Parts Of Nebraska Research Articles

Sedimentology, petrography, and deposition of the Upper Cretaceous Codell Sandstone in the Denver Basin

We integrate new and previous stratigraphic and petrographic data for the mid-Turonian Codell Sandstone to interpret its provenance, depositional characteristics, and environments. Our focus is on sedimentologic, X-ray diffraction, and X-ray fluorescence analyses of cores and thin sections spread throughout the Denver Basin, augmented by interpretation and correlation of well logs, isopach maps, outcrops, and provenance data. Although we treat the Codell as a single mappable unit, it actually consists of two geographically disjunct sandstone packages separated by a southwest-northeast-trending gap, the NoCoZo, short for No Codell Zone. The Codell is everywhere capped by a significant unconformity and across much of the northern Denver Basin rests unconformably on the underlying shales of the Carlile Shale. In the southern Denver Basin, the Codell commonly contains two parasequences, each of which becomes less muddy upward. Biostratigraphic and geochonologic data suggest that the unit represents deposition over a relatively brief time, spanning ~0.4 Ma from ~91.7 to ~91.3 Ma. The Codell is predominantly a thin (<50 ft) sheet-like package of pervasively bioturbated coarse siltstone and very fine-grained sandstone dominated by quartz and chert grains 50 to 100 μm in diameter. The unit is more phosphatic than the underlying members of the Carlile Shale, and its grain size coarsens to medium-grained in the northern part of the basin. An unusual aspect of the Codell across our study area is the generally excellent grain sorting despite the presence of an intermixed clay matrix. This duality of well sorted grains in a detrital clay matrix is due to the bioturbation that dominates the unit. Such burrowing created a textural inversion that obscures most of the unit’s primary sedimentary structures, except for thin intervals dominated by interlaminated silty shale and very fine sandstone. A relatively widespread and unburrowed example of this bedded facies is preserved in a thin (<10 ft) interval that extends across most of the northern Denver Basin where it is informally called the middle Codell bedded to laminated lithofacies. Sparse beds with hummocky or swaley cross-stratified and ripple cross-laminated fine-grained sandstone are present locally in this bedded facies. We hypothesize that Codell sediments were derived from a major deltaic source extending into the Western Interior Seaway from northwestern Wyoming, and that the Codell was deposited and reworked southward on the relatively flat floor of the Seaway by waxing and waning shelf currents as well as storms and waves. Codell sediments were spread across an area of more than 100,000 mi2 in this epeiric shelf system that spans eastern Colorado, southeastern Wyoming, western Kansas, parts of Nebraska and beyond.

Effects of drought on groundwater-fed lake areas in the Nebraska Sand Hills

Study regionThe Nebraska Sand Hills (NSH) lies in the western part of Nebraska, United States. We chose the north-eastern, central, and western parts of NSH with distinct climate, topography, and hydrology. Study focusThe study assesses the response of hundreds of shallow groundwater-fed lakes to drought. Total lake area (TLA), determined by classifying Landsat satellite images from 1984 to 2018, was juxtaposed with published Palmer Drought Severity Index (PDSI) and detrended cumulative PDSI (DeCumPDSI) at monthly and annual timescales. The PDSI and DeCumPDSI were time lagged to incorporate the preceding climatic effect (groundwater time lag) and evaluated against TLA using Bayesian regression analysis. New hydrologic insight for the regionTLA in the NSH respond to the seasonal as well as long-term climatic effects moderated by topography, surface, and subsurface hydrology. A higher determination coefficient R2 and lower mean square error of TLA at annual PDSI and DeCumPDSI illustrate the effect of long-term climatic fluctuations and groundwater influence: the evaporative losses from lakes are modulated by the lake-groundwater exchange, but the groundwater recharge has a longer response time to the drought. The study provides a simple method of assessment of the climate impact that results from the satellite data, gridded climate observation, and statistics for sensitive landscape of the NSH.

