CENTRAL NEBRASKA RIVER BASINS,NEBRASKA1

ABSTRACT: The Central Nebraska Basins (NAWQA) study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Platte River flows are variable in the western part of the study unit because of diversions, but the Loup and Elkhorn Rivers originate in an area of dune sand covered by grassland that generates consistent base flows. More frequent runoff in the eastern part of the study unit also sustains stream flow. Ground water in the study unit has no regional confining units and the system is a water table aquifer throughout. Macroinvertebrate and fish taxa at biological sampling sites in the state were related to stream flow. One of the four wetland complexes identified in the study unit includes habitat for threatened and endangered bird species. The study unit is an agricultural area that includes row crops, both irrigated and nonirrigated in the eastern and southern parts, and rangeland in the Sand Hills of the western part. A water quality assessment will be based on the differences in environmental setting in each of four subunits within the study unit.]     

Biodegradable plastic made from soybean products. II. Effects of cross-linking and cellulose incorporation on mechanical properties and water absorption

Soy isolate was treated with formaldehyde and glyoxal at 1.0, 2.5, and 5.0% (w/w isolate) and with adipic and acetic anhydrides. The materials were then compression-molded into plastic tensile bars and tested for tensile and yield strength, percentage elongation, Young's modulus, and water absorption. Treatment with 5% formaldehyde increased the tensile strength significantly, to 4.9 kg/mm², compared with the untreated sample (3.7 kg/mm²). The yield strength increased slightly, to 0.68 kg/mm². Elongation was significantly less after treatment with formaldehyde. Young's modulus increased after treatment and leveled off at 174 kg/mm². Water absorption decreased as the formaldehyde concentration increased. Treatment with either glyoxal or adipic/acetic anhydride had a detrimental effect on the mechanical properties of the plastic specimens. Water absorption was decreased by glyoxal treatment but was not affected by adipic/acetic anhydride treatment. Long-fiber (lf), short-fiber (sf), and microcrystalline (mc) cellulose were incorporated into soy isolate at various levels. Cellulose addition decreased the percentage elongation and increased the rigidity of the plastic. All three cellulose additions increased Young's modulus. The tensile strength increased with the addition of sf-cellulose to soy isolate; lf-cellulose decreased the tensile strength, whereas the incorporation of mc-cellulose did not have a significant effect. The yield strength increased slightly with the addition of sf-cellulose and was less affected by the addition of lf- or mc-cellulose. All three types of cellulose slightly decreased water absorption at ca. 15% content.Journal Paper No. J-15563 of the Iowa Agriculture and Home Economics Experiment Station, Ames; Project No. 2863.     

Evaluation of a chemical stabilization process

Environmental Resources Management (ERM) performed an evaluation of a biosolids chemical stabilization process known as BIO*FIX®, marketed by Bio Gro Systems, Inc., of Annapolis, Maryland. The purpose of the evaluation was (1) to assess major characteristics of the process and its final product, (2) to determine the quantity and final disposition of all components in the incoming biosolids, and (3) to determine if the process conforms to new regulations promulgated and administered by the U.S. Environmental Protection Agency (EPA) titled “Standards for the Use or Disposal of Sewage Sludges” (40 CFR Part 503). The BIO*FIX® chemical stabilization process involves the addition of calcium oxide (CaO) to dewatered biosolids at rates that achieve the pathogen reduction and vector attraction reduction requirements of the 503 program while creating a marketable end product used as an agricultural amendment. ERM's project involved the testing of four process streams in order to create a mass balance on the process. Laboratory analyses were performed on samples of the dewatered biosolids, the chemically-stabilized end product, and the scrubber water effluent. The primary components of concern tested in the above process streams were ammonia, metals, odorous compounds, particulate matter, and organic matter. Through the tests described in the article, ERM drew the following conclusions: (1) The major gaseous pollutant resulting from the BIO*FIX® process is gaseous ammonia. The total gaseous ammonia released from the product depends on the ammonia nitrogen content of the biosolids, and pH and temperature levels reached in the process. Additional ammonia is emitted when the end product is loaded in trucks and stored. Any gaseous ammonia remaining in the end product after processing will slowly dissipate over time. (2) Other potential odor pollutants such as hydrogen sulfide (H₂S) and mercaptans were found to be below detectable levels in the uncontrolled exhaust gas. (3) Metals were not found in the exhaust gas in any detectable quantities. They would not be expected to volatilize during the process. Particulate matter emissions were found to be very low. (4) The pathogen reduction and vector attraction reduction requirements of the 40 CFR 503 regulations were met or exceeded. (5) Finally, through observations and tests, ERM found that the BIO*FIX® chemical stabilization process provides for a simple, viable, and effective conversion of biosolids into a beneficial use product in compliance with all pertinent regulations.     

