A MULTICOMPONENT MODEL OF PHOSPHORUS DYNAMICS IN RESERVOIRS1

The models available for simulating phosphorus dynamics and trophic state in impoundments vary widely. The simpler empirically derived phosphorus models tend to be appropriate for long-term, steady or near steady state analyses. The more complex ecosystem models, because of computational expense and the importance of input parameter uncertainty, are impractical for very long-term simulation and most applicable for time-variable water quality simulations generally of short to intermediate time frames. An improved model for time variable, long-term simulation of trophic state in reservoirs with fluctuating inflow and outflow rates and volume is needed. Such a model is developed in this paper representing the phosphorus cycle in two-layer (i.e., epilimnion and hypolimnion) reservoirs. The model is designed to simulate seasonally varying reservoir water quality and eutrophication potential by using the phosphorus state variable as the water quality indicator. Long-term simulations with fluctuating volumes and variable influent and effluent flow rates are feasible and practical. The model utility is demonstrated through application to a pumped storage reservoir characteristic of these conditions.     

Cross-boundary management between national parks and surrounding lands: A review and discussion

Protecting biodiversity on public lands is difficult, requiring the management of a complex array of factors. This is especially true when the ecosystems in question are affected by, or extend onto, lands outside the boundaries of the protected area. In this article we review recent developments in the cross-boundary management of protected natural resources, such as parks, wildlife reserves, and designated wilderness areas. Five ecological and 11 anthropic techniques have been suggested for use in cross-boundary management. The categories are not mutually exclusive, but each is a distinct and representative approach, suggested by various authors from academic, managerial, and legal professions. The ecological strategies stress the collection of basic data and documentation of trends. The anthropic techniques stress the usefulness of cooperative guidelines and the need to develop a local constituency which supports park goals. However, the situation is complex and the needed strategies are often difficult to implement. Diverse park resources are influenced by events in surrounding lands. The complexity and variability of sources, the ecological systems under protection, and the uncertainty of the effects combine to produce situations for which there are no simple answers. The solution to coexistence of the park and surrounding land depends upon creative techniques and recommendations, many still forthcoming. Ecological, sociological, legal, and economic disciplines as well as the managing agency should all contribute to these recommendations. Platforms for change include legislation, institutional policies, communication, education, management techniques, and ethics.     

The structure of work values: A cross cultural comparison

Several years ago a research project on work values was originated. The study strived to examine the relative importance of work value items and to analyze the structure of the domain for samples from various cultural environments. A facet definition of work values was suggested that provided guidelines for constructing the Work Values Questionnaire and the formulation of hypotheses regarding the structure of relationships among components of work values. Based on data collected from 2280 respondents in eight countries the hypotheses were tested by means of Guttman's Smallest Space Analysis. The results support the hypotheses. An empirical double-ordered conceptual system, a radex structure, was obtained in each of the samples reflecting the facets of the definition: modality of outcome — cognitive, affective and instrumental, and system - performance contingency — reward, resource. In terms of the issue of cultural differences the results indicate the presence of cultural differences in the rating of a limited number of specific values. These differences are only minor variations within a much broader pattern of structural similarity. The fact that essentially the same structure was obtained in eight independent samples lends substantial support to the definitional framework of work values suggested.     

WATER PROBLEMS AND DEVELOPMENTS OF THE PAST1

Present-day climatic conditions of the Earth were reached between 5,000 and 8,000 years ago. These are essentially the conditions under which the earliest civilizations arose. Ancient basic water problems were the same as those of today, and remarkable technologies for coping with these problems were developed. Few water technologies, except for water treatment, are modern creations. Dry farming began about 8000 B.C. Irrigation began about 5000 B.C. and became extensive by about 3500 B.C., principally in Mesopotamia, the Nile Valley of Egypt, and the Indus Valley of Pakistan. Ancient irrigators developed ingenious structures for obtaining groundwater without the use of wells or sweeps. One device, the Khanat (a kind of infiltration gallery), is still widely used in the Mediterranean area, southwest Asia and China. The khanat was invented during the First Millenium B.C. Ancient peoples also learned to collect surface runoff in areas of scanty precipitation and to use it for local groundwater recharge. The water was recovered from dug wells and used for domestic supply and stock watering. Damming of rivers began at least by the early part of the First Millenium B.C. in the Arabian Peninsula. Most early dams were for irrigation but some were also for city water supply. Many canals in various areas served the dual purposes of water supply and navigation. Soil and water salinity have been persistent problems throughout the history of irrigation and we still have not solved these problems. Irrigation practices were developed independently in the New World but much later than in the Old. North American Indians in some areas still follow the ancient practices. The chinampa system, still used in Mexico, is one of the most intensive methods of farming ever devised. Ancient peoples in the Old World also developed ingenious methods for conserving and increasing soil moisture and for retarding runoff and erosion. During the time of classical Greece and imperial Rome practical water engineering developed to a high degree. Water tunnels, aqueducts, canals, drainage ditches, and dams become commonplace. Even so, water supply and management came relatively late in Europe, where dependence had been largely on natural supply and distribution until the 19th Century.     

