首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Summary In Queensland, Australia, instream resources planning ranges from "fragmentary" to overlooked. But the State of Queensland, with engineer dominant water management, is only a little behind some other Australian States and Western countries in evaluating the environmental uses and values of river systems. Management is pragmatic about its abundant water endowment! Highly contrasting biophysical environments, from arid to tropical rainforest, as well as a dominance of ephemeral river systems should not preclude instream assessment. The new coastal $A430 million, Burdekin Falls Dam, the "1800's dream" has radically altered that river and delta region for economically amorphous agricultural purposes and, seemingly, to encourage crocodiles to recreate. In comparison, the "urbanised" Brisbane River is the focus of southern state water use competition issues such as flooding, eutrophication, turbidity, public access, preservation of river islands, sand and gravel mining, and recreation. A veritable host of river related management authorities preside!Dr Diana Day is trained as a fluvial geomorphologist and a water policy analyst. Her research has focused on natural resources management especially related to water and soil/land assets. Dr Day is an editor of the newAustralian Journal of Soil and Water Conservation. Her many publications include a recent book entitledWater and Coal -Industry, Environment and Institutions in the Hunter Valley, N.S.W., published by The Australian National University, Canberra, where until recently she was a Research Fellow. Dr Day is currently a Water Planner in the public sector.  相似文献   

2.
水生态环境保护事关美丽中国目标的实现。本文阐释了我国从水污染防治向水环境、水生态、水资源“三水”统筹转变的新时代水生态环境保护内涵,从国内视角梳理我国水污染防治实践取得的成效,识别美丽中国水生态环境保护面临的制约性问题,首次在全国层面与欧美发达国家的水环境质量、水生态保护和水资源保障情况进行国际对标分析,提出以水生态系统保护目标为指引、以流域生态环境空间管控为基础、以“三水”统筹系统治理为路径、以治理体系和治理能力现代化为保障的水生态环境保护战略建议。  相似文献   

3.
有毒重金属污染已成为我国的重大环境问题。对有毒重金属污染进行有效监管,首先,必须明确认定,对第一类污染物实施《源头总量控制》是污控执法和促进经济结构改革的保证条件。这种监管方式自2008年《笫一次全国污染源普查工业产排污系数手册》公布以来,更具有切实实施的可行性。《源头总量控制》与《水环境容量总量控制》两种监管方式既是各自独立、缺一不可,又是相互依赖和相互补充的关系,目前一些地方的规划管理者模糊和混淆了两类污染物和两种监管的内容和方式,笼统以《水环境总量控制》来监管所有污染物,丢弃了《源头总量控制》,使本应严加管理的饮用水水源地丧失了控制第一类污染物的能力。我国《地面水环境质量标准》(GB3838-88)中第一类污染物的水质指标与我国实际的水环境背景值有很大差距,存在"放宽允排量"和"价态转化引发危害"的问题,以一个10t电解铅的企业为例,证明两种监管方式的铅允排量相差甚大。总之,把第一类污染物与第二类污染物统一实施《水环境容量总量控制》将带来众多的危害,应当严格实施《源头总量控制》与《水环境总量控制》相结合的监管方式。  相似文献   

4.
Abstract: In efforts to control the degradation of water quality in Lake Tahoe, public agencies have monitored surface water discharge and concentrations of nitrogen, phosphorus, and suspended sediment in two separate sampling programs. The first program focuses on 20 watersheds varying in size from 162 to 14,000 ha, with continuous stream gaging and periodic sampling; the second focuses on small urbanized catchments, with automated sampling during runoff events. Using data from both programs, we addressed the questions (1) what are the fluxes and concentrations of nitrogen and phosphorus entering the lake from surface runoff; (2) how do the fluxes and concentrations vary in space and time; and (3) how are they related to land use and watershed characteristics? To answer these questions, we calculated discharge‐weighted average concentrations and annual fluxes and used multiple regression to relate those variable to a suite of GIS‐derived explanatory variables. The final selected regression models explain 47‐62% of the variance in constituent concentrations in the stormwater monitoring catchments, and 45‐72% of the variance in mean annual yields in the larger watersheds. The results emphasize the importance of impervious surface and residential density as factors in water quality degradation, and well‐developed soil as a factor in water quality maintenance.  相似文献   

