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.
An annual water balance model for Wadi Rajil, in Northern Jordan, is used to simulate the ancient water supply system for the Early Bronze Age site of Jawa. The model includes: water delivery from the catchment; local pond storage; and water demand for people, animals and irrigation. A Monte Carlo approach is used to incorporate the uncertainty associated with a range of factors including rainfall, evaporation, water losses and use. The stochastic simulation provides estimates of potential population levels sustainable by the water supply system. Historical precipitation estimates from a Global Circulation Model, with uncertainty bounds, are used to reconstruct the climate at Jawa in the Early Bronze Age (EBA). Model results indicate that the population levels in the predicted wetter conditions during parts of the EBA could have risen to ∼6000 and may have been higher in wet years. However, palaeoclimatic proxies also suggest prolonged droughts in the EBA; and during these periods the water management system was unable to provide adequate supply for a population of 6000. The utility of Monte Carlo based hydrological modelling as a tool within archaeological science is discussed.  相似文献   

2.
3.
Abstract

Flushing time (Tf) is an important factor which determines the hydrological, ecological and chemical functioning of lakes. However, it has never been calculated on the basis of underground supply for Polish Lakes. Due to their high altitudes, the lakes in question constitute a distinctive group among the ??czna-W?odawa Lakes. They are located in the borderland of the Cretaceous Che?m Hills (part of the Polish Uplands) and Polish Lowland. The quantity of the underground water supply was one of the key factors which make these lakes so distinctive. During periods of low precipitation, water shortages occurred in the lakes, especially Pniówno and Syczyńskie. The ??czna-W?odawa Lakes are commonly distinguished, among other Polish water bodies, as super-passive due to their water flushing time (>10 years). However, the average flushing time of the water in lakes Tarnowskie, Chuteckie, Pniówno and Syczyńskie, based on the underground supply, amounted to 606, 211, 54 and 79 days, respectively. The territorial conditions (e.g. geologic structure of catchment areas or thickness of unsaturated and saturated zones) were the most important factors that determined seasonal fluctuations of the supply to the lakes.  相似文献   

4.
In the mid-1980s, fiscal incentives were introduced to encourage the construction and refurbishment of residential developments in declining inner-city districts in Ireland. These were abolished in 2006 but, during the intervening period, their focus was extended to include: large towns, small towns and a large rural region. Concurrently, the context for their implementation changed as an economic boom replaced prolonged economic stagnation. This article examines the changing design of these incentives, their outputs and their intended and unintended impacts. It argues that, initially they were successful in drawing development into declining neighbourhoods, but the extension of their lifespan and spatial focus created negative perverse impacts and deadweight costs for the exchequer. Thus it concludes that this regeneration strategy is useful for animating development in brownfield sites, where there is demand for housing but also barriers to its development. If applied to rural areas where housing demand is weaker, they can generate excess supply and limited benefits for public investment.  相似文献   

5.
Emerging and future climatic change across the Australian continent has been identified as a significant threat to the successful sustainable management of the nation's water resources. However, the impacts of climate change must be viewed within the context of past, present and future climatic variability and human agency. A qualitative screening‐level risk assessment was undertaken for Australia's 325 surface water management areas by aggregating a suite of six relevant risk indicators. Four indicators addressed the antecedent conditions upon which future climate change will act. These included 50‐year trends in rainfall, the status of surface and groundwater development, and catchment condition. Two indicators addressed future drivers of supply and demand; specifically, projected changes in runoff and population. The results indicate that the management challenges currently experienced in Australia's population centres and key agricultural areas such as the Murray‐Darling Basin are likely to increase in future decades. Furthermore, the geographic distribution of net risk, inclusive of multiple biophysical and socioeconomic drivers, is more extensive than is suggested by consideration of surface water development and availability alone. Comparison of at‐risk catchments with the spatial distribution of various social and environmental assets identified a high degree of overlap among catchment risk and human populations, water storages, irrigated agricultural land, and wetlands of international significance. This suggests that the catchments of the greatest value are also those judged to be at greatest risk. Though considerable work remains in evaluating the security of Australia's water resources to climatic and other stressors, this study provides a first‐order scheme for prioritising the risks to which catchments are exposed and an assessment of how some key drivers are likely to interact to drive risk.  相似文献   