Spatial and temporal trends and variabilities of hailstones in the United States Northern Great Plains and their possible attributions

AbstractFollowing on our study of hail for the Southern Great Plains (SGP), we investigated the spatial and temporal hail trends and variabilities for the Northern Great Plains (NGP) and the contributing factors for summers (June–August) focusing on the period of 2004–2016 using two independent hail datasets. Analysis for an extended period (1994–2016) with the hail reports was also conducted to more reliably investigate the contributing factors. Both severe hail (1″ < diameter ≤ 2″) and significant severe hail (SSH; diameter > 2″) were examined and similar results were obtained. The occurrence of hail over the NGP demonstrated a large interannual variability, with a positive slope overall. Spatially, the increase is mainly located in the western part of Nebraska, South Dakota, and North Dakota. We find the three major dynamical factors that most likely contribute to the hail interannual variability in the NGP are the El Niño-Southern Oscillation (ENSO), North Atlantic subtropical high (NASH), and low-level jet (LLJ). With a thermodynamical variable integrated water vapor transport that is strongly controlled by LLJ, the four factors can explain 78% of the interannual variability in the number of SSH reports. Hail occurrences in the La Niña years are higher than the El Niño years since the jet stream is stronger and NASH extends further into the southeastern United States, thereby strengthening the LLJ and in turn water vapor transport. Interestingly, the important factors impacting hail interannual variability over the NGP are quite different from those for the SGP, except for ENSO.

A Brief History of Nebraska by Ronald Naugle

Reviewed by: A Brief History of Nebraska by Ronald Naugle Bill Hayes A Brief History of Nebraska. By Ronald Naugle. Lincoln: History Nebraska Press, 2018. 135 pp. Figures, further reading, index. $14.95, paper. This volume is an introduction to the exciting past of the land, people, events, and institutions that make up the history of the territory and the state of Nebraska. Authored by emeritus professor of history Naugle of Nebraska Wesleyan University, this study starts with an examination of the prehistorical past, a description of the land for the last 12,000 years, the early inhabitants, the coming of European and American explorers, territorial settlement, and the conflict between natives and settlers. The wildlife of that early period was made up of now extinct animals including mammoths, mastodons, sloths, and saber-toothed cats. Spear points found in Nebraska have been dated back to 11,500 to 10,500 years ago, indicating the presence of human hunters. Little is known about these early inhabitants who lived mainly by hunting. Pottery remains have been found dating back to about 2,000 years. There appears to have been a drought that led to the lack of an archeological record from the late 1300s to 1500s. A people known as Village Farmers lived in parts of Nebraska between AD 1000 and 1500, but the relationship between them and modern native peoples is unknown. Attention is given to the native peoples, mainly Otoe and Missouria, Omaha, Ponca, Pawnee, Arapaho, Cheyenne, and Lakota that lived in the region prior to Jefferson's acquisition of the Louisiana Purchase in 1803. After the description of territorial beginnings, the American Civil War, the politics surrounding the location of the state capitol, the conflict with Native Americans, and the coming of the railroad, emphasis is placed on the role of cattle drives from Texas and the spread of ranches in the Sandhills. In succession, Table Rock, Nebraska City, Plattsmouth, Schuyler, Kearney, and Ogallala became cattledrive towns where meat on the hoof was sent back East. Politically, Nebraska is still operating on the State Constitution drawn up in 1875, although it has been amended many times. The most significant changes came in 1917 when women were given the right to vote in local elections, and in 1934 when Nebraska adopted the Unicameral (or one-house) legislature. Populism had a big influence on the state of Nebraska. Its goals included a graduated income tax, old-age pensions for Union Civil War veterans, the Australian secret ballot, eight-hour workday, and the direct election of US senators (previously picked by the state legislatures). At about the same time, the state's first irrigation laws were passed. Unique in Nebraska history was the role played by William Jennings Bryan in state and national politics in the late nineteenth and early twentieth centuries. Although he ran for president three times and lost, he is forever remembered for his role in the Scopes Trial of [End Page 169] 1925 dealing with the teaching of evolution in the public schools. World War I brought about significant tension in Nebraska between residents of German ancestry and those of other backgrounds, over such issues as loyalty and the teaching of German in public schools. State Councils of Defense were created to make Nebraskans more patriotic. George Norris was another consequential politician in state and national politics who led Nebraska to becoming the only state with a unicameral form of government. He also played a major role in creating public power in the Tennessee Valley as well as in Nebraska (that is, in 1929 about 6 percent of Nebraska farmers had public power, but by 1951, 87 percent had it). More recent history has been affected by the location of the Strategic Air Command Base near Bellevue, the civil rights struggles of the sixties to the present in Omaha and elsewhere, and the tensions of the war in Vietnam. Conflicts continued regarding the rights of Native Americans, the Equal Rights Amendment, Mexican American employment in meatpacking plants, how to control the state's water resources, what to do with nuclear waste, how to encourage economic development in Nebraska, and whether or not to allow the TransCanada pipeline to...