5.
Ethanol fuels: Energy security,economics, and the environment   总被引:6,自引:0,他引:6  
Problems of fuel ethanol production have been the subject of numerous reports, including this analysis. The conclusions are that ethanol: does not improve U.S. energy security; is uneconomical; is not a renewable energy source; and increases environmental degradation. Ethanol production is wasteful of energy resources and does not increase energy security. Considerably more energy, much of it high- grade fossil fuels, is required to produce ethanol than is available in the energy output. About 72% more energy is used to produce a gallon of ethanol than the energy in a gallon of ethanol. Ethanol production from corn is not renewable energy. Its production uses more non- renewable fossil energy resources in growing the corn and in the fermentation/distillation process than is produced as ethanol energy. Ethanol produced from corn and other food crops is also an unreliable and therefore a non-secure source of energy, because of the likelihood of uncontrollable climatic fluctuations, particularly droughts which reduce crop yields. The expected priority for corn and other food crops would be for food and feed. Increasing ethanol production would increase degradation of agricultural land and water and pollute the environment. In U.S. corn production, soil erodes some 18- times faster than soil is reformed, and, where irrigated, corn production mines water faster than recharge of aquifers. Increasing the cost of food and diverting human food resources to the costly and inefficient production of ethanol fuel raise major ethical questions. These occur at a time when more food is needed to meet the basic needs of a rapidly growing world population.  相似文献   

6.
This study simulated crop and water yields in the Missouri River Basin (MRB; 1,371,000 km2), one of the largest river basins in the United States, using the Soil and Water Assessment Tool (SWAT) at a fine resolution of 12‐digit Hydrological Unit Codes (HUCs) using the regionalization calibration approach. Very few studies have simulated the entire MRB, and those that have developed were at a coarser resolution of 8‐digit HUCs and were minimally calibrated. The MRB was first divided into three subbasins and was further divided into eleven regions. A “head watershed” was selected in each region and was calibrated for crop and water yields. The parameters from the calibrated head watershed were extrapolated to other subwatersheds in the region to complete comprehensive spatial calibration. The simulated crop yields at the head watersheds were in close agreement with observed crop yields. Spatial validation of the aggregated crop yields resulted in reasonable predictions for all crops except dryland corn in a few regions. Simulated and observed water yields in head watersheds and also in the validation locations were in close agreement in naturalized streams and poor agreement in streams with high groundwater‐surface water interactions and/or reservoirs found upstream of the gauges. Overall, the SWAT model was able to reasonably capture the hydrological and crop growth dynamics occurring in the basin despite some limitations.  相似文献   

7.
ABSTRACT: Climate variations can play an important, if not always crucial, role in successful conjunctive management of ground water and surface water resources. This will require accurate accounting of the links between variations in climate, recharge, and withdrawal from the resource systems, accurate projection or predictions of the climate variations, and accurate simulation of the responses of the resource systems. To assess linkages and predictability of climate influences on conjunctive management, global climate model (GCM) simulated precipitation rates were used to estimate inflows and outflows from a regional ground water model (RGWM) of the coastal aquifers of the Santa Clara‐Calleguas Basin at Ventura, California, for 1950 to 1993. Interannual to interdecadal time scales of the El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) climate variations are imparted to simulated precipitation variations in the Southern California area and are realistically imparted to the simulated ground water level variations through the climate‐driven recharge (and discharge) variations. For example, the simulated average ground water level response at a key observation well in the basin to ENSO variations of tropical Pacific sea surface temperatures is 1.2 m/°C, compared to 0.9 m/°C in observations. This close agreement shows that the GCM‐RGWM combination can translate global scale climate variations into realistic local ground water responses. Probability distributions of simulated ground water level excursions above a local water level threshold for potential seawater intrusion compare well to the corresponding distributions from observations and historical RGWM simulations, demonstrating the combination's potential usefulness for water management and planning. Thus the GCM‐RGWM combination could be used for planning purposes and — when the GCM forecast skills are adequate — for near term predictions.  相似文献   