6.
An assessment of slope erosion at Tin Camp Creek catchment, Arnhem Land, Northern Territory, Australia, was carried out using the fallout environmental radioisotope caesium‐137 (137Cs) as an indicator of soil erosion status, two numerical models (SIBERIA and the Revised Universal Soil Loss Equation (RUSLE)) and erosion pins. This undisturbed drainage basin is situated in the seasonally wet‐dry tropics, with high energy storms and a mean annual rainfall of 1389 mm. Tin Camp Creek catchment is unaffected by European agriculture or pastoral activities, but often experiences fire during the dry season. Two transects were sampled for 137Cs in 2002 and 2004, and two models were used to convert 137Cs measurements into soil loss estimates. Two methods using the theoretical Profile Distribution Model (PDM) gave net soil redistribution rates between +2.72 and –22.19 t ha?1 yr?1 and +2.95 and –24.06 t ha?1 yr?1, respectively, while an Australian empirical model (AEM) for uncultivated soils produced estimates between +1.84 and –7.00 t ha?1 yr?1 (negative values indicate soil erosion, positive, deposition). The RUSLE gave estimated soil losses for the two transects of approximately 10 t ha?1 yr?1, while the SIBERIA model produced values between 0.5 and 2 t ha?1 yr?1 for the transects and between 3.5 and 11 t ha?1 yr?1 for the total catchment. Average net soil losses of 14 and 15 t ha?1 yr?1 for the total catchment and slopes, respectively, were measured by erosion pins. The soil losses in the catchment are similar to those for some other transects in the Northern Territory and the Kimberley region of Western Australia (measured by the 137Cs AEM), even though these areas are affected by pastoral activities. This may be at least partly explained by erosion in Tin Camp Creek catchment during high intensity rainstorms at the commencement of the wet season, especially if the slopes have been affected by fire during the previous dry season.  相似文献   

7.
Annual flow records, monthly flow records, peak and low flow records were used to derive an objective hydrological regionalization for 77 Tasmanian rivers. Twelve hydrological indices were determined, and the 12 × 77 matrix was analysed using principal coordinates analysis and complete linkage cluster analysis. Four groups were determined for Tasmania, with the south-east region of the island exhibiting hydrological regimes similar to those of the drier areas of mainland Australia. The wettest areas, in the south and west, have regimes with no analogue elsewhere within mainland Australia. Significant least-squares relationships between the variables enables catchment area, mean annual runoff and coefficient of variation of annual flows to be used to extrapolate other hydrological indices.  相似文献   

8.
Medium to large natural catchments are often more spatially heterogeneous than small catchments or single landforms. Attempting to model landform evolution of large areas is consequently more complex. This paper demonstrates that modelling landform evolution in medium to large catchments can be improved by calibrating the model to smaller, more geomorphologically homogenous sub‐catchments. The paper investigates landform evolution in the Ngarradj catchment in the Northern Territory of Australia (a medium scale catchment of approximately 67 km2). The catchment is complex and contains two distinct landform regions; an upland plateau region with highly dissected sandstone and shallow, sandy soils, and a lowlands region with gentle, wooded slopes and floodplains with deep, sandy soils. The SIBERIA landform evolution model is calibrated and applied to the Ngarradj catchment. The complexity of the Ngarradj catchment is incorporated into the modelling by dividing the catchment into three sub‐catchments (Swift Creek (SC), Upper Main (UM) and East Tributary (ET)) which are relatively homogeneous and for which hydrology and sediment transport data are available. A discharge‐area relationship and long‐term, sediment loss rates for the catchment are derived based on an annual series flood frequency analysis of a 20 year runoff record predicted in a previous study. Sediment transport modelling incorporates both suspended and bedload sediment loss. The denudation rates derived using these data are 37, 63 and 77 mm kyr?1 for the SC, UM and ET sub‐catchments, respectively. Model predictions indicate that the UM sub‐catchment will have the greatest mean erosion. This is balanced by the large amount of deposition that will occur in the upper Ngarradj valley of the UM sub‐catchment. Further deposition occurs on the floodplain of Ngarradj, with the area between the SC and ET/UM (up‐stream) sub‐catchments experiencing a small net accretion of sediment (15 mm kyr?1).  相似文献   

9.
Summary. This study, based on evidence from archaeological surveys and excavations in southern Greece, demonstrates two major shifts in the subsistence economy during the Neolithic. In the EN and MN periods the presence of large villages in locations near reliable water-sources and permanently moist or seasonally flooded soils of high and sustained productivity illustrates a village farming economy concentrating on arable agriculture. The first economic shift occurred in the late MN-LN with occupation of highland caves and islands, indicating increased sheep/goat pastoralism, fishing, and perhaps hunting, with a reduced number of farming villages present in the plains. The second shift took place in the FN-EBA, when a dispersal of agricultural settlements into dry upland regions indicates expanding plough agriculture and pastoralism, important factors contributing to the development of the flourishing EBA economy. The expansion of settlement was most marked in southeastern Greece, and it is suggested here that the extensive grazing areas provided by the open vegetation and mountainous terrain of this dry region, and its relative scarcity of well-watered fertile lowlands, may have stimulated the LN-FN expansion of pastoralism.  相似文献   

