LOW-HEAD HYDROPOWER IMPACTS ON STREAM DISSOLVED OXYGEN1

ABSTRACT: A method to evaluate the effect of hydropower development on downstream dissolved oxygen (DO) is presented for a low head dam. Water, previously aerated during release over spillways and under gates, is diverted through the hydropower facility without further aeration. The oxygen transfer that occurs as a result of air entrainment at the various release points of a dam is measured. Oxygen transfer efficiencies are calculated and incorporated into an oxygen transfer model to predict average release DO concentrations. This model is used to systematically determine the effect of hydropower operation on downstream DO. Operational alternatives are investigated and a simple operational guide is developed to mitigate the effects of hydropower operation. Combinations of reduced generation and optimal releases from the dam allow the hydropower facility to operate within DO standards.     

ALTERNATIVES TO THE USE OF AGRICULTURAL DRAINAGE WELLS1

ABSTRACT: A large number of agricultural drainage wells (ADWs) are located in north-central Iowa. These wells permit sediments, pesticides, nitrate, and bacteria in surface and subsurface drainage water to enter regional aquifers that are currently being used for drinking-water supplies, mostly by rural families and communities. This paper reports some possible alternatives to control the entry of surface and subsurface drainage waters into groundwater systems, and describes a methodology to make comprehensive economic feasibility studies of alternative drainage outlets. The estimated cost of providing main subsurface drains varied from $220 to $960 per hectare. If the use of ADWs was completely eliminated without providing alternative drainage, it is estimated that the average annual loss to the farmers of the area would be at least $270 per hectare in reduced crop yields. Of course, losses would be weather dependent and highly variable. Management practices to reduce the pollutant load in water draining to ADWs are also discussed.     

ALTERNATIVES FOR SALINITY MANAGEMENT IN THE COLORADO RIVER BASIN1

ABSTRACT The Colorado River Basin faces the dilemma of an increasing demand for water while presently struggling with salinity concentrations approaching critical levels for some water uses. Based upon projected development salinity concentrations are predicted to exceed 1200 mg/1 at Imperial Dam by the year 2010. Annual losses to the basin economy associated with increased salinity will exceed $50 million by the year 2010. Although methods of controlling salt discharges are relatively unrefined, certain conclusions, based upon Bayesian statistical methods, can be reached. Five basic alternatives for coping with the problem are presented and evaluated in this paper: (1) do nothing; (2) adopt arbitrary salinity standards; (3) limit development; (4) control salt discharges at a cost equal to the cost of doing nothing, or (5) minimize total costs to the basin. Total costs associated with any given alternative, or the given salinity resulting, are the sum of salinity detriments (cost to users for water of increased salinity plus economic multiplier effects) plus the cost of constructing salt discharge control works. These impacts upon basin economy and Colorado River water quality for each alternative are presented and related to questions of equity which will play a role in arriving at any long-term solution to the Basin's problem.     

Risk assessment of aquifer storage transfer and recovery with urban stormwater for producing water of a potable quality

The objective of the Parafield Aquifer Storage Transfer and Recovery research project in South Australia is to determine whether stormwater from an urban catchment that is treated in a constructed wetland and stored in an initially brackish aquifer before recovery can meet potable water standards. The water produced by the stormwater harvesting system, which included a constructed wetland, was found to be near potable quality. Parameters exceeding the drinking water guidelines before recharge included small numbers of fecal indicator bacteria and elevated iron concentrations and associated color. This is the first reported study of a managed aquifer recharge (MAR) scheme to be assessed following the Australian guidelines for MAR. A comprehensive staged approach to assess the risks to human health and the environment of this project has been undertaken, with 12 hazards being assessed. A quantitative microbial risk assessment undertaken on the water recovered from the aquifer indicated that the residual risks posed by the pathogenic hazards were acceptable if further supplementary treatment was included. Residual risks from organic chemicals were also assessed to be low based on an intensive monitoring program. Elevated iron concentrations in the recovered water exceeded the potable water guidelines. Iron concentrations increased after underground storage but would be acceptable after postrecovery aeration treatment. Arsenic concentrations in the recovered water continuously met the guideline concentrations acceptable for potable water supplies. However, the elevated concentration of arsenic in native groundwater and its presence in aquifer minerals suggest that the continuing acceptable residual risk from arsenic requires further evaluation.     