8.
ABSTRACT: Following an enclosure of a sink-hole connecting Lake Tarpon to the Gulf of Mexico, the chloride concentration of lake waters decreased. Water and chloride budgets for the lake in 1975 were prepared, and predictions using the model of Lerman and Brunskill (1971) were made as to the time required for the lake to achieve fresh water status. Model verification indicated good agreement with predictions in 1976; however, data on [C1-] for 1977 and 1978 are not as supportive of the model used. The information concerning the Lake Tarpon watershed provided by this latter fact is discussed.  相似文献   

9.
The construction of artificial wetlands has become a measure increasingly applied to reduce nonpoint-source (NPS) pollution and to contribute to the restoration of eutrophic lakes and coastal waters. In a 2-yr study monitoring fluxes of particulate and dissolved phosphorus (P) in a small artificial wetland for the treatment of agricultural drainage water in Central Switzerland, water residence time was identified as the main factor controlling P retention in the system. Since most of the annual P load (62% as dissolved reactive phosphorus, DRP) was related to high discharge events, it was not average but minimum water residence time during flood events that determined the wetland's P retention. In agreement with a continuous stirred tank reactor (CSTR) model, our investigations suggest a minimum water residence time of 7 d to retain at least 50% of the bioavailable P. The investigated wetland retained only 2% of the bioavailable P, since the water residence time was shorter than 7 d during 61% of time in both years. Settling of phytoplankton rather than DRP uptake into phytoplankton limited the retention of bioavailable P. The overall retention efficiency of 23% total phosphorus (TP), corresponding to a surface related retention of 1.1 g P m(-2) yr(-1), was due to the efficient trapping of pedogenic particles.  相似文献   

10.
In China's west since the 1950s large-scale ecosystem degeneration has occurred through water diversions for agricultural purposes. Since 2000, 1038 x 10(6) m(3) of water have been released into the Tarim River with the result that water reached the terminal Taitema Lake for the first time in 30 years. This environmental flow raised water-table levels along 350 km of the river. To assess the response of the water-table, a comparison "pristine" site is compared with downstream monitored sites. The results show huge changes in water-table levels. The study verifies that the water-table is extremely responsive to environmental flows, that strong internal similarities exist along the length of the river, and that the effect on the water-table and hence likely riparian vegetation recovery can be tentatively predicted. The actual impacts of the restoration strategy are less than those originally expected politically, socially and within the scientific community. We make recommendations on more effective release strategies.  相似文献   

11.
Ambient water quality and bacterial populations in the water resources of Pulau Perhentian, a Marine Park of Malaysia, were studied during a peak tourist arrival, off-monsoon period. The overall water and bacteriological quality of swimming/boating sites in the island is at an acceptable condition, although the conductivity (0.88–60 mS m–1) due to high dissolved solid concentrations is slightly high, when compared with the recommended standard and published guidelines for the protection/maintenance of recreation water and its aesthetic enjoyment (Universiti Malaya, Department of Environment, Malaysia, 1986). However, the bacteriological quality of the drinking/bathing water wells is poor, with faecal coliform counts (2 up to 1,600 MPN per 100 ml sample water) exceeding the permissible levels defined for raw water supplies (with or without treatment). This suggests that the groundwater, seepage and run-off into the wells is contaminated. Contrary to the belief of the water users being interviewed in a social survey, the untreated drinking/bathing water is not bacteria-free. The excessive counts are attributable to deoxygenated conditions (12–42 percent corresponding to 0.9–3.3 mg l–1) prevailing in the wells, high total suspended solids (up to 202 mg l–1) which promote bacterial growth, lack of adequate sewerage systems to receive effluents from lavatories of dwellings, chalets and resorts, as well as the lack of centralised water treatment plants and storage tanks to cope with water scarcity and waterway contamination.  相似文献   

12.
Abstract: Residential water demand is a function of several factors, some of which are within the control of water utilities (e.g., price, water restrictions, rebate programs) and some of which are not (e.g., climate and weather, demographic characteristics). In this study of Aurora, Colorado, factors influencing residential water demand are reviewed during a turbulent drought period (2000‐2005). Findings expand the understanding of residential demand in at least three salient ways: first, by documenting that pricing and outdoor water restriction policies interact with each other ensuring that total water savings are not additive of each program operating independently; second, by showing that the effectiveness of pricing and restrictions policies varies among different classes of customers (i.e., low, middle, and high volume water users) and between predrought and drought periods; and third, in demonstrating that real‐time information about consumptive use (via the Water Smart Reader) helps customers reach water‐use targets.  相似文献   

