Thames River Research Articles

Late Pleistocene Vertebrate, Plant and Insect Remains from the lnnerkip Site, Southwestern Ontario

Remains of white-tailed deer (Odocoileus virginianus), meadow voles (Microtus pennsylvanicus), muskrat (Ondatra zibethicus) and Blanding's turtle (Emydoidea blandingi) have been recovered from a peat deposit exposed on a tributary of the Thames River in southwestern Ontario. Numerous insect fossils, principally Coleoptera, and a variety of plants recovered from the same stratigraphie horizon have permitted a partial reconstruction of a larger community at the site of peat deposition. The plant, vertebrate and invertebrate fossils represent part of an assemblage which existed in. or beside, a small pond. Deposition probably occurred at the end of the Sangamon Interglaciation (Isotope Stage 5e) or during warm Early Wisconsinan interstadial (Isotope Stage 5c or 5a).

Water quality along a river continuum subject to point and diffuse sources

Summary The water quality along the River Kennet, in the Thames basin of southern England, was examined in terms of the influence of point- and diffuse-nutrient inputs. The river is supplied mainly from a Cretaceous Chalk aquifer and hence the waters are of a calcium bicarbonate type. The nitrate largely comes from agricultural sources, with concentrations decreasing downstream due to plant uptake and probable denitrification. In contrast, soluble reactive phosphorus (SRP) is largely associated with sewage inputs and concentrations increase downstream in line with effluents from major towns such as Newbury and Reading. Adjacent to the river in the lower half of the catchment is the Kennet and Avon Canal and the two are in places hydrologically connected. The canal inputs may influence calcium carbonate (calcite) precipitation and increase suspended sediment and particulate phosphorus concentrations in the river. Monitoring upstream and downstream of Marlborough sewage treatment works (STW) showed that SRP concentrations in the effluent were highly variable due to variable efficiency of P stripping and still sufficiently concentrated to dominate downstream river SRP with potential impacts on stream ecology. Biological recovery in this river following P stripping at STWs is complex and controlling those spikes in SRP that are above a threshold of 100 μg l −1 may be a critical requirement. More stringent effluent targets than are currently recommended may be needed (less than 800 μg RP l −1 ) to achieve good ecological status in this river depending on SRP concentrations upstream.

Urban Managed Realignment: Application to the Thames Estuary, London

Over the centuries, London has progressively encroached into the tidal Thames River as it has developed into a “World City”. This encroachment has exacerbated the flood risk to new and adjacent land, despite continual upgrading of flood defences. The pressure for further encroachment remains, despite the new threat of human-induced climate change—that is, the combined effect of (1) increased peak river flow in the winter, (2) more intense precipitation events, (3) accelerated sea-level rise, and possibly (4) more severe storms and resulting storm surges. Costly upgrade of defences is inevitable to manage the increased flood risk, and this has caused a re-evaluation of the Thames Estuary's flood defence program. For the first time, managed realignment in urban areas is being considered as a flood management tool. This offers a range of potential benefits including (1) increasing storage for floodwater, (2) improving ecological functioning, (3) improving riverside access for people, and (4) reversing the long-term trend of encroachment into the river. Planned managed realignment can widen the scope for future defence upgrade, but has been limited in urbanised areas. Several projects in London (e.g., Tate Modern and Millennium Dome) have shown that realignment can achieve the benefits described above, which supports the government's recent “Making Space for Water” policy.This study investigates the feasibility of managed realignment in the Thames Estuary. Fragmentation between flood defence and spatial development policies, lack of political support, and riverside encroachment continue to delay urban realignment projects. Successful application will require long-term planning (over decades) that exploits all opportunities for landward realignment offered by redevelopment. With the uncertainties behind climate change and more development in the “Thames Gateway”, further research is needed to understand the contribution of urban realignment to any flood management strategy that may be applied to other coastal urban areas.

Low-Nitrate-Days (LND), a Potential Indicator of Cyanobacteria Blooms in a Eutrophic Hardwater Reservoir

Abstract When nitrate was low in a hypereutrophic, hardwater reservoir, cyanobacteria proliferated into blooms. Based on this observation an index was developed that relates an easily measurable variable, the period of Low-Nitrate-Days (LND), to the period when nuisance cyanobacteria (blue-greens) proliferate and “bloom”. The bloom indicator LND (d·yr-1) was defined as the period of time during summer and early fall when nitrate concentration is below a lake-specific threshold. This concept was valuable in Fanshawe Lake, a southern Ontario reservoir of the Thames River in the Lake Erie catchment basin, where traditional bloom indicators are rare. A nitrate threshold of 1 to 2 mg·L-1 is supported by occasional observations of chlorophyll (Chl) concentration, blue-green biomass, visual inspection, and photographic documentation. Fanshawe Lake's water quality (phosphorus, Chl, and Secchi disk transparency) varied from summer to summer and LND ranged from 0 to 175 d·yr-1 with a long-term average of 62 d·yr-1 for 38 years. LND was positively and significantly correlated with average summer total phosphorus concentration (available for 8 years), but not Chl (n = 6) nor transparency (n = 11), possibly because of an invasion by the zebra mussel Dreissena. LND values agreed well with cyanobacteria biomass indicators predicted from other models. Significant relationships with 38 years of flows and the climatic index (winter North Atlantic Oscillation) reveal that during high-flow years estimated cyanobacteria blooms are infrequent, while during low-flow years bloom periods are extended and the water quality is poor. Investigations on other man-made lakes and river sections of the Thames River, and preliminary studies on natural lakes with differing trophic states show that LND may be a useful variable in all lakes and reservoirs where nutrient limitation switches from phosphorus to nitrogen during summer.

The Thames catchment: a river basin at the tipping point

“There is nothing so practical as a good theory” Bertrand Russell The paper recapitulates the theory of catchment water deficits and the use of density analysis previously published in this journal. Thereafter theory and method are applied to the Thames River Basin in England where it is shown that the catchment is marginally in deficit but that future developments in population growth, output growth and climate change require the application of specific redemptive options if a serious deficit situation is to be avoided. In particular, strict house-building controls are called for as well as the universal metering of domestic water use.

"Libro de buen amor" Studies. Edited by G. B. Gybbon-Monypenny. Tamesis Book, London, 1970; 256 pp.

Se reseñó: "Libro de buen amor" Studies.

Challenges in using probabilistic climate change information for impact assessments: an example from the water sector

Climate change impacts and adaptation assessments have traditionally adopted a scenario-based approach, which precludes an assessment of the relative risks of particular adaptation options. Probabilistic impact assessments, especially if based on a thorough analysis of the uncertainty in an impact forecast system, enable adoption of a risk-based assessment framework. However, probabilistic impacts information is conditional and will change over time. We explore the implications of a probabilistic end-to-end risk-based framework for climate impacts assessment, using the example of water resources in the Thames River, UK. We show that a probabilistic approach provides more informative results that enable the potential risk of impacts to be quantified, but that details of the risks are dependent on the approach used in the analysis.

Walleye in the Grand River, Ontario: an Overview of Rehabilitation Efforts, Their Effectiveness, and Implications for Eastern Lake Erie Fisheries

Walleye ( Sander vitreus) from the Grand River (Ontario) are recognized as genetically and physiologically distinct from other Lake Erie stocks. The low abundance of these walleye in the early 1980s triggered rehabilitation efforts that included intensive research, transfers of walleye from the Thