INTEGRATING SCIENCE AND TECHNOLOGY TO SUPPORT STREAM NATURALIZATION NEAR CHICAGO,ILLINOIS1

ABSTRACT: Many urban and suburban communities in the Midwest are seeking to establish sustainable, morphologically and hydraulically varied, yet dynamically stable fluvial systems that are capable of supporting healthy, biologically diverse aquatic ecosystems — a process known as stream naturalization. This paper describes an integrated research program that seeks to develop a scientific and technological framework to support two stream naturalization projects near Chicago, Illinois. The research program integrates theory and methods in fluvial geomorphology, aquatic ecology, hydraulic engineering and social theory. Both the conceptual and the practical challenges of that integration are discussed. Scientific and technical support emphasize the development of predictive tools to evaluate the performance of possible naturalization designs at scales most appropriate to community based projects. Social analysis focuses on place based evaluations of how communities formulate an environmental vision and then, through decision making, translate this vision into specific stream naturalization strategies. Integration of scientific and technical with social components occurs in the context of community based decision making as the predictive tools are employed by project scientists to help local communities translate their environmental visions into concrete environmental designs. Social analysis of this decision making process reveals how the interplay between the community's vision of what they want the watershed to become, and the scientific perspective on what the watershed can become to achieve the community's environmental goals, leads to the implementation of specific stream naturalization practices.     

EFFECTS OF WATERSHED BEST MANAGEMENT PRACTICES ON HABITAT AND FISH IN WISCONSIN STREAMS1

ABSTRACT: We evaluated the effectiveness of watershed‐scale implementations of best‐management practices (BMPs) for improving habitat and fish attributes in two coldwater stream systems in Wisconsin. We sampled physical habitat, water temperature, and fish communities in multiple paired treatment and reference streams before and after upland (barnyard runoff controls, manure storage, contour plowing, reduced tillage) and riparian (stream bank fencing, sloping, limited rip‐rapping) BMP installation in the treatment subwatersheds. In Spring Creek, BMPs significantly improved overall stream habitat quality, bank stability, instream cover for fish, abundance of cool‐ and coldwater fishes, and abundance of all fishes. Improvements were most pronounced at sites with riparian BMPs. Water temperatures were consistently cold enough to support coldwater fishes such as trout (Salmonidae) and sculpins (Cottidae) even before BMP installation. We observed the first‐time occurrence of naturally reproduced brown trout (Salmo trutta) in Spring Creek, indicating that the stream condition had been improved to be able to partially sustain a trout population. In Eagle Creek and its tributary Joos Creek, limited riparian BMPs led to localized gains in overall habitat quality, bank stability, and water depth. However, because few upland BMPs were installed in the subwatershed there were no improvements in water temperature or the quality of the fish community. Temperatures remained marginal for coldwater fish throughout the study. Our results demonstrate that riparian BMPs can improve habitat conditions in Wisconsin streams, but cannot restore coldwater fish communities if there is insufficient upland BMP implementation. Our approach of studying multiple paired treatment and reference streams before and after BMP implementation proved effective in detecting the response of stream ecosystems to watershed management activities.     

充分利用水资源 改善生态环境

本文结合攀枝花地区实际,论述了水资源利用率高低是影响经济发展和改善生态环境的重要因素,调查分析了攀枝花地区水资源利用率低的原因;提出了提高水资源利用率的对策和措施。为促进经济发展和改善生态环境提供了依据。     

STREAM TEMPERATURE ESTIMATION FROM AIR TEMPERATURE1

ABSTRACT: Air temperatures are sometimes used as substitutes for stream temperatures. To examine the errors associated with this procedure, linear relationships between stream temperatures, T, and air temperatures, T_a, recorded for 11 streams in the central U.S. (Mississippi River basin) were analyzed. Weather stations were an average 42 miles (range 0 to 144 miles) from the rivers. The general equations, T_w= 5.0 + 0.75 T_a and T_w= 2.9 + 0.86 T_a with temperatures in °C, were derived for daily and weekly water temperatures, respectively, for the 11 streams studied. The simulations had a standard deviation between measurements and predictions of 2.7°C (daily) and 2.1°C (weekly). Equations derived for each specific stream individually gave lower standard deviations, i.e., 2.1°C and 1.4°C, respectively. Small, shallow streams had smaller deviations than large, deep rivers. The measured water temperatures follow the air temperatures closely with some time lag. time lags ranged from hours to days, increasing with stream depth. Taking into account these time lags improved the daily temperature predictions slightly. Periods of ice cover were excluded from the analysis.     

CENTRAL NEBRASKA RIVER BASINS,NEBRASKA1

ABSTRACT: The Central Nebraska Basins (NAWQA) study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Platte River flows are variable in the western part of the study unit because of diversions, but the Loup and Elkhorn Rivers originate in an area of dune sand covered by grassland that generates consistent base flows. More frequent runoff in the eastern part of the study unit also sustains stream flow. Ground water in the study unit has no regional confining units and the system is a water table aquifer throughout. Macroinvertebrate and fish taxa at biological sampling sites in the state were related to stream flow. One of the four wetland complexes identified in the study unit includes habitat for threatened and endangered bird species. The study unit is an agricultural area that includes row crops, both irrigated and nonirrigated in the eastern and southern parts, and rangeland in the Sand Hills of the western part. A water quality assessment will be based on the differences in environmental setting in each of four subunits within the study unit.]     

