Using Ecological Risk Assessment to Identify the Major Anthropogenic Stressor in the Waquoit Bay Watershed,Cape Cod,Massachusetts

The Waquoit Bay Watershed ecological risk assessment was performed by an interdisciplinary and interagency workgroup. This paper focuses on the steps taken to formulate the analysis plan for this watershed assessment. The workgroup initially conducted a series of meetings with the general public and local and state managers to determine environmental management objectives for the watershed. The workgroup then decided that more information was needed on the impacts of six stressors: nutrient enrichment, physical alteration of habitat, altered freshwater flow, toxic chemicals, pathogens, and fisheries harvesting. Assessment endpoints were selected to establish the link between environmental management objectives, impacts of stressors, and scientifically measurable endpoints. The following assessment endpoints were selected: estuarine eelgrass cover, scallop abundance, finfish diversity and abundance, wetland bird distribution and abundance, piping plover distribution and abundance, tissue contaminant levels, and brook trout distribution and abundance in streams. A conceptual model was developed to show the pathways between human activities, stressors, and ecological effects. The workgroup analyzed comparative risks, by first ranking stressors in terms of their potential risk to biotic resources in the watershed. Then stressors were evaluated by considering the components of stressors (e.g., the stressor chemical pollution included both heavy metals and chlorinated solvents components) in terms of intensity and extensiveness. The workgroup identified nutrient enrichment as the major stressor. Nutrient enrichment comprised both phosphorus enrichment in freshwater ponds and nitrogen enrichment within estuaries. Because phosphorus impacts were being analyzed and mitigated by the Air Force Center for Environmental Excellence, this assessment focused on nitrogen. The process followed to identify the predominant stressor and focus the analyses on nitrogen impacts on eelgrass and scallops will serve as an example of how to increase the use of the findings of a watershed assessment in decision making.     

A river might run through it again: criteria for consideration of dam removal and interim lessons from California

Resource managers are increasingly being challenged by stakeholder groups to consider dam removal as a policy option and as a tool for watershed management. As more dam owners face high maintenance costs, and rivers as spawning grounds for anadromous fish become increasingly valuable, dam removal may provide the greatest net benefit to society. This article reviews the impact of Endangered Species Act listings for anadromous fish and recent shifts in the Federal Energy Regulatory Commission's hydropower benefit-costs analysis and discusses their implications for dam removal in California. We propose evaluative criteria for consideration of dam removal and apply them to two case studies: the Daguerre and Englebright Dams on the Yuba River and the Scott and Van Horne Dams on the South Eel River, California.     

Making Collaborative Watershed Management Work: The Confluence of State and Regional Initiatives

Initiatives in the Neponset, Ipswich, and Sudbury-Assabet-Concord watersheds highlight how watershed-scale innovation in engaging nongovernment participants is influenced, but not dominated, by the statewide program, the Massachusetts Watershed Initiative. The presence or absence of three elements—external support, process, and issue—and the order in which they occur, shape the viability of collaborative watershed-scale management initiatives. External support includes providing personnel or funding from outside an initiative. Process is the interaction among individuals undertaking watershed-wide policy development and/or implementation. An issue is an attention-requiring concern, vital to a watershed, that can most effectively be addressed by a coordinated strategy among different parties. A process generated by an issue is sustainable and amenable to enhancement through external support. The contribution of external support is most apparent when outside assistance is provided after an issue has crystallized into clear problem needs that can be addressed through specific research projects or implementation activities. Process is central in shaping issues, utilizing external support, and generating management results. The outcomes of voluntary processes in the three watershed initiatives highlight how the evolution of the Massachusetts Watershed Initiative leads to, and depends upon, the development of watershed-scale initiatives.     

