The term ''urban stream syndrome'' describes the consistently observed ecological degra- dation of streams draining urban land. This paper reviews recent literature to describe symptoms of the syndrome, explores mechanisms driving the syndrome, and identifies appropriate goals and methods for ecological restoration of urban streams. Symptoms of the urban stream syndrome include a flashier hy- drograph, elevated concentrations of nutrients and contaminants, altered channel morphology, and reduced biotic richness, with increased dominance of tolerant species. More research is needed before generaliza- tions can be made about urban effects on stream ecosystem processes, but reduced nutrient uptake has been consistently reported. The mechanisms driving the syndrome are complex and interactive, but most impacts can be ascribed to a few major large-scale sources, primarily urban stormwater runoff delivered to streams by hydraulically efficient drainage systems. Other stressors, such as combined or sanitary sewer overflows, wastewater treatment plant effluents, and legacy pollutants (long-lived pollutants from earlier land uses) can obscure the effects of stormwater runoff. Most research on urban impacts to streams has concentrated on correlations between instream ecological metrics and total catchment imperviousness. Recent research shows that some of the variance in such relationships can be explained by the distance between the stream reach and urban land, or by the hydraulic efficiency of stormwater drainage. The mech- anisms behind such patterns require experimentation at the catchment scale to identify the best management approaches to conservation and restoration of streams in urban catchments. Remediation of stormwater impacts is most likely to be achieved through widespread application of innovative approaches to drainage design. Because humans dominate urban ecosystems, research on urban stream ecology will require a broadening of stream ecological research to integrate with social, behavioral, and economic research.

https://www.jstor.org/stable/10.1899/04-028.1

The urban stream syndrome: current knowledge and the search for a cure

This section is composed of three basic subareas: combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), and stormwater discharges. Much of the literature cited came from documents covering noteworthy global conferences (Bathala, 1996; Engineering Foundation, 1996; Hallam et al., 1996; Maxwell et al., 1996; Sieker and Verworn [Eds.], 1996; Society of Environmental Toxicology and Chemistry, 1996; U.S. EPA 1996a; Water Environment Federation, 1996a,b,c). In addition, the U.S. Environmental Protection Agency (U.S. EPA) published guidance documents (U.S. EPA, 1996,c,d,e), which are discussed in more detail in the subsection Regulatory Policies and Financial Aspects.

https://www.jstor.org/stable/pdfplus/29763265.pdf

Urban wet-weather flows

U.S. Environmental Protection Agency developed a decision-support system, System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN), to evaluate alternative plans for stormwater quality management and flow abatement techniques in urban and developing areas. SUSTAIN provides a public domain tool capable of evaluating the optimal location, type, and cost of stormwater best management practices (BMPs) needed to meet water quality and quantity goals. It is a tool designed to provide critically needed support to watershed practitioners in evaluating stormwater management options based on effectiveness and cost to meet their existing program needs. SUSTAIN is intended for users who have a fundamental understanding of watershed and BMP modeling processes. How SUSTAIN is setup described here using a case study, conducted by actual data from an existing urban watershed. The developed SUSTAIN model was calibrated by observed rainfall and flow data, representing the existing conditions. The SUSTAIN model developed two BMP cost-effectiveness curves for flow volume and pollutant load reductions. A sensitivity analysis was also conducted by varying important BMP implementation specifications.

A watershed-scale design optimization model for stormwater best management practices

The role of agency in overcoming path dependence and enabling sustainability transitions is receiving increasing attention. Currently lacking are more empirically derived explanations of the co-evolutionary dynamics between actors and institutional change that could potentially provide guidance on facilitating such transitions into the future. This paper investigates these dynamics through a longitudinal case analysis of Melbourne's transition to improved stormwater quality treatment. The complex data collection, analysis and validation approach, which included oral histories, semi-structured interviews, industry workshops and documentary analysis, examined the nuances of the actor-related strategies and institutional enabling processes throughout the different phases of the transition over the last fifty years. The results revealed the importance of a small group of loosely connected frontrunners from across government, private, community and scientific sectors who, through a mix of creating and disrupting institutional strategies, managed to facilitate a growing and diverse actor-network that steered this transition over decades. The establishment of networked bridging organisations was also instrumental because they formed different types of networks and alliances over time for protecting and deepening the reach of the transition dynamics across the city. The findings suggest there is no single cause–effect relationship nor one dominant intervention or action that shifted the urban stormwater management regime. Rather, it showed that the co-evolutionary processes between the broader transitional dynamics were played into by frontrunners and their actor-networks in such a way that emerging new narratives diffused, giving meaning to the evolving scientific agendas and on-the-ground experiments, which led to new institutional structures and enabling administrative tools. It seems as though each one of these dimensions is as crucial as the other in explaining the outcomes of this successful sustainability transition.

Actors working the institutions in sustainability transitions: The case of Melbourne's stormwater management

It is now well established that the traditional practice of urban stormwater management contributes to the degradation of receiving waterways, and this practice was more recently critiqued for facilitating the wastage of a valuable water resource. However, despite significant advances in alternative "integrated urban stormwater management" techniques and processes over the last 20 years, wide-scale implementation has been limited. This problem is indicative of broader institutional impediments that are beyond current concerns of strengthening technological and planning process expertise. Presented here is an analysis of the institutionalization of urban stormwater management across Sydney with the objective of scoping institutional impediments to more sustainable management approaches. The analysis reveals that the inertia with the public administration of urban stormwater inherently privileges and perpetuates traditional stormwater management practices at implementation. This inertia is characterized by historically entrained forms of technocratic institutional power and expertise, values and leadership, and structure and jurisdiction posing significant impediments to change and the realization of integrated urban stormwater management. These insights strongly point to the need for institutional change specifically directed at fostering horizontal integration of the various functions of the existing administrative regime. This would need to be underpinned with capacity-building interventions targeted at enabling a learning culture that values integration and participatory decision making. These insights also provide guideposts for assessing the institutional and capacity development needs for improving urban water management practices in other contexts.

Impediments to Integrated Urban Stormwater Management: The Need for Institutional Reform

In the 1990's, a number of best management practices (BMPs) manuals have been developed that address the control of urban runoff to protect receiving water quality. More recently, several papers have investigated the effectiveness of these BMPs in protecting small urban watercourses, and have concluded that they do not. Investigations of both design practices and effectiveness reveals that there is a lot of ignorance in the scientific and engineering community about what constitutes a properly designed BMP and what it really achieves, with respect to environmental protection. This paper discusses the state-of-practice in BMP design in the United States and points out its strengths and weaknesses with respect to real protection of the downstream receiving water environment. The paper recommends an approach to design criteria development that can be applied over a wide variety of climatologic, topologic, and geologic conditions to protect receiving waters systems.

Robert W. Brashear

Papers

Are Best-Management-Practice Criteria Really Environmentally Friendly?

Are BMP Criteria Really Environmentally Friendly