. A forward projecting population model with an imbedded stochastic Ricker stock-recruitment relationship, adjusted for the estimated LS productive capacity of the Milwaukee River, estimated the timing and scale of LS recovery during 2004–2048 predicting a 18.3% annual average population rate of increase during the stocking period, and a 5.7% post-stocking rate. Accelerated LS growth and maturity due to goby consumption built into the model resulted in projections of gravid adult males present in 2012 and spawning adult females and natural recruitment in 2019. During the 2020 spawning period a group of adult-sized LS were observed in the Milwaukee River below an intermittent barrier on the river. The model predicted adult LS densities to grow from 22 in 2012 to 8088 in 2048, and annual natural recruitment to grow steadily from 76 yearlings in 2019 to an average of 4000 yearlings/year during 2039-2049. The estimated number of yearling recruits per spawning (gravid) female dropped steadily from 21 in 2019 to 8 recruits per gravid female in 2048 as a function of the Ricker stock-recruitment relationship built into the model. The model results indicate that significant LS recovery can possibly begin in a shorter time frame on Great Lakes tributaries than originally expected through systematic resolution of habitat issues and LS stocking. Results can also be used to help anticipate recovery trends, fine tune stocking and habitat strategies, and plan LS recovery assessments.

Using CANARY event detection software for water quality analysis in the Milwaukee River

Urban water sources are susceptible to various contamination events as a result of natural, accidental, and human-induced occurrences. An early warning monitoring system provides timely information on changes in urban water quality. In this study, an analysis was made with CANARY event detection software (EDS) to monitor water quality parameters in river water and to identify the onset of anomalous water quality periods. Water quality signals including pH, conductivity, and turbidity from the Milwaukee River over specified periods during the summer season of 2018–2020 were employed as inputs to event detection algorithms in CANARY. The data analysis results show that CANARY can be useful as an early warning system for monitoring contamination in urban water sources and help to identify abnormal conditions quickly. The sensibility of the model relies on optimizing the configuration parameters, which involves selecting the ideal set of parameters for the event detection algorithm and adjusting the BED parameters to increase or decrease the probability of generating an alarm. The number of events reported between the Linear Prediction Correction Filter (LPCF) and Multivariate Nearest Neighbor (MVNN) algorithms varied as a result of different residual calculation mechanisms. Climate factors that contributed to the abnormal water quality events in the river were examined. The analysis of rainfall on water quality was carried out using a statistical method by determining whether there is a significant difference (p-value) between the seasonal mean water quality data and the mean value of water parameters during the sampling duration. Regression analysis was also performed to estimate the best model that describes the relationship between each of the water quality parameters and temperature.

Vertical Distribution of Microplastics in the Water Column and Surficial Sediment from the Milwaukee River Basin to Lake Michigan.

Microplastic contamination was studied along a freshwater continuum from inland streams to the Milwaukee River estuary to Lake Michigan and vertically from the water surface, water subsurface, and sediment. Microplastics were detected in all 96 water samples and 9 sediment samples collected. Results indicated a gradient of polymer presence with depth: low-density particles decreased from the water surface to the subsurface to sediment, and high-density particles had the opposite result. Polymer identification results indicated that water surface and subsurface samples were dominated by low-density polypropylene particles, and sediment samples were dominated by more dense polyethylene terephthalate particles. Of the five particle-type categories (fragments, films, foams, pellets/beads, and fibers/lines), fibers/lines were the most common particle-type and were present in every water and sediment sample collected. Fibers represented 45% of all particles in water samples and were distributed vertically throughout the water column regardless of density. Sediment samples were dominated by black foams (66%, identified as styrene-butadiene rubber) and to a lesser extent fibers/lines (29%) with approximately 89% of all of the sediment particles coming from polymers with densities greater than 1.1 g cm-3. Results demonstrated that polymer density influenced partitioning between the water surface and subsurface and the underlying surficial sediment and the common practice of sampling only the water surface can result in substantial bias, especially in estuarine, harbor, and lake locations where water surface concentrations tend to overestimate mean water column concentrations.

Impacts of Climate Change and Urban Expansion on Hydrologic Ecosystem Services in the Milwaukee River Basin

