Projecting Cumulative Benefits of Multiple River Restoration Projects: An Example from the Sacramento-San Joaquin River System in California

Despite increasingly large investments, the potential ecological effects of river restoration programs are still small compared to the degree of human alterations to physical and ecological function. Thus, it is rarely possible to “restore” pre-disturbance conditions; rather restoration programs (even large, well-funded ones) will nearly always involve multiple small projects, each of which can make some modest change to selected ecosystem processes and habitats. At present, such projects are typically selected based on their attributes as individual projects (e.g., consistency with programmatic goals of the funders, scientific soundness, and acceptance by local communities), and ease of implementation. Projects are rarely prioritized (at least explicitly) based on how they will cumulatively affect ecosystem function over coming decades. Such projections require an understanding of the form of the restoration response curve, or at least that we assume some plausible relations and estimate cumulative effects based thereon. Drawing on our experience with the CALFED Bay-Delta Ecosystem Restoration Program in California, we consider potential cumulative system-wide benefits of a restoration activity extensively implemented in the region: isolating/filling abandoned floodplain gravel pits captured by rivers to reduce predation of outmigrating juvenile salmon by exotic warmwater species inhabiting the pits. We present a simple spreadsheet model to show how different assumptions about gravel pit bathymetry and predator behavior would affect the cumulative benefits of multiple pit-filling and isolation projects, and how these insights could help managers prioritize which pits to fill.     

Book reviews

Planning in the Public Domain: From Knowledge to Action

John Friedmann. Princeton University Press, 1987, 501pp.

New Communities for Urban Squatters: Lessons from the Plan that Failed in Dhaka, Bangladesh

Charles L. Choguill, Plenum Press, New York 1987, pp. 213.

Models of Urban and Regional Systems in Developing Countries

George Chadwick, Oxford, Pergamon Press, 1987, xv +320pp.

Price: £17.50.     

Direct-push geochemical profiling for assessment of inorganic chemical heterogeneity in aquifers

Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO(3), Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors.     

Contaminated land clean-up using composted wastes and impacts of VOCs on land

This paper describes experiments that demonstrate the effects and potential for remediation of a former steelworks site in Wales polluted with polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Under field conditions, PAH-contaminated soil was composted in-vessel, with or without organic feedstocks, receiving forced aeration for 80 days followed by 4 months maturation. Treatments compared PAH removal in contaminated soil to contaminated soil mixed with three different organic waste mixes after composting and after composts were spread to land. After composting, PAH concentrations declined in all treatments, by up to 38%. Sixteen months after the composts were landspread and vegetation was established, only those containing contaminated soil with organic additions exhibited further PAH removal, by up to 29%. Composting resulted in a decline in the relative concentration of small PAHs, whereas the landspreading-vegetation phase saw a decline in the relative concentration of medium PAHs in two of the three composts exhibiting PAH removal. Under controlled glasshouse conditions, vegetated soil columns of differing depths were exposed to VOCs from beneath. VOC vapour affected both shoot and root growth and soil microbial activity; effects varied with distance from the VOC source. This work demonstrated that on-site remediation of aged PAH-contaminated land can be successfully initiated by in-vessel co-composting followed by land spreading and vegetation, within a practical timeframe.     

Remediation of metal polluted mine soil with compost: co-composting versus incorporation

Trace element contamination of post-industrial sites represents a major environmental problem and sustainable management options for remediating them are required. This study compared two strategies for immobilizing trace elements (Cu, Pb, Zn, and As) in mine spoil: (1) co-composting contaminated soil with organic wastes and (2) conventional incorporation of mature compost into contaminated soil. Sequential chemical extraction of the soil was performed to determine temporal changes in trace element fractionation and bioavailability during composting and plant growth. We show that mine spoil can be co-composted successfully and this action causes significant shifts in metal availability. However, co-composting did not lead to significant differences in metal partitioning in soil or in plant metal uptake compared with simply mixing mine spoil with mature compost. Both treatments promoted plant growth and reduced metal accumulation in plants. We conclude that co-composting provides little additional benefit for remediating trace-element-polluted soil compared with incorporation of compost.     

