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141.
Domestic water conservation in arid climates can result in efficient utilization of existing water supplies. The impacts of
conservation measures such as the installation of water-saving devices, water metering and pricing schemes, water rationing
and public awareness programs, strict plumbing codes, penalties for wasting water, programs designed to reduce leakage from
public water lines and within the home, water-efficient landscaping, economic and ethical incentives are addressed in detail.
Cost savings in arid climates, with particular reference to Saudi Arabia, in relation to some conservation techniques, are
presented. Water conservation technology and tentative demonstration and implementation of water conservation programs are
discussed. 相似文献
142.
Disturbance regimes,resilience, and recovery of animal communities and habitats in lotic ecosystems 总被引:6,自引:0,他引:6
Disturbance regime is a critical organizing feature of stream communities and ecosystems. The position of a given reach in
the river basin and the sediment type within that reach are two key determinants of the frequency and intensity of flow-induced
disturbances. We distinguish between predictable and unpredictable events and suggest that predictable discharge events are
not disturbances.
We relate the dynamics of recovery from disturbance (i.e., resilience) to disturbance regime (i.e., the disturbance history
of the site). The most frequently and predictably disturbed sites can be expected to demonstrate the highest resilience.
Spatial scale is an important dimension of community structure, dynamics, and recovery from disturbance. We compare the effects
on small patches (⩽1 m2) to the effects of large reaches at the river basin level. At small scales, sediment movements and scour are major factors
affecting the distribution of populations of aquatic insects or algae. At larger scales, we must deal with channel formation,
bank erosion, and interactions with the riparian zone that will affect all taxa and processes.
Our understanding of stream ecosystem recovery rests on our grasp of the historical, spatial, and temporal background of contemporary
disturbance events. 相似文献
143.
The premise of this article is that the planning and design of new rest camps in conservation areas should be based on ecological
principles in such a way that the plant ecology within the camp be an integral part and extension of the natural ecology of
its immediate vicinity. This is desirable so that visitors to the camp will be provided not only with facilities for resting,
eating, and sleeping, but also be able to enjoy and study the natural environment in a relaxed atmosphere. The Berg-en-Dal
rest camp, which was established in Kruger National Park, was planned in such a way and designed according to the principles
outlined by the authors in a companion article.
The planning included six zones: a control zone, day visitor zone, overnight visitor zone, staff accommodation zone, recreation
zone, and service zone. The point is stressed that plant species selected to be used as additional vegetation to those already
growing in the camp were endemic to the nine landscape facets identified in the camp. The design allowed for separation of
the various land-use zones in such a way that they would complement each other rather than be a hindrance to each other. The
camp has been built according to the plans included in this article and has proved to be a great success. The conclusion is
drawn that the planning principles are sound and should be used in the future for the planning and design of rest camps for
conservation areas in South Africa. 相似文献
144.
Solid waste collection services in Ilorin, Nigeria are shown to be unsatisfactory. The poor service is related to rapid population growth, insufficient data and inconsistent government policies. Surveys have been conducted to assess the quantities and types of solid waste and to show how these, in part, vary according to the nature of the land use and the properties being served. Suggestions for an improved service are offered. 相似文献
145.
Lauren E. Hay Gregory J. McCabe 《Journal of the American Water Resources Association》1998,34(1):103-112
ABSTRACT: Observed April 1 snowpack accumulations within and near the Gunnison River basin in southwestern Colorado are compared with simulations from the Rhea-orographic-precipitation model to determine if the model simulates reliable magnitudes and temporal and spatial variability in winter precipitation for the basin. Twenty simulations of the Rhea model were performed using‘optimal’parameter sets determined for 10-kilometer (km) grids (10-km by 10-km grid cells) through stochastic calibration. Comparisons of Rhea-model simulations of winter precipitation with April 1 snowpack accumulations at 32 snowcourse stations were performed for the years 1972–1990. For most stations and most years the Rhea model reliably simulates the temporal and spatial variability in April 1 snowpack accumulations. However, in general, the Rhea-model underestimates April 1 snowpack accumulations in the Gunnison River basin area, and the underestimation is greatest for locations that receive the largest amount of snow. A significant portion of the error in Rhea-model simulations is due to the calibration of the Rhea model using gauge-catch precipitation measurements which can be as much as 50 percent below actual snowfall accumulations. Additional error in the Rhea-model simulations is a result of the comparison of gridded precipitation values to observed values measured at points. 相似文献
146.
Indicators and indices are important tools that assist decision makers to formulate and implement plans for management at local, national and international levels. Four indicators for hazardous waste management are described that have recently been adopted within the United Nations framework of Indicators of Sustainable Development. Although these four indicators will be useful tools, the need for a broader range of policy-relevant qualitative and quantitative indicators, proxy indicators and indices is outlined. The argument is advanced that in order for all nations to better manage the range of hazardous waste issues, including waste generation, export/import and disposal, a set of innovative indicators and indices is required. Useful indicators and indices are described that could be used to link and quantify likely environmental, ecosystem and health impacts and risks especially from hazardous waste disposal. Indicators are also suggested that could be used to illustrate the shift in industrial strategy away from end-of-pipe processes towards waste recycling, cleaner production and integrated life-cycle analysis. It was concluded that until the lack of reliable and harmonized data on hazardous waste is addressed, indicator development and use by national and international decision makers cannot readily be implemented. 相似文献
147.
Jamie W. Baxter John D. Eyles Susan J. Elliott 《Journal of Environmental Planning and Management》1999,42(4):501-525
This paper contributes to the noxious facilities siting literature by exploring some implications of adhering to some recommended principles and practices for competent siting. Through a qualitative case study of a landfill siting process in Peel (Ontario, Canada) three principles are critically assessed: trust; equity; and community participation. While laudable notions in principle, in practice they can impact each other in important ways which can (potentially) undermine the siting process. These impacts result mainly from the failure to achieve meaningful goals associated with one principle (e.g. community participation) which can exacerbate problems achieving goals associated with other principles (e.g. trust). The resulting discord can be further aggravated by the snowballing of adverse effects over time. In particular, practices for achieving trust and equity were adversely linked, as were the relationships between spatial equity and procedural equity and interregional and intraregional equity. These adverse synergisms were linked together with ineffective community participation which brought the process to a halt. Siting inertia (a process momentum difficult to redirect) and an inflexible siting context contributed to these conflicts. Implications for siting and further research are discussed. 相似文献
148.
The Clean Air Act Amendments of 1977 designated national parks and wilderness areas larger than 1894 ha to be class I areas
for air quality management, setting more restrictive criteria than the National Ambient Air Quality Standards. Class I areas
are afforded the greatest degree of air quality protection under the Clear Air Act of 1970. In recent years, several studies
have documented air pollution effects in the Great Smoky Mountains National Park (GSMNP), the second-largest class I area
in the eastern United States. Air pollution problems of greatest concern in the GSMNP are effects of acid deposition, visibility
impairment, and tropospheric ozone. Several recent events have increased concerns about air quality management in the class
I area of the GSMNP. A forum, sponsored by the Southern Appalachian Man and the Biosphere Cooperative (SAMAB), was held in
March 1992, which involved representative. parties-at-interest and began to address strategies for better management of air
resources in the Southern Appalachians. This paper summarizes those discussions and recommendations and reports actions occurring
as a result of the forum. Another objective of this paper is to present a conceptual framework for more effective management
of the class I area of the GSMNP. 相似文献
149.
150.