The long term effect of agricultural, vadose zone and climatic factors on nitrate contamination in Nebraska's groundwater system

A four-decade dataset (1974–2013) of 107,823 nitrate samples in 25,993 wells from western and eastern parts of Nebraska was used to assess long-term trends of groundwater nitrate concentration and decadal changes in the extent of groundwater nitrate-contaminated areas (NO3-N ≥ 10 mg N/L) over the entire state. Spatial statistics and regressions were used to investigate the relationships between groundwater nitrate concentrations and several potential natural and anthropogenic factors, including soil drainage capacities, vadose zone characteristics, crop production areas, and irrigation systems. The results of this study show that there is no statistically significant trend in groundwater nitrate concentrations in western Nebraska, in contrast with the increasing trend (p < .05) to the east. The spatial extent and nitrate concentrations in contaminated groundwater in center pivot-irrigated areas was less than in gravity-irrigated areas. Areas with a thicker vadose zone and larger saturated thickness of the aquifer have relatively lower nitrate concentrations. The results of a classification and regression tree (CART) model indicate the difference in the influence of physical factors on groundwater nitrate concentrations between western and eastern Nebraska, namely that groundwater nitrate concentrations correspond with vadose zone thickness, effective hydraulic conductivity, and saturated thickness in the west, while in eastern Nebraska, concentrations are correlated with average percent sand in the topsoil (0–150 cm), well depth, and effective hydraulic conductivity.

416 Economics of Field Pea Supplementation for Cattle Grazing Crested Wheat Grass.

Field peas are widely grown in the western part of Nebraska because they offer benefits for wheat production in subsequent years. However, typical field pea markets can become saturated and new avenues are being explored. Field peas contain 20-25% CP, of which approximately 40% is RUP. A two year experiment was conducted comparing field peas to dry distillers grains with solubles (DDGS) as an RUP supplement for yearlings grazing crested wheat grass in the summer. The objective was to establish a price producers could pay for field peas relative to DDGS. The first year 112 heifers (294 kg; SD = 34.6) grazing crested wheat grass pastures (n = 12) were used in a 2 × 2 factorial design. The grazing season began May 20 and ended September 19. The second year of the study used 114 spayed heifers (306 kg; SD = 16.3) and supplementation began May 23 and ended September 7. Cattle were blocked by BW. Treatments included field peas or DDGS supplemented daily at either 0.4% or 0.8% of BW. Supplement amount was prorated for 6 days of delivery and fed in bunks. Pasture was the experimental unit and cattle were rotated every two weeks to remove any effects due to pasture. Body weights were collected on 2 consecutive days and averaged for both beginning and ending BW. A 1-d interim BW was also collected to adjust the amount of supplement offered. All other procedures were the same in years 1 and 2. Each treatment was replicated six times (3/yr) over the two year study. Effects of weight block and year were not significant (P ≥ 0.26) and were removed from the model. There was also no interaction between type and level of supplement (P = 0.27). Level of supplement was not statistically significant (P = 0.20), cattle fed field peas at 0.4 or 0.8% of BW gained 0.97 and 0.98 kg/d, respectively. Cattle fed DDGS gained 1.02 and 1.15 kg/d for the 0.4 and 0.8% of BW levels, respectively. There was a significant difference in ADG due to type of supplement (P = 0.03). Field pea supplemented heifers had 10% lower ADG compared to DDGS supplemented heifers. Economically, this means if corn is priced at $124.58/ 909 kg DM, and DDGS is priced similar to corn, a producer should pay $112.13/ 909 kg DM, or $2.89/ 27 kg, for field peas.

