128 research outputs found

    TB208: Biological Water Quality Standards to Achieve Biological Condition Goals in Maine Rivers and Streams: Science and Policy

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    This publication describes the philosophy, history, methodology, and management applications of numeric biological criteria in water quality standards in Maine. The presentation describes the decision-making process used by the Maine Department of Environmental Protection (MDEP) for assessing attainment of aquatic life uses in water quality standards using benthic macroinvertebrates in Maine streams and rivers including eight case studies of management applications and the improved environmental outcomes that have resulted. The MDEP, University of Maine, and business and nonprofit stakeholders participated in the development and testing of Maine’s numeric biological criteria. This publication further discusses the broader relevance of numeric biological criteria in water quality management at both the state and federal levels and considers parallels and differences between Maine’s biological criteria and other biological assessment methods in the United States and the European Union.https://digitalcommons.library.umaine.edu/aes_techbulletin/1205/thumbnail.jp

    Assessing Uncertainty Associated with Groundwater and Watershed Problems Using Fuzzy Mathematics and Generalized Regression Neural Networks

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    When trying to represent an environmental process using mathematical models, uncertainty is an integral part of numerical representation. Physically-based parameters are required by such models in order to forecast or make predictions. Typically, when the uncertainty inherent in models is addressed, only aleatory uncertainty (irreducible uncertainty) is considered. This type of uncertainty is amenable to analysis using probability theory. However, uncertainty due to lack of knowledge about the system, or epistemic uncertainty, should also be considered. Fuzzy set theory and fuzzy measure theory are tools that can be used to better assess epistemic, as well as aleatory, uncertainty in the mathematical representation of the environment. In this work, four applications of fuzzy mathematics and generalized regression neural networks (GRNN) are presented. In the first, Dempster-Shafer theory (DST) is used to account for uncertainty that surrounds permeability measurements and is typically lost in data analysis. The theory is used to combine multiple sources of subjective information from two expert hydrologists and is applied to three different data collection techniques: drill-stem, core, and pump-test analysis. In the second, a modification is made to the fuzzy least-squares regression model and is used to account for uncertainty involved in using the Cooper-Jacob method to determine transmissivity and the storage coefficient. A third application, involves the development of a GRNN to allow for the use of fuzzy numbers. A small example using stream geomorphic condition assessments conducted in the state of Vermont is provided. Ultimately, this fuzzy GRNN will be used to better understand the relationship between the geomorphic and habitat conditions of stream reaches and their corresponding biological health. Finally, an application of the GRNN algorithm to explore links between physical stream geomorphic and habitat conditions and biological health of stream reaches is provided. The GRNN proves useful; however, physical and biological data collected concurrently is needed to enhance accuracy

    Monitoring and assessment of macroinvertebrate communities in support of river management in northern Vietnam

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    The thesis aimed to develop a water quality biological monitoring and assessment based on macro-invertebrates to analyse the status of watercourses and to select sustainable restoration measures in order to support river. The research was carried in the Du river basin in northern Vietnam. Spatial and temporal analysis showed that macro-invertebrate community compositions in the Du river were not only driven by morphological characteristics but also by water quality issues. A relatively small temporal variation was detected that requires no remarkable modifications in the development of a bio-assessment methodology for watercourses in the specific river. Multivariate analyses using CCA and Bray-Curtis cluster analysis provided a similar discrimination between pristine and impacted sites in the Du river basin. Qualitative biotic indices including the BMWP-Viet proved to be appropriate for use in the studied watercourses in Vietnam. The BMWP-Viet could differentiate study sites into classes ranging from very good to very poor ecological conditions. The current BMWP-Viet approach can be useful at an early stage of bio-assessment application in Vietnam. However, this method should be improved by optimising the scoring system for common taxa and development of more robust assessment approaches such as multi-metric indices. Data mining techniques including classification trees and support vector machines were applied to develop predictive models for BMWP-Viet as well as presence/absence of macro-invertebrate taxa (ecological indicators). Optimised models indicate the major environmental variables influencing the presence/absence of macro-invertebrates, which in the mean time also reflect the river characteristics that river managers have to consider in their policy plans. A decision support system, the WFD-Explorer was combined with classification trees to link human activities with the ecological river conditions and analyse the relevance of several restoration options

