A prototype expert system for fishway design

The design of structures for fish passage in rivers and streams provides an opportunity to apply expert system concepts to a design problem. Fishways contribute to the sustainable development of water resources projects by providing a path that allows fish migrations to be maintained. A prototype expert system (FDES) has been developed to recommend the most suitable fishway type for given design conditions. A recommendation is provided on the basis of fishway hydraulics, fish passage performance, and cost requirements. Fishway design demands expertise in various scientific disciplines such as hydrology, hydraulics, and fish biology. Expert system technology may be used to reduce design time requirements and to serve as a teaching aid to inexperienced engineers by organizing and accessing the cumulative knowledge of the most experienced designers. The rule-based expert system development tool, VP-Expert, supplies the backward chaining control structure for accessing the knowledge within the prototype.     

Application of a Sediment Quality Index to the Lower Laurentian Great Lakes

A sediment quality index (SQI) was developed using an equation incorporating three elements; scope--the % of variables that did not meet guidelines; area frequency--the % of failed tests divided by the total number of tests in a group of sites; and amplitude - the magnitude by which failed variables exceeded guidelines. The SQI calculation produces a numerical score with a maximum value of 100 representing the highest sediment quality. A modified SQI was also developed using only the scope and amplitude elements, which computed a score per site with no grouping. The SQI was applied to assessment of sediment quality in Lakes Erie and Ontario using Canadian Federal and Ontario Provincial guidelines for 34 compounds, Spatial trends in sediment quality in both lakes reflected overall trends for most individual contaminant classes, including mercury and polychlorinated biphenyls. In Lake Erie, there was a trend toward lower SQI values from the eastern basin to the western basin, and from the northern area to the southern area of the central basin. Sediment quality in the eastern basin and the northern area of the central basin was classified as excellent (>95); sediments in other areas of Lake Erie ranged from fair to good. In Lake Ontario, the poorest sediment quality was associated with the three major depositional basins; sediment quality among the three basins was quite consistent. The SQI values based on all three elements (scope, frequency and amplitude) for the Niagara basin. Mississauga Basin and Rochester Basin were 67 (fair), 65 (fair) and 70 (fair), respectively. Comparison of SQI values for all lower lake basins showed generally poorer sediment quality in Lake Ontario, compared to Lake Erie.     

Saturated and Unsaturated Water Flow in Inclined Porous Media

This paper considers the two-dimensional saturated and unsaturated flow of water through inclined porous media, namely a waste dump or hill slope. Since the partial differential equation governing this water flow transforms from being parabolic to elliptic as the water flow varies from unsaturated to saturated, an iterative, finite differencing scheme is used to develop a numerical solution. The model can be used to investigate the effects that hill slope angle, depth of soil cover and hilltop width have on water accumulation in the dump and the time required for saturation to occur at different areas in the dump domain. The accuracy and reliability of the computer based solution is tested for two different boundary conditions – (1) no flow on all boundaries (i.e., the internal redistribution of soil moisture to steady state) and (2) a constant rainfall flux on the dump surface. Numerical studies then show the effects of changing the hill slope angle, depth of layer, and dump geometry on the flow characteristics in the dump.     

Book reviews

The Economics of Art and Culture: An American Perspective

James Heilbrun & Charles M. Gray

New York, Cambridge University Press, 1993, 378 pp., £14.95 pb

Building Cities that Work

Edmund Fowler

Montreal & Kingston, McGill‐Queen's University Press, 1992, 315 pp.

Interactive Decision Making: The Graph Model for Conflict Resolution

Liping Fang, Keith W. Hipel & D. Marc Kilgour

New York, Wiley, 1993, 221 pp., £49.50

The Politics of Nature: Explorations in Green Political Theory

Andrew Dobson & Paul Lucardie (Eds)

London, Routledge, 1993, 240 pp. + xv, £37.50

Urban Transport in Asia: An Operational Agenda for the 1990s, World Bank

Technical Paper No. 224

Peter Midgley

Washington, DC, The World Bank, 1994, 98 pp.