Motoring West, Volume 1: Automobile Pioneers, 1900–1909 ed. by Peter J. Blodgett (review)

Reviewed by: Motoring West, Volume 1: Automobile Pioneers, 1900–1909 ed. by Peter J. Blodgett John A. Jakle Motoring West, Volume 1: Automobile Pioneers, 1900–1909. Edited by Peter J. Blodgett. Norman: University of Oklahoma Press, 2015. 360pp. Illustrations, map, index. $34.95 cloth. Published by the University of Oklahoma Press under its Arthur H. Clark imprint, historian Peter J. Blodgett offers the first of two intended edited works focused on early automobile travel in the western United States. Volume 1 contains excerpts from eighteen articles originally published between May 1901 and June 1909 in serials, including Country Life in America, Harper’s Weekly, Outing: An Illustrated Monthly Magazine of Recreation, Scientific American, Sunset, and World’s Work. Authors in the anthology include car owners, their hired drivers, and accompanying passengers, including journalists not just along for the ride but specifically to write about the adventure implicit. Blodgett first offers an introduction to the overall two-volume project. He tells the story of how motoring in the American West evolved from “audacious stunt to a curiosity to a commonplace occurrence over a few decades” (19). There follows a short introduction to the current volume. It focuses on the earliest periods of “stunt” and “curiosity” in emphasizing early transcontinental endurance runs and speed contests: sporting events widely covered in newspapers and magazines that pitted drivers against their machines, topography, weather, and, ultimately, time. Reports emphasized not only the primitive motor cars used but also the very poor roads (and even the lack of roads) that generally characterized the West, especially in the mountainous areas of the Rockies, the Sierra Nevada, and the Cascades. Each vignette is preceded by a short introduction, Blodgett providing a biographical sketch of each author (or authors) as well as contextual outline for the specific travel episodes reported. One might argue over the items chosen for the anthology, and, as well, over the editor’s abridging (or choice of specific excerpts). The anthology does contain much redundancy with authors seemingly making the same sorts of observations over and over again. But is that a problem? Perhaps not. By including such repetition Blodgett accomplishes something important. Significant ideas are hammered home thus to clearly establish in the reader’s mind what was and what was not commonplace regarding motoring in the earliest decades of the twentieth century, especially in the West. Importantly, insight into sense of place is offered. For example, the reader is challenged to consider the West not just as a geographical area but as a mythical locale of challenge and redemption. Interesting regional stereotypes underlie much of the reporting, themes that strongly echo today when Americans think about their nation west of the Mississippi River. In early motoring there was substantial concern for the passing scene. In western travel, mountainous courses stood out in the remembering—if only for the lack of passable roads and the resulting hard going. In contrast the Great Plains (especially the High Plains) provided less interest. Roads tended to be minimally improved (although they could turn to mud in wet weather) and services (for example, garages with gasoline, lubricating oil, and tires) were generally available relatively close at hand. But flat landscapes could become monotonous, drivers and their passengers, for example, seemingly facing ever-receding horizons, scenes dominated by grass [End Page 77] and sky. Wrote one author, having motored from San Francisco to the East Coast: “The hardest part of the trip was over when Denver was reached, though beyond that city barbed-wire cattle fences and irrigation ditches were often annoying. Through part of Nebraska and Iowa the muddy condition of the roads made the travel almost amphibious” (207). [End Page 78] John A. Jakle Department of Geography and Geographical Information Science University of Illinois at Urbana–Champaign Copyright © 2016 Center for Great Plains Studies, University of Nebraska–Lincoln

