The environmental audit. II. Application to stream network design

The planning and execution of water quality management programs requires careful collection and analysis of data coupled with a systematic review and analysis of programmatic success. The environmental audit is a tool which facilitates improved water quality planning and management. This article demonstrates the utility of the environmental audit by reviewing portions of a comprehensive review of the water quality management program for the state of Idaho. The audit is a tool which forces careful design of a sampling program before data are collected. In the audit approach, program objectives are clearly stated prior to initiation of sampling. Stated objectives are also evaluated regularly to identify tension points, that is, conflicts between expectations and reality. In the example taken from Idaho, a management review team followed a directive to redesign the water quality monitoring program. We present a summary of the redesign as proposed by that team, to illustrate the results of a typical review of monitoring programs. That summary is followed by an example of how the proposed program would differ if the audit approach had been used. The two approaches offered both coincident and conflicting recommendations. Management review team and audit recommendations for lake sampling programs were similar even though a different process was used to develop the recommendations. The most striking contrast between the two results lies in the review team's approach to the problem. The directives followed, and the team's responses, concentrate on tools, such as increasing biological monitoring or reliance on monthly BWMP stations. In contrast, the audit results stress addressing management questions for which clear objectives have been stated, depending on specific tools only as needed to meet stated objectives. Although the audit does integrate externalities in its structure, it is little affected by economic or political influences. A major strength of the audit approach is its ability to provide defensible data for management decision making.     

A conceptual model and empirical analysis of children's acquisition of spatial knowledge

How adults and children come to understand, represent and behave within their spatial environment are topics of great interest to geographers, psychologists, environmental planners and laypeople. Considerable research and theory has been published on these and related topics. In this paper, we will review some of what is known and theorized about spatial cognition and then consider elements of our research program on the acquisition of spatial knowledge. We focus on two intimately related topics. The first is the development of a conceptual model of the knowledge structures and processes associated with acquiring, representing and accessing knowledge of a given environment. The conceptual model forms the basis for a formal computational process model intended as a simulation of actual knowledge and performance in way finding tasks. The second emphasis is an in-depth case study of the acquisition of spatial knowledge. The case study focuses on a single child acquiring knowledge of a lengthy route through an unfamiliar suburban neighborhood. It is presented as an empirical test of certain assumptions embodied within the conceptual model.Before introducing the conceptual model and the case study, we first review the state of current theory and data on spatial cognition and identify four central issues confronting researchers in this field. This review provides a necessary context for describing and evaluating our program of research. The second section of this paper discusses elements of the conceptual model and its relationship to other formal computational models. The third section considers specific hypotheses about the acquisition and representation of spatial knowledge and tests of these hypotheses from the single in-depth case study. The final discussion section of this paper is a reconsideration of the four issues raised in the first section and necessary and proposed extensions of the current research.     

RISK OF EXTREME EVENTS IN A MULTIOBJECTIVE FRAMEWORK1

ABSTRACT: This paper summarizes advances made in risk-based decisionmaking in water resources through use of the partitioned multiobjective risk method (PMRM). (Risk is a measure of the probability and severity of adverse effects.) In the PMRM, the risk of extreme events is differentiated from risk involving less extreme damage severity and is evaluated within a multiobjective framework. Study of the extreme-event risk function f₄(*) has addressed the following issues: methods for calculating f₄(*); the sensitivity of f₄(*) to various parameters, particularly to the partitioning point of the extreme-event range and the selection of probability density functions; insight provided by the statistics of extremes; and the impact of f₄(*) on risk management, for example, in the application of the PMRM to water resources problems. In particular, this paper shares with the reader recent research results on the PMRM, the relationship between the statistics of extremes and the conditional expected value, derived formulas for f₄(*), distribution-free estimates of f₄(*), documented case studies in dam safety, and future research directions.     

