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801.
Thomas R. Harris Chauncey T. K. Ching 《Journal of the American Water Resources Association》1983,19(2):205-210
ABSTRACT: Tradeoffs between regional economic development and resource use is a question often confronting local decisionmakers. A resource-interindustry model can be used to depict the interrelationships between regional economic sectors as to household income and/or employment and resource use. A resource-interindustry model was developed for Humboldt and Lander Counties in Nevada which shows the tradeoffs between regional household income (wages, salaries, profits, and rents) and/or employment and water usage. Water income and water employment multipliers can be ranked, enabling decisionmakers to realize sectors which require greatest regional water usage to regional household income and/or employment. 相似文献
802.
Development of a bird integrity index: using bird assemblages as indicators of riparian condition 总被引:7,自引:0,他引:7
We describe the development of a bird integrity index (BII) that uses bird assemblage information to assess human impacts
on 13 stream reaches in the Willamette Valley, Oregon, USA. We used bird survey data to test 62 candidate metrics representing
aspects of bird taxonomic richness, tolerance or intolerance to human disturbance, dietary preferences, foraging techniques,
and nesting strategies that were affected positively or negatively by human activities. We evaluated the metric responsiveness
by plotting each one against a measure of site disturbance that included aspects of land use/land cover, road density, riparian
cover, and stream channel and substrate conditions. In addition, we eliminated imprecise and highly correlated (redundant)
metrics, leaving 13 metrics for the final index. Individual metric scores ranged continuously from 0 to 10, and index scores
were weighted to range from 0 to 100. Scores were calibrated using historical species information to set expectations for
the number of species expected under minimally disturbed conditions. Site scores varied from 82 for the least disturbed stream
reach to 8.5 for an urban site. We compared the bird integrity index site scores with the performance of other measures of
biotic response developed during this study: a fish index of biointegrity (IBI) and two benthic macroinvertebrate metrics.
The three assemblages agreed on the general level of disturbance; however, individual sites scored differently depending on
specific indicator response to in-stream or riparian conditions. The bird integrity index appears to be a useful management
and monitoring tool for assessing riparian integrity and communicating the results to the public. Used together with aquatic
indicator response and watershed data, bird assemblage information contributes to a more complete picture of stream condition. 相似文献
803.
Understanding how hydraulic factors control alluvial river meander migration can help resource managers evaluate the long-term
effects of floodplain management and bank stabilization measures. Using a numerical model based on the mechanics of flow and
sediment transport in curved river channels, we predict 50 years of channel migration and suggest the planning and ecological
implications of that migration for a 6.4-km reach (river miles 218–222) of the Sacramento River near the Woodson Bridge State
Recreation Area, California, USA.
Using four different channel management scenarios, our channel migration simulations suggest that: (1) channel stabilization
alters the future channel planform locally and downstream from the stabilization; (2) rock revetment currently on the bank
upstream from the Woodson Bridge recreation area causes more erosion of the channel bank at the recreation area than if the
revetment were not present; (3) relocating the channel to the west and allowing subsequent unconstrained river migration relieves
the erosion pressure in the Woodson Bridge area; (4) the subsequent migration reworks (erodes along one river bank and replaces
new floodplain along the other) 26.5 ha of land; and (5) the river will rework between 8.5 and 48.5 ha of land in the study
reach (over the course of 50 years), depending on the bank stabilization plan used. The reworking of floodplain lands is an
important riparian ecosystem function that maintains habitat heterogeneity, an essential factor for the long-term survival
of several threatened and endangered animal species in the Sacramento River area. 相似文献
804.
The objective of this paper is to develop a general pricing model for Turkish Lignite, which is mainly sold to thermal plants. This model will contribute to the development of coal mining within the scope of privatization efforts of the Turkish energy market. The paper consists of two stages. First, data of 10 thermal plants have been evaluated by using hedonic pricing analysis to determine influential price parameters. The results of hedonic regression analysis indicate the effect and importance of calorific value and electricity price on lignite prices. Second, a general coal-pricing model has been developed by taking into account the results of hedonic analysis. Comparison of the coal prices estimated by the developed pricing model and the coal prices obtained from thermal plants indicates an acceptable relation. 相似文献
805.
806.
Chao‐Hsien Liaw Yao‐Lung Tsai Mow‐Soung Cheng 《Journal of the American Water Resources Association》2006,42(2):311-322
The Keelung River Basin in northern Taiwan lies immediately upstream of the Taipei metropolitan area. The Shijr area is in the lower basin and is subject to frequent flooding. This work applies micromanagement and source control, including widely distributed infiltration and detention/ retention runoff retarding measures, in the Wudu watershed above Shijr. A method is also developed that combines a genetic algorithm and a rainfall runoff model to optimize the spatial distribution of runoff retarding facilities. Downstream of Wudu in the Shijr area, five dredging schemes are considered. If 10‐year flood flows cannot be confined in the channel, then a levee embankment that corresponds to the respective runoff retarding scheme will be required. The minimum total cost is considered in the rule to select from the regional flood mitigation alternatives. The results of this study reveal that runoff retarding facilities installed in the upper and middle parts of the watershed are most effective in reducing the flood peak. Moreover, as the cost of acquiring land for the levee embankment increases, installing runoff retarding measures in the upper portion of the watershed becomes more economical. 相似文献
807.