13.
This article discusses the attempts by the Working Group of the UN General Assembly's 6th Committee, which held its first session from 7 to 25 October 1996, to elaborate a framework convention on the Law of the Non-navigational Uses of International Watercourses. The Convention is based on the 1994 draft articles by the International Law Commission, and is intended to have a residual character. As such it will apply to States parties in the absence of specific watercourse agreements, and serve as a guideline. However, the persistence of a fragmented defence of short-term national self-interest on the part of many delegations prevented the finalization of a universal legal instrument in the first round of the negotiations. The major stumbling blocks relate to the natural adversarity between "upstream" and "downstream" riparians. Deep seated conflicts of interest were particularly prominent in discussions of concepts such as the "equitable utilization principle" vis-à-vis the "no-harm rule" (art. 7), the concept of "optimal utilization" (art. 5); the determination of when a particular use is "equitable and reasonable" (art. 6); constraints on the freedom of exploitation of natural resources (art. 7); and the obligation to notify co-riparians of planned measures which may have adverse effects upon other watercourse states (arts. 11–19). Despite many obstacles, the Working Group made considerable progress in identifying language that would balance respective interests in the Convention. It is hoped that agreement may be reached on the final text during the next session, scheduled for 24 March–4 April 1997 While the present article traces the deliberations at the UN in October 1996, and some of the main conflicts, a separate article by Maurizio Arcari in the forthcoming August 1997 issue of Natural Resources Forum will discuss the draft articles submitted by the International Law Commission.  相似文献   

14.
Assistant Professor in Human Ecology, in the Indira Gandhi Centre for Human Ecology, Environment and Population Studies at the University of Rajasthan. Although fluorine is an essential element for human growth and development, its intake in excessive amounts beyond the permissible limits can be very harmful. Dental and skeletal fluorosis are some of the common afflictions of fluorine poisoning and it can even have crippling effects in aged individuals. With the rise in industrialization fluoride contamination is increasing in the human environment as it is a basic component of the ground water. Certain regions of India, particularly the arid zones of Rajasthan, have serious fluoride problems and it has become a serious health hazard in several villages of Rajasthan.  相似文献   

15.
Contamination of unfenced streams with P, sediments, and pathogenic bacteria from cattle (Bos taurus) activity may be affected by the availability of shade and alternative water sources. The objectives of this study were to evaluate water quality in two streams draining tall fescue (Festuca arundinacea Schreb.)-common bermudagrass (Cynodon dactylon L.) pastures with different shade distribution, and to quantify the effects of alternative water sources on stream water quality. For 3 yr, loads of dissolved reactive phosphorus (DRP), total phosphorus (TP), and total suspended solids (TSS) were measured during storm flow, and loads of DRP, TP, TSS, and Escherichia coli were measured every 14 d during base flow. We also used GPS collars to determine amount of time cattle spent in riparian areas. Our results showed that cattle-grazed pastures with unfenced streams contributed significant loads of DRP, TP, TSS, and E. coli to surface waters (p < 0.01). Time spent by cattle in riparian areas as well as storm flow loads of DRP, TP, and TSS were larger (p < 0.08) in the pasture with the smaller amount of nonriparian shade. Water trough availability decreased base flow loads of TSS and E. coli in both streams, and decreased time cattle spent in riparian areas in the pasture with the smaller amount of nonriparian shade (p < 0.08). Our results indicate that possible BMPs to reduce contamination from cattle-grazed pastures would be to develop or encourage nonriparian shade and to provide cattle with alternative water sources away from the stream.  相似文献   

16.
ABSTRACT Evaporation is identified as having two additive components: natural evaporation in the absence of wind and forced evaporation in the presence of wind. An evaporation equation is obtained for an open body of water exposed at the atmosphere by conversion of standard horizontal flat plate heat transfer relationships to a mass transfer or evaporation equation. For an average air temperature of 68°F, the final equation for evaporative heat flux is A comparison of numerical values predicted by the above equation is made with evaporation equations deduced from field measurements, and the agreement is favorable. The major differences between this equation and those previously developed are: a) the above equation was derived strictly from standard heat transfer expressions, and b) a dependency of average fetch and air temperature (through transport properties) is shown. This approach establishes the correct dependencies of the field parameters so that future experimental measurements will have a sound theoretical basis.  相似文献   

