Goals and remedial strategies for water quality and wildlife management in a coastal lagoon--a case-study of Ringkøbing Fjord, Denmark

The aim of this work is (1) to discuss approaches and tools to set management goals using operational indicators for coastal management (i.e., indicators that are easy to measure, understand and predict) and validated predictive models and (2) to discuss remedial strategies for sustainable coastal management regarding water quality and the abundance of fish, waterfowl and large aquatic plants. These approaches are exemplified using data from Ringkøbing Fjord, Denmark, which has undergone two major regime shifts during the last decades. This work discusses the changes taken place during the period from 1980 to 2004 (when there are good empirical data). For Ringkøbing Fjord, which is a very shallow, well-oxygenated lagoon dominated by resuspension processes, we have targeted on the following operational indicators, which are meant to reflect seasonal median values for the entire defined coastal area (the ecosystem scale) and not conditions at individual sites or data from shorter time periods: Secchi depth (as a standard measure of water clarity) and chlorophyll-a concentrations (as a key measure of algal biomass). The operational indicators are regulated by a set of standard abiotic factors, such as salinity, suspended particulate matter (SPM), nutrient concentrations (N and P), coastal morphometry and water exchange. Such relationships are quantified using well-tested, general quantitative models, which illustrate how these indicators are interrelated and how they reflect fundamental aspects of coastal ecosystems. We demonstrate that the regime shift in the lagoon can be modelled and quantitatively explained and is related to changes in salinity and nutrient inflow. A very important threshold is linked to increased salinities in the lagoon. For example, when the mean annual salinity is higher than about 9.5‰, large numbers of saltwater species of clams can survive and influence the structure and function of the ecosystem in profound ways. The model also illustrates the dynamic response to changes in nutrient loading. We have presented several management strategies with the goal of keeping the Secchi depth at 2 m, which would stimulate the growth of higher aquatic plants, which are fundamental for fish production and bird abundance in the lagoon. Given the fact that the Secchi depth depends on many variable factors (temperature, TP-inflow from land, salinity, changes in biomasses of macrophytes and clams, which are accounted for in these simulations), our results indicate that in practice it will likely be very difficult to reach that goal. However, it would be realistic to maintain a Secchi depth of 1.5 m if the variability in salinity is minimized and the mean salinity is kept at about 10.2‰.     

Identifying rainfall effects in an arid Gulf of California coastal lagoon

At Ensenada de La Paz, a coastal lagoon on the western side of the Gulf of California, nutrient and salinity data before and after rain events were evaluated using a mass balance model to estimate the exchange of conservative and non-conservative variables with the adjacent sea. Surface salinity, nitrogen (N-NO3, N-NO2), and phosphorus (PO4) were used in the model to obtain the hydraulic balance, water residence time, and nitrogen and phosphorus fluxes. Results showed that residual volume was mainly influenced by evaporation. Rainfall and runoff increased the mixed volume and reduced water residence time. Pre-rainfall hydraulic balance conditions were reestablished about 10 days after a rain storm. Rainwater inputs also modified the quality of the coastal lagoon: the pre-rainfall scenario showed that more nitrogen is consumed than produced, and there is a phosphorus sufficiency. A rain disturbance induces a nitrogen and phosphorus increase. Eleven days after a rain storm, nitrogen and phosphorus levels did not return to the pre-rainfall scenario. Rain disturbances in arid zone coastal lagoons modify their water quality and exchange with the adjacent ocean; some management strategies are suggested.     

The influence of metal source uncertainty on cost-effective allocation of mine water pollution abatement in catchments

In mine water pollution abatement, it is commonly assumed that known mine waste sites are the major pollution sources, thus neglecting the possibility of significant contribution from other old and diffuse sources within a catchment. We investigate the influence of different types of pollution source uncertainty on cost-effective allocation of abatement measures for mine water pollution. A catchment-scale cost-minimization model is developed and applied to the catchment of the river Dalälven, Sweden, in order to exemplify important effects of such source uncertainty. Results indicate that, if the pollution distribution between point and diffuse sources is partly unknown, downstream abatement measures, such as constructed wetlands, at given compliance boundaries are often cost-effective. If downstream abatement measures are not practically feasible, the pollution source distribution between point and diffuse mine water sources is critical for cost-effective solutions to abatement measure allocation in catchments. In contrast, cost-effective solutions are relatively insensitive to uncertainty in total pollutant discharge from mine water sources.     