EXPOSURE ASSESSMENT OF POPULATIONS USING ENVIRONMENTAL MODELING,DEMOGRAPHIC ANALYSIS,AND GIS1

ABSTRACT: Simulation of ground-water flow and fate of contaminants in the subsurface environment constitutes a major phase of most environmental assessment and site remediation studies. These simulation studies yield information on spatial and temporal distributions of contaminants in the subsurface media. An important use of this information is to conduct exposure assessment studies. Spatial and temporal distributions of both chemical concentrations and exposed populations render this integrated exposure analysis task rather difficult. Geographic Information Systems (GIS), on the other hand, provide a platform in which layered, spatially distributed databases can be manipulated with ease, thereby simplifying exposure analysis tasks significantly. In this paper, we describe procedures that combine the simulation models and demographic databases under a GIS platform to automate the exposure assessment phase of a typical health assessment study. Procedures developed herein significantly simplify the post-processing phase of the analysis, and render the overall task more ‘user friendly.’ A site-specific application is included as a demonstration of the proposed process.     

PARTITIONING SMALL SCALE SPATIAL VARIABILITY OF RUNOFF AND EROSION ON SAGEBRUSH RANGELAND1

ABSTRACT: Most hydrologic models require input parameters which represent the variability found across an entire landscape. The estimation of such parameters is very difficult, particularly on rangeland. Improved model parameter estimation procedures are needed which incorporate the small-scale and temporal variability found on rangeland. This study investigates the use of a surface soil classification scheme to partition the spatial variability in hydrologic and interrill erosion processes in a sagebrush plant community. Four distinct microsites were found to exist within the sagebrush coppice-dune dune-interspace complex. The microsites explained the majority of variation in hydrologic and interrill erosion response found on the site and were discernable based on readily available soil and vegetation information. The variability within each microsite was quite low and was not well correlated with soil and vegetation properties. The surface soil classification scheme defined in this study can be quite useful for defining sampling procedures, for understanding hydrologic and erosion processes, and for parameterizing hydrologic models for use on sagebrush range-land.     

Control of upland bank erosion through tidal marsh construction on restored shores: Application in the maryland portion of Chesapeake Bay

During the period of 1972 through 1993, Environmental Concern Inc. (EC) and its recent (1989) affiliate Environmental Construction Company (ECC) have completed 216 marsh construction projects to control upland bank erosion in tributaries of the Maryland portion of Chesapeake Bay. Of these projects, 26 have involved marsh construction on unaltered existing shores and 190 have utilized marsh construction on shores that have been restored to former increased elevations through shoreline filling and grading. This paper describes the latter restoration technique. Throughout the 21-year period of applying the technique for long-term upland bank erosion control, refinements to the design standards and criteria for site suitability have been made so as to optimize its successful application. As a result of this experience, a reliable bioengineering restoration technique has evolved to control upland bank erosion. This paper describes the details of this successful technique through a review of: (1) its objectives and benefits, (2) suitability of sites for its application, (3) the design of its shore restoration, (4) its construction, (5) its maintenance, and (6) comparison of its cost with those of structural techniques for bank erosion control. Although the technique has only been applied in the Maryland portions of Chesapeake Bay, its applicability should, with modifications, be broadly applicable to all water bodies.     

Earthquake risk reduction: An examination of local regulatory efforts

We develop an understanding of local governmental efforts to address earthquake risks. Our data for a sample of California and Washington cities' risk-reduction efforts sort into two different clusters of leading jurisdictions as contrasted with a cluster of lagging jurisdictions. We explain differences among the three categories of cities in terms of different political-economic factors. Local governmental willingness and ability to undertake risk-reduction programs have more to do with local political demands and community resources than with objective risk or previous earthquake experience. State mandates have a selective impact on local risk-reduction efforts. The principal policy lessons concern the need to address gaps in local risk-reduction efforts through more careful targeting of federal and state earthquake programs and by including stronger teeth within state mandates.     

Trends and issues in land and water resources management: Setting the agenda for change

The classical model of a paradigm shift is used to explore changes that are occurring in public lands and water resources management. Recent policy developments suggest that the traditional paradigm, which is characterized by sustained yield, is in the process of being invalidated. While no new paradigm has been fully accepted, the emerging paradigm does appear to be based on two principles: ecosystem management and collaborative decision making. Implementation of these two principles is likely to require extensive revision of traditional management practices and institutions. Failure to address these issues could result in adoption of the rhetoric of change without any lasting shift in management practices or professional attitudes.     

The costs to farmers and estate owners of public access to the countryside

This paper considers the external costs of public access on privately‐owned farm and estate land in Scotland. The increased costs and reductions in income associated with public access are found to be highly variable and site‐specific, with the main effects on land in areas of high population density or high scenic quality, or with recreational attributes. Although costs were on average higher for estates, reflecting their larger area and recreational potential, on a per‐hectare basis the costs of access were greater for the farm sector. Whilst much of the public access exists through de facto rights on open‐access land, there was evidence for an increasing commercialization of open‐air recreation, particularly with respect to more specialized activities. The discussion considers the extent to which the costs of access for land managers are reflected in policies determining the public provision of countryside access.     

Case study: Browning-ferris industries' computerized system for managing audit and environment performance

While some companies have established scoring systems within their audit programs, few utilize the full potential for measurement of the information gathered and subsequently produced from audits. In this article, the use of a computerized tracking system developed and used by Browning-Ferris Industries is discussed, along with a data report that details the completion of audit items and helps assure that action plans resulting from environmental audits are completed. This and other summary reports from the computer tracking system have provided meaningful measures of individual facilities' and overall company performance.