Natural and unnatural complexities: flood control along Manitoba's Assiniboine River

Flooding and flood control long have been topics of concern for geographers and historians of North America, from Gilbert White's foundational work to attempts to understand the recent disaster in New Orleans. This paper considers the problem of flood control along the Assiniboine River in the province of Manitoba, Canada. The first section addresses the local landscape and the larger context, explaining changes in the relevant human and physical geography. The second section examines efforts to mitigate flooding, focusing on how the risk of inundation was shifted in location (not eliminated altogether) and compounded through time (not progressively resolved). The third focuses on a further source of complexity: the contested character of government jurisdiction. This final section also addresses major mid twentieth century changes in mitigation efforts: in the light of flooding on an unprecedented scale, governments became more open to compromise and more willing to undertake substantial projects. Gilbert White asserted that while floods are natural occurrences, flood damages are the responsibility of humanity. The question of responsibility might seem relatively clear in relation to flood mitigation, given that dykes are human constructions. The history of flood mitigation along the Assiniboine would suggest, however, that assigning responsibility for the failures and successes of flood mitigation is not so straightforward.     

Recent Hydrological Changes in the Avoca River Catchment,Victoria

Since the early 1970s the Avoca River catchment has experienced a marked increase in all discharges, particularly high magnitude ones. This results from a change in the rainfall/runoff relationship, which is probably due to rising groundwater tables. Since 1973 the frequency of flooding in the lower Avoca, Loddon and Avon-Richardson catchments has increased markedly, placing pressure on downstream flood mitigation and irrigation works, as well as contributing to the degradation of environmentally sensitive wetlands. It also has the potential to exacerbate rising groundwater/salinity problems of the lower catchments. Human interference and changes in the rainfall regime are assessed to explain the nature of the apparent change in streamflows of the Avoca River catchment.     

History and Effects of Channelisation on the Latrobe River,Victoria

Channel changes on the lower Latrobe River since the late 1800s include a 25 per cent reduction in channel length due to artificial meander cutoffs, increases in mean channel width, increased channel instability and incision of up to 1.05 m. Hydraulic changes at the Rosedale gauge include increases in bankfull flow velocity and a 67 per cent increase in channel capacity, resulting in a threefold reduction of over-bank flow duration. The extensive channelisation works have reduced the frequency of minor flooding and the period offloodplain inundation, but these and other human impacts have severely degraded the stream environment.     

Geomorphological setting and Native American acquisition of buff-firing ceramic clays in the Lower and Middle Gila River Valley, Arizona

This study addresses buff-firing clay sources in dynamic alluvial settings along Arizona’s Gila River in the U.S. Southwest. We establish clay resource distribution relative to the geomorphic histories of the Lower and Middle Gila River based on 38 clay samples and ethnographic data from two US Bureau of Reclamation (BOR) projects. Buff-firing clayey alluvium, deposited in the Gila River floodplain 800 to 1,500 or more years ago, was a surficial ceramic raw material source for prehistoric Hohokam and lowland Patayan potters. This geomorphic unit was later removed in some places and buried by up to 3-4 m of sediment in others, reducing the availability of buff-firing clays in the Hohokam Classic period and requiring historic Pee Posh and Akimel O’odham potters to dig pits to access it. Sources were further destroyed in catastrophic floods in the late 19th and early 20th century, affecting ceramic manufacture patterns and ultimately contributing to the decline of pottery production by the O’odham living in the Gila River Valley. Our results contribute to regional ceramic ecology and should also be of interest to others investigating alluvial clay use in general or buff-firing alluvial clays in particular. The study also illustrates the value of combining geomorphic and ethnographic data to examine major changes in resource distribution and use.     

Transport costs: measures, determinants, and regional policy implications for France

We develop a methodology to accurately compute transport costs.Based on the real transport network, our measure encompassesthe characteristics of infrastructure, vehicle and energy used,as well as labor, insurance, tax and general charges borne bytransport carriers. Computed for the 341 French employment areas,road transport shipments and the period 1978–1998, thisnew measure is compared to alternative ones such as great circledistance, real distance, or real time. We conclude that theseproxies do a very good job in capturing transport costs in cross-sectionanalysis. However, important discrepancies limit the possibilityof using them in time series analysis. Moreover, our measureallows us to identify the policies that most impact transportcosts. We show that transport technology and market structureare responsible for most of the transport cost decrease. Infrastructureimprovements only condition the spatial distribution of thegains. Finally, some implications for researchers and regionalpolicy makers are derived.     