Factors associated with fatal accident involvement among California drivers

The primary objectives of this study were to examine characteristics of drivers involved in fatal accidents and to determine if those drivers could be distinguished from California's general driving population on the basis of prior driving record. A sample of drivers involved in 1970–1971 fatal accidents was analyzed and compared to a sample of drivers from the general driving population during the same time period. Drivers who had been drinking prior to the accident, who were considered at-fault for the accident, or whose accident occurred at night were found to have worse prior driving records than other fatal accident-involved drivers. The results also indicated that, as a whole, drivers involved in fatal accidents had worse violation and/or accident records, as well as different demographic and license characteristics than drivers in the general population. The classification functions derived to predict fatal accidents, however, did not differ greatly from regression equations that have been constructed to predict total accidents. It was therefore concluded that prediction systems keyed to total accidents will, to a large extent, also identify high-risk fatal accident drivers.     

Environmental performance optimization using process water integration and Sustainable Process Index

Water integration studies have focused on reducing the amount of water used by a process on the assumption that environmental impact is reduced through efficient water reuse. However, the environmental impact of retrofitting the water network through the installation of pumps and pipes and energy for their utilization which may even lead to a network with a higher environmental cost as measured using a more comprehensive metric, is rarely, if at all, considered. Using the Sustainable Process Index (SPI) as a means of measuring environmental impact, this study addresses the question on water integration and environmental impact and shows that there is a balance that must be struck between water savings and water network modifications.     

The Missoula Valley semivolatile and volatile organic compound study: seasonal average concentrations

The city of Missoula is located in a high mountain valley (elevation 3200 ft.) in western Montana and contains one of the largest populations in the entire Rocky Mountain Region completely enclosed by mountains. During the 2000/2001 Missoula Valley Sampling Program, ambient levels of 61 semivolatile organic compounds (SVOCs) and 54 volatile organic compounds (VOCs) were originally quantified before refining the analytical program to 28 of the most prominent SVOCs and VOCs found in the Missoula Valley airshed. These compounds were measured over 24-hr periods at two locations throughout an entire year. This study provides the first, comprehensive appraisal of the levels of SVOCs and VOCs measured simultaneously throughout all four seasons at two locations in the Missoula Valley, including those levels measured during the 2000 Montana wildfire season. Generally, SVOC levels were comparable between both sides of the Missoula Valley. However, there were nearly double the amount of VOCs measured at the more urban Boyd Park site compared with the rural Frenchtown sampling site, a result of the greater number of automobiles on the eastern side of the Valley. SVOCs and VOCs were measured at their highest levels of the sampling program during the winter. Forest fire smoke samples collected during the summer of 2000 showed significant increases in SVOC phenolic compounds, including phenol, 2-methylphenol, 4-methylphenol, and 2,4-dimethylphenol. Although there were modest increases in some of the other SVOCs and VOCs measured during the fire season, none of the increases were as dramatic as the phenolics.     

Application of satellite remote-sensing data for source analysis of fine particulate matter transport events

Satellite sensors have provided new datasets for monitoring regional and urban air quality. Satellite sensors provide comprehensive geospatial information on air quality with both qualitative imagery and quantitative data, such as aerosol optical depth. Yet there has been limited application of these new datasets in the study of air pollutant sources relevant to public policy. One promising approach to more directly link satellite sensor data to air quality policy is to integrate satellite sensor data with air quality parameters and models. This paper presents a visualization technique to integrate satellite sensor data, ground-based data, and back trajectory analysis relevant to a new rule concerning the transport of particulate matter across state boundaries. Overlaying satellite aerosol optical depth data and back trajectories in the days leading up to a known fine particulate matter with an aerodynamic diameter of <2.5 microm (PM2.5) event may indicate whether transport or local sources appear to be most responsible for high PM2.5 levels in a certain location at a certain time. Events in five cities in the United States are presented as case studies. This type of analysis can be used to help understand the source locations of pollutants during specific events and to support regulatory compliance decisions in cases of long distance transport.