Farmers' Choices: Management Practices to Reduce Nutrient Leakage within a Swedish Catchment

This paper analyses farmers' strategies on management practices for the reduction of nutrient releases, within a Swedish catchment. The main objective of the European Union water framework directive is to obtain good ecological water quality, and the approach is specifically stipulated to be catchment-based. Eutrophication is generally stated as the main environmental problem in water management and agricultural production is the major cause of nutrient leakage. The analysis concentrates on current agricultural management practices to reduce nutrient leakage. Farmers are beginning to experience a new awareness about nutrient use and see manure as a resource instead of a waste product. Further, those factors that are decisive for decision making are investigated, including information sources. The farm economy, the level of ecological knowledge and regulations illustrate the main obstacles linked to decision making. Professional magazines and informal discussions are considered the most esteemed information sources. Farmers' disposition to change, and co-operation, are also discussed, both of which are of vital importance for the development of new official administrative procedures.     

Multicriteria analysis of environmental quality in Taipei: public preferences and improvement strategies

The public preferences for environmental quality should be a primary consideration of planners and decision-makers in environmental systems planning. In the first stage of multicriteria analysis, a multi-attribute evaluation model for determining public preferences is formulated. The environmental indices are defined for a comparison of environmental quality in different metropolitan districts. The public preferences of the environmental quality in Taipei are obtained using the weighted average rating method. The results indicate air quality and noise pollution as main public concern. In the second stage of multicriteria analysis, strategies are proposed to improve the air quality, and criteria are established. The experts evaluated all alternative strategies according to the criteria. The alternatives are ranked applying the compromise ranking method.     

Sustainable Water Quality Management Framework and a Strategy Planning System for a River Basin

In Taiwan, the authorities have spent years working on remedying polluted rivers. Generally, the remediation planning works are divided into two phases. During the first phase, the allowed pollution discharge quantity and abatement quantity of each drainage zone, including the assimilative capacity, are generated based on the total river basin. In the second phase, the abatement action plans for each pollution source in each drainage zone are respectively devised by the related organizations based on the strategies generated during the first phase. However, the effectiveness of linking the two phases is usually poor. Highly integrated performances are not always achieved because the separate two-phase method does not take system and management thinking into consideration in the planning stage. This study pioneers the use of the Managing for Results (MFR) method in planning strategies and action plans for river water quality management. A sustainable management framework is proposed based on the concept and method of MFR, Management Thinking, and System Analysis. The framework, consisting of planning, implementation, and controlling stages, systematically considers the relationships and interactions among four factors: environment, society, economy, and institution, based on the principles of sustainable development. Based on the framework, the Modified Bounded Implicit Enumeration algorithm, which is used as a solving method, is combined with Visual Basic software and MS Excel to develop a computer system for strategy planning. The Shetzu River, located in northern Taiwan, is applied as a case study. According to the theoretical, practical, and regulatory considerations, the result-oriented objectives are defined to first improve the pollution length of the Shetzu River in specific remediation periods to finally meet regulated water quality standards. The objectives are then addressed as some of the constraints for the strategy planning model. The model objective is to pursue the maximum assimilative capacity (environmental phase) subjected to the constraints of water quality standards (institutional phase), social equity (social phase), and proper available technology (economic phase). The pollution quantity abatement and allocation, which are named the top strategies, of each drainage zone for different scenarios can be obtained based on each water quality standard. The middle as well as lower strategies and action plans, which consist of pollution quantity abatement and allocation of each class (domestic, industrial, livestock, and non-point pollution sources) and their individual pollution sources in each drainage zone, are then generated based on the top strategies. The performance indicators and measure plans are proposed based on the action plans to promote the comprehensive effectiveness of river water quality management. The authorities have begun to develop a budget based on the strategies and action plans developed in this study. The analytical results indicate that the objectives, strategies, and action plans developed based on the sustainable management framework and strategy planning system can effectively help the related authorities to fulfill the tasks of water quality management for a river basin.     

Recovery of Fish Communities in a Warm Water Stream Following Pollution Abatement

The long-term recovery process for fish communities in a warm water stream in East Tennessee was studied using quantitative measurements over 20 years. The stream receives effluents from a U. S. Department of Energy (DOE) facility, but since 1985 these effluents have been greatly reduced, eliminated, or diluted as part of a substantial long-term pollution abatement program. The resulting changes in water quantity and quality led to a recovery of the fish communities, evidenced by significant changes in species richness, abundance (density and biomass), and community composition (e.g., number of fish species sensitive to stress). The fish community changes occurred over a spatial gradient (downstream from the headwater release zone nearest the DOE facility) and temporally, at multiple sampling locations in the stream. Changes in measured parameters were associated with specific remedial actions and the intervening steps within the recovery process are discussed with regard to changes in treatment processes.     

