Search

ABSTRACT The winter of 2013-14 had unusual weather in many parts of the world. Here we analyze the cold extremes that were widely reported in North America and the lack [...]

A modeling framework that combines both two-dimensional (2D) and one-dimensional (ID) numerical models for the evaluation of organic-matter transport across the bed-water interface is presented. Emphasis is placed on capturing oxygen demand in the water column associated with the resuspension of organic sediments from the bottom. The proposed numerical approach solves the hydrodynamics coupled with sediment transport and water quality dynamics and represents a substantial improvement to the state of the art of water quality modeling methodologies available in the literature. A biochemical oxygen demand (BOD)--dissolved oxygen (DO) water quality module is incorporated into the 2D depth-averaged numerical model STREMR-HySedWq. The model is applied to the South Fork of the South Branch of the Chicago Riven known as Bubbly Creek, with the goal of modeling combined sewer overflow (CSO) events and their impact on DO levels in the short-term (hours or days). Given the intermittent nature of this kind of events, STREMR-HySedWq was used for modeling the overflow phase, while the period following a given CSO event, when water is essentially quiescent in the creek, was modeled with a simpler 1D, area-averaged, dispersion-reaction BOD-DO model. The proposed conceptual and numerical approach is capable of capturing the key processes, thus providing both useful preliminary results as well as important guidance to assess potential water quality improvement and sediment management solutions in Bubbly Creek, Illinois. DOI: 10.1061/(ASCE)EE.1943-7870.0000228 CE Database subject headings: Oxygen demand: Dissolved oxygen: Organic matter: Sediment: Combined sewers; Overflow; Streams; Illinois. Author keywords: Biochemical oxygen demand; Dissolved oxygen; Organic sediment resuspension; Sediment oxygen demand; Combined sewer overflow.

This paper presents the results and analysis of a laboratory investigation of the behavior of lightly overconsolidated compressible Chicago glacial clays over a wide strain range. Each specimen was trimmed from high quality block samples taken from an excavation in Evanston, Illinois. Specimens were instrumented with three sets of bender elements and local LVDTs. After [K.sub.0] consolidation to the in situ vertical effective stress of the block, drained stress probe tests were conducted. Results of bender elements tests obtained prior to stress probing show that compressible Chicago glacial clay initially is cross anisotropic. Propagation velocities measured by bender elements in axial direction after [K.sub.0] reconsolidation and drained creep agrees well with the in situ shear wave velocity measured by seismic cone penetration tests. Results of drained stress probe tests are analyzed in terms of shear, volumetric and coupled stiffness, stiffness degradation, and direction of loading. The significant variability of shear, bulk and cross-coupling response depending on stress path direction and strain level provide experimental evidence that the Chicago clays are incrementally nonlinear at the strain levels investigated. DOI: 10.1061/(ASCE)GT.1943-5606.0000186 CE Database subject headings: Clays; Anisotropy; Stiffness; Limit state; Experimentation; Stress strain relations; Sampling. Author keywords: Chicago clay; Cross anisotropy; Stiffness; Limit state; Bender element; Experiments.

Since 1984, the major water reclamation plants discharging to the Chicago Waterway System (CWS) have not disinfected their effluents. The possible addition of disinfection at these plants is the subject of an ongoing use attainability analysis (UAA). For the UAA, Escherichia coli (E. coli) is used as the indicator of bacterial contamination. However, only a few years of E. coli data are available for the CWS and the treatment plants discharging to the CWS. Thus, it was decided to develop a model based on fecal coliforms for which more data are available and to develop a relation between fecal coliform and E. coli counts for the CWS. A 1:1 relation was found between fecal coliform and E. coli counts in the CWS by Limnotech (2004, written communication) as part of the UAA. In order to evaluate the effects of possible disinfection measures on fecal coliform and related E. coli counts in the CWS, a simple first-order fecal coliform decay model was added to the continuous-simulation flow-water quality model DUFLOW applied to the CWS system. Due to the limited amount (monthly samples) of measured fecal coliform concentration data for the CWS, a reasonable calibration of the model would have been difficult to achieve based on the traditional trial and error method. In this paper, a new concept of model parameter estimation based on historical data analysis and its application to model calibration is presented. The fecal coliform decay rate k was estimated for every reach of the CWS based on analysis of historical data (1990-2003) between each two consecutive sampling locations and the related travel time between these stations. The fecal coliform decay rate then was determined on the basis of many years (14 years, in this case) of monthly fecal coliform samples rather than the few monthly samples taken in a typical calibration period. The results obtained indicate that the calibration process was successful, and a good match between measured and simulated fecal coliform concentrations at almost all locations along the CWS is achieved with one model run for several multiple month periods in 1998, 1999, 2001, and 2002. DOI: 10.1061/(ASCE)0733-9372(2007)133:7(681) CE Database subject headings: Calibration; Simulation models; Water reclamation; Chicago; Illinois; Disinfection.

