A Comparison of Holocene and Historical Channel Change along the Macdonald River,Australia

Changes in channel morphology that occurred along the Macdonald River between 1949 and 1955 are often cited as an example of catastrophic channel change. However, the question of whether these changes represented one component of a cyclical evolutionary pattern, or a systematic and persistent shift to a new morphologic state remains to be clearly defined, as does the significance of these dramatic channel changes when viewed against the river's longer‐term Holocene history. In this paper, new measurements of the Macdonald River's channel morphology are used to resolve the river's evolution in the ～50 years since these major channel‐altering floods. By 2002, the Macdonald River's bed had narrowed considerably from its 1955 post‐flood maximum due to the construction of a new floodplain surface within the widened channel. In some locations, the 2002 bed width is comparable to that of the pre‐1949 channel. This aspect of the river's evolution follows models of cyclical channel evolution proposed for the region. However, in light of recent research into the river's longer term Holocene evolution, it is clear that other channel changes that occurred in response to the 1949–1955 floods, particularly the 2 metres of river bed aggradation and 7 kilometres down‐valley shift in the thalweg's intersection with mean sea level, are less cyclic in nature. The capacity of coastal rivers to prograde into estuaries, which in turn induces river bed aggradation, can be seen in this case to counteract the incisional tendencies associated with post‐flood channel contraction, such that persistent river bed aggradation occurs.     

我国的运河遗产及其保护面临的问题

为突破自然河流的局限性和更好地利用水资源或治水防洪,人类很早就开始了运河的开凿.运河遗产保护不仅因其反映了人类和国家的政治、经济、军事、农业、水利等方面演进的历史而显得格外重要,运河遗产保护中的遗产调查、遗产评估、保护规划、遗产管理、遗产监测等各方面都因其时空演变复杂、跨水系甚至跨流域、遗产体量巨大、动态性和在用性等特征表现为尤其困难.我国是最早开凿和利用运河的国家之一,也是拥有运河数量最多、长度最大的国家,同时也是运河保护面临问题最多、最尖锐的国家。以拟申遗的中国大运河为例,阐述我国快速城市化进程背景下运河遗产保护面临的新的历史机遇和挑战,期望对解决我国运河遗产保护的现实问题有所裨益。     

Water,Wind, Wood,and Trees: Interactions,Spatial Variations,Temporal Dynamics,and their Potential Role in River Rehabilitation

Recent Australian research has quantified the role of large wood (wood of any origin and length with a diameter greater than 0.1 m) in dissipating stream energy, forming pool habitats by local bed scour, protecting river banks from erosion, and damming rivers with long rafts causing avulsions. Large wood in Australian streams is sourced by a range of processes from the nearby riparian zone which has usually been degraded by post‐European settlement vegetation clearing. Large wood loadings within the bankfull channel are dependent not only on the type and quality of the riparian plant community but also on bankfull specific stream power, channel width, and the processes of large wood delivery to the stream. While bank erosion and floodplain stripping by catastrophic floods are obvious and important delivery mechanisms, treefall and trunk and branch breakage by strong winds during tropical cyclones and severe storms are also significant in the tropics. Furthermore, wood decay and downstream transport produce temporally dynamic large wood distributions. The longevity of natural large wood structures in rivers, such as rafts, debris dams, and log steps, requires determination. River rehabilitation programs need to not only include the reintroduction of large wood, but also carefully plan the spatial distribution of that wood, the most appropriate type and range of large wood structures, and, most importantly, the revegetation of the riparian zone to ensure a natural long‐term source of large wood. Exotic species management is an essential part of river rehabilitation.     

Rugged Plateaus and Extensive Floodplains — Modelling Landform Evolution in a Northern Australian Catchment

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).     