The Oral Tradition,Environmental Change and River Basin Management: Case Studies from Queensland and Victoria

River basin management activities are often carried out in the context of real or perceived environmental change. Views of environmental change provided by the oral tradition are compared with histories of change reconstructed from the historical documentary record for the Nogoa River, Queensland, and the Avon River, Victoria. Quite different perspectives on the nature and causes of river channel change are provided by the two types of sources. River basin managers appear to have generally adopted the views provided by the more easily accessible oral tradition, leading to management strategies that are not necessarily justifiable in the light of the documentary history.     

History,Geomorphological Problems and Effects of Dredging in Cleveland Bay,Queensland

The history of dredging is examined for Cleveland Bay, 1883–1988, as the port of Townsville developed. Between 1883 and 1964 only intermittent data exist on localities, depths and quantities dredged but later much more detailed records are available for analysis. Geomorphological problems emerged and are considered with particular reference to material forming the seabed, the sediment yield from the coastal catchments and its seasonally and annually irregular delivery to the coast by the rivers, and sediment movement within the bay in response to wind, wave and tidal processes. Analysis of aerial photographs, 1941–1988, has enabled some dredging effects to be studied, especially relating to localised land reclamation and more widespread probable effects on seagrass beds and mangroves.     

The paleolithic site of Longwangchan in the middle Yellow River,China: chronology,paleoenvironment and implications

The Longwangchan Paleolithic site, situated on the Yellow River terraces in the Hukou area, Shaanxi province, China, was found in 2003–2004, and two areas (Localities 1 and 2) of the site were excavated in 2005–2008. Abundant stone artifacts including microliths, a grinding stone fragment and a shovel, with some animal bones and shells, were recovered from Locality 1. In this study, the cultural deposits from Locality 1 were dated using radiocarbon and optical dating techniques, and the sediment properties of the deposits were analyzed. The results show that the age of the deposits ranges from 29 to 21 ka and most of them were deposited between 25 ka and 29 ka. This indicates that corresponds to late Marine Isotope Stage (MIS) 3 and early MIS 2. During the human occupation period, the climate in this area became colder and drier. Sediments from beds where the grinding slab and the shovel were found were dated to ∼25 ka, which is the oldest among the grinding stones found in China. The microliths and the grinding stone are important evidence for an incipient socio-economic process that eventually led to the regional transition from hunting-foraging to farming.     

A Geomorphological Study of the Giza Necropolis,with Implications for the Development of the Site

There are a number of features of weathering and erosion within the enclosure surrounding the Great Sphinx of Giza that suggest the action of flowing water. That this erosion is not uniformly distributed is consistent not with erosion by rainfall per se but by rainfall run‐off—an erosive agent that is known to have been experienced at Giza until the late Fifth Dynasty. When the spatial relationship of various features within the Giza necropolis is considered, the extant erosion indicates that the Sphinx may pre‐date the reign of Khufu, the builder of the first Giza pyramid. The existence of pre‐Fourth Dynasty development at Giza can be inferred from this—support for which is provided by a number of archaeological finds excavated from the site.     

Palaeoenvironmental significance of grain-size distribution of river flood deposits: a study of the archaeological sites of the Apengjiang River Drainage,upper Yangtze region,Chongqing, China

The grain-size distribution (based on cumulative probability curves) in the sediments produced by potential palaeofloods at the Shiniusi archaeological site is similar to that of modern flood sediments from the Wujiang River Drainage in the upper Yangtze River. There is an obvious pattern in the curves, with two segments, and the mean grain size (Mz), standard deviations (σ1), skewness, and kurtosis are all similar. Combined with the AMS¹⁴C dating data and the ages judged based on the presence of cultural remains, our data suggests frequent palaeoflood events within the Wujiang River Drainage. We hypothesize the existence of seven high flood possibility layers in the QST4 unit from Shiniusi archaeological site: during the periods of the Ming Dynasty (1368–1644 AD) to the Qing Dynasty (1616–1911 AD), and the end of the Eastern Zhou Dynasty (770 BC–256 BC) to the Shang Dynasty (1600–1100 BC). We also hypothesize ten high flood probability layers in the QST2 unit from Shiniusi archaeological site: during the periods of the Ming Dynasty to the Qing Dynasty, the periods of Song Dynasty (960–1279 AD) to the Yuan Dynasty (1206–1368 AD), as well as during the Han Dynasty (207 BC–220 AD) to the Eastern Zhou Dynasty (770 BC–256 BC). These results are consistent with palaeoflood events inferred from pollen and spore analysis and from historical records in other rivers.     