Coyotes (Canis latrans) are an opportunistic predator that have adapted to many human-modified environments. Conflicts between coyotes and humans are an increasing concern for managers in urban areas. We examined the spatial and temporal utilization and availability of natural and human-associated food for coyotes in the Chicago metropolitan area, Illinois, USA. We collected 1429 coyote scats from May 2000 to December 2002, and conducted prey surveys in 2002, in 4 sites that varied in their degree of urban development. Dominant food items included small rodents, white-tailed deer (Odocoileus virginianus), fruit, eastern cottontail (Sylvilagus floridanus) and birds. Their availability and occurrence in scats varied among sites and seasons. The occurrence of human-associated food items, which was only found in significant amounts in the most developed site, varied seasonally (2-25%). Because coyotes in less-developed areas had lower dietary diversity, these coyotes may have to venture into developed areas when there is a decline in the abundance of major prey species for that specific area.

ABSTRACT Material balance of fine particulate matter (P[M.sub.2.5]) measured with the Federal Reference Method (FRM) is developed for one rural and five urban locations in the eastern half of the [...]

The lake-breeze circulation that forms over Lake Michigan during the summer influences the Chicago. Illinois, metropolitan area's weather in several ways. Of particular significance is the circulation's effect on the dispersion of pollutants such as ozone and aerosols produced in and around the city. To investigate these effects, the fifth generation Pennsylvania State University National Center for Atmospheric Research Mesoscale Model (MM5) was used to perform numerical simulations for two lake-breeze events one in July 1999 and another in July 2002. The model runs were verified with data from several locations around the Chicago area. The simulated breeze circulation decreased the rate of increase in air temperature while penetrating roughly 12 km inland and lasting about 8 h, in reasonable agreement with observations. Furthermore, the inland penetration distance was related to the strength of the maximum vertical velocity within the front. Calculations of trajectories and transport of particles showed that the breeze tended to transport particles trapped within it to the north when release occurred before the circulation came ashore, whereas particles released at the time of the breeze's landfall or afterward moved more northeasterly, in the direction of the prevailing wind. Thirty-four percent of all released particles were trapped by the circulation and raised to a height of at least 300 m, and 20% of the particles remained in the lowest 100 m above the surface. In addition, sensitivity tests showed little change in the modeled breeze when measured surface temperatures for Lake Michigan were used as initial conditions and boundary conditions in the place of surface skin temperature (as derived by the National Centers for Environmental Prediction). Raising the lake temperatures significantly in the simulation yielded a more elongated vertical circulation and a briefer lake-breeze event that did not reach as far inland.

Research indicates that philopatry and high survival rates of white-tailed deer in suburban areas contribute to their overabundance in metropolitan regions. Data were obtained from 208 marked deer from Chicago, Illinois forest preserves between 1994-1998. Philopatry consisted of dispersals of less than 9 km, with deer-auto collisions producing the highest mortality rate.

Research examining the behavior of monk parakeets residing in Hyde Park in Chicago, United States, is presented. Particular attention is given to behavior exhibiting tendencies of vigilance, as well as to the birds' diet and flock sizes.

A record-breaking 24-h rainstorm on 17-18 July 1996 was centered on south Chicago and its southern and western suburbs, areas with a population of 3.4 million. The resulting flash flooding in Chicago and 21 suburbs broke all-time records in the region and brought the Illinois and Mississippi Rivers above flood stage. More than 4300 persons were evacuated from the flooded zones and 35 000 homes experienced flood damage. Six persons were killed and the total estimated cost of the flood (losses and recovery actions) was $645 million, ranking as Illinois' second most costly weather disaster on record after the 1993 flood. Extensive damages and travel delays occurred on metropolitan transportation systems (highways and railroads). Commuters were unable to reach Chicago for up to three days and more than 300 freight trains were delayed or rerouted. Communities dealt with removal of flood-damaged materials, as well as damage to streets, bridges, and sewage treatment and water treatment plants. Reduced crop yields in adjacent rural areas represented a $67 million loss of farm income. Conflicts between communities developed over blame for the flooding due to inadequate storage capacity resulting in new regional flood planning. Federal and state aid ultimately reached $265 million, 41% of the storm costs. More than 85 000 individuals received assistance, and 222 structures have been relocated under the federal Hazard Mitigation Grant Program at a cost of $19.6 million.