APPLICATION OF THE GREEN-AMPT INFILTRATION EQUATION TO WATERSHED MODELING1

ABSTRACT: A computer model was developed, based on the Green-Ampt infiltration equation, to computed rainfall excess for a single precipitation event. The model requires an estimate of parameters related to hydraulic conductivity, wetting front section, and fillable porosity of the soil layers. Values of parameters were estimated from soil textural averages or regression equations based on percent sand, percent clay, and porosity. Average values of effective porosity and wetting front suction were largely acceptable due to the relatively low variability and low model sensitivity to the parameters. Hydraulic conductivity was the most erratic constituent of the loss rate computation due to the high variability and the high sensitivity of the computed infiltration to the parameter. The performance of the Green-Ampt infiltration model was tested through a comparison with the SCS curve number procedure. Seven watersheds and 23 storms with precipitation of one inch or greater were used in the comparison. For storms with less than one inch of rainfall excess, the SCS curve number procedure generally gave the best results; however, for six of the seven storms with precipitation excess greater than one inch, the Green-Ampt procedure delivered better results. In this comparison, both procedures used the same initial abstractions. The separation of rainfall losses into infiltration, interception, and surface retention is, in theory, an accurate method of estimating precipitation excess. In the second phase of the study using nine watersheds and 39 storms, interception and surface retention losses were computed by the Horton equations. Green-Ampt and interception parameters were estimated from value sin the literature, while the surface retention parameter was calibrated so that the computed runoff volumes matched observed volumes. A relationship was found between the surface retention storage capacity and the 15-day antecedent precipitation index, month of year, and precipitation amount.     

Process hazards review applied to the use of anhydrous ammonia in agriculture: an example of chemical process safety for small business

Process hazards review (PHR) techniques have generally been applied by large, sophisticated companies in the nuclear, aerospace, and chemical process industries. There remains, however, a large population of smaller distributors and consumers of hazardous materials which could benefit equally from the application of PHR. These consumers unfortunately are generally less sophisticated and individually lack the necessary resources required to apply such state-of-the-art safety techniques.

Where common processes can be identified, it is possible to conduct a more generic PHR that will provide a sound technical basis for recognizing and preventing the development of hazards wherever these processes are used. Some facility-specific issues will always need to be considered, but the existence of the generic PHR should make the conduct of a PHR by each facility considerably easier and less costly.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) contracted with DNV Technica Inc. to lead a hazard and operability study (HAZOP) of agricultural handling of anhydrous ammonia, from the receipt of ammonia at the retail distribution centre to the application of the ammonia by farmers to the fields. The multidisciplinary HAZOP team consisted of representatives from NIOSH, an agricultural chemical trade association, an ammonia producer, state ammonia facility inspectors, a retail distributor, and an equipment manufacturer. Several participants were part-time farmers with ammonia application experience.

Some specific aspects of applying the HAZOP technique in the context of this study, the findings obtained, and the plans to disseminate the important safety information developed during the course of the PHR are discussed. Finally, it is suggested that this approach could prove to be a useful addition to the product stewardship activities of chemical producers.     

Mineral development prospects of the Indochina area

Reform is under way in several nations within the Indochina area to stimulate economic growth and foreign investment. Though once forbidden, participation by foreign companies in mining exploration and development activities in Myanmar, Kampuchea, Laos, Thailand and Vietnam is now being solicited by the respective governments. This paper presents a preliminary evaluation of mineral and energy resources in the region and outlines possible development scenarios based on economic policies, financial and infrastructural constraints and industry interest. The investment climates for resource-related projects are assessed qualitatively by country. Clearly, the long-term development potential of mineral and energy resources in the Indochina area is large, and the potential gains outweigh any of today's problems.     

Risk-taking, warning labels, training, and regulation: Are they associated with the use of helmets by all-terrain vehicle riders?

Training programs and warning labels have been advocated as a means of convincing consumers to follow safety precautions when using all-terrain vehicles (ATVs), and are emphasized in the recent consent decree signed between the Consumer Product Safety Commission and ATV manufacturers. An alternative approach is to mandate safe behavior through regulations and law. This field study of ATV operator behavior conducted in six states in 1988 and 1989 provides initial insight into the effectiveness of these approaches. Logit analysis revealed that helmet use was significantly higher when required by law or when riders had 3 or more years of riding experience. Helmet use was significantly lower when riders rode frequently, when helmets were perceived as uncomfortable or not used on motorcycles, and when subjects had been moderately or seriously injured in ATV accidents. The presence of warning labels, reading of a manual, and participation in a training course were not significantly related to helmet use.