Bats of the Wildcat Hills and Surrounding Areas in Western Nebraska

During the last few decades, detailed studies of bats have been conducted in many parts of Nebraska, but comprehensive surveys were lacking in the Wildcat Hills and other western regions of the state. The Wildcat Hills represent a unique and isolated area of rugged buttes, ridges, and canyons dominated by ponderosa pine forests (Pinus ponderosa) in central parts of Nebraska's panhandle. This area also contains landscapes with some of the highest wind speeds in the state, making it conducive for future wind-energy development. To better understand the natural history of bats and to promote conservation efforts in the region, we report on the distribution of bats and their habitats, as well as on their relative abundance, seasonal activity, and reproduction in the Wildcat Hills and surrounding areas. From August 1997 to July 2011, we captured 968 bats representing 7 species, and we also examined museum specimens previ- ously collected by other researchers from the region. For 5 species, we extend the known period of nonhibernating activity in the state, and we provide evidence of reproducing populations for 7 species in the region based on presence of lactating females. New reproductive information for bats in Nebraska also includes timing of pregnancy and lactation, as well as presence of volant young. For migratory species during autumn migration, hoary bats (Lasiurus cinereus) and eastern red bats (Lasiurus borealis) began moving through the region earlier (late July / early August) than silver-haired bats (Lasionycteris noctivagans). Documentation of the little brown bat (Myotis lucifugus) in riparian areas and buildings along the North Platte River represents a range extension for this species from the Pine Ridge in northwestern Nebraska. Knowledge gained from our long-term study will assist resource managers and biologists in efforts to protect and manage bats as these bats face unprecedented challenges in the future with development of additional wind-energy facilities and likely westward spread of white-nose syndrome in North America.

Long-Term Trends in Air Temperature Distribution and Extremes, Growing Degree‐Days, and Spring and Fall Frosts for Climate Impact Assessments on Agricultural Practices in Nebraska

AbstractAir temperature influences agricultural practices and production outcomes, making detailed quantifications of temperature changes necessary for potential positive and negative effects on agricultural management practices to be exploited or mitigated. Temperature trends of long-term data for five agricultural locations, ranging from the subhumid eastern to the semiarid western parts of Nebraska, were studied to determine local temperature changes and their potential effects on agricultural practices. The study quantified trends in annual and monthly average maximum and minimum air temperature (Tmax and Tmin), daily temperature range (DTR), total growing degree-days, extreme temperatures, growing‐season dates and lengths, and temperature distributions for five heavily agricultural areas of Nebraska: Alliance, Central City, Culbertson, Fremont, and Hastings. July and August were the months with the greatest decreases in Tmax for the central part of Nebraska—Culbertson, Hastings, and Central City. Alliance, Culbertson, and Fremont had year-round decreases in DTR. Central City and Hastings experienced growing‐season decreases in DTR. Increases in growing‐season length occurred at rates of 14.3, 16.7, and 11.9 days century−1 for Alliance, Central City, and Fremont, respectively. At Hastings, moderately earlier last spring frost (LS) at a rate of 6.6 days century−1 was offset by an earlier (2.7 days century−1) first fall frost (FF), resulting in only a 3.8 days century−1 longer growing season. There were only slight changes in LS and FF dates of around 2 days earlier and 1 day later per century, respectively, for Culbertson.

Tracking a Medically Important Spider: Climate Change, Ecological Niche Modeling, and the Brown Recluse (Loxosceles reclusa)

Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses.