Habitat Assessment of Non-Wadeable Rivers in Michigan

Habitat evaluation of wadeable streams based on accepted protocols provides a rapid and widely used adjunct to biological assessment. However, little effort has been devoted to habitat evaluation in non-wadeable rivers, where it is likely that protocols will differ and field logistics will be more challenging. We developed and tested a non-wadeable habitat index (NWHI) for rivers of Michigan, where non-wadeable rivers were defined as those of order ≥5, drainage area ≥1600 km², mainstem lengths ≥100 km, and mean annual discharge ≥15 m³/s. This identified 22 candidate rivers that ranged in length from 103 to 825 km and in drainage area from 1620 to 16,860 km². We measured 171 individual habitat variables over 2-km reaches at 35 locations on 14 rivers during 2000–2002, where mean wetted width was found to range from 32 to 185 m and mean thalweg depth from 0.8 to 8.3 m. We used correlation and principal components analysis to reduce the number of variables, and examined the spatial pattern of retained variables to exclude any that appeared to reflect spatial location rather than reach condition, resulting in 12 variables to be considered in the habitat index. The proposed NWHI included seven variables: riparian width, large woody debris, aquatic vegetation, bottom deposition, bank stability, thalweg substrate, and off-channel habitat. These variables were included because of their statistical association with independently derived measures of human disturbance in the riparian zone and the catchment, and because they are considered important in other habitat protocols or to the ecology of large rivers. Five variables were excluded because they were primarily related to river size rather than anthropogenic disturbance. This index correlated strongly with indices of disturbance based on the riparian (adjusted R² = 0.62) and the catchment (adjusted R² = 0.50), and distinguished the 35 river reaches into the categories of poor (2), fair (19), good (13), and excellent (1). Habitat variables retained in the NWHI differ from several used in wadeable streams, and place greater emphasis on known characteristic features of larger rivers.     

Utilization of environmental knowledge for watershed management in Northern Michigan

The Northern Michigan Environmental Research Program was conducted by the University of Michigan's Biological Station and Institute for Social Research to obtain information about the aquatic and human resources of water-rich, resort-oriented northern lower Michigan. Results of the study were directed toward long-term environmental management. Multiple methods were used to communicate study results, including self-contained information briefs, regular contacts and seminars with community leaders and public officials, and mass media. Selected illustrations of project data applied to environmental management problems are cited, e.g., curtailment of nutrient loadings, wetlands protection, improved effectiveness of riparian organizations, and highway planning. A series of shortLakeland Reports, designed to present factual information, general environmental principles, and action implications to a lay audience, proved to be effective. However, it became apparent that environmental decisions were not strongly affected by reports alone. Instead, several mutually reinforcing channels of communication must be employed to develop a climate of receptiveness and understanding to insure environmentally sound decisions.     

GENERATION OF HOURLY RAINFALL1

ABSTRACT: A rainfall model was developed to divide daily rainfall into storms and distribute storm depths over storm duration for input into the Stanford Watershed Model.     

Stream corridor management in the Pacific Northwest: I. Determination of stream-corridor widths

King County, Washington is a part of the rapidly growing Pacific Northwest region. This growth has placed pressure on stream corridors. Past studies about regional stream corridors provide a rich source of information for environmental planners and managers. This article draws on existing literature and case studies to provide guidelines for determining optimal stream corridor widths in a watershed located in King County, Washington.     

图们江流域生态环境研究态势分析

利用文献计量学方法,基于维普数据库的检索结果,定量分析国内发表的图们江流域生态环境相关研究论文的主题、作者、机构及时间等信息,结合定性研究内容,分析图们江流域生态环境的研究态势和现有的数据表明:图们江流域生态环境研究较薄弱,发展较缓慢,研究热点是水质水环境和流域生态等,相关研究的资金、人力、与机构投入不足。     

用于流域管理的河流水生态系统健康评价初探

对生态健康、河流生态系统健康概念进行了简要的总结,回顾了国内外河流生态系统健康评价的方法,提出了现阶段河流生态系统健康评价的不足及今后应该进一步研究的内容,并提出了河流生态系统健康评价在流域科学管理中的作用。     

滇池流域TN、TP入湖负荷预报预警系统

以流域模型HSPF和贝叶斯递归回归树算法(BRRT)为计算模块,建立了滇池流域27条主要入湖河流和33个散流区的TN、TP入湖负荷预报预警系统.同时,构建了考虑历史排放规律和预测负荷计算预警指数(EWI)评价预警等级的两套预警体系.结果表明:BRRT替代模型在流域内以农业面源为主的柴河子流域校准和验证的可决系数R2均大于0.8,模拟结果相对可靠;根据预警时间选取预警体系;适用于6月份之前的预警体系一(EWS-1),利用现状排放量和历史排放量的关系计算预警指数.适用于6月份之后的预警体系二(EWS-2),主要考虑现状排放量、历史平均排放量、排放限值和预测排放量之间的关系计算3个预警指数,最终以最严格的作为综合预警指数EWI评价预警等级;根据柴河子流域"十二五"规划的TN和TP排放限值为130.2 t·a-1、6.8 t·a-1,应用此系统对2011年2、4、9和11月做出预警检验,各月份预警结果基本处于红色和黑色预警,该系统可为流域提供预警支持.