Integrated assessment: Missing link in the acid rain debate?

The United States is finding it difficult to develop a coherent policy on acid rain. Despite more than a decade of scientific research and policy initiatives, no clear course of action has been identified. This article argues that what is missing is an integrated assessment of the scientific knowledge that will guide the political process. The role of the integrated assessment is described, and a conceptual framework presented that would accomplish the desired goal. Currently available acid rain assessment models are compared against this framework and found to be less than satisfactory. The article concludes by stressing the opportunity now available to the National Acid Precipitation Assessment Program to perform such an assessment and break the logjam.     

A new look at the old problem of eutrophication management in southern Africa

Summary This paper contrasts the traditional engineering approach to eutrophication management with a proposed systems approach. Legislative, social, economic and technical aspects of eutrophication are identified. Through the use of some recent case studies, the importance of the socioeconomic factors relative to the legal-technical aspects of eutrophication management is highlighted. Whilst the latter retain their vital role in eutrophication control programmes, this paper suggests that the former cannot be ignored, and recommends adoption of a systems approach to the management of eutrophication.Dr Jeffrey A. Thornton and Guy Boddington are Senior Planning Professionals in the Environmental Planning Section of the Town Planning Branch, City Planner's Department, Cape Town, with practical interests in water quality management and integrated environmental management in the African urban environment. Dr Thornton is a registered professional ecologist and editor of the research journal,Journal of the Limnological Society of Southern Africa.     

LOW-HEAD HYDROPOWER IMPACTS ON STREAM DISSOLVED OXYGEN1

ABSTRACT: A method to evaluate the effect of hydropower development on downstream dissolved oxygen (DO) is presented for a low head dam. Water, previously aerated during release over spillways and under gates, is diverted through the hydropower facility without further aeration. The oxygen transfer that occurs as a result of air entrainment at the various release points of a dam is measured. Oxygen transfer efficiencies are calculated and incorporated into an oxygen transfer model to predict average release DO concentrations. This model is used to systematically determine the effect of hydropower operation on downstream DO. Operational alternatives are investigated and a simple operational guide is developed to mitigate the effects of hydropower operation. Combinations of reduced generation and optimal releases from the dam allow the hydropower facility to operate within DO standards.     

CONFLICT ANALYSIS OF THE SHOAL LAKE SUBDWISION1

ABSTRACT: The techniques of conflict analysis derived from game theory were applied to the Shoal Lake water supply conflict in southeastern Manitoba, Canada. The issue of conflict is the desire of an Indian Band in the area to build cottage lots near the intake for water supply for the City of Winnipeg. The City of Winnipeg contends that such a development would seriously affect the quality of water supplied to the City, thereby increasing its treatment costs significantly. The four major players defined for the conflict are the City of Winnipeg, Indian Band No. 40, the Province of Manitoba, and the Federal Department of Indian and Northern Affairs. The results of the conflict analysis suggest that the introduction of the provincial and federal government into the conifict will not assist significantly in its resolution and that further progress on the resolution is unlikely until the results of Federal Environment Assessment Review office hearing become available.     

Motorcycle conspicuity: An evaluation and synthesis of influential factors

Motorcycles are overrepresented in fatal motor vehicle accidents: The death rate for motorcycle riders of about 35 per 100,000,000 miles of travel compares with an overall vehicle death rate of 2.57 per 100,000,000 miles. In the attempt to reduce the frequency of automobile-motorcycle collisions, numerous studies have manipulated motorcycle and motorcyclist characteristics to enhance conspicuity. In this paper, we give a review of studies that examined the effectiveness of these measures. Subsequently, we take a critical look at the methods used in these studies to evaluate the effectiveness of conspicuity treatments. Furthermore, we identify factors yet to be considered in the empirical research in this area that may contribute to collisions with motorcycles. These include information-processing failures at the identification and decision stage, as well as more or less permanent factors potentially responsible for different information-processing failures. Transient factors related to the failure to detect motorcycles might include alcohol, fatigue/lack of sleep, inattention, and information overload, whereas more permanent factors might include “cognitive” conspicuity and fi eld dependence.     

Low energy comsumption management of agricultural residues

In this paper, a mechanical filtering system to treat pig slurry is proposed. The filter was made from the aerobic decomposition product of the organic fraction of municipal wastes and wheat straw was used as the support.Using a pilot plant to treat 2100 liters of swine slurry, an adequate reduction in BOD₅; COD, and other parameters was obtained. The organic matter content of the material trapped in the filter was similar to that of compost and farmyard manure, but the nitrogen and phosphorous levels and the C/N ratio were more similar to farmyard manure. After passing through a filtering system, the treated liquid can be used for fertirrigation and as a feed for algae ponds. After a period of stabilization, the solid material can be mixed to produce manure. Although wheat straw was used as the support in this experiment, other agricultural wastes such as rice straw, corn stalks, millet stems, banana, cotton, and coconut trash can be used. Rather than municipal solid waste compost, other kinds of compost obtained from agricultural wastes such as leaves, bark, husks, etc., can be used as the filter.     

Development and use of site-specific chemical and biological criteria for assessing New Bedford Harbor pilot dredging project

Numerical site-specific chemical and biological criteria were established to assess the impact of a pilot dredging project on water quality at the New Bedford Harbor, Massachusetts, USA, Superfund site. Because most existing chemical concentrations in the water column and indigenous biota exceeded federal and state water quality limits, the derivation of site-specific criteria was required. Prior to any operational phases of the project (i.e., dike construction, dredging), criteria values were developed from background concentrations of PCBs and metals in water and biota, as well as for the toxic effects of water quality on the biota. During each operational phase of the project, water samples were collected, analyzed within 16 h, and the data supplied to a management committee in order to assess the environmental impact of the previous days' operation. The ambient unfiltered water concentration of PCBs and metals were the only chemical or biological criteria exceeded. Modification of the next days' operations resulted in a return of these concentrations to background levels. The combined use of site-specific criteria and a real-time decision making management process allowed for successful completion of this project with a minimal effect on water quality.