Landscape Ecology: Theory and Application, 2nd edition

Zev Naveh & Arthur Lieberman

New York, Springer‐Verlag, £34.50     

What are the implications of sea-level rise for a 1.5, 2 and 3 °C rise in global mean temperatures in the Ganges-Brahmaputra-Meghna and other vulnerable deltas?

Even if climate change mitigation is successful, sea levels will keep rising. With subsidence, relative sea-level rise represents a long-term threat to low-lying deltas. A large part of coastal Bangladesh was analysed using the Delta Dynamic Integrated Emulator Model to determine changes in flood depth, area and population affected given sea-level rise equivalent to global mean temperature rises of 1.5, 2.0 and 3.0 °C with respect to pre-industrial for three ensemble members of a modified A1B scenario. Annual climate variability today (with approximately 1.0 °C of warming) is potentially more important, in terms of coastal impacts, than an additional 0.5 °C warming. In coastal Bangladesh, the average depth of flooding in protected areas is projected to double to between 0.07 and 0.09 m when temperatures are projected at 3.0 °C compared with 1.5 °C. In unprotected areas, the depth of flooding is projected to increase by approximately 50% to 0.21–0.27 m, whilst the average area inundated increases 2.5 times (from 5 to 13% of the region) in the same temperature frame. The greatest area of land flooded is projected in the central and north-east regions. In contrast, lower flood depths, less land area flooded and fewer people are projected in the poldered west of the region. Over multi-centennial timescales, climate change mitigation and controlled sedimentation to maintain relative delta height are key to a delta’s survival. With slow rates of sea-level rise, adaptation remains possible, but further support is required. Monitoring of sea-level rise and subsidence in deltas is recommended, together with improved datasets of elevation.

     

The legacy of lead pollution: (dis)trust in science and the debate over Superfund

Lead contamination is a significant health hazard in communities around the world, but this environmental toxin often remains unknown to residents living near hazardous sites. This research investigates a unique case where residents were informed of lead contamination but rejected official and scientific narratives regarding environmental risks. The case study involves a decommissioned smelter in Colorado. Drawing from data collected over three years, the researchers examine how officials and experts communicated the severity of environmental health hazards. Despite these efforts, residents opposed the Environmental Protection Agency’s attempts to place the site on the National Priorities List for federal cleanup. The government’s framing of science and environmental risk failed to resonate with homeowners, despite the known and significant scientific evidence confirming environmental health hazards, and residents’ perceptions of lead contamination were mitigated by material concerns, including property values and community stigma. Implications for future research on lead contamination, environmental risk, and trust in science are discussed.     

The Role of Biological Indicators in a State Water Quality Management Process

State water quality agencies are custodians of water quality management programs under the Clean Water Act of which the protection and restoration of biological integrity in surface waters is an integral goal. However, an inappropriate reliance on chemical/physical stressor and exposure data or administrative indicators in place of the direct measurement of ecological response has led to an incomplete foundation for water resource management. As point sources have declined in significance, the consequences of this flawed foundation for dealing with the major limitations to biological integrity (nonpoint sources, habitat degradation) have become more apparent. The use of biocriteria in Ohio, for example, resulted in the identification of 50% more impairment than a water chemistry approach alone and other inconsistencies of a flawed monitoring foundation are illustrated in the national 305(b) report statistics on waters monitored, aquatic life use attainment, and habitat degradation. Biological criteria (biocriteria) incorporates the broader concept of water resource integrity to supplement the roles of chemical and toxicological approaches and reduces the likelihood of making overly optimistic estimates of aquatic life condition. A carefully conceived ambient monitoring approach comprised of biological, chemical, and physical measures ensures all relevant stressors to water resource integrity are identified and that the efficacy of administrative actions can be directly measured with environmental results. New multimetric indices, such as the IBI, ICI, and BIBI represent a significant advancement in aquatic resource characterization that have allowed the inclusion of biological information into many States water quality management programs. Ohio adopted numerical biocriteria in the Ohio water quality standards regulations in May 1990 and, through multiple aquatic life uses that reflect a continuum of biological condition, represents a tiered approach to water resource management. Biocriteria provide the impetus and opportunity to recognize and account for natural, ecological variability in the environment, something which previously was been lacking in state water quality management programs. The upper Great Miami River in Ohio illustrates a case study where bioassessment data documented the efficacy of efforts to permit, fund, and construct municipal treatment systems in restoring aquatic life. In contrast, in the Mahoning River similar administrative actions were inadequate to restore aquatic life in an environment with severe sediment contamination and impacts from combined sewer overflows. A biocriteria-based goal of restoring 75% of aquatic life uses by the year 2000 in Ohio has led to the use of biological data to identify trends and forecast the status and the causes and sources of impairment to Ohio streams, an effort that should affect the strategic focus of our water resource management efforts. A biocriteria-based approach has profoundly influenced strategic planning and priority setting, water quality based permitting, water quality standards, basic monitoring and reporting, nonpoint source assessment, and problem discovery within Ohio EPA.     