Water quality and restoration in a coastal subdivision stormwater pond

Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants in stormwater ponds can lead to a number of water quality problems including high nutrient, chemical contaminant, and bacterial levels. This study examined the interaction between land use and coastal pond water quality in a South Carolina residential subdivision pond. Eutrophic levels of chlorophyll and phosphorus were present in all seasons. Harmful cyanobacterial blooms were prevalent during the summer months. Microcystin toxin and fecal coliform bacteria levels were measured that exceeded health and safety standards. Low concentrations of herbicides (atrazine and 2,4-D) were also detected during summer months. Drainage from the stormwater pond may transport contaminants into the adjacent tidal creek and estuary. A survey of residents within the pond's watershed indicated poor pet waste management and frequent use of fertilizers and pesticides as possible contamination sources. Educational and outreach activities were provided to community members to create an awareness of the water quality conditions in the pond. Pond management strategies were then recommended, and selected mitigation actions were implemented. Water quality problems identified in this study have been observed in other coastal stormwater ponds of varying size and salinity, leading this project to serve as a potential model for coastal stormwater pond management.     

MATHEMATICAL MODELING OF GULF COAST ESTUARIES1

The environmental pollution problems prevalent in gulf coast estuaries are a cause of great concern to those in water quality management. This paper outlines the dominant characteristics which affect the properties of these estuaries including geography, tide and current effects, wind effects, salinity and density regime, nature and level of waste discharge, low inflow levels, dredging effects and present quality levels. Two basic levels of analytical modeling which are useful in water quality management are presented. The first is a relatively crude completely mixed estuarine model which permits economical evaluation of varying parameters. The second is a very general steady state model which permits analysis of stratified systems. The ESTPOL computer language designed to simplify the use of the steady state model is described. The practical use of the analytical models as management tools for the solution of Texas Estuarine quality problems is demonstrated.     

Integrating economic and biophysical data in assessing cost-effectiveness of buffer strip placement

The European Union Water Framework Directive (WFD) requires Member States to set water quality objectives and identify cost-effective mitigation measures to achieve "good status" in all waters. However, costs and effectiveness of measures vary both within and between catchments, depending on factors such as land use and topography. The aim of this study was to develop a cost-effectiveness analysis framework for integrating estimates of phosphorus (P) losses from land-based sources, potential abatement using riparian buffers, and the economic implications of buffers. Estimates of field-by-field P exports and routing were based on crop risk and field slope classes. Buffer P trapping efficiencies were based on literature metadata analysis. Costs of placing buffers were based on foregone farm gross margins. An integrated optimization model of cost minimization was developed and solved for different P reduction targets to the Rescobie Loch catchment in eastern Scotland. A target mean annual P load reduction of 376 kg to the loch to achieve good status was identified. Assuming all the riparian fields initially have the 2-m buffer strip required by the General Binding Rules (part of the WFD in Scotland), the model gave good predictions of P loads (345-481 kg P). The modeling results show that riparian buffers alone cannot achieve the required P load reduction (up to 54% P can be removed). In the medium P input scenario, average costs vary from ￡38 to ￡176 kg P at 10% and 54% P reduction, respectively. The framework demonstrates a useful tool for exploring cost-effective targeting of environmental measures.     

Policy Utopias for Nutrient Credit Trading Programs with Nonpoint Sources

A promising program to address water contamination from nutrients is water quality trading (WQT), whereby entities with high abatement costs purchase credits from entities with lower abatement costs. The concept has found some success with point source water pollution, but very few trades have occurred in over 50 programs in the United States (U.S.) that have focused on nonpoint sources (NPSs). To understand why success has been slow, we identified three environments needed for programs to succeed: physical, economic, and institutional. We estimate that only 5% of watersheds in the U.S. currently listed as nutrient impaired provide a viable physical environment for trading nitrogen; 13% are suitable for phosphorus. Economic and institutional challenges would shrink that domain even further. Therefore, we find places with the ideal physical, economic, and institutional environments necessary for feasible WQT programs are virtual policy utopias — rare places with ideal environments. Fortunately, a growing literature provides the tools necessary to identify where these policy utopias are and to expand that domain through a better understanding about how to manage WQT programs more effectively.     