10.
以湖北省内A级景区和客源地为研究对象,运用数理统计和空间计量方法系统探究旅游供需的空间结构特征.结果表明:①湖北省旅游供需要素具有较强的集聚分布态势,供需状况整体较差且区域差异显著,呈现明显的资源和人口指向性;②客源密集的江汉平原腹地和交通不便、高等级景区稀疏的外围边缘山区供需联系强度较低,高等级景区集聚的区域供需联系...  相似文献   

11.
The Blue Mountains region of New South Wales, including the World Heritage listed Blue Mountains National Park, is arguably one of Australia's most highly valued and iconic wilderness areas. Common to this region are upland swamps (formally ‘temperate highland peat swamps on sandstone’), which play a vital hydrological role at the headwaters of the river catchments, as well as providing the habitat for an array of flora and fauna species. This paper involves an interdisciplinary examination into the need and potential for adaptive management in the Blue Mountains. It uses geomorphic (physical) knowledge of swamp condition and social data about the volunteers who rehabilitate them. Research involved using the River Styles river condition framework across 47 swamps and questionnaires and interviews with local rehabilitation volunteers. It is proposed that there is a need and a potential to combine geomorphic understanding with further engagement of community volunteers in order to enable an interdisciplinary approach to adaptive management. Such an approach could result in the effective environmental management of upland swamps in the Blue Mountains.  相似文献   

12.
Sydney's water crisis has been attributed to long-term drought, a population growing at >50 000 a year, the early impacts of global warming and the demands of a 4.2 million population leading a water-thirsty lifestyle. In this paper the drought is linked with a return to a drought-dominated flow regime in eastern New South Wales. This began in 1991 and is associated with a shift from flood to drought domination that occurs every 20 to 50 years. Its impacts will be further exaggerated by global warming. The reduction of runoff into Sydney's reservoirs is due primarily to regime shift, resulting in the diminution of inflows to about 25% of their levels in the 42 years before 1991. Possible ways of managing these dwindling water resources include building more reservoirs, exploiting largely unknown sources of groundwater, constructing a desalination plant, harvesting rainwater in the city, recycling used urban water and reducing individual water use. Despite arguments against the first three of these options, a desalination plant is currently under construction and investigations of deep groundwater proceed (shelved 18th June, 2008). Given that sources of water are distant and located in areas where rainfall reductions have been significant, greater efforts should be made to use water already in the city (rainfall and recycled water). Water restrictions and better domestic management of water are also areas where great savings can be and have been made.  相似文献   

13.
Pollen analyses are presented spanning the Bronze and Iron Ages at two sites within one river catchment in north east Scotland, one upland and one lowland site, to test the hypothesis that subsistence agricultural communities relocated their activities in response to major climatic deterioration at the end of the Bronze Age. Such responses were identified, involving the probable cessation of arable farming around the upland site and increases in the intensity of anthropogenic impacts around the lowland site. These changes are consistent with a model that posits a restructuring of agricultural activities, but are not considered indicative of settlement abandonment in the face of climatic stress.  相似文献   

14.
This article summarizes the evolution of consumption in Germany in the last decades with special focus on the intricacy of demand. The authors discuss some established approaches of marketing and compare it with the actual impact of basic meta trends. Further, the impact of consumption on establish retail locations and new areas to supply is discussed.  相似文献   

15.
This article argues that the persistence of non-capitalist dimensions within land relations in the Philippines is basic to rural livelihood strategies, and has been a major but widely-neglected factor in the failure of land reform programmes. Addressing the issue of non-capitalist relationships brings into focus the indigenous or ‘customary’ land tenure relationships that exist in lowland land tenure arrangements, with the result that the conventional dichotomy between lowland and upland ‘cultural minority’ land relations becomes spurious. The article offers some suggestions as to why, for the major part of this century, the indigenous norms of lowlanders have been overlooked, with a discussion which links up to issues of national identity and nation building.  相似文献   