Incorporating Habitat Mapping into Practical Koala Conservation on Private Lands

Abstract: Identifying and conserving faunal habitat on private lands has been conducted largely on a site-by-site basis as development proposals arise. We sought to map koala habitat at a scale suitable for use by a local planning authority so that habitat remnants could be protected and managed while remaining in private ownership. At this scale, the level of detail and accuracy needed by local planners required a new approach to mapping koala habitat. Two independent techniques, community and field surveys, were employed. We mailed a survey to every household in Coffs Harbour shire. Respondents told of 3309 koala sightings. We conducted a field survey, a plot-based scat (  fecal pellet) search, to determine which vegetation types and tree species were preferred by koalas. We surveyed 119 sites, which contained 42 different vegetation types. Of these, 37 (31%) had been used by koalas. The outcomes of the community and field surveys were combined to produce a distribution map of koala habitat. The most striking outcome has been the use of our results by the local government authority, Coffs Harbour City Council: planners have incorporated the koala habitat map into their local environmental plan. Our procedure offers a rigorous, repeatable, and publicly accessible method for identifying and mapping important habitat for the purposes of land-use planning, an essential procedure for conserving habitat outside the reserve system.     

Assessing Water Quality Improvement Schemes: The Multi-Attribute Technique of the UK's Environment Agency

The Environment Agency for England and Wales is required to take account of likely costs and benefits in carrying out its duties. Given the complex nature of environmental problems, this task requires sensitivity to issues such as uncertainty, multiple objectives and conflicting value systems. This paper describes a multi-attribute methodology used to carry out this duty in one area of the Agency's work, the regulation of the water industry. The method includes nine attributes measuring the benefits from water quality improvement schemes, and one attribute measuring scheme costs. It is a workable method that clearly satisfies the requirements for the Environment Agency to take account of the costs and benefits of its actions. Refinements are suggested to improve the individual attribute scores, the weights used in prioritisation and the incorporation of costs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Assessment of temporal variations of water quality in inland water bodies using atmospheric corrected satellite remotely sensed image data

The spatial distribution of silicate, ammonium, nitrate, nitrite, phosphate, chlorophyll a and dissolved oxygen in Obidos lagoon was obtained by surveying five sites in eight campaigns, between October 2004 and October 2006. A confined inner branch of the lagoon showed higher availability of ammonium (1.2-81 micromol l(-1)), phosphate (1.9-17 micromol l(-1)), silicate (0.85-86 micromol l(-1)) and chlorophyll a (0.30-18 microg l(-1)) than other sites (0.47-25 micromol l(-1), 0.10-3.9 micromol l(-1), 0.47-25 micromol l(-1), 0.25-11 microg l(-1), respectively). According to several trophic classification tools, that branch is considered eutrophic to polytrophic, emphasising its deteriorated conditions, while the rest of the lagoon is of better quality. In autumn/winter nutrients were inversely correlated to salinity (r > 0.93) reflecting the freshwater inputs enriched in nitrogen and phosphorous compounds to the inner branch. In warmer periods, dissolved oxygen concentrations dropped during the night, and sediments of the branch become an important source of ammonium and phosphate. The low DIN:P ratio (median = 10) obtained in the branch, which suggests an excess of phosphate, that increased in warmer periods and changed the limiting nutrient in the entire lagoon. These results emphasize the spatial heterogeneity of water quality in Obidos lagoon, its seasonal variability, and the importance of recognising these distributions before defining homogenous water body on the scope of Water Framework Directive.