SOIL CONSERVATION PRACTICES AND WATER QUALITY: IS EROSION CONTROL THE ANSWER?1

ABSTRACT: This paper is a computer simulation analysis of an agricultural nonpoint pollution problem. Computer modeling is a universally applicable tool that can be used for establishing the linkages between and the quality of agricultural runoff in both surface and subsurface flow. The tradeoffs between the costs of soil conservation practices and water quality are reported, and the economic implications of such tradeoffs are discussed. Soil and nutrient losses resulting from crop production practices are analyzed using a field-scale computer simulation model (CREAMS). No-till planting, reduced tillage, and sod waterway systems are more cost effective than other practices for controlling soil and nutrient runoff losses. Nitrate leaching losses are increased slightly by most soil conservation practices. Terrace systems and permanent vegetative cover impose the greatest societal cost for water quality protection. Public cost sharing and tax incentives encourage farmers to adopt expensive structural practices, and policies are needed to get cost-effective practices implemented on critical acreage. Extensive treatment of land is necessary for agricultural best management practices (BMPs) to significantly improve water quality in areas that are intensively farmed.     

THE IMPACT OF WATER RESOURCE QUALITY CHANGES ON SURROUNDING PROPERTY VALUES1

ABSTRACT: A case study is used to demonstrate a methodology for measuring the residential property value benefit of water pollution abatement. Increases in the value of single-family homes attributable to improvement in the water quality of the nearby Willamette River (Clackamas County, Oregon) were measured using a regression analysis technique. Sales prices and tax assessment data were used to estimate the change in property values coincident with the changes in water quality. The percentage increase in property value due to pollution abatement is expressed as a function of the distance between properties and the river bank.     

CORRELATION OF SELECTED WELL WATER QUALITY PARAMETERS WITH SOIL AND AQUIFER HYDROLOGIC PROPERTIES1

ABSTRACT: The geographical distribution of well water specific electrical conductivity and nitrate levels in a 932 km² ground water quality study area in the Fresno-Clovis, California, indicated that frequently areas of lower ground water salinity were also areas of relatively greater soil and aquifer permeability. From these observations and certain assumptions we hypothesized that the quality of the well water should be better in areas with permeable soils and geological formations. Correlation and multiple linear regression analysis supported this hypothesis for well water salinity. However, well water nitrate levels were significantly negatively correlated with only the estimated equivalent specific yield of the aquifer system. The multiple R² values of the most significant multiple linear regression models showed that only a fourth to a third of the variability in well water specific electric conductivity and nitrate levels could be ascribed to the effects of the hydrogeological parameters considered with more than 90 percent confidence. This indicates that three-fourths to two-thirds of the variability in ground water salinity and nitrate levels may be related to land use. Thus, there is considerable room for land use management techniques to improve ground water quality and reduce its variability.     

IMPACTS OF CLIMATE CHANGE ON AQUATIC ECOSYSTEM FUNCTIONING AND HEALTH1

ABSTRACT: We review published analyses of the effects of climate change on goods and services provided by freshwater ecosystems in the United States. Climate-induced changes must be assessed in the context of massive anthropogenic changes in water quantity and quality resulting from altered patterns of land use, water withdrawal, and species invasions; these may dwarf or exacerbate climate-induced changes. Water to meet instream needs is competing with other uses of water, and that competition is likely to be increased by climate change. We review recent predictions of the impacts of climate change on aquatic ecosystems in eight regions of North America. Impacts include warmer temperatures that alter lake mixing regimes and availability of fish habitat; changed magnitude and seasonality of runoff regimes that alter nutrient loading and limit habitat availability at low flow; and loss of prairie pothole wetlands that reduces waterfowl populations. Many of the predicted changes in aquatic ecosystems are a consequence of climatic effects on terrestrial ecosystems; shifts in riparian vegetation and hydrology are particularly critical. We review models that could be used to explore potential effects of climate change on freshwater ecosystems; these include models of instream flow, bioenergetics models, nutrient spiraling models, and models relating riverine food webs to hydrologic regime. We discuss potential ecological risks, benefits, and costs of climate change and identify information needs and model improvements that are required to improve our ability to predict and identify climate change impacts and to evaluate management options.     

Nitrogen in the Baltic Sea--policy implications of stock effects

We develop an optimal control model for cost-effective management of pollution, including two state variables, pollution stock and ecosystem quality. We apply it to Baltic Sea pollution by nitrogen leachates from agriculture. We present a sophisticated, non-linear model of leaching abatement costs, and a simple model of nitrogen stocks. We find that significant abatement is achievable at reasonable cost, despite the countervailing effects of existing agricultural policies such as price supports. Successful abatement should lead to lower nitrogen stocks in the sea in 5 years or less. However, the rate of ecosystem recovery is less certain. The results are highly dependent on the rate of self-cleaning of the Baltic Sea, and less so on the discount rate. Choice of target has a radical effect on the abatement path chosen. Cost-effectiveness demands such a choice, and should therefore be used with care when stock effects are present.     