The rainstorm on 17-18 July 1996 in northern Illinois produced three rainfall records. The 43.0-cm total storm rainfall at Aurora was the greatest point rainfall recorded for storm durations of 24 hours or less in this century in Illinois and most surrounding states. The 27.9-cm storm rainfall recorded in the southwestern part of the Chicago metropolitan area was the heaviest 24-h amount ever recorded in that city. The July 1996 storm also produced the heaviest 24-h mean rainfall recorded in Illinois over areas of 5200 and 13 000 [km.sup.2] immediately surrounding the storm center. An area of approximately 12 000 [km.sup.2] experienced 24-h point rainfall amounts that exceeded those expected to occur, on the average, once in 10 years. Similarly, the 25-, 50-, and 100-yr frequency values were exceeded over areas of 6730, 4920, and 3500 [km.sup.2], respectively. One concern resulting from a major rainfall event such as this storm is its impact on the rainfall frequency analysis. This new information may result in changes in the estimated rainfall amounts at selected return periods, which are used to design water-handling structures. based on previous research, the Aurora rainfall appears to exceed the 1000-yr return period. However, fitting a statistical distribution to the annual maximum time series and using regional averages minimized the effect of this storm on rainfall frequency estimates.

A unique rainstorm in northern Illinois produced 43 cm of precipitation in mid-July 1996, the highest 24-h precipitation amount ever recorded officially in the upper Midwest. Rains exceeding 20 cm fell over an area of 4400 [km.sup.2], creating extremely damaging flash floods in portions of Chicago and its suburbs. Measurements from 496 rain gauges, including 80 recording gauges in the heavy rain area, made it possible to accurately define this storm. The heavy rains were the result of two massive mesoscale convective systems, one in the afternoon and one at night. These systems formed to the north of a nearby stationary warm front. Several factors contributed to the excessive rainfall. Excessive moisture was present to the southwest of the warm front over Iowa and western Illinois; atmospheric moisture content was enhanced by surface evaporation from a very wet surface created by heavy rains the previous day, creating a conditionally unstable atmosphere. A cool air mass transported by easterly winds off Lake Michigan strengthened and slowed the movement of the warm front. A low-level jet oriented perpendicular to the warm front resulted in rising motion north of the warm front. These factors (instability, moisture availability, lifting mechanism) combined to form intense storms. This paper, the first of a three-part series, describes the storm in detail, including its morphology and causes, and the resulting rainfall distributions.

The transport of polycyclic aromatic hydrocarbons (PAHs) from the emissions from urban areas around Chicago, IL< and Gary, IN, to Lake Michigan was investigated by measuring the concentration of PAHs in the lake sediments. High concentrations of PAHs from the same location were found, particularly phenanthrene, benzo[b+k]fluoranthane, benzo[a]-pyrene and perylene. The accumulation of these compounds in lake sediments was attributed to historical coal use in IllINNis and extensive steel production in IllINNis and Gary, IN, as a result of in-lake integration processes.

Elderly people with chronic diseases who live alone and have no social contacts appear to have the highest risk of dying during a prolonged heat wave. Following the heat wave in July, 1995, in Chicago, researchers interviewed relatives and friends of 339 who had died and 339 survivors, who served as the control group. Those who were bedridden, lived alone on an upper floor and did not engage in social activities had the highest risk of dying. An air conditioner reduced the risk of death substantially as did access to transportation. At least 700 people died during the heat wave who might not have died otherwise.

X-ray fluorescence spectrometry and neutron activation analysis were used to analyze trace elements from airborne inhalable particulate matter collected in southeast Chicago and East St. Louis, IL. The most important sources of toxic trace elements were traced using models incorporating wind trajectory analysis, factor analysis and chemical mass balance. Smelters were the major sources of copper and cadmium in East St. Louis, while steel mills were the main sources of manganese and chromium in southeast Chicago. Some sources may not significantly affect overall levels of particulate matter, but may have large effects on the levels of specific toxic metals in the air.

This study concerns effects along the Illinois shoreline resulting from the record-low levels of Lake Michigan during 1964-65, and the potential impacts of future low water levels at Chicago resulting from potential climate changes. The low lake levels of the 1960s did not cause major impacts at Chicago when they occurred. The two major impacts discerned (damage to shoreline protection structures and the encroachment of structures onto areas too close to the lake) resulted from a sequence of low-water levels followed by high-water levels a few years later. Climate scenarios, derived from general circulation models (GCMs) and extreme historical precipitation values, were used in a basin hydrologic model to determine potential future lake levels. Possible impacts were then estimated by 29 lakeshore experts. If the average lake level were reduced less than or equal to 1.0 m during the next 50 yr, shoreline impacts would not be severe and cost about $100 million. Many of the adjustment costs could be offset by normal maintenance and replacement costs. If the average lake level was reduced more than 1.5 m during the next 50 yr, very sizable economic impacts would occur, costing between $3 and $35 billion (1988 dollars). Some of the adjustment cost could be offset by normal replacement costs, particularly if a master plan for changing affected facilities were implemented in advance. The type of climate change and degree of lake-level change will greatly affect the severity of the effects at Chicago.