Moon Seong Rang Min Goo Kang Seung Woo Park Jeong Jae Lee Ryung Hak Yoo 《Journal of the American Water Resources Association》2006,42(2):473-486
The main focus of this study was to compare the Grey model and several artificial neural network (ANN) models for real time flood forecasting, including a comparison of the models for various lead times (ranging from one to six hours). For hydrological applications, the Grey model has the advantage that it can easily be used in forecasting without assuming that forecast storm events exhibit the same stochastic characteristics as the storm events themselves. The major advantage of an ANN in rainfall‐runoff modeling is that there is no requirement for any prior assumptions regarding the processes involved. The Grey model and three ANN models were applied to a 2,509 km2 watershed in the Republic of Korea to compare the results for real time flood forecasting with from one to six hours of lead time. The fifth‐order Grey model and the ANN models with the optimal network architectures, represented by ANN1004 (34 input nodes, 21 hidden nodes, and 1 output node), ANN1010 (40 input nodes, 25 hidden nodes, and 1 output node), and ANN1004T (14 input nodes, 21 hidden nodes, and 1 output node), were adopted to evaluate the effects of time lags and differences between area mean and point rainfall. The Grey model and the ANN models, which provided reliable forecasts with one to six hours of lead time, were calibrated and their datasets validated. The results showed that the Grey model and the ANN1010 model achieved the highest level of performance in forecasting runoff for one to six lead hours. The ANN model architectures (ANN1004 and ANN1010) that used point rainfall data performed better than the model that used mean rainfall data (ANN1004T) in the real time forecasting. The selected models thus appear to be a useful tool for flood forecasting in Korea. 相似文献
808.
Dynamics of Bacterial Abundance,Biomass, Activity,and Community Composition in the Oligotrophic Traunsee and the Traun River (Austria) 总被引:1,自引:0,他引:1
Klammer Susanne Posch Thomas Sonntag Bettina Griebler Christian Mindl Birgit Psenner Roland 《Water, Air, & Soil Pollution: Focus》2002,2(4):137-163
The holomictic Traunsee is the deepest and second largest lakein Austria. The special characteristic of this ecosystem isthe fact that local salt and soda industries presumably alterthe lake by the discharge of waste materials. Since thebeginning of the 20th century salt and soda works areannually releasing up to 50,000 tons of solid wastes and up to150,000 tons of chloride into Traunsee. To assess potentialeffects of these anthropogenic impacts on the bacterioplanktonthree sampling sites, influenced as well as not influenced bythe industrial discharge, were chosen for comparison andsampled monthly from November 1997 to October 1998. Bacterialabundance ranged between 0.4 to 3.0 × 106 cells ml-1 with decreasing numbers along the depth profile. Theproportion of actively respiring bacteria, i.e. INT [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride]reducing cells, never exceeded 10% of DAPI (4',6'-diamidino-2-phenylindole) stained cells. Fluorescence in situ hybridization (FISH) was used to examine the seasonal and spatial distribution of dominant phylogenetic groups of thebacterioplankton. Up to 84% of bacteria detected with DAPIcould be detected via FISH applying the universal bacterialprobe EUB338. Percentages of alpha- and beta-Proteobacteriaand members of the Cytophaga-Flavobacterium cluster did notexceed 60% of DAPI-stained cells.Beta-Proteobacteriaappeared to be the most abundant group, not only in Traunsee butalso in two reference lakes, Attersee and Hallstättersee. No significant differences in any of the bacterial parameters couldbe detected between the three sampling sites and all measurementswere found in the range reported for oligotrophic lakes. The highdischarge of the Traun River, resulting in a lake water renewaltime of only one year, may diminish possible effects of industrial waste discharge in the pelagic zone. 相似文献
809.
Efthymios Darakas 《The Environmentalist》2002,22(4):367-375
Transboundary water resources require the cooperation of the countries involved, not only on the various uses of the water, but also on overall water quality and the protection of ecosystems. Transboundary rivers and their management constitute a contemporary issue of great significance. Cooperation between neighboring countries is not always easy, due to different socio-economic and political conditions. Therefore, the different needs and priorities between the countries involved need to be solved first. Since pollution does not stop at a State border, it is an example of something that can be solved only at the cross-border level. This paper presents the cross-border cooperation between two transnational Institutions; the Aristotle University of Thessaloniki (Greece) and the University of Sofia (Bulgaria), within the framework of Interreg programs. The first collaborated attempt was to carry out a coordinated program for monitoring the pollution of the Nestos River. The second was the protection and restoration of the ecosystem through the education of young engineers and the transfer of experiences and scientific knowledge across the borders. 相似文献
810.