MODELING FLOW IN THE EVERGLADES AGRICULTURAL AREA IRRIGATION/DRAINAGE CANAL NETWORK1

ABSTRACT: The south Florida ecosystem and Lake Okeechobee are important water resource areas that have degraded due to changes in hydroperiod, water supply, and water quality. Approximately 56 percent of the total phosphorus in water discharged from the Everglades Agricultural Area (EAA) is in particulate form. Currently, farm-level best management practices are being implemented in the effort to reduce total phosphorus and sediment in off-farm discharges. The objective of this work was to develop and calibrate a model describing water movement in primary EAA canals as a first step to development of a water quality (i.e., nutrient, sediment) model. The Netherlands-developed mechanistic flow and water quality model (DUFLOW) was adapted for the EAA. Flow, stage, geometry, canal network, and meteorological data, October 13, 1993, to February 13, 1994, were used to adapt and calibrate the DUFLOW model for EAA water level and flow in primary canals. Direct runoff discharge into the primary canals from farm-pump stations was used as runoff input for the model. The model results are comparable to an independently-calculated water balance for the EAA. The calibrated flow model will be the basis for the calibration of sediment and chemical transport in the future.     

MULTIVARIATE ANALYSIS OF WATER QUALITY IN THE RICHIBUCTO DRAINAGE BASIN (NEW BRUNSWICK,CANADA)1

ABSTRACT: Specific conductivity, pH, dissolved oxygen, carbon, phosphorous, and nitrogen species were measured at 36 stations in the Richibucto River drainage basin, including the estuary, in New Brunswick, Canada, over the six‐year period 1996 through 2001. Each station was sampled between 1 and 26 times (mean = 7.5, standard deviation = 6.0) during the ice free seasons without regard to tide. There was significant variance among stations in most parameters. Principal component analysis (PCA) was used to identify the processes explaining the observed variance in water quality. Because of the high variability in specific conductance, stations were first grouped in a freshwater subset and an estuarine (brackish water) subset. For freshwater stations, most of the variance in water quality was explained by pH and total organic carbon, as well as high nutrient concentrations. These high nutrient concentrations, along with water salinity, which varies with flow and tides, are also important in determining water quality variability in brackish water. It is recommended that water quality parameters that were found to explain most of the variance by PCA be monitored more closely, as they are key elements in understanding the variability in water quality in the Richibucto drainage basin. Cluster analyses showed that high phosphorous and nitrate concentrations were mostly found in areas of peat runoff, tributaries receiving treated municipal effluent, and lentic zones upstream of culverts. Peat runoff was also shown to be acidic, whether it is runoff from a harvested area or a natural bog.     

Economic Impacts of Zebra Mussels on Drinking Water Treatment and Electric Power Generation Facilities

Invasions of nonnative species such as zebra mussels can have both ecological and economic consequences. The economic impacts of zebra mussels have not been examined in detail since the mid-1990s. The purpose of this study was to quantify the annual and cumulative economic impact of zebra mussels on surface water-dependent drinking water treatment and electric power generation facilities (where previous research indicated the greatest impacts). The study time frame was from the first full year after discovery in North America (Lake St. Clair, 1989) to the present (2004); the study area was throughout the mussels’ North American range. A mail survey resulted in a response rate of 31% for electric power companies and 41% for drinking water treatment plants. Telephone interviews with a sample of nonrespondents assessed nonresponse bias; only one difference was found and adjusted for. Over one-third (37%) of surveyed facilities reported finding zebra mussels in the facility and almost half (45%) have initiated preventive measures to prevent zebra mussels from entering the facility operations. Almost all surveyed facilities (91%) with zebra mussels have used control or mitigation alternatives to remove or control zebra mussels. We estimated that 36% of surveyed facilities experienced an economic impact. Expanding the sample to the population of the study area, we estimated $267 million (BCa 95% CI = $161 million–$467 million) in total economic costs for electric generation and water treatment facilities through late 2004, since 1989. Annual costs were greater ($44,000/facility) during the early years of zebra mussel infestation than in recent years ($30,000). As a result of this and other factors, early predictions of the ultimate costs of the zebra mussel invasion may have been excessive.     