Land use/land cover (LULC) and climate changes could affect water quantity and quality and thus hydrologic ecosystem services (ES). However, studies of these impacts on hydrologic ES are limited by the current methods and techniques. We attempted to find out how the LULC and climate changes impact hydrologic ES at different temporal scales so that decision-makers can easily understand hydrologic ES variations for guiding management plans. In this study, we analyzed the impacts of LULC and climate changes on hydrologic ES in the Milwaukee River basin, USA with a conceptual modeling framework for hydrologic ES. The model framework was applied to a series of climate and urban expansion scenarios. Two hydrologic responses (streamflow and sediment) and three hydrologic ES (water provision index (WPI), flood regulation index (FRI), and sediment regulation index (SRI)) were calculated. Major findings include: (1) Climate change has much larger impacts than LULC at the monthly scale. For example, the impacts of climate change on streamflow were −6 to 9 m3/s whereas those of LULC change were −0.4 to 0.2 m3/s. Also, WPI (ranging from 0 to 1) changed between −0.16 and 0.07 with climate change but between −0.02 and −0.001 with LULC changes. (2) Compared to changes at the annual scale, the results show much larger variabilities as monthly time-series and mean monthly numbers. These findings suggest that the climate change weighs more than the realistic LULC change in term of impacts on hydrologic ES and those impacts can be identified with results at the monthly temporal scale. This approach with the framework and scenarios can better support management planning for decision-makers with detailed results and temporal precision.

Application of large scale PIV in river surface turbulence measurements and water depth estimation

Large-Scale Particle Image Velocimetry (LSPIV) has emerged as a reliable technology to measure river surface flow velocity distribution and can be applied to estimate river discharge. Fewer studies have explored the capability of surface turbulence measurements using LSPIV. In this paper, LSPIV is applied to evaluate statistics of surface turbulence of a natural river. Turbulence measurements including velocity fluctuation, velocity spectra and the dissipation rate of turbulent kinetic energy (TKE) are validated by comparing with those measured by an Acoustic Doppler Velocimeter (ADV). Traditionally, estimation of stream discharge through LSPIV needs a secondary measurement to determine river bathymetry and water depth. A new method is presented here to demonstrate that for a fully developed and channel-controlled flow, the cross section geometry can be estimated from the combined measurements of surface mean velocity and the dissipation rate, following the Manning-Strickler formula. Therefore, river discharge can be estimated with LSPIV along with a calibrated Manning's roughness, without additional bathymetry survey. The proposed new method is applied to measure discharge in Milwaukee River (Milwaukee, Wisconsin, U.S.A.), which agreed well with data obtained from a nearby streamgage station.

Effects of urban imperviousness scenarios on simulated storm flow

The amount and distribution of impervious surfaces are important input parameters of hydrological models, especially in highly urbanized basins. This study tests three different methods to input impervious surface area information to a semi-distributed hydrological model in order to examine their effects on storm flow. The three methods being evaluated include: (1) a constant value for impervious surfaces in the entire urban area, (2) constant values of imperviousness for commercial and residential land uses, respectively, and (3) different imperviousness for the residential land use in each subbasin. Storm flow of the Milwaukee River Basin in southeastern Wisconsin (USA) was modeled using the Hydrological Simulation Program-Fortran. The results show that the three methods resulted in substantially different amounts of storm flow. The storm flow simulated with the third method was the largest and had the largest variability between the subbasins. The differences between the scenarios are generally larger in subbasins with high percentage of urban land use types. The results suggest that the effect of different input methods is amplified in urbanized subbasins and the spatial variability of imperviousness should be commensurate with the spatial variability of the model configuration.

Exposure to ZnO nanoparticles alters neuronal and vascular development in zebrafish: Acute and transgenerational effects mitigated with dissolved organic matter

Exposure to ZnO-nanoparticles (NPs) in embryonic zebrafish reduces hatching rates which can be mitigated with dissolved organic material (DOM). Although hatching rate can be a reliable indicator of toxicity and DOM mitigation potential, a fish that has been exposed to ZnO-NPs or any other toxicant may also exhibit other abnormal phenotypes not readily detected by the unaided eye. In this study, we moved beyond hatching rate analysis to investigate the consequences of ZnO-NPs exposure on the nervous and vascular systems in developing zebrafish. Zebrafish exposed to ZnO-NPs (1–100 ppm) exhibited an array of cellular phenotypes including: abnormal secondary motoneuron (SMN) axonal projections, abnormal dorsal root ganglion development and abnormal blood vessel development. Dissolved Zn (<10 kDa) exposure also caused abnormal SMN axonal projections, but to a lesser extent than ZnO-NPs. The ZnO-NPs-induced abnormal phenotypes were reversed in embryos concurrently exposed with various types of DOM. In these acute mitigation exposure experiments, humic acid and carbohydrate, along with natural organic matter obtained from the Suwannee River in Georgia and Milwaukee River in Wisconsin, were the best mitigators of ZnO-NPs-induced motoneuron toxicity at 96 h post fertilization. Further experiments were performed to determine if the ZnO-NPs-induced, abnormal axonal phenotypes and the DOM mitigated axonal phenotypes could persist across generations. Abnormal SMN axon phenotypes caused by ZnO-NPs-exposure were detected in F1 and F2 generations. These are fish that have not been directly exposed to ZnO-NPs. Fish mitigated with DOM during the acute exposure (F0 generation) had a reduction in abnormal motoneuron axon errors in larvae of subsequent generations. Therefore, ZnO-NPs exposure results in neurotoxicity in developing zebrafish which can persist from one generation to the next. Mitigation with DOM can reverse the abnormal phenotypes in an acute embryonic exposure context, as well as across generations, resulting in healthy fish.