17.
Summary The paper reviews emerging international principles of environmental protection, as well as their refinement, during the last two decades of implementation. It is argued that international efforts were primarily directed towards the prevention of transfrontier pollution and could only succeed if there was agreement on the meaning of the term pollution. The concept of pollution is therefore explored in some detail. Confusion about the meaning of pollution, combined with the impact of international regulation (both global and European) on British practice, help to explain some of the fundamental problems now facing the traditional British pollution control regime, especially its legal and philosophical basis. It is argued that recent and proposed administrative changes will be insufficient to comply with European expectations. Political changes and a more active involvement by the judiciary and the public may be required.Dr Sonja Boehmer-Christiansen is a Research Fellow at the Science Policy Research Unit of the University of Sussex. She obtained her first degree in Geography from the University of Adelaide and her D Phil in International Relations from the University of Sussex.  相似文献   

18.
Water security: Old concepts,new package,what value?   总被引:1,自引:0,他引:1  
“Water security” has come to infiltrate prominent discourse in the international water and development community, and achieving it is often viewed as a new water sector target. Despite the elevated status that the concept has increasingly acquired, understandings of the term are murky and quantification is rare. To promote a more tangible understanding of the concept, this paper develops an index for evaluating water security at a country level. The index is comprised of indicators in five components considered to be critical to the concept: (i) basic needs; (ii) agricultural production; (iii) the environment; (iv) risk management; and (v) independence. Achieving water security in these components can be considered necessary but insufficient criteria to measure the achievement of security in related areas such as health, livelihoods, and industry. After populating indicators with data from Asia‐Pacific countries, results are interpreted and the viability of methods is discussed. This effort comprises an important first step for quantifying and assessing water security across countries, which should spur more concrete understanding of the term and discussion of its added value.  相似文献   

19.
New ideas about conserving wildlife are emerging to compete with conventional national park policies. But methods of analyzing wildlife conservation problems in Africa are inadequate for the analysis of complex issues of policy. Much of the analysis of conservation policy attempts to be apolitical on issues charged with social conflict. Analyses are too often ahistorical when history can say a great deal about the origins of present-day ecological problems. Further-more, problems are commonly analyzed within narrow discilinary frameworks which predetermine the nature of conclusions and lead to professionally biased proposals. This case study of the Luangwa Valley, Zambia, is used to demonstrate a method which attempts to remedy these weaknesses,In the first part of the article we examine the role of the Luangwa National Parks in the context of the Zambian political economy, and identify social groups which compete for the resources of the national parks. Next we trace the historical origins of present-day ecological changes. These analyses lead toward a model of the Parks and some of their relationships with the national economy. We end with a proposal for communal use of wildlife which attempts to resolve some of the contradictions inherent in current policy.  相似文献   

20.
Climate change is one of the major worldwide environmental concerns. It is especially the case in many developed countries, where the greenhouse gas emissions responsible for this change are mainly concentrated. For the first time, the Kyoto Protocol includes an international agreement for the reduction of the net emissions of these gases. To fulfil this agreement measures designed to reduce or limit current emissions have to be brought into force. Consequently, fears have arisen about possible consequences on competitiveness and future development of manufacturing activities and the need for support mechanisms for the affected sectors is obvious. In this paper, we carry out a study of the emissions of gases responsible for climate change in Asturias (Spain), a region with an important economic presence of sectors with intensive emissions of CO(2), the chief greenhouse gas. To be precise, in the first place, the volumes of direct emissions of the said gases in 1995 were calculated, showing that the sectors most affected by the Kyoto Protocol in Asturias are iron and steel and electricity production. Secondly, input-output analysis was applied to determine the direct and indirect emissions and the direct, indirect and induced emissions of the different production sectors, respectively. The results derived from the direct and indirect emissions analysis and their comparison with the results of the former allow us to reach some conclusions and environmental policy implications.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号