Developing a decision support tool for life-cycle cost assessments

Recent years have seen advancements in the development and use of life-cycle assessment (LCA) analytic techniques. Although these techniques have highlighted the power of LCA to identify the environmental consequences of a product system through its entire life cycle, they have also highlighted a major shortcoming of LCA—the lack of cost information. Because companies make daily decisions that involve trade-offs between economics and the environment, including cost information in LCA is critical for advancing its use as an overall environmental decision-making tool. This article outlines the current state of LCA methodology development, defines key life-cycle cost assessment terms and concepts, and evaluates existing cost assessment techniques with the objective of building an integrated life-cycle cost assessment tool.     

Information as a management tool: An evaluation of the Pemigewasset Wilderness management plan

The newly instituted management plan for the Pemigewasset Wilderness area of New Hampshire, USA, which relies principally on providing information to visitors, represents a departure from traditional plans. Logit analysis of survey data indicates limited evidence of the plan having much direct impact on visitor behavior. There is evidence of success in information dissemination to area users; however, the type of information that is being relayed to backcountry users does not appear to be that which the management plan is attempting to promote.     

Finding local answers to fuelwood problems

This paper presents an analytical approach to the identification of characteristic fuel-wood situations in developing countries. This approach recognizes the tension between achieving a level of generalization needed for policy formulaion and the need to capture the specifics of fuelwood production and use at a local level. A typology, based on environmental and socioeconomic criteria, is advanced which is intended to form the basis of a refining of policy principles to the specifics of different localities. A series of brief case studies is presented to illustrate the characteristics of different types of locality, and conclusions of the future direction of fuelwood policy are advanced.     

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.     

Techniques for rapidly evaluating the progress of in-situ remediation

Although standard methods of monitoring the progress of in-situ remediation may provide general results for the most permeable zones affected by soil vapor extraction or bioventing, they are essentially unsuccessful at providing information on the degree of heterogeneity within the remediation zone and on the existence of “hot spots.” Data are presented that suggest that monitoring the concentrations of fixed and biogenic gases and measuring soil permeability on a small-scale basis may circumvent the common problems associated with assessing the progress of in-situ remediation. The costs of these monitoring techniques are minor compared to those of designing and operating an in-situ remediation system, and may save additional time and costs by identifying problem areas early in the cleanup process.