Stream Recovery Post Channelization: A Case Study of Low-Gradient Streams in Central Illinois, USA

Stream channelization, which entails reducing the sinuosity of a stream, widening, and in some cases deepening the stream channel, is a widespread practice in agricultural regions. Channelization efforts in central Illinois have significant impacts on the geomorphology, flow regime, and sediment transport both in and adjacent to modified reaches. The goal of this study was to characterize the changes in stream channels by comparing three streams that are at various stages of recovery post channelization, 5 years (1900N), 7 years (Frog), and 35 years (Bray), to an unmodified stream reach (Crooked) and estimate a recovery rate. Measured channel slopes within the modified streams were one order of magnitude larger than the measured channelized streams in Crooked. The two streams most recently channelized exhibited little geomorphic change since their channelization, while the segment modified 35 years ago experienced bank failure and immature meander development. The lack of redevelopment resulted in sinuosity values lower than that of Crooked, and the reestablishment of meanders similar to Crooked would take an estimated 11,000 years. The distributions of the sediments within all the streams comprised poorly sorted sand and pebbles. The distribution of the sediment resembles the source, the glacial diamicton that serves as the surficial sediments. Mobilization of the sediment is frequent, with recorded scour greater than sedimentation. Overall, the channelized segments experienced limited recovery. The segments are still degrading (1900N and Frog) or are transitioning into a threshold stage (Bray)

Three-Dimensional Geologic Modeling and Groundwater Flow Modeling Above a CO2 Sequestration Test Site

As temperatures rise and climate change becomes an increasingly important issue, geologic carbon dioxide (CO2) sequestration is a viable solution for reducing greenhouse gas emissions. Subsurface 3-D modeling and groundwater flow modeling were completed as a component of a CO2 sequestration feasibility study in the city of Decatur, Illinois. The Decatur Archer Daniels Midland Company Ethanol Plant (ADM) serves as the injection site for a CO2 sequestration project within a deep saline reservoir. Petrel was successfully used to model the glacial deposits in the area. The 3-D geologic model shows the Peoria Silt, Wedron Formation, and Cahokia Formation at the surface with the Wedron Formation holding up the steep slopes along the east and west banks of Lake Decatur. The groundwater flow model outlined the location of a local groundwater divide and showed flow from the injection site would flow towards Lake Decatur, reaching the lake in 80 days

Stratigraphy and Porosity Modeling of South-Central Illinois (USA) Chester (Upper Mississippian) Series Sandstones Using Petrel

Maximizing resource extraction from mature oilfields requires enhanced and secondary recovery techniques. The success of these methods relies on knowledge and understanding of the reservoir geology and hydraulics. At the Loudon Oilfield (Illinois, USA), enhanced oil recovery is being used to extend the production life of the reservoir. The suitability and placement of additional wells for oil recovery processes required three-dimensional (3D) facies and porosity modeling of the oilfield. The purpose of this work was to assess the ability of a porosity model to predict sandstone facies. The facies model for the Loudon field was generated using data obtained from digitized-wireline logs. The facies model provided sand thickness and insight in the geometries and interconnections of the producing formations. The porosity model identified zones of high porosity, and illustrated the discontinuous nature of the porosity zones within the oilfield. Comparison of facies and porosity models revealed strong correlation and similarity between the models

The Effectiveness of an Artificial Floating Wetland to Remove Nutrients in an Urban Stream: A Pilot-Study in the Chicago River, Chicago, IL USA

Ever expanding urbanized landscapes are increasingly impacting streams that run through them. Among other stressors, urban streams often are host to elevated concentrations of nutrients, salts, and heavy metals. The pollutants, coupled with high temperatures, are drivers of ecosystem degradation in urban streams. The installation of artificial floating wetlands (AFWs) has been successful in mitigating the effects of urbanization in lakes and wastewater treatment ponds, but rarely have they been tested in streams. This pilot-study examined the ability of an AFW to improve water quality in an urban stream. The small, 90 m2 AFW was installed to improve the aquatic habitat and aesthetics of a small section of the Chicago River, Chicago, IL USA.Water samples and in-situ measurements were collected from the surface and at 0.3 m depth of upstream and downstream of the AFW. Samples were analyzed for nitrate-as-nitrogen, phosphate, chloride, and heavy metals. Comparison of upstream and downstream waters showed that the AFW lowered the concentrations of nitrate-as-nitrogen and phosphate during the growing season by 6.9% and 6.0%, respectively. Nitrate was also removed during the dormant season; however, phosphate was not removed during that time. Plant or microbial uptake of the nutrients are believed to be the dominant mechanisms in the growing season with denitrification serving as the primary pathway in the dormant season. Despite not having a measurable effect on the water temperature, the AFW was an effective means to reduce concentrations of nitrate and phosphorus, decreasing the potential for eutrophication

Three-Dimensional Geologic Model of the Pecatonica Gas Storage Field, Winnebago County, Illinois

This study involves the construction of a three-dimensional (3D) geologic model of Paleozoic strata that are part of an underground gas storage field in northern, Illinois, USA. The Pecatonica Anticline trends 60W and plunges gently to the southeast. It is 10 km long and 3 km wide, and verges to the NE. Six water wells and 22 gas wells were used to create the 3-D geologic model in Petrel using well tops as determined from wire-line logs. The following horizons were created for the Cambrian and Ordovician strata: the Ancell, Trempealeau, Franconia, Ironton-Galesvilles, Eau Claire Proviso A and B, Eau Claire Proviso C “Ligthsville (top), and Eau Claire Proviso C “Lightsville (bottom). The horizons, edges, and intersections were then color-coded and an initial model was created. In the model area, the “Lightsville”, which is the principal layer used for gas storage, has about 10 m of closure over 0.80 Km2 with a volume 199x10-3 km3 . No faults or other structural discontinuities that may influence gas migration are evident in the model area