16.
Ancient cultures have a wide range of water control management techniques, each associated with a particular purpose, including water for consumption, agriculture, flood control, drought relief, and rituals (Scarborough, 2003). One technique that has received limited archaeological attention is the purposeful creation of water pressure to perform useful work. Perhaps the earliest such example was found on the island of Crete in a Minoan palace and dates as early as 1400 BC. Terracotta pipe segments with graded diameter reductions were used to create fountains (Evans, 1921–1935). Although gravity and the weight of water are the most efficient means of generating water pressure in a closed conduit, natural conditions (climate, geology, topographic slope, etc.) that might lead to the construction of water pressure systems are less clear. Here we show that the Classic Maya (AD 250–600) constructed a water pressure system with the potential to control the flow of water within an urban area. By burying a conduit along a steep ephemeral channel passing through a residential group, upland springs could be diverted to build pressure in the conduit to provide a dry-season supply of water. Up to 6 m of hydraulic head could have been recovered to lift water from the pressurized conduit to a point of use. Water pressure systems were previously thought to have entered the New World with the arrival of the Spanish. Yet, archaeological data, seasonal climate conditions, geomorphic setting, and simple hydraulic theory clearly show that the Maya of Palenque in Chiapas, Mexico had empirical knowledge of closed channel water pressure predating the arrival of Europeans.  相似文献   

17.
A noted Japanese economist analyzes the history, present status, and future prospects for Russo-Japanese economic relations. The author demonstrates that the boom in trade between the two countries in the 2000s is unprecedented, ending the stagnation in bilateral trade that began in the early 1980s, when the era of large-scale Siberian resource development projects came to an end. He argues that underlying the current boom is an eastward shift in the Russian economy, characterized by its energy and investment policies as well as foreign economic relations. The paper considers in detail two important factors supporting this boom: (1) Japan’s exports of automobiles to Russia; and (2) Russia’s exports of oil and gas to Japan. He concludes with a guardedly optimistic prognosis suggesting growth in the bilateral economic relations on the grounds of the continuing eastward shift of the Russian economy and a marked correspondence between the demand and supply of the two countries. Journal of Economic Literature, Classification Numbers: F140, O520, P280, Q430. 7 figures, 4 tables, 50 references.  相似文献   

18.
This article examines the impact of decentralization reforms on improving access to domestic water supply in the rural districts of Kondoa and Kongwa, Tanzania, using a users' and a gender perspective. The article addresses the question whether and to what extent the delivery of gender-sensitive water services to rural households improved after the reforms. Household- and village-level data were obtained through a household survey and qualitative methods. The findings show an increase of the proportion of households using improved sources of domestic water between 2002 and 2011. However, more than half of users still travel over a kilometre and use more than an hour to collect water in the dry season. Despite the increased proportion of women in water management committees, the outcomes of these decentralized arrangements differ for men and women. Overall, the reforms have produced contradictory effects by improving access to water supply for some users, and creating or reinforcing existing inter- and intra-village inequalities.  相似文献   

19.
A sudden decline of solar activity around 850 calendar years BC caused a shift to a cool and wet climate in northwest Europe. Food production suddenly became problematic because of shorter, wetter growing seasons and increased night frost. This climate change triggered innovation and the development of a new agricultural system in continental northwestern Europe: arable farming on raised beds (Celtic field banks) laid out in a more or less checked pattern. This kind of agriculture mitigated the effects of the climate shift by providing better drainage and lessening damage by night frost and thus lengthening the growing season. Once the advantages of this kind of cultivation, soil enrichment and optimum root growth besides the hydrological effects, became obvious it will have been practised on a large scale and introduced when people thought it useful, independent of the local hydrological situation.  相似文献   

20.
Scientists advise limiting global warming to 1.5°C with substantial actions by 2030. Our viewpoint argues that climate response strategies in Canada have underemphasized and underestimated the potential contribution deep energy retrofits can make to greenhouse gas (GHG) emissions reductions, leading to inadequate responses in the building sector, and that Canada can (and should) be ambitious with building retrofits over the next decade. GHG savings from building retrofits can be realized more quickly than GHG reductions from other sectors, and either deliver net cost savings or are cost‐effective when compared to other mitigation measures. Retrofits can also provide social and economic benefits, such as improved health and comfort, and lower energy costs. This paper reviews energy use and building retrofits in Canada and argues the following should be implemented: (1) focus innovation on deep energy retrofit processes, not singular retrofit actions; (2) maximize both social and environmental benefits; (3) improve data gathering and availability for analysis and delivery; (4) innovate for a process of decisions and to avoid “dropouts” during the retrofit process; and (5) focus innovation on business models that maximize benefits.  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