EFFECTS OF INTERBASIN TRANSFERS UPON WATER MANAGEMENT ALTERNATIVES IN CENTRAL UTAH1

ABSTRACT. Most of Utah's rapid population and industrial expansion is taking place along the western base of the Wasatch Mountains, with consequent increases in water demand. As a part of Utah's “Developing a State Water Plan,” a foundation investigation of the Utah Lake drainage area, which is at the Southern end of the Wasatch Front, was completed which delineated the quantity and quality of the water resources, present water uses, and opportunities for further water conservation. To prepare water budgets, land use data was collected to delineate all areas using water in excess of normal precipitation, which includes agricultural croplands, phreatophytes, open water surfaces, industrial areas, and urban areas. The water budgets were prepared for the time base 1931-1960, but adjusted to physical conditions existing in 1960. The Initial Phase of the Bonneville Unit of the Central Utah Project is presently under construction, with costs expected to exceed 300 million dollars. The principal feature of this project is the exportation of waters from the Colorado River Basin into the Utah Lake drainage area (Great Basin). This importation provides a large number of alternatives for allocation, reallocation of present supplies, and exportation. The possible effects of the Central Utah Project for realizing some of the above alternatives is delineated. Fortunately, the features of this project allow a wide latitude for water management in Utah, thereby facilitating its corporation into a “State Water Plan.”     

溶解氧对好氧颗粒污泥影响的研究进展

好氧颗粒污泥技术是一种新颖废水处理技术。溶解氧(DO)是好氧颗粒污泥形成和稳定运行的一个重要参数。好氧颗粒污泥需要的曝气量大,能耗高。高曝气量带来的高DO浓度不利于氨氮通过SND去除。当DO扩散在颗粒内部受到限制时,颗粒中心形成的厌氧层不利于颗粒污泥的长期稳定运行。本文系统分析了DO浓度对好氧颗粒污泥影响的国内外研究现状,对好氧颗粒污泥中DO浓度这一重要参数的研究进行了总结。研究在低DO浓度下保持好氧颗粒污泥的稳定性有利于降低运行成本,采取合适的方法降低颗粒内部的扩散限制有利于增强颗粒的稳定性能。     

Current and Future Strategies for Water and Wastewater Management of Istanbul City

Istanbul has experienced rapid increases in population to more than 12 million people, which has created infrastructure problems of water supply and wastewater treatment and disposal. In this article, the achievements and approaches of the Istanbul Water and Sewerage Administration (ISKI) to solve the water shortage problem and to improve services are summarized. Istanbul had a very severe water shortage problem in 1994 because of ignorance of the implementation of the needed projects. After reviewing the reasons and causes of the problem, new priority criteria adopted after 1994 are given. Following the implementation of the projects determined according to the aforementioned criteria, water supplied has exceeded the water demand. The added capacity is equal to one to three times of the capacity built up to 1994 for water treatment, service reservoirs, pumping stations, transmission lines, and the water distribution network; water quality has been improved the meet local and international potable water standards. Unaccounted for water has been reduced from 60% to 27%. The percentage of treated wastewater has been increased from 10% to 90% in 8 years, resulting in drastic improvements and rehabilitation of the Golden Horn and coastal water quality. Through improved customer services, complaints were reduced from 33% in 1994 to 0.3%. Some of the main criteria and the approaches behind this success are summarized. Published online     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN THE PIRACICABA RIVER BASIN,BRAZIL1

ABSTRACT: The spatial and temporal variability of dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrate concentration and total coliform (TC) were investigated at nine sampling stations distributed along the main rivers of the Piracicaba River Basin, a 12,400 km² catchment located in São Paulo State, one of the most developed regions of Brazil. Spatially, a downstream impoverishment of water quality conditions was observed, as seen by the decrease of DO, and increase of BOD, nitrate, and TC. These changes were probably caused by accumulating downstream discharge of domestic and industrial sewage. Temporal evaluation of 18 years of data showed that DO decreased with time for the majority of the sampling stations, while BOD, nitrate, and TC increased. A law, approved at the end of 1991, proposed a new water tax for river water extraction for industrial and agricultural use. The amount of this tax is determined according to the water quality of the extracted water. Therefore, the evaluation of the water quality status in this basin is a first step to help resources managers to determine the values for this tax.     

