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101.
Catherine Denault Robert G. Millar Barbara J. Lence 《Journal of the American Water Resources Association》2006,42(3):685-697
ABSTRACT: Stationarity of rainfall statistical parameters is a fundamental assumption in hydraulic infrastructure design that may not be valid in an era of changing climate. This study develops a framework for examining the potential impacts of future increases in short duration rainfall intensity on urban infrastructure and natural ecosystems of small watersheds and demonstrates this approach for the Mission/Wagg Creek watershed in British Columbia, Canada. Nonstationarities in rainfall records are first analyzed with linear regression analysis, and the detected trends are extrapolated to build potential future rainfall scenarios. The Storm Water Management Model (SWMM) is used to analyze the effects of increased rainfall intensity on design peak flows and to assess future drainage infrastructure capacity according to the derived scenarios. While the framework provided herein may be modified for cases in which more complex distributions for rainfall intensity are needed and more sophisticated stormwater management models are available, linear regressions and SWMM are commonly used in practice and are applicable for the Mission/Wagg Creek watershed. Potential future impacts on stream health are assessed using methods based on equivalent total impervious area. In terms of impacts on the drainage infrastructure, the results of this study indicate that increases in short duration rainfall intensity may be expected in the future but that they would not create severe impacts in the Mission/Wagg Creek system. The equivalent levels of imperviousness, however, suggest that the impacts on stream health could be far more damaging. 相似文献
102.
S. Mostaghimi T. M. Younos U. S. Tim 《Journal of the American Water Resources Association》1992,28(3):545-552
ABSTRACT: Simulated rainfall was used on experimental field plots to compare the effect of chemical fertilizer and sludge application on sediment, nitrogen, and phosphorus in runoff from no-till and conventional tillage systems. Chemical fertilizer application under the no-till system resulted in the least amount of total N and P in surface runoff. However, sludge application under the no-till system resulted in the least amount of NO3-N and sediment in surface runoff. The worst water quality scenarios were observed when either sludge or chemical fertilizer were surface-applied under a conventional tillage system. Nitrogen losses from the conventional tillage system were minimized when sludge was incorporated into the soil. However, phosphorus and sediment yield from such a system were significantly higher when compared to phosphorus and sediment yield from the no-till system. The results from this study indicate that the use of sludge on agricultural land under a no-till system can be a viable alternative to chemical fertilizer for nitrogen and phosphorus control in runoff. A more cautious approach is recommended when the sludge is incorporated into the soil in a conventional tillage system because of potential for high sediment and phosphorus yield in surface runoff. 相似文献
103.
我国是发展中的国家,农业在国民经济中占有十分重要的地位,环境污染和生态破坏是农业潜伏着的生态危机,也是农业发展过程中亟待解决的重大问题。如何从我国农业环境问题的特点和农业经济现状出发,制定出与农业经济发展相适应遥农业环境保护战略,是我国农业发展和环境保护工作中的一项重要任务。本文就我国农业环境保护的战略地位和作用、指导思想和方针、目标和重点、措施等一系列战略问题,进行初步探讨。 相似文献
104.
Dan M. Wells Ellis W. Huddleston Robert G. Rekers 《Journal of the American Water Resources Association》1971,7(1):124-132
ABSTRACT. .Eighteen rural lakes in Lubbock County were sampled on a routine basis following runoff-producing rainfall for a period of approximately eighteen months to determine whether or not runoff from intensively farmed agricultural areas contained significant concentrations of nitrates, phosphates, herbicides, or insecticides. An additional fifteen lakes lying within a triangle bounded by the cities of Plainview, Canyon, and Hereford, Texas, were sampled one time during the summer of 1969 to provide additional data regarding the nature and extent of the potential problem in an area with a different soil type and a slightly different cropping pattern. Based on results of detailed analyses of approximately two hundred samples of water collected from the lakes and an equal number of sediment samples collected from the same lakes at the same time, it appears that the concentrations of all chemical pollutants in runoff from agricultural lands in the High Plains are well below the allowable concentrations for drinking water. 相似文献
105.
Peter E. Black 《Journal of the American Water Resources Association》1970,6(2):153-162
Three fundamental concepts linking drainage basin characteristics, stream behavior, and management of watersheds are deduced from field data and observations. An electrical analogy of a watershed clarifies definitions and broadens understanding of this complex natural resource. The three basic principles deal with (1) the interrelationships of watershed morphology, constitution, and appearance; (2) the nature of the control man can exert over runoff-influencing forces, and (3) the efficiency of watershed management efforts. Recognition of these principles can assist educators, managers, planners and researchers to more fully inform students and to more effectively guide and evaluate management decisions. 相似文献
106.
Human impacts on the stream-groundwater exchange zone 总被引:13,自引:0,他引:13
Hancock PJ 《Environmental management》2002,29(6):763-781
Active exchanges of water and dissolved material between the stream and groundwater in many porous sand- and gravel-bed rivers
create a dynamic ecotone called the hyporheic zone. Because it lies between two heavily exploited freshwater resources—rivers
and groundwater—the hyporheic zone is vulnerable to impacts coming to it through both of these habitats. This review focuses
on the direct and indirect effects of human activity on ecosystem functions of the hyporheic zone. River regulation, mining,
agriculture, urban, and industrial activities all have the potential to impair interstitial bacterial and invertebrate biota
and disrupt the hydrological connections between the hyporheic zone and stream, groundwater, riparian, and floodplain ecosystems.