DIGITAL SIMULATION OF THE EFFECT OF THERMAL DISCHARGE ON STREAM WATER QUALITY1

A modified transient version of the Streeter-Phelps model along with the energy balance equation is employed to analyze the effects of waste heat discharge from power plants on stream water quality. Analysis is also made to examine the effects of the upstream water quality and stream velocity on the downstream DO concentration level. The resulting coupled nonlinear hyperbolic partial differential equations representing the energy, BOD and DO concentrations are solved by the method of characteristics and simulated on a digital computer. Final numerical results indicate that the allowable quantity of thermal discharge does heavily depend on the upstream quality.     

DETECTION OF FRESH WATER AQUIFERS IN THE GLACIAL DEPOSITS OF NORTHWESTERN MISSOURI BY GEOELECTRICAL METHODS1

Geoelectrical investigations in Grundy County of northwestern Missouri, where the groundwater resources of the glacial deposits have already been examined through an extensive drilling program by the Missouri Geological Survey and Water Resources, indicate that water-bearing gravel deposits can be distinguished from glacial deposits containing appreciable amounts of clay and limited amounts of water. The Schlumberger method used for the geoelectric depth soundings in the vicinity of the Survey's drillholes demonstrates the exploratory usefulness of the method in that it can partly replace the more expensive procedure of drilling. The method also provides improved interpretation between drillholes. Results of the investigation show that, in the area, clay has a resistivity below 20in, that the fresh water-bearing gravel at the bottom of the buried glacial stream channels has a resisitivity of 40 to 50fim, and that the near surface glacial gravel deposits have a resistivity above lOOfim. Interpretation of the depth soundings and the conductivity of water obtained from a local well implies that its water is drawn from the saline water of the bedrock. A recommendation is made for the quality improvement of this particular well.     

How Corridors Reduce Indigo Bunting Nest Success

Abstract:  Corridors are a popular strategy to conserve biodiversity and promote gene flow in fragmented landscapes. Corridor effectiveness has been bolstered by the fact that no empirical field studies have shown negative effects on populations or communities. I tested the hypothesis that corridors increase nest predation in connected habitat fragments relative to unconnected fragments. I evaluated this hypothesis in a large-scale experimental system of open-habitat fragments that varied in shape and connectivity. Corridors increased nest predation rates in connected fragments relative to unconnected fragments with lower edge:area ratios. Nest predation rates were similar between connected and unconnected fragments with higher edge:area ratios. These results suggest that the increase in predator activity is largely attributable to edge effects incurred through the addition of a corridor. This is the first field study to demonstrate that corridors can negatively impact animal populations occupying connected fragments.     

Integrated Management to Create New Breeding Habitat for Dalmatian Pelicans (Pelecanus crispus) in Greece

/ An integrated management plan to create favorable nesting habitat for the world-endangered Dalmatian pelicans, was tested at Kerkini irrigation reservoir, a Ramsar wetland. The lake is the major wintering site of Dalmatian pelicans in Europe, where the species lives year-round without breeding. The rise of water level at the reservoir during spring (exceeding 5 m) has an impact on the whole system, including several birds, which lose their nesting habitat. Although the integrity of the wetland demands ecological restoration with changes in its hydrologic regime, local socioeconomic conditions allow only habitat level interventions. During the planning phase of the management plan, both the ecological and social context of the interventions were considered. Monitoring of all pelican habitats and populations provided the scientific basis, while a socioecological survey on knowledge/attitudes of local fishermen toward wetland identified conflicts with specific resources and planned management. To gain public support, a broad information/education program was implemented. The education program for fishermen was based on the findings of the socioecological survey. The in situ management involved experimental construction of floating rafts, platforms over water, dredged-spoil islands, and platforms at various sites of the wetland. Monitoring of the managed habitats showed that most waterbirds used them for resting and roosting. Common terns nested on the rafts, cormorants on the platforms, and Dalmatian pelicans on the man-made island. Under the prevailing hydrologic and weather conditions, islands seem to be the most suitable habitat for pelican nesting. It is concluded that wildlife habitat management should integrate the ecological component, related to the needs of the species and ecosystem, with the social one, expressed by cooperation and involvement of the local community.KEY WORDS: Integrated management; Pelican; Nesting habitat; Habitat management; Reservoir-wetland; Public participation, Greece     

WEP的安全技术分析及对策

在对无线局域网WLAN标准IEEE80 2 .11的WEP描述的基础上 ,笔者深入研究了WEP协议的设计上和实际应用中存在的密钥序列重复使用、消息认证和完整性等严重安全漏洞 ;详细分析了标准无线局域网中WEP协议解决方案 ;提出了WEP的改进算法WEP2 ,WEP2将IV大小增加到 12 8bit,以增强抗攻击能力 ;分析了AES解决方案的可行性 ;在密钥再生与分配方面 ,提出在MAC层实现经认证的密钥交换 ,用来改善WEP的安全脆弱性等解决措施。最后 ,还对今后的研究方向作出进一步的展望