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931.
The biological removal of phosphates was carried as a part of treatment strategy. Vetiveria zizanioides (L.) Nash belonging to the family Poaceae was used for biological removal of biostimulants. Vetiver reportedly has mycorrhizal
association; besides having potential for removal of PO4
−3 also showed allelopathic affect on the microorganisms present in the water. In fact after a period of 96 h old roots of this
plant have been found to have killing effects on the E. coli, Enterobacter spp. Pseudomonas spp. belonging to the family Enterobacteriaceae. The paper is opening a new face of study. 相似文献
932.
933.
934.
水资源价值是一个复杂的体系,主要由三方面要素构成,即:自然因素、经济因素、社会因素。以成都市为例,选取水质、水资源量、人口密度、国民收入作为评价要素,采用模糊综合评价方法对该市水资源价值进行了评价,结果表明:成都市水资源价格为2.93元/m3,明显高于目前的成都市平均水价。因此,应通过优化产业结构、扩大生产规模、提高用水效率和技术水平、加强环境保护与文化教育、合理控制人口等措施来提高水资源价值。 相似文献
935.
Assessing Watershed-Scale, Long-Term Hydrologic Impacts of Land-Use Change Using a GIS-NPS Model 总被引:25,自引:0,他引:25
Land-use change, dominated by an increase in urban/impervious areas, has a significant impact on water resources. This includes
impacts on nonpoint source (NPS) pollution, which is the leading cause of degraded water quality in the United States. Traditional
hydrologic models focus on estimating peak discharges and NPS pollution from high-magnitude, episodic storms and successfully
address short-term, local-scale surface water management issues. However, runoff from small, low-frequency storms dominates
long-term hydrologic impacts, and existing hydrologic models are usually of limited use in assessing the long-term impacts
of land-use change. A long-term hydrologic impact assessment (L-THIA) model has been developed using the curve number (CN)
method. Long-term climatic records are used in combination with soils and land-use information to calculate average annual
runoff and NPS pollution at a watershed scale. The model is linked to a geographic information system (GIS) for convenient
generation and management of model input and output data, and advanced visualization of model results.
The L-THIA/NPS GIS model was applied to the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana, USA. Historical
land-use scenarios for 1973, 1984, and 1991 were analyzed to track land-use change in the watershed and to assess impacts
on annual average runoff and NPS pollution from the watershed and its five subbasins. For the entire watershed between 1973
and 1991, an 18% increase in urban or impervious areas resulted in an estimated 80% increase in annual average runoff volume
and estimated increases of more than 50% in annual average loads for lead, copper, and zinc. Estimated nutrient (nitrogen
and phosphorus) loads decreased by 15% mainly because of loss of agricultural areas. The L-THIA/NPS GIS model is a powerful
tool for identifying environmentally sensitive areas in terms of NPS pollution potential and for evaluating alternative land
use scenarios for NPS pollution management. 相似文献
936.
It is difficult to make general recommendations that apply to all ecosystems. There is still a relative dearth of studies
that allow the manager or visitor to come up with specific practices that are the best for their area. The preferred method
of disposal remains to dig a small hole (cat hole) and bury the waste. Other site specific methods are also discussed.
Treatment of drinking water has become standard practice for most backcountry travel. With such treatment, there is little
evidence currently to suggest that the health hazard to humans is great enough to impose further regulation in areas currently
using cat holes. 相似文献
937.
Minimal models and agroecological policy at the regional scale: An application to salinity problems in southeastern Australia 总被引:2,自引:0,他引:2
John M. Anderies 《Regional Environmental Change》2005,5(1):1-17
A minimal dynamical systems model that couples agricultural activity, native vegetation, and hydrological processes is developed to explore policy options regarding regional-scale soil and water salinization in southeastern Australia. The analysis suggests that although considerable revegetation is required to restore catchment water balance, the current value of water in uses other than agriculture is too low for revegetation to be economically viable. In contrast, groundwater pumping generates significant short-term gains by preventing soil salinization but is not a viable long-term solution. Thus, effective salinity management policy must include mechanisms to increase the value of water in uses other than irrigated agriculture to achieve sufficient long-term revegetation. These results are robust over a wide range of parameter values and thus provide a basis for policy action in the face of uncertainty about groundwater flow characteristics. 相似文献
938.
Application of a Physical Input–Output Table to Evaluate the Development and Sustainability of Continental Water Resources in Spain 总被引:1,自引:0,他引:1
Continental waters are complex resources in terms of a measurable physical quantity, and measuring them requires a good knowledge of total water availability. In this research, an accounting physical input–output table (PIOT) was applied to evaluate total water resources and gross annual availabilities at each stage of the natural-artificial water cycle. These stages are considered subsystems of a continental water resource system describing water transfers for an average year within 13 administrative basins of Spain. Water transfers between various subsystems are characterized by internal flows decreasing the water resource availabilities. The PIOT analysis establishes these internal flows, and the origins and final uses of the total resources for each subsystem. The input-output balance registered an unsustainable negative net accumulation in eight water basins. The PIOT analysis also allowed the calculation of significant indicators such as water resource developments (RDI) and their sustainable use (SUI). RDI and SUI demonstrate that groundwater is a critical resource affecting the environment (e.g., wetlands in the upper Guadiana) and the water supply (e.g., irrigation in the Segura basin). The results of this model suggest that above-/below-ground hydrological links are important when decisions have to be made in order to provide a satisfactory supply of water in Spain. The model integrates the different water basins under territorial criteria, and therefore it may be useful for the Spanish National Hydrological Plan. 相似文献
939.
Emerging approaches to water resources development and management typically highlight equity and productivity as two main objectives. In the context of integrated water resources management within a river basin, managers and stakeholders often need a comparative assessment of different options for water augmentation and/or allocation. Pitting such options against predefined objectives, such as equity and productivity, requires an assessment of the effects that available options will have on these objectives. Available documentation indicates that not only does the interpretation of such objectives vary widely, but also the available methods for assessing equity and productivity run into significant limitations in the availability of adequate data. This limitation has largely kept decision makers from gaining a comprehensive overview of equity and productivity scenarios, whether within or across sectors, that could facilitate better‐informed decisions. To address this methodological gap, this article scrutinizes different notions associated with equity and water productivity, and limitations in prevalent assessment methods with the view to develop and demonstrate pragmatic methodologies for assessing equity and productivity in data‐scarce contexts. The discussion and findings are based on a review of relevant literature and empirical and consultative research work in the Olifants River basin in South Africa. The demonstrated methodologies for assessing equity and productivity, besides being useful in data‐scarce contexts, are insightful for initiating several policy measures and also for exploring the relationship between equity and water productivity. 相似文献
940.
Leonard Champney 《Journal of the American Water Resources Association》1979,15(6):1602-1607
ABSTRACT: A general model of the policy implementation process is utilized to facilitate a discussion of the way Section 208 of PL 92-500 is being carried out on an areawide basis. A study of four “208 areas” in the “New York-Philadelphia corridor” highlights the operation of several variables used in the model. The varying political and socioeconomic conditions in geographic areas which have similar water quality problems are leading to the evolution of vastly different implementing structures, or institutional arrangements. The analysis suggests that these differences may have important implications for the success of the program in each of these areas. A major underlying theme is that such problems are characteristic of the 208 process nationwide and reflect general difficulties associated with managing water quality in a federal system. 相似文献