Is a clean river fun for all? Recognizing social vulnerability in watershed planning.

Watershed planning can lead to policy innovation and action toward environmental protection. However, groups often suffer from low engagement with communities that experience disparate impacts from flooding and water pollution. This can limit the capacity of watershed efforts to dismantle pernicious forms of social inequality. As a result, the benefits of environmental changes often flow to more empowered residents, short-changing the power of watershed-based planning as a tool to transform ecological, economic, and social relationships. The objectives of this paper are to assess whether the worldview of watershed planning actors are sufficiently attuned to local patterns of social vulnerability and whether locally significant patterns of social vulnerability can be adequately differentiated using conventional data sources. Drawing from 35 in-depth interviews with watershed planners and community stakeholders in the Milwaukee River Basin (WI, USA), we identify five unique definitions of social vulnerability. Watershed planners in our sample articulate a narrower range of social vulnerability definitions than other participants. All five definitions emphasize spatial and demographic characteristics consistent with existing ways of measuring social vulnerability. However, existing measures do not adequately differentiate among the spatio-temporal dynamics used to distinguish definitions. In response, we develop two new social vulnerability measures. The combination of interviews and demographic analyses in this study provides an assessment technique that can help watershed planners (a) understand the limits of their own conceptualization of social vulnerability and (b) acknowledge the importance of place-based vulnerabilities that may otherwise be obscured. We conclude by discussing how our methods can be a useful tool for identifying opportunities to disrupt social vulnerability in a watershed by evaluating how issue frames, outreach messages, and engagement tactics. The approach allows watershed planners to shift their own culture in order to consider socially vulnerable populations comprehensively.

Meteorological and Streamflow Droughts: Characteristics, Trends, and Propagation in the Milwaukee River Basin

This study examined meteorological and streamflow droughts for the period from 1951 to 2006 using the Milwaukee River basin in Wisconsin as the study area in an effort to improve the understanding of drought propagation. Specifically, this study aimed to answer the following research questions: (1) What are the temporal trends of meteorological and streamflow droughts identified by drought indicators? (2) How do the drought indicators manifest drought propagation? Meteorological droughts were identified using the Effective Drought Index (EDI), and streamflow droughts were identified using a threshold-level approach. The intensity and duration of both types of drought were found to have decreased over time, most likely due to increasing precipitation. Therefore, in the study area, and likely in the larger region, drought has become of less concern. The propagation of meteorological drought into streamflow drought was detected generally after moderate and severe sequences of negative EDI that eventually led to extreme meteorological drought events. The study finds that both EDI and the threshold-level approach are effective in diagnosing meteorological and streamflow drought events of all durations.

Estabrook Dam Removal: A step in improving the health of the Milwaukee River

Estabrook Dam Removal: A step in improving the health of the Milwaukee River

Milwaukee Mayhem: Murder and Mystery in the Cream City's First Century by Matthew J. Prigge