    Water quality and ecological assessment of natural wetlands in Southwest Ethiopia

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    A Primer for Monitoring Water Funds

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    This document is intended to assist people working on Water Funds to understand their information needs and become familiar with the strengths and weaknesses of various monitoring approaches. This primer is not intended to make people monitoring experts, but rather to help them become familiar with and conversant in the major issues so they can communicate effectively with experts to design a scientifically defensible monitoring program.The document highlights the critical information needs common to Water Fund projects and summarizes issues and steps to address in developing a Water Fund monitoring program. It explains key concepts and challenges; suggests monitoring parameters and an array of sampling designs to consider as a starting-point; and provides suggestions for further reading, links to helpful resources,and an annotated bibliography of studies on the impacts that result from activities commonly implemented in Water Fund projects

    The Definition and Choice of Environmental Commodities for Nonmarket Valuation

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    Economic analyses of nature must somehow define the “environmental commodities” to which values are attached. This paper articulates a set of principles to guide the choice and interpretation of nonmarket commodities. We describe how complex natural systems can be decomposed consistent with what can be called “ecological production theory.” Ecological production theory--like conventional production theory--distinguishes between biophysical inputs, process, and outputs. We argue that a systems approach to the decomposition and presentation of natural commodities can inform and possibly improve the validity of nonmarket environmental valuation studies. We raise concerns about the interpretation, usefulness, and accuracy of benefit estimates derived without reference to ecological production theory.nonmarket valuation, stated preference, revealed preference, commodities, endpoints

    Regional distribution and significance of stream turbidity in Victoria

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    This thesis investigates the distribution and significance of stream turbidity in Victoria; specifically exploring the factors that may have influenced the pattern of regional variation in turbidity, and factors that give it significance in the regional, social, cultural and environmental context. The limits to water availability are set, not only by the quantity of water in storages or streams but, more fundamentally, by acceptable levels of water quality and catchment health. To make effective judgements of water availability managers of water resources need to know the significance of measured natural resource condition in the regional context. Stream turbidity can be considered by the agricultural community as a sign of soil erosion and a loss of agricultural potential, while from the ecological perspective it can be considered a sign of deteriorating river health. Fundamentally, levels of turbidity are closely bound with land use practice and, in the Australian context, turbidity can be considered a measure of the consequences of land management practices on soil erosion and run-off. Measured levels of turbidity in Victoria should be interpreted within the context of a unique history and geography. The spread of European colonisation and the introduction of massive land use change to the Victorian landscape have meant that over most of Victoria current levels of turbidity reflect the effects of over a hundred and fifty years of large scale intervention with its controlling factors. In Victoria current levels of turbidity are interpreted in a cultural context far different from that of early colonists or even of a few decades ago. The concept of Ecologically Sustainable Development which has dominated natural resource management in recent times brings new responsibilities to resource managers. Ecologically sustainable management means that resources must be considered in a more inclusive spatial and temporal context. In the early stage of Victoria's history sustainable management of water meant having enough water left from winter rains to supplement summer supply. However, in recent years, it has begun to have more complex associations; sustainable water use is now, almost universally considered to include maintenance of the environmental health of waterways, and by implication, the environmental health of the whole catchment. In this context, stream turbidity can be considered a useful indicator of catchment health, in particular, because levels of turbidity bear a direct physical relationship to catchment processes. New tools are needed to explore the relationship between land use and water quality at the regional scale. The results of this current research include a regional statistical model of stream turbidity, which is conceptually designed to offer useful predictions of stream turbidity and underpin sustainable resource management. The statistical model was used as input to the development of a unique map display using Geographic Information Systems (GIS). The GIS is used to display the distribution of model predictions over a large region of south-eastern Australia. The practical advantage of this modelling approach is that it provides managers with the ability to identify locations in Victoria where measured water quality differs significantly from modelled water quality and flag them for further investigation. The major project outputs are a map of Victorian Water Quality Monitoring Network (VWQMN) catchments showing catchments in Victoria where measured turbidity differs from model predictions and a raster representation of the state of Victoria in which cell values indicate predicted stream turbidity. Important to this project was the novel use of GIS technology to process large national and regional scale digital data sets using tools developed for catchment scale hydrological models