Until recently, our scientific ignorance of hyporheic processes has perhaps excused the inclusion of this ecotone in river
management policy. However, this no longer is the case as we become increasingly aware of the central role that the hyporheic
zone plays in the maintenance of water quality and as a habitat and refuge for fauna. To fully understand the impacts of human
activity on the hyporheic zone, river managers need to work with scientists to conduct long-term studies over large stretches
of river. River rehabilitation and protection strategies need to prevent the degradation of linkages between the hyporheic
zone and surrounding habitats while ensuring that it remains isolated from toxicants. Strategies that prevent anthropogenic
restriction of exchanges may include the periodic release of environmental flows to flush silt and reoxygenate sediments,
maintenance of riparian buffers, effective land use practices, and suitable groundwater and surface water extraction policies. 相似文献
107.
Three mathematical models, the runoff curve number equation, the universal soil loss equation, and the mass response functions,
were evaluated for predicting nonpoint source nutrient loading from agricultural watersheds of the Mediterranean region. These
methodologies were applied to a catchment, the gulf of Gera Basin, that is a typical terrestrial ecosystem of the islands
of the Aegean archipelago. The calibration of the model parameters was based on data from experimental plots from which edge-of-field
losses of sediment, water runoff, and nutrients were measured. Special emphasis was given to the transport of dissolved and
solid-phase nutrients from their sources in the farmers' fields to the outlet of the watershed in order to estimate respective
attenuation rates. It was found that nonpoint nutrient loading due to surface losses was high during winter, the contribution
being between 50% and 80% of the total annual nutrient losses from the terrestrial ecosystem. The good fit between simulated
and experimental data supports the view that these modeling procedures should be considered as reliable and effective methodological
tools in Mediterranean areas for evaluating potential control measures, such as management practices for soil and water conservation
and changes in land uses, aimed at diminishing soil loss and nutrient delivery to surface waters. Furthermore, the modifications
of the general mathematical formulations and the experimental values of the model parameters provided by the study can be
used in further application of these methodologies in watersheds with similar characteristics. 相似文献
108.
Integrated Resource Management: Moving from Rhetoric to Practice in Australian Agriculture 总被引:1,自引:0,他引:1
/ Implementing the concept of sustainability through integrated approaches to natural resource management poses enormous challenges for both the rural communities and government agencies concerned. This paper reviews the underlying rhetoric of sustainable agricultural systems and the integrated resource management paradigm and identifies some of the challenges being experienced in translating this rhetoric into practice. A relatively recently implemented community-based integrated catchment management (ICM) process in a rural community in northeast Australia is examined in terms of some of the lessons learned that may be relevant to other similar integrated resource management (IRM) processes. It reveals a pragmatic, opportunistic, and evolving implementation process based on adaptive learning rather than a more traditional "rational" planning approach. Some essential characteristics of a community-based IRM process are identified, including fostering communication; providing a structure that fosters cooperation and facilities coordination among community, industry, and government agencies; the integration of IRM principles into local government planning schemes; and an emergent strategic approach to IRM program implementation. We conclude by identifying some essential characteristics of an IRM process that can assist a community to adapt to, and manage change for, sustainable resource use. 相似文献
109.
Warren A. Gebert Mandy J. Radloff Ellen J. Considine James L. Kennedy 《Journal of the American Water Resources Association》2007,43(1):220-236
Abstract: The average annual base flow/recharge was determined for streamflow‐gaging stations throughout Wisconsin by base‐flow separation. A map of the State was prepared that shows the average annual base flow for the period 1970‐99 for watersheds at 118 gaging stations. Trend analysis was performed on 22 of the 118 streamflow‐gaging stations that had long‐term records, unregulated flow, and provided aerial coverage of the State. The analysis found that a statistically significant increasing trend was occurring for watersheds where the primary land use was agriculture. Most gaging stations where the land cover was forest had no significant trend. A method to estimate the average annual base flow at ungaged sites was developed by multiple‐regression analysis using basin characteristics. The equation with the lowest standard error of estimate, 9.5%, has drainage area, soil infiltration and base flow factor as independent variables. To determine the average annual base flow for smaller watersheds, estimates were made at low‐flow partial‐record stations in 3 of the 12 major river basins in Wisconsin. Regression equations were developed for each of the three major river basins using basin characteristics. Drainage area, soil infiltration, basin storage and base‐flow factor were the independent variables in the regression equations with the lowest standard error of estimate. The standard error of estimate ranged from 17% to 52% for the three river basins. 相似文献
110.
J. Marsalek T. M. Dick P. E. Wisner W. G. Clarke 《Journal of the American Water Resources Association》1975,11(2):306-328
ABSTRACT: Three urban runoff models, namely, the Road Research Laboratory Model (RRLM), the Storm Water Management Model (SWMM) and the University of Cincinnati Urban Runoff Model (UCURM), were examined by comparing the model simulated hydrographs with the hydrographs measured on several instrumented urban watersheds. This comparison was done for the hydrograph peak points as well as for the entire hydrographs using such statistical measures as the correlation coefficient, the special correlation coefficient and the integral square error. The results of the study indicated that, when applying the three selected non-calibrated models on small urban catchments, the SWM model performed marginally better than the RRL model and both these models were more accurate than the UCUR model. On larger watersheds, the comparisons between the SWM model and the other two models would be likely even more favourable for the SWM model, because it has the most advanced flow routing scheme among the studied models. 相似文献