No Other River

It's an annual rite. Sometime between late February and early April, I drive west on Interstate 80. In south-central Nebraska, both the Platte River and the interstate swing low toward the Nebraska-Kansas state line. Somewhere along the bottom of this catenary curve, I pull off the interstate and drive gravel roads south of the river. What I'm looking for is the world's largest gathering of migrating sandhill cranes. They're easy to find. The half-million cranes are concentrated, more or less, within the forty-mile stretch of the river between Grand Island and Kearney, the narrow waist on the hourglass-shaped Central Flyway and the narrowest part of the crane's migratory route. Because this part of Nebraska is relatively flat and open, one doesn't have to look hard or far to see the elegant, leggy, four-foot tall, red-capped, gray birds. I come to watch them feast and dance and drop out of and rise into the sky. Most of the cranes congregating on the Platte are lesser sandhills, the crane with the longest migration. The remaining cranes are greater sandhills and the endangered whooping cranes. After the roughly 600-mile trip from their winter homes in eastern New Mexico, northwestern Texas, and northern Mexico, the sandhill cranes are lean and hungry. Once in Nebraska, they glean corn left from the harvest and slurp up snails, worms, grubs, insects, snakes, and crayfish in the wet meadows near the Platte. Each crane stays in Nebraska about four weeks and adds a pound or so of fat during this time. At night, they return to the shallow river where they sleep standing in water, usually on one leg in roosts of as many as 10,000 to 15,000 cranes per half mile of river. From the air, these sleeping masses, some of which are a mile long, look sandbar-shaped, and the individual cranes are evenly spaced, as if, writes Steve Grooms in The Cry of the Sandhill Crane, positioned on a grid of four-foot squares, each bird staying just beyond the reach of its neighbors' sharp bills. At dawn, the cranes head for the fields near the river. And there, they dance, bowing, strutting, pumping their heads, raising their bills, flapping their wings, tossing corncobs into the air, and gracefully hopping as high as twenty feet. Great bouncing

Characterization of a Contact Zone between Two Subspecies of the Big Brown Bat (Eptesicus fuscus) in Nebraska

Abstract Two subspecies of the big brown bat (Eptesicus fuscus) are reported to occur in Nebraska. The eastern race, E. f. fuscus, is reportedly bigger and darker than its western counterpart E. f. pallidus. Where these 2 subspecies come in contact is the subject of debate. We used external, cranial, and colorimetric data to investigate geographic variation among populations of E. fuscus in Nebraska to determine the location of the zone of contact between E. f. fuscus and E. f. pallidus. We discovered significant variation in external, cranial, and colorimetric data, suggesting that E. fuscus is represented by 2 subspecies in Nebraska. Our results showed that E. f. pallidus is smaller, possesses lighter pelage, and is restricted to the northern and western parts of Nebraska, whereas E. f. fuscus is larger, possesses darker pelage, and occurs in southern and southeastern parts of the state. Populations located between these regions represent intergrades of the 2 subspecies. We suggest that the subspecific ...

A Strategy for Evaluating District Developed Assessments for State Accountability

As part of Nebraska's assessment and accountability system, districts' local assessment systems are evaluated for their psychometric quality. This article provides an overview of a two‐stage evaluation strategy, discusses how it was applied in Nebraska, and presents results from the first three years of the evaluation process. Benefits of the method include an emphasis on formative evaluation and promotion of improved assessment quality at the local level. A limitation of the model is the inability to make refined comparisons of student performance across districts on the assessments. Results from the first three years suggest that greater specificity in the review criteria and additional reviewer calibration activities are needed.

Distance Realities

SUMMARY In the eastern part of Nebraska, schools received a state grant to build a two-way audio-video network for the purpose of improving student skills in technology. A few network teachers were trained and earned Microsoft Office User Specialist (MOUS) and Windows NT certification. These skilled instructors then trained others and developed a team approach to offer computer networking and Microsoft Office courses to students in 8-11 small districts in the region. At the conclusion of the Office courses, a randomly selected group of students took the MOUS exams with favorable results. The distance system's management team has given careful consideration to the complex management issues and appropriate incentives for teachers which has resulted in high performance that may not otherwise have been possible.