Developing Environmentally Respectful Policy Programmes: Five Key Principles

In contemporary governance situations, varying, but often similar, ecological, economic, cultural and social challenges are experienced by differing stakeholder groups in a variety of policy sectors. To meet such challenges requires attention both to policy agendas and to policy processes, the ways in which policy is developed. This paper sets out some principles for policy making that can help to meet these challenges while acknowledging the inevitable limits to policy success. Such principles have particular pertinence in relation to environmental issues that often suffer from being divorced from mainstream institutional structures and often lack policy communities with a specific remit to champion their concern. The authors suggest that to maximize success and minimize failure, policy processes must be deliberative rather than solely technocratic and should attempt as far as possible to: articulate their message clearly; frame activity in the policy sector and as far as possible help guide strategies and programmes in other relevant sectors; help co-ordinate policy interventions through links to other policy communities operating across differing spatial scales; be legitimized through working with a broad range of stakeholder groups; and mobilize stakeholders toward implementing programme goals.     

Place attachment and place identity: First-year undergraduates making the transition from home to university

This paper examines the issues emanating from the transition into a new social and cultural environment distant from the home, the context of which is provided by the transition from home to university. The study analyses the transitional process over a period of 5 months, using data obtained from in-depth semi-structured interviews and participant observation of ten first-year undergraduates who moved to study at the University of Gloucestershire in Cheltenham. It explores the mediating variables that impact place attachment and place identity during the transition from home to university. Within this context consideration is given to how participants made sense of changes in their socio-spatial environment, the ensuing problems and challenges of doing so, and how these meanings affected self-perceptions and self-evaluations. The analysis demonstrates how participant's stories of the transition evince an abiding concern with the loss of place, manifest in terms of an erosion of a sense of belonging, attachment and continuity and an undermining of home's capacity to symbolise the self. The implications of such accounts for our understanding of place attachment and identity are then explored. The paper concludes by advocating a holistic approach to our conceptualisation of place, given that place meanings are constantly being evaluated and redefined in light of changing social and physical relationships with place and between people and place.     

Vulnerability of Fraser River sockeye salmon to climate change: A life cycle perspective using expert judgments

Fraser River sockeye salmon have been the basis for a major commercial fishery shared by Canada and the United States, and an important cultural foundation for many aboriginal groups; they are also of huge ecological significance throughout the Fraser Basin. The potential for altered aquatic habitat and temperature regimes due to climate change is an important concern for Fraser River sockeye salmon. This paper characterizes the vulnerability of Fraser River sockeye salmon to future climate change using an approach that is novel on three counts. First, previous efforts to assess the vulnerability of salmon to climate change have largely focused on only part of the life cycle, whereas we consider climate vulnerability at all stages in the life cycle. Second, we use the available scientific literature to provide a basis for structuring and eliciting judgments from fisheries science and management experts who research and manage these systems. Third, we consider prospects for mitigating the effects of climate change on sockeye salmon. Tests showed that participants’ judgments differentiated in statistically significant ways among questions that varied in terms of life stages, spawning regions and climate scenarios. The consensus among participants was that Fraser River sockeye are most vulnerable to climate change during the egg and returning adult stages of the life cycle. A high temperature scenario was seen as imposing the greatest risk on sockeye stocks, particularly those that migrate to the upper reaches of the Fraser River system and spawn earlier in the summer. The inability to alter water temperature and the highly constrained nature of sockeye management, with competing gear types and sequential fisheries over a long distance, suggest the potential to mitigate adverse effects is limited. Fraser River sockeye already demonstrate a great deal of adaptive capacity in utilizing heterogeneous habitats in different river sub-basins. This adaptability points to the potential value of policies to make stocks more resilient to uncertain futures.