Use of man-made impoundment in mitigating acid mine drainage in the North Branch Potomac River

The US Department of the Army, Baltimore District Corps of Engineers, oversees a long-term monitoring study to assess and evaluate effects of the Jennings-Randolph reservoir on biota in the North Branch Potomac River. The reservoir was intended, in part, to mitigate effects of acid mine drainage originating in upstream and headwater areas. The present study assessed recovery of benthos and fish in this system, six years after completion of the reservoir. Higher pH and lower iron and sulfate concentrations were observed upstream of the reservoir compared to preimpoundment conditions, suggesting better overall water quality in the upper North Branch. Water quality improved slightly directly downstream of the reservoir. However, the reservoir itself was poorly colonized by macrophytes and benthic organisms, and plankton composition suggested either metal toxicity and/or nutrient limitation. One large tributary to the North Branch and the reservoir (Stony River) was shown to have high (and possibly toxic) levels of manganese, iron, zinc, and aluminum due to subsurface coal mine drainage. Macroinvertebrate diversity and number of taxa were higher in sites downstream of the reservoir in the present study. Compared with previous years, the present study suggested relatively rapid recovery in the lower North Branch due to colonization from two major unimpacted tributaries in this system: Savage River and South Branch Potomac. Abundance of certain mayfly species across sites provided the most clear evidence of longitudinal gradients in water quality parameters and geomorphology. Fish data were consistent with macroinvertebrate results, but site-to-site variation in species composition was greater. Data collected between 1982 and 1987 suggested that certain fish species have unsuccessfully attempted to colonize sites directly downstream of the reservoir despite the more neutral pH water there. Our results show that recovery of biota in the North Branch Potomac was attributed to decreased acid inputs from mining operations and dilution from the Savage River, which contributed better water quality. Continued improvement of North Branch Potomac biota may not be expected unless additional mitigation attempts, either within the reservoir or upstream, are undertaken.     

CHICAGO METROPOLITAN FLOODWATER MANAGEMENT PLAN1

ABSTRACT: The Chicago Metropolitan Floodwater Management Plan is a cooperative planning program under Public Law 566 of the 83rd Congress (The Watershed Protection and Flood Prevention Act). The planning effort was jointly sponsored by the U.S. Department of Agriculture, Soil Conservation Service, and the Metropolitan Sanitary District of Greater Chicago. The project is unique in that it studies a 1260 square mile (3266 sq. kilometer) watershed, which is approximately 35 percent urbanized and contains approximately 7.5 million people. At present, approximately 4.4 percent or 330,600 people live in a floodplain. It is presently estimated that 80,000 acres (32,000 ha.) of the study area are subject to flooding with a current average annual damage estimated at approximately $10 million. The Plan which has been developed to reduce or eliminate these damages is divided into six separate watershed plans, and has been developed through extensive use of local citizen watershed steering committees. The paper discusses the planning process, public participation and implementation both at an overall river basin level and watershed case study level.     

The use of constructed wetlands in the treatment of acid mine drainage

US government regulations require that all effluents from industrial operations, including mining, meet certain water quality standards. Constructed wetlands have proven to be useful in helping to attain those standards. Application of this biotechnology to mine water drainage can reduce water treatment costs and improve water quality in streams and rivers adversely affected by acidic mine water drainage from abandoned mines. Over 400 constructed wetland water treatment systems have been built on mined lands largely as a result of research by the US Bureau of Mines. Wetlands are passive biological treatment systems that are relatively inexpensive to construct and require minimal maintenance. Chemical treatment costs are reduced sufficiently to repay the cost of construction in less than a year. The mine waste water is typically treated in a series of excavated ponds that resemble small marsh areas. The ponds are engineered to facilitate bacterial oxidation of iron. Ideally, the water then flows through a composted organic substrate supporting a population of sulphate-reducing bacteria which raises the pH. Constructed wetlands in the USA are described - their history, functions, construction methodologies, applicabilities, limitations and costs.     