Strontium isotope geochemistry of groundwater in the central part of the Dakota (Great Plains) aquifer, USA

The Dakota aquifer of the central and eastern Great Plains of the United States is an important source of water for municipal supplies, irrigation and industrial use. Although the regional flow system can be characterized generally as east to northeasterly from the Rocky Mountains towards the Missouri River, locally the flow systems are hydrologically complex. This study uses Sr isotopic data from groundwater and leached aquifer samples to document the complex subsystems within the Dakota aquifer in Nebraska and Kansas. The interaction of groundwater with the geologic material through which it flows has created spatial patterns in the isotopic measurements that are related to: long-term water–rock interaction, during which varying degrees of isotopic equilibrium between water and rock has been achieved; and the alteration of NaCl fluids by water-rock interaction. Specifically, Sr isotopic data distinguish brines from Kansas and western Nebraska from those in eastern Nebraska: the former are interpreted to reflect interaction with Permian rocks, whereas the latter record interaction with Pennsylvanian rocks. The Sr isotopic composition of groundwater from other parts of Nebraska and Kansas are a function of the dynamic interaction between groundwater and unlithified sediments (e.g., glacial till and loess), followed by interaction with oxidized and unoxidized sediments within the Dakota Formation. This study illustrates the power of combining Sr chemistry with more conventional geochemical data to obtain a more complete understanding of groundwater flow systems within regional aquifer systems where extensive monitoring networks do not exist.

Regional estimation of base recharge to ground water using water balance and a base-flow index.

Naturally occurring long-term mean annual base recharge to ground water in Nebraska was estimated with the help of a water-balance approach and an objective automated technique for base-flow separation involving minimal parameter-optimization requirements. Base recharge is equal to total recharge minus the amount of evapotranspiration coming directly from ground water. The estimation of evapotranspiration in the water-balance equation avoids the need to specify a contributing drainage area for ground water, which in certain cases may be considerably different from the drainage area for surface runoff. Evapotranspiration was calculated by the WREVAP model at the Solar and Meteorological Surface Observation Network (SAMSON) sites. Long-term mean annual base recharge was derived by determining the product of estimated long-term mean annual runoff (the difference between precipitation and evapotranspiration) and the base-flow index (BFI). The BFI was calculated from discharge data obtained from the U.S. Geological Survey's gauging stations in Nebraska. Mapping was achieved by using geographic information systems (GIS) and geostatistics. This approach is best suited for regional-scale applications. It does not require complex hydrogeologic modeling nor detailed knowledge of soil characteristics, vegetation cover, or land-use practices. Long-term mean annual base recharge rates in excess of 110 mm/year resulted in the extreme eastern part of Nebraska. The western portion of the state expressed rates of only 15 to 20 mm annually, while the Sandhills region of north-central Nebraska was estimated to receive twice as much base recharge (40 to 50 mm/year) as areas south of it.

ASSESSING WINTER WHEAT RESPONSES TO CLIMATE CHANGE SCENARIOS: A SIMULATION STUDY IN THE U.S. GREAT PLAINS

Hard red winter wheat (Triticum aestivum L.) is a major crop in the Great Plains region of the U.S. The goal of this assessment effort was to investigate the influence of two contrasting global climate change projections (U.K. Hadley Center for Climate Prediction and Research and Canadian Centre for Climate Modelling and Analysis) on the yield and percent kernel nitrogen content of winter wheat at three locations in Nebraska. These three locations represent sub-humid and semi arid areas and the transition between these areas and are also representative of major portions of the winter wheat growing areas of the central Great Plains. Climate scenarios based on each of the projections for each location were developed using the LARS-WG weather generator along with data from automated weather stations. CERES-Wheat was used to simulate the responses for two contrasting cultivars of wheat using two sowing dates. The first sowing date represented current sowing dates appropriate for each location. The second sowing date was later and represents the approximate date when the mean air temperature from the climate scenarios is the same as the mean air temperature from the actual climate data at the current sowing dates. The yield and percent kernel nitrogen content using the two climate scenarios generally decrease going from the sub-humid eastern to the semi arid western parts of Nebraska. Results from these simulations indicate that yield and percent kernel nitrogen content using the two climate scenarios could not both be maintained at levels currently simulated. Protein content (directly related to kernel nitrogen content) and end-use quality are the primary determinants for the use of hard red winter wheat in baked goods. Nitrogen management and new cultivars, which can enhance the uptake and translocation of nitrogen, will be proactive steps to meet the challenges of global climate change as represented by these climate scenarios.