抗战时期贵州城市发展特点

长期以来,贵州的城市空间布局与发展相对缓慢。经过抗战时期的建设,城市现代化发展有了长足的进步,但受高原、民族等限制,与西南其它省份和内地相比,城市发展相对滞后,却表现出典型的西南民族地区特有的城市发展的时代特征。     

新中国治淮方略演进研究

淮河流域是我国经济欠发达、生态环境较脆弱的区域,在我国生态环境演变中具有典型意义。淮河是新中国第一条进行系统治理的河流,也是第一条从立法层面进行污染综合治理和生态经济带建设的河流。新中国对淮河的治理,从提出“蓄泄兼筹”的治淮方针到贯彻“节水优先、空间均衡、系统治理、两手发力”的新时代治水思路,从关注行蓄洪区群众生产生活到脱贫攻坚,从治理污染到建设淮河生态经济带,对治理的规律性认识不断深化,治理方略不断演进,为探索河流治理、流域生态经济带建设、推动人与自然和谐发展等积累了宝贵经验,留下了深刻的历史启示。     

The Waikato River: Changing Properties of a Living Māori Ancestor

In Māori cosmology, rivers and other waterways are conceptualised as living ancestors, who have their own life force and spiritual strength. The special status of rivers in Māori society also explains why they are sometimes separated from other Māori claims to natural resources of which they were dispossessed in the 19th century. Until recently, Māori were often eager to contend that ownership of rivers is not their prime interest, but instead, they argued that they feel obliged and responsible to keep rivers fresh, clean, and flowing. This perspective, however, changed under the impact of a new government policy of selling shares in energy corporations that use freshwater and geothermal resources for energy production. In this paper, I provide an ethnohistorical account of the Waikato River and show how conceptions of this ‘ancestral river’ changed in the course of colonial and postcolonial history, more specifically in response to a recent shift in government policy. In 2008, a joint management agreement was signed between the government and Waikato Māori for a ‘clean and healthy river’, leaving the issue of ‘ownership’ undecided. Only two years later, however, Māori felt forced to claim ownership when the government moved to sell shares of power‐generating energy companies located along the river, which effectively transformed their ‘ancestor’ into a property object.     

Rainfall,floods and river channel changes in the upper Hunter

Since 1946, there has been a significant increase in annual rainfall in the Hunter Valley, especially for stations in the western sector. Contemporaneous increases in rainfall intensities of frequent storms and flood peaks have also been recorded. From analyses of the data, together with a review of recent environmental changes in the Hunter Valley, it is concluded that human disturbance of the catchment has played no significant part in the increase in flood magnitude. Instead, the change in floods may be completely attributed to the variation in rainfall regime. The altered hydrologic regime combined with a decrease in sediment yield from extra-channel sources appears to be the primary cause of recent river channel changes.     

‘Torrents of Terror’: the August 1998 Storm and the Magnitude,Frequency and Impact of Major Floods in the Illawarra Region of New South Wales

The Illawarra Region some 80 kilometres south of Sydney is characterised by a prominent coastal escarpment that rises to 700 m within 12 km of the coast and forms a locus for frequent, high intensity rainfall events. One of the most recent recorded events occurred on 17 August 1998 with rainfall intensities at several pluviometers exceeding 120 mm hr^‐1 over a duration of one hour, with up to 249 mm falling in 3.5 hours during the main storm burst. Detailed pluviometer data indicate that the storm was non‐stationary and moved down catchment producing a widespread zone of 120 mm hr^‐1 intensity rainfall over a 30 minute duration across mid‐lower catchment areas after similar intensity but longer duration rainfall in catchment headwaters. Slope‐area reconstructions of peak discharge indicate that small catchments on the escarpment within the zone of maximum intensity experienced close to 100% rainfall‐runoff relationships, with peak discharges correlated to short duration (<1 hr) peak rainfall intensities. Widespread erosion occurred particularly where urban development had encroached on natural water courses. Debris/hyperconcentrated flows originating from both anthropogenic and natural sediment sources caused damage to urban areas. This paper provides an overview of the spatial and temporal characteristics of the 17 August 1998 storm, the hydrologic and geomorphic response of the streams, and the nature of damage to urban areas. It reassesses the frequency of recent high‐magnitude rainfall/flood events in the region, discussing the relationships between rainfall intensities, estimates of flood magnitudes and stormwater channel capacities.     