Identification of Potential Vertical Gas Migration Pathways Above Gas Storage Reservoirs

Natural gas is stored underground in geologic structures throughout the United States. However, complexities associated with these geologic structures may provide vertical pathways for gas migration, and thus gas loss. Possible upward migration (loss) of natural gas in an underground gas storage field in Illinois stimulated this investigation that aims to identify potential migration pathways. Spatial analysis of volume of shale (Vsh) and formation porosity (n) values were conducted in conjunction with high-resolution shallow seismic surveys to identify potential vertical pathways. Surficial gas accumulations within glacial deposits were confirmed by the seismic surveys. These gas pockets accumulated by migration along steeply inclined structural discontinuities, most likely faults and fracture zones within the underlying shallow bedrock units. With the seismic technique limited to a depth of 100 m, Vsh data were used to assess the reservoir’s seal rocks ability to limit vertical gas migration. The Vsh data indicate that the seal rocks are best classified as heterogeneous siltstones. Spatial analysis highlights an aligned pattern of low Vsh values in both the reservoir rocks and the seal rocks. The low Vsh values lie beneath the faults and fracture zones and the documented surficial gas deposit. Higher n values for the sandstones in the reservoir area as opposed to other areas suggest porosity enhancement associated with deformation. Structural deformation, faults and fracture zones, appears to provide a pathway for vertical gas migration. However, stratigraphic (lateral) heterogeneities associated with the reservoir and seal rocks may provide additional vertical pathways

Geology and Aquifer Sensitivity of Quaternary Glacial Deposits Overlying a Portion of the Mahomet Buried Bedrock Valley Aquifer System

To characterize the distribution of Holocene and Late Quaternary deposits and to assess the contamination potential of the Mahomet Aquifer, surficial geologic and aquifer sensitivity maps of the Gibson City East 7.5-Minute Quadrangle were created. Geologic data, extent, and thickness of the geologic materials were coupled with LiDAR topographic data and analyzed using ESRI’s ArcGIS 10.6.1. Aquifer sensitivity to contamination was calculated based on the depth to the first aquifer unit, aquifer thickness, and the lithology of the aquifer materials. The surficial geologic mapping identified five lithostratigraphic units: the Cahokia Formation, the Equality Formation, the Henry Formation, and the Yorkville and Batestown Members of the Lemont Formation. The southeast to northwest trending Illiana Morainic System is the most prominent feature in the study area and delineates the maximum extent of the glaciers during the Livingston Phase of glaciation. Postglacial deposits of the Cahokia Formation, alluvium, interfinger, and overlie with glacial outwash of the Henry Formation along channels and drainage ways downslope of the moraine. The areas of least sensitivity are located over the Illiana Morainic System, whereas the greatest potential to contamination occurs where the thickest deposits of the Henry Formation and Cahokia Formation lie at or just below the land surface

Crystal structure of the cowpox virus-encoded NKG2D ligand OMCP

The NKG2D receptor is expressed on the surface of NK, T, and macrophage lineage cells and plays an important role in antiviral and antitumor immunity. To evade NKG2D recognition, herpesviruses block the expression of NKG2D ligands on the surface of infected cells using a diverse repertoire of sabotage methods. Cowpox and monkeypox viruses have taken an alternate approach by encoding a soluble NKG2D ligand, the orthopoxvirus major histocompatibility complex (MHC) class I-like protein (OMCP), which can block NKG2D-mediated cytotoxicity. This approach has the advantage of targeting a single conserved receptor instead of numerous host ligands that exhibit significant sequence diversity. Here, we show that OMCP binds the NKG2D homodimer as a monomer and competitively blocks host ligand engagement. We have also determined the 2.25-Å-resolution crystal structure of OMCP from the cowpox virus Brighton Red strain, revealing a truncated MHC class I-like platform domain consisting of a beta sheet flanked with two antiparallel alpha helices. OMCP is generally similar in structure to known host NKG2D ligands but has notable variations in regions typically used to engage NKG2D. Additionally, the determinants responsible for the 14-fold-higher affinity of OMCP for human than for murine NKG2D were mapped to a single loop in the NKG2D ligand-binding pocket

Assessing Differences Between Physician\u27s Realized And Anticipated Gains From Electronic Health Record Adoption

Return on investment (ROI) concerns related to Electronic Health Records (EHRs) are a major barrier to the technology’s adoption. Physicians generally rely upon early adopters to vet new technologies prior to putting them into widespread use. Therefore, early adopters’ experiences with EHRs play a major role in determining future adoption patterns. The paper’s purposes are: (1) to map the EHR value streams that define the ROI calculation; and (2) to compare Current Users’ and Intended Adopters’ perceived value streams to identify similarities, differences and governing constructs. Primary data was collected by the Texas Medical Association, which surveyed 1,772 physicians on their use and perceptions of practice gains from EHR adoption. Using Bayesian Belief Network Modeling, value streams are constructed for both current EHR users and Intended Adopters. Current Users and Intended Adopters differ significantly in their perceptions of the EHR value stream. Intended Adopters’ value stream displays complex relationships among the potential gains compared to the simpler, linear relationship that Current Users identified. The Current Users identify “Reduced Medical Records Costs” as the gain that governs the value stream while Intended Adopters believe “Reduced Charge Capture Costs” define the value stream’s starting point. Current Users’ versus Intended Adopters’ assessments of EHR benefits differ significantly and qualitatively from one another