PATTERN OF GROUND‐WATER LEVEL DECLINE IN THE HIGH PLAINS AQUIFER NEBRASKA1

ABSTRACT: Ground‐water level decline patterns in parts of Nebraska conform to the circular island concept of Bredehoeft et al. (1982), which indicates how water is derived by wells developed in a circular island. If elongated, the center of the island corresponds to a regional ground‐water divide while the shoreline corresponds to a regional river. In both versions, ground‐water table elevation is a function of recharge and transmissivity. A dynamic equilibrium exists such that the gradient of the water table will convey all recharge to discharge areas. Withdrawals of ground water result initially in mining, with a new equilibrium attained when pumping equals capture. During early development, capture is an important source of water in discharge areas, while mining is more significant in recharge areas. The pattern observed in many areas shows the greatest ground‐water level decline in the vicinity of ground‐water divides and the steepest gradient near regional rivers. A similar pattern has been observed adjacent to the Arkansas River in south‐central Kansas. Similar decline patterns can be modeled for a hypothetical ground‐water basin. This is of major importance to water‐resource managers because it dictates that management programs be applied to the entire hydrologic system.

June streamflow

Streamflow remained below the normal range in parts of most of the northeastern, southeastern, and Gulf Coast states, as well as parts of Nebraska, Missouri, Montana, South Dakota, and southern California during June, according to a month end check on the nation's water resources by the U.S. Geological Survey (USGS). USGS hydrologists said that streamflows during June decreased into the below‐normal range in parts of Wisconsin, Minnesota, Iowa, Hawaii, and additional areas of southern California, adding to the generally dry conditions in many parts of t he country.

The Effects of Boating upon Lead Concentrations in Fish

The concentration of lead in fish muscle tissue from lakes where boating is heavy and where it is prohibited was measured. The lead levels ranged from less than 0.05 to 1.35 ppm but did not differ significantly between those in the controlled and noncontrolled boating lakes. Lead levels apparently pose no public health hazard. Trans. Kans. Acad. Sci., Vol. 79 (3-4), 1976. In recent years, studies have revealed that lead concentrations are increasing in our environment. This increase can be attributed to the combustion of leaded gasoline (Page and Panje, 1970). Investigators have demonstrated significant correlations between motor vehicle traffic density and the amount of lead associated with soils (Page and Panje, 1970; Satterlee et aI., 1975) and plants (Schuck and Locke, 1970; Lagerwerff and Specht, 1970). It was hypothesized that heavy motor boating traffic might contribute significantly to lead concentrations in the aquatic environment. Lead in the aquatic environment from exhaust wastes is most likely to occur in relatively insoluble forms as in soil (Daines et aI., 1970). Sedimentallead may be assimulated by plants and certain invertebrates. If biomagnification does occur, fish tissues would be expected to contain lead. Lead is known to be toxic, cumulative and deposited in bone tissue (Bowen, 1966). Immediate concern was over excessive amounts of lead occuring in edible portions of fish. English et al. (1963a and 1963b) and Su rber (1971) examined the tainting of the taste of fish due to outboard motor exhaust wastes. Lead in fish tissue was not determined at that time, but palatability was deleteriously affected. Several lakes in the eastern part of Nebraska are subject to heavy recreational use by both fishermen and water skiers. A study to determine lead levels in tissues of selected species of fish was therefore initiated. The purpose was to determine if fish from lakes receiving heavy motor boating pressure might constitute a health hazard. Fish samples were taken from three lakes which received considerable boating pressure (Connestoga and Pawnee near Lincoln and Victory Lake at Fremont State Recreational Area). Two control lakes were chosen from the same areas: Yankee Hill near Lincoln and Lake #2 at Fremont. Victory Lake and Fremont Lake #2 are sandpit type lakes;