《水经》周水、存水考

由于《水经》、《汉书.地理志》、《水经注》对周水、存水、刚水记载简略,加之这一地区多岩溶地形,河流常常变成地下河,导致历代志书在今柳江、红水河流域指代三河不一。实际上三河各有所指,周水即今广西龙江一段;存水即今龙江,而非源于犍为郡县境;刚水或与周水为同一水,或为红水河下游,而非今柳江上源都柳江。     

An allosaurid theropod dinosaur from the Early Cretaceous of Victoria,Australia

The discovery of an astragalus of an allosaurid theropod in southeastern Australia extends the geographic range of the Allosauridae to include all continents except Antarctica and the Indian subcontinent. In addition, it confirms the presence of this family during the Early Cretaceous.     

Memories of the Past,Visions of the Future: Changing Views of Ebenezer Mission,Victoria, Australia

Former missions and reserves occupy an increasingly important place in Australian Aboriginal heritage, as sites of recent memory, ancestral resting-places, and the foci of social action in the present. Since the 1970s heritage managers have drawn heavily upon archaeological research in reclaiming places such as Ebenezer Mission for Aboriginal descendants as well as the non-Aboriginal community. This program of research and conservation has been shaped by Aboriginal memories and values that express the community’s self-understandings and its hopes for the future, in a process that reveals the relationship between tangible and intangible aspects of the past.     

The Pre-Settlement Vegatation of the Western and Central Wimmera Plains of Victoria,Australia

Historical records indicate that the fertile soils of the western and central Wimmera Plains of Victoria, Australia formerly supported grassy woodlands on rises and flats, and grasslands on shallow depressions and clay plains. Soil type and micro-relief appear to have been the major factors that determined the distribution of these communities. Burning of the woodlands by Aborigines may have contributed to their open grassy nature. The few ungrazed remnants of Buloke (Allocasuarina luehmannii) woodland support a suite of species that are absent from or uncommon in other Buloke woodland remnants in the region. This work demonstrates that in districts where little intact native vegetation remains, investigation of the distribution and floristic composition of the pre-settlement vegetation can provide useful information for the maintenance and restoration of remnant vegetation.     

Absolute chronology of fluvial events in the Upper Dnieper River system and its palaeogeographic implications

A set of 121 radiocarbon and OSL dates has been compiled from the Upper Dnieper River and tributary valleys, Western European Russia. Each date was attributed according to geomorphic/sedimentological events and classes of fluvial activity. Summed probability density functions for each class were used to establish phases of increasing and reducing fluvial activity. The oldest detected reduction of fluvial activity was probably due to glacial damming at LGM. Within the Holocene three palaeohydrological epochs of millennial-scale were found: (1) high activity at 12,000–8,000 cal BP marked by large river palaeochannels; (2) low activity at 8,000–3,000 cal BP marked by formation of zonal-type soils on -floodplains; short episodes of high floods occurred between 6,500—4,400 cal BP; (3) contrasting hydrological oscillations since 3,000 cal BP with periods of high floods between 3,000–2,300 (2,000) and 900–100 cal BP separated by long interval of low floods 2,300 (2,000)-900 cal BP when floodplains were not inundated — zonal-type soils were developing and permanent settlements existed on floodplains. In the last millennium, four centennial-scale intervals were found: high flooding intervals are mid-11–mid-15^th century and mid-17–mid-20^th century. Intervals of flood activity similar to the present-day were: mid-15–mid-17^th century and since mid-19^th century till present. In the context of palaeohydrological changes, discussed are selected palaeogeographic issues such as: position of the glacial boundary at LGM, role of changing amounts of river runoff in the Black Sea level changes, floodplain occupation by Early Medieval population.