Reviewed by: Milwaukee Mayhem: Murder and Mystery in the Cream City's First Century by Matthew J. Prigge Lawrence H. Larsen Matthew J. Prigge, Milwaukee Mayhem: Murder and Mystery in the Cream City's First Century. Madison: Wisconsin State Historical Society, 2015. 207 pp. $12.99. Matthew J. Prigge is a Milwaukee-based freelance author, historian, and radio personality. His fascinating and informative new book Milwaukee Mayhem: Mystery and Murder in the Cream City's First Century, covering the 1830s to 1930s, is a modern version of the Sins of the City books of the last half of the nineteenth century. These literary efforts, popular in their day but mostly forgotten now, dwelled on the unsavory side of life in the then-new urban America. The more lurid and sensational of the works described in great detail the interiors of widely patronized dance halls, taverns, and other places of amusement, giving the street addresses and warning visitors to stay away from them. Sins of the City books were considered fit for sale in religious book stores. Those for the Midwest included J. A. Dacus's and James W. Burel's 1878 A Tour of St. Louis or the Inside Life of a Great City and Harold Richard Vynne's 1892, Chicago by Day and Night: The Pleasure Seeker's Guide to the Paris of America. Like the nineteenth-century authors, Prigge accepts the proposition that urbanization inevitably has an underreported dark side: "There are few heroes and even fewer lessons to be learned. This is an incomplete history, dredged from the memory and prejudices of the times and unable to access those secrets the city wishes to keep," Prigge states. "This is a history that rides that dark and often senseless arc that slices through the daily happenings of a forgotten class of killers, liars, and crooks. This is the history of a city's one-hundred-year struggle to leave its past behind, to understand itself, and to make sense of the everyday mayhem of life in a metropolis being born" (xiv, which is incorrectly numbered and should be xvi). Prigge uses eighty-two short accounts to make his point. Some of what he calls the "orphans of history" run several pages and others only a couple paragraphs. They have such titles as "Love with a Bullet"; "Misfire"; "Dirty [End Page 63] Books"; and "The Missing Head." Many of the accounts are culled from the pages of Milwaukee newspapers, especially the Milwaukee Sentinel. The four chapters consist of eighteen entries under "Murders," seventeen under "Accidents," twenty-two under "Vice," and twenty-five under "Secrets." The various stories are not in chronological order. So, a 1928 tale is followed immediately by one from 1893, and so on. The stories range from the strange to the gruesome, as the following examples illustrate: • In 1929, a seventeen-year old high school girl was one of several people who received threatening letters. The police thought the sender an immigrant. The letters stopped, ending the matter. The note to the girl was signed, "Ed, the Bad Man."• In 1893, fift een skilled workers, trapped in a crib off the Milwaukee harbor during a Lake Michigan storm, faced possibly suffocating or opening a hatch. They opened the hatch. Water from high waves rushed in drowning fourteen workers. One escaped. • In 1871, police accepted the conclusion reached by a fortune-teller that a missing seventeen-year-old woman had been kidnapped. Eventually, her bloated body surfaced in a Milwaukee river. In the aft ermath, the city council passed an ordinance requiring fortune-tellers and other seers to have licenses in order to ply their trade. • In 1927, a nineteen-year-old woman candy store worker went on a blind date in a red car with an attractive man. A month later, police recovered her body, which did not appear to have been sexually molested. No one was ever arrested in the case. An assumption by the police that she had eloped proved wrong. • In 1892, a young switchman in a Milwaukee railroad yard left a switch open, causing the wreck of a shop train and the deaths of seven railroad workers. After only twenty minutes of...

Predicting future urban impervious surface distribution using cellular automata and regression analysis

Urban impervious surfaces are considered as key indicator of urbanization intensity and environmental quality. Due to their significant impact on surface runoff, flood frequency, and water quality, impervious surfaces have been identified as an important indicator for examining the hydrological impact of urbanization. The amount and distribution of impervious surfaces have been estimated using remote sensing and geographic information system (GIS) techniques. Little research, however, has been conducted to predict future impervious surface distributions. To address this problem, we developed an integrated residential/commercial growth and impervious surface distribution model to predict urban impervious surface distribution. Taking Milwaukee River Basin, Wisconsin as a case study, we simulated future residential and commercial developments using a CA model. Further, we developed a linear regression model to predict impervious surface distributions in residential and commercial land uses. Analysis of results suggests that the proposed model performs significantly better than the traditional approaches.

Impacts of climate change and urban growth on the streamflow of the Milwaukee River (Wisconsin, USA)

Hydrological impact studies of climate change increasingly take land use changes into account. However, the Midwestern USA is still understudied in this context. This study investigated the impacts of potential climate change and urban growth on the streamflow characteristics of the Milwaukee River located in southeastern Wisconsin. The Hydrological Simulation Program-Fortran (HSPF) was set up for the catchment and calibrated against observed streamflow data. The calibrated HSPF model was run with a series of climate and urban growth scenarios generated from nine global climate models (GCMs) and a land use simulation model, respectively. The outcomes from the GCMs, statistically downscaled at 10-km grid spacing, generally indicated a warmer and wetter climate by the mid-twenty-first century, and the land use simulation model projected moderate urban growth by the time. Major findings from the study include: (1) land use changes alone resulted in negligible streamflow changes; (2) low flows showed more sensitivity than mean streamflow to climate change; (3) streamflow variability increased with both land use and climate changes, and (4) uncertainty in simulated streamflow among GCMs was larger than uncertainty among the GCM output themselves. The findings suggest that the current pace of urban growth would not pose much threat to the water resources in the area. Considering that low flow indices responded more sensitively than mean streamflow to climate change, measures to improve resilience to drought conditions are recommended. Because land use change impacts were quite small, considering the impact of both climate and land use scenarios did not produce a significantly different result.

Failure of Steel Bridges due to Constraint Induced Fracture

This paper discusses issues related to the failure of steel bridge structures attributable to a certain type of fracture called Constraint Induced Fracture (CIF). It focuses on the causes of and factors associated with this phenomenon as it has been responsible for the failure of several bridges in the last dozen years. The strength aspects of the CIF phenomenon are analyzed using the example of the failure of the Hoan Bridge over the Milwaukee River in the US.