ECONOMIC EFFECTS OF RIVER RECREATION ON LOCAL ECONOMIES1

ABSTRACT: Outdoor recreation is a major, growing use of water resources in the United States. The economic effects of expenditures by visitors to three recreational river sites on local economies surrounding the sites were estimated using an input-output model (IMPL.AN). Expenditure data were from the Public Area Recreation Visitors Study (PARVS). Results indicate that visitor spending stimulates a considerable amount of economic activity and growth in local economies. Economic effects include increases in total gross output ranging from $2.6 million to $13.4 million, increases in total income ranging from $1.2 million to $5.6 million, and increases in employment ranging from 60 to 292 jobs.     

A COST‐BENEFIT ANALYSIS OF WATER QUALITY PROTECTION IN THE CATAWBA BASIN1

ABSTRACT: The primary objective of this study was to perform a cost‐benefit analysis of maintaining the current level of water quality in the Catawba River basin. Economic benefits were estimated using a stated preference survey method designed to value respondents' willingness to pay for a management plan to protect water quality in the Catawba basin over time. From the surveys conducted with 1,085 area residents, we calculated an annual mean willingness to pay of $139 for the management plan, or more than $75.4 million for all taxpayers in the area. Over the five‐year time horizon in which respondents were asked to pay for the management plan, this resulted in a total economic benefit of $340.1 million. The Watershed Analysis Risk Management Framework model was used to estimate the amount of management activities needed to protect the current level of water quality in the basin over time. Based on the model results, the total cost of the management plan was calculated to be $244.8 million over a ten‐year period. The resulting cost‐benefit analysis indicated that the potential benefits of this management plan would outweigh the costs by more than $95 million.     

Conceptualization of a robust performance assessment and evaluation model for consolidating community water systems

Community water systems (CWS) face significant competing forces for change from decreasing water resource availability, stricter water quality regulations, decreasing federal subsidies, increasing public scrutiny, decreasing financial health, and increasing infrastructure replacement costs. These competing forces necessitate increasing consolidation responses among financially stressed CWS. Consolidation responses allow financially stressed CWS to increase levels of service by taking advantage of economy of scale benefits, such as eliminating service duplications across administration and operational functions. Consolidation responses also promote improved financial accountability among consolidating CWS, especially when operating as integral subsystems of a larger regional drinking water supply (RDWS) system. The goal of this paper is to propose a conceptual model for robust performance assessment and evaluation (PAE) among consolidating CWS. The objectives of this paper are to conceptualize methods for: (1) consistent performance assessment and (2) uniform summative performance evaluation among consolidating CWS. The expected outcome from implementing robust PAE among consolidating CWS is increased levels of service through transparent benchmarking and improved financial accountability. The proposed robust PAE model provides the basis for constructing decision support system (DSS) tools that estimate efficient solutions for allocating limited financial resources among consolidating CWS. The paper is a significant departure from current CWS PAE approaches in two ways. First, it provides a goal-oriented approach for robust PAE among consolidating CWS. Second, it constructs efficiency-based performance metrics to temporally and spatially monitor the degree of attainment of the RDWS systems' goal.     

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.     

间歇曝气短程硝化控制新途径的初步试验研究

采用SBR,以间歇曝气的方式控制短程硝化,分别研究了在限制曝气量和不限制曝气量条件下,亚硝酸盐的积累情况.试验表明,间歇曝气可以作为短程硝化的控制条件,在一定条件下,亚硝化率可达到90%以上.限制曝气量时,在低DO情况下,采用间歇曝气控制短程硝化更为有效、经济.     

PERCEIVED WATER QUALITY AND THE VALUE OF SEASONAL HOMES1

ABSTRACT: The impact of degraded water quality on the value of seasonal homes adjacent to St. Albans Bay on Lake Champaign in northern Vermont is estimated using hedonic price functions. The Value of properties located adjacent to the bay are depressed by about 20 percent, or $4,500 on average, compared with similar nearby properties on the larger but cleaner lake. Water quality degradation resulted in decressed property values of approximately two million dollars in the area surrounding the Bay.