Urban geo-archaeology in medieval alzira (Prov. Valencia,Spain)

Alzira is situated in a cut-off meander loop of the Rio Júcar. Geo-archaeological study shows that the Islamic city wall was built during the second quarter of the 11th century AD, at a time when the river had a low-amplitude and low-energy flood regime. After mid-century, overbank silts began to invade the city as peak flood discharge increased, with a spate of destructive floods reflected by high-energy deposits during the late 11th century. Urban expansion within the city wall is dated to the later 11th or early 12th century, interrupted by local abandonment and moderate-energy flood silts. Major construction during the mid-12th century was followed by protracted abandonment (after a siege in AD 1171?) and further, moderate-energy flood silts that redistributed occupation and collapse debris. Reoccupation, during the late 14th century, was terminated by catastrophic floods in 1517 and 1571, after which much of the western end of Alzira was not rebuilt. Following further flood catastrophes during the 17th century, parts of the central walled city remained abandoned until the 19th century. with new occupation atop flood sands of yet another disaster in 1864. The change in flood regime after 1150 was a result of deforestation of the watershed, but progradation of a downstream tributary fan after 1517 created an unstable, aggrading floodplain increasingly prone to severe flooding. Climatic anomalies were responsible for periods of recurrent severe floods, archaeologically verified during the 11th and 12th centuries, and historically documented, beginning in 1318. The geo-archaeological methodology illuminates the constructional and settlement history of Alzira, allows distinction of fluvial and cultural components, and provides the necessary microstratigraphic detail and dating control to document the true complexity of alluvial processes during the last 1000 years.     

The need for river management and stream restoration practices to integrate hydrogeomorphology

There is growing support amongst scientists worldwide about the need for a shift in river management approaches to include hydrogeomorphic processes. However, the degree to which these concepts are transferred to governmental agencies and practitioners varies widely. In Quebec, for example, many stream restoration projects are based on the (incorrect) assumption that river mobility and its inevitable consequences (bank erosion of meanders, presence of woody debris in the channel) are problematic for salmonids. This paper presents examples drawn from current guidelines on stream restoration for fish habitat in Quebec to demonstrate the need to improve the knowledge exchange among scientists and decision makers about the positive impact of river mobility and large wood dynamics on biodiversity. Our observations reveal that existing guidelines for stream restoration in Quebec need to be revised to better integrate hydrogeomorphic concepts and to no longer assume that maintaining rivers in a static state is beneficial for fish. Adopting the “freedom space for rivers” approach would likely result in improved habitat as it combines natural processes related to mobility, flooding, and riparian wetland connectivity to determine the minimal space around rivers where development should not be allowed, thus allowing river processes to be restored.     

Professional ethics and the 'good' of science

Abstract

The Netherlands Delta Project is a 30 year endeavour to dam the estuaries of the river Rhin, Meuse and Scheldt with the aim of increasing the country's flood protection and improving its water management. From the beginning, a variety of scientists have been co-operating on planning, model making and monitoring the physical and ecological consequence. In the following article the Chief Engineer to the project discusses present and future problem of interdisciplinary co-operation and cites examples of successful solutions.     