A Comparison of Alternative Strategies for Cost-Effective Water Quality Management in Lakes

Roughly 45% of the assessed lakes in the United States are impaired for one or more reasons. Eutrophication due to excess phosphorus loading is common in many impaired lakes. Various strategies are available to lake residents for addressing declining lake water quality, including septic system upgrades and establishing riparian buffers. This study examines 25 lakes to determine whether septic upgrades or riparian buffers are a more cost-effective strategy to meet a phosphorus reduction target. We find that riparian buffers are the more cost-effective strategy in every case but one. Large transaction costs associated with the negotiation and monitoring of riparian buffers, however, may be prohibiting lake residents from implementing the most cost-effective strategy. An erratum to this article is available at .     

Water Quality and Land Use Changes in the Alafia and Hillsborough River Watersheds,Florida, USA1

Abstract: Spatial distribution of land use can have a substantial effect on surface and groundwater quality. Our objective was to test for trends in flow components and water quality related to changes in land use in the Alafia and Hillsborough River watersheds in Florida, USA, over the period 1974‐2007. In addition, water quality statistics were evaluated in the perspective of numeric water quality criteria and proposed reclassification of segments of the Alafia River. Trends in 10 water quality parameters and three discharge variables were evaluated using a nonparametric trend detection test. Results of land use analysis indicated substantial urbanization and loss of agricultural land in the study area. Discharge variables did not exhibit significant trends, whereas trends in the majority of water quality concentrations were negative or nonsignificant with total nitrogen and total Kjeldahl nitrogen as exceptions showing positive trends. Changes in nutrient pathways could not be clearly identified. Considering recently promulgated numeric nutrient criteria and standards for dissolved fluoride, much of the Alafia River was found to be out of compliance. While there were land use changes and changes in water quality over the study period, it was difficult to identify a direct cause‐effect relationship. Responses to regulatory efforts, such as the Clean Water Act and improvements in phosphate mining practices, may have had greater impacts on water quality than changes in land use.     

Long-Term Biological Monitoring of an Impaired Stream: Synthesis and Environmental Management Implications

The long-term ecological recovery of an impaired stream in response to an industrial facility’s pollution abatement actions and the implications of the biological monitoring effort to environmental management is the subject of this special issue of Environmental Management. This final article focuses on the synthesis of the biological monitoring program’s components and methods, the efficacy of various biological monitoring techniques to environmental management, and the lessons learned from the program that might be applicable to the design and application of other programs. The focus of the 25-year program has been on East Fork Poplar Creek, an ecologically impaired stream in Oak Ridge, Tennessee with varied and complex stressors from a Department of Energy facility in its headwaters. Major components of the long-term program included testing and monitoring of invertebrate and fish toxicity, bioindicators of fish health, fish contaminant accumulation, and instream communities (including periphyton, benthic macroinvertebrate, and fish). Key parallel components of the program include water chemistry sampling and data management. Multiple lines of evidence suggested positive ecological responses during three major pollution abatement periods. Based on this case study and the related literature, effective environmental management of impaired streams starts with program design that is consistent across space and time, but also adaptable to changing conditions. The biological monitoring approaches used for the program provided a strong basis for assessments of recovery from remedial actions, and the likely causes of impairment. This case study provides a unique application of multidisciplinary and quantitative techniques to address multiple and complex regulatory and programmatic goals, environmental stressors, and remedial actions.     

Application of Biochemical and Physiological Indicators for Assessing Recovery of Fish Populations in a Disturbed Stream

Recovery dynamics in a previously disturbed stream were investigated to determine the influence of a series of remedial actions on stream recovery and to evaluate the potential application of bioindicators as an environmental management tool. A suite of bioindicators, representing five different functional response groups, were measured annually for a sentinel fish species over a 15 year period during which a variety of remedial and pollution abatement actions were implemented. Trends in biochemical, physiological, condition, growth, bioenergetic, and nutritional responses demonstrated that the health status of a sentinel fish species in the disturbed stream approached that of fish in the reference stream by the end of the study. Two major remedial actions, dechlorination and water flow management, had large effects on stream recovery resulting in an improvement in the bioenergetic, disease, nutritional, and organ condition status of the sentinel fish species. A subset of bioindicators responded rather dramatically to temporal trends affecting all sites, but some indicators showed little response to disturbance or to restoration activities. In assessing recovery of aquatic systems, application of appropriate integrative structural indices along with a variety of sensitive functional bioindicators should be used to understand the mechanistic basis of stress and recovery and to reduce the risk of false positives. Understanding the mechanistic processes involved between stressors, stress responses of biota, and the recovery dynamics of aquatic systems reduces the uncertainty involved in environmental management and regulatory decisions resulting in an increased ability to predict the consequences of restoration and remedial actions for aquatic systems.