    Weight of evidence to assess sediment quality

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    Estuaries are perhaps the most threatened environments in the coastal fringe; the coincidence of high natural value and attractiveness for human use has led to conflicts between conservation and development. These conflicts occur in the Sado Estuary since its location is near the industrialised zone of Peninsula of SetĂșbal and at the same time, a great part of the Estuary is classified as a Natural Reserve due to its high biodiversity. These facts led us to the need of implementing a model of environmental management and quality assessment, based on methodologies that enable the assessment of the Sado Estuary quality and evaluation of the human pressures in the estuary. These methodologies are based on indicators that can better depict the state of the environment and not necessarily all that could be measured or analysed. Sediments have always been considered as an important temporary source of some compounds or a sink for other type of materials or an interface where a great diversity of biogeochemical transformations occur. For all this they are of great importance in the formulation of coastal management system. Many authors have been using sediments to monitor aquatic contamination, showing great advantages when compared to the sampling of the traditional water column. The main objective of this thesis was to develop an estuary environmental management framework applied to Sado Estuary using the DPSIR Model (EMMSado), including data collection, data processing and data analysis. The support infrastructure of EMMSado were a set of spatially contiguous and homogeneous regions of sediment structure (management units). The environmental quality of the estuary was assessed through the sediment quality assessment and integrated in a preliminary stage with the human pressure for development. Besides the earlier explained advantages, studying the quality of the estuary mainly based on the indicators and indexes of the sediment compartment also turns this methodology easier, faster and human and financial resource saving. These are essential factors to an efficient environmental management of coastal areas. Data management, visualization, processing and analysis was obtained through the combined use of indicators and indices, sampling optimization techniques, Geographical Information Systems, remote sensing, statistics for spatial data, Global Positioning Systems and best expert judgments. As a global conclusion, from the nineteen management units delineated and analyzed three showed no ecological risk (18.5 % of the study area). The areas of more concern (5.6 % of the study area) are located in the North Channel and are under strong human pressure mainly due to industrial activities. These areas have also low hydrodynamics and are, thus associated with high levels of deposition. In particular the areas near Lisnave and Eurominas industries can also accumulate the contamination coming from Águas de Moura Channel, since particles coming from that channel can settle down in that area due to residual flow. In these areas the contaminants of concern, from those analyzed, are the heavy metals and metalloids (Cd, Cu, Zn and As exceeded the PEL guidelines) and the pesticides BHC isomers, heptachlor, isodrin, DDT and metabolits, endosulfan and endrin. In the remain management units (76 % of the study area) there is a moderate impact potential of occurrence of adverse ecological effects and in some of these areas no stress agents could be identified. This emphasizes the need for further research, since unmeasured chemicals may be causing or contributing to these adverse effects. Special attention must be taken to the units with moderate impact potential of occurrence of adverse ecological effects, located inside the natural reserve. Non-point source pollution coming from agriculture and aquaculture activities also seem to contribute with important pollution load into the estuary entering from Águas de Moura Channel. This pressure is expressed in a moderate impact potential for ecological risk existent in the areas near the entrance of this Channel. Pressures may also came from AlcĂĄcer Channel although they were not quantified in this study. The management framework presented here, including all the methodological tools may be applied and tested in other estuarine ecosystems, which will also allow a comparison between estuarine ecosystems in other parts of the globe
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