Our history is not false: perspectives from the revitalisation culture

Two dominant themes in architectural conservation doctrine are to (1) avoid the fabrication of ‘false’ histories through the clear differentiation of ‘new’ from ‘old’ building fabric; and (2) the deprecation of subjective ways in which the perception of building fabric engenders sense of place. This study explores the cultural values of a group of citizens engaged in revitalising their historic downtown through the ‘Main Street’ program in Anderson, South Carolina, United States. This ‘revitalisation culture’ values and promotes treatments to its historic environment that emphasise the conjectural fabrication of ‘historic’ elements to existing buildings and the use of historicised design for new, infill construction. Whilst these values go against the grain of conservation doctrine, the revitalisation culture is preserving a kind of authenticity that stems from socially and culturally constructed values in an effort to maintain the ability of the historic environment to engender ‘spontaneous fantasies’, which serve to emotionally attach the revitalisation culture with its historic downtown. Ultimately, the revitalisation culture is engaging in ‘unethical’ behaviour from the perspective of conservation professionals, which begs the question of whose values deserve attention and if the field of heritage conservation is able and willing to accept pluralistic concepts of how the authenticity of historic places can and should be conserved.     

安岳石窟经目塔5.12汶川大地震后抢救性修缮——兼论三维激光扫描、计算机模拟技术在文物保护中的运用

"5.12汶川特大地震"对安岳石窟所属的孔雀洞经目塔产生了较大的影响和破坏。本次勘察修缮设计目标是修复经目塔震后的直接残损,对其结构进行必要的加固,减缓风化对塔体的影响,由于破坏的突然性及抢救工作的迫切性要求,从勘察到设计仅仅1个多月时间,勘察设计方在工作之初便决定引入三维激光扫描技术,并在评估及设计过程使用计算机模拟复原技术,力求准确翔实的得出经目塔震后的评估结论,及为震落构件找到准确的原有位置。作为最终修缮设计的依据。并通过结构计算,最终确定经目塔的修缮方案。本次勘察设计过程中引入的三维激光扫描技术及计算机模拟技术在石质文物勘察设计中均具有突破性进展,为今后石质文物的科技保护进行了切实有效的探索。     

Geoarchaeology and Archaeological Site Patterning on the Middle Gila River,Arizona

Abstract

Archaeological surveys and prehistoric settlement patterns are best interpreted when placed on a geomorphic map that defines the distribution and age of physical landforms. Survey data can thus be used to address questions of archaeological site visibility and synchronic and diachronic site patterning on the Gila River Indian Reservation, Arizona. A chronological series of alluvial and eolian landforms are defined on the reservation. The age of the landforms and underlying sediments has affected the preservation and visibility of the archaeological record. Further, late prehistoric Hohokam settlements (A.D. 700–1500) and their associated agricultural lands show a clear landform zonation and that the intensity of use of these landforms has changed over time.     

Hydrogeomorphic Effects of River Training Works: the Case of the Allyn River,NSW

Since 1955 the NSW Department of Water Resources has undertaken extensive river training works on many NSW streams. In the Hunter Valley alone over $23 million have been spent and more than 850 km of channel have been treated Published work suggests that river training works are usually undertaken in response to a pre-existing problem of river instability but can also induce adverse hydrogeomorphic effects. One of the treated streams, the Allyn River, had been supposedly degraded by the constructed works. It was alleged that vegetation clearing, channel excavations, alignment straightening and bank protection works had decreased roughness thus increasing velocity and flood frequency. As a result, what were thought to be relatively moderate floods were eroding the banks and destroying the floodplain. A critical evaluation of the available hydraulic, hydrologic and geomorphic data revealed that the river training works were a response to, rather than a cause of river instability.     

论河北省根治海河运动的特点及经验教训

1963年海河流域发生了特大洪水灾害,引起了党和国家的高度重视,刘少奇提出了“上蓄、中疏、下排”的治水方针,为根治海河指出了正确的方向。在毛泽东“一定要根治海河”的号召下,河北省于1965年开始开展了规模宏大的根治海河运动,这是新中国水利建设史上一个重大事件。根治海河运动历经15年,取得了巨大的成就,其经验可归结为:相对稳定的、综合性的组织机构;民工的军事化管理;合理的出工政策;依靠群众,自力更生,勤俭治水;精心设计,科学施工。作为一场大规模的群众性治水运动,其经验教训弥足珍贵,影响深远。     

Assessing the Scale and Pace of Large Shell-Bearing Site Occupation in the Prince Rupert Harbour Area,British Columbia

Methodological advancements in geoarchaeology and spatial and chronological modeling are opening new avenues to interpreting large coastal shell-bearing sites. We document the developmental histories of two such sites around Prince Rupert Harbour, Canada, using systematic percussion coring, intensive radiocarbon dating, and 3D surface mapping with Total Station and LiDAR. We also re-analyze a third site (Boardwalk/GbTo-31) excavated and radiocarbon dated in the 1960s, 1970s, and early 2000s using archival field notes, site maps, and stratigraphic profiles georectified using LiDAR. We map the natural landform beneath the sites and document the degree to which people physically modified landforms through the deposition of massive shell accumulations. We model site development through time and space and use accumulation rates and OxCal modeling to test for intentional deposition events. All three sites demonstrate complex and heterogeneous occupation histories. At each we identify instances of very rapid deposition that effectively terraced and extended parts of the natural landform to create places for constructing houses, though these episodes take place within longer histories of slower quotidian deposition. The anthropogenic modifications to the coastline in this area are the result of these mixed processes associated with long histories of occupation.     

River metamorphosis and environmental change in the Macdonald Valley,New South Wales,since 1949

A significant metamorphosis of channel form occurred on the lower Macdonald River between 1949 and 1955; width and width-depth ratio increased and depth, sinuosity and weighted mean per cent silt-clay in the channel perimeter decreased. The channel has remained unstable since 1955, exhibiting frequent variations in bed elevation and a recent period of minor channel contraction followed by slight enlargement. Since 1946 there has been an increase in summer and annual rainfall and an abrupt, upward shift of the annual series flood frequency curve. As a result an increased proportion of the total sediment load of the river is now being transported as bed-material load. The change in sediment load is a result of greater stream competence and the consequent reworking of sandy sediment temporarily stored within the channel as benches. The observed channel changes are a quasi-adjustment to the increased flood and bed-material load discharges.     

Terrestrial implications for the maritime geoarchaeological resource: A view from the Lower Palaeolithic

Stone tools and faunal remains have been recovered from the English Channel and the North Sea through trawling, dredging for aggregates, channel clearance, and coring. These finds highlight the potential for a maritime Lower Palaeolithic archaeological resource. It is proposed here that any Lower Palaeolithic artefacts, faunal remains, and sediments deposited in the maritime zone during dry, low-stand phases were once (and may still be) contextually similar to their counterparts in the terrestrial Lower Palaeolithic records of north-western Europe. Given these similarities, can interpretive models and analytical frameworks developed for terrestrial archaeology be profitably applied to an assessment of the potential value of any maritime resource? The terrestrial geoarchaeological resource for the Lower Palaeolithic is dominated by artefacts and ecofacts that have been fluvially reworked. The spatio-temporal resolution of these data varies from entire river valleys and marine isotope stages to river channel gravel bar surfaces and decadal timescales, thus supporting a variety of questions and approaches. However, the structure of the terrestrial resource also highlights two fundamental limitations in current maritime knowledge that can restrict the application of terrestrial approaches to any potential maritime resource: (i) how have the repetitive transgressions and regressions of the Middle and Late Pleistocene modified the terrace landforms and sediments associated with the river systems of the English Channel and southern North Sea basins?; and (ii) do the surviving submerged terrace landforms and fluvial sedimentary deposits support robust geochronological models, as is the case with the classical terrestrial terrace sequences? This paper highlights potential approaches to these questions, and concludes that the fluvial palaeogeography, Pleistocene fossils, and potential Lower Palaeolithic artefacts of the maritime geoarchaeological resource can be profitably investigated in future as derived, low-resolution data sets, facilitating questions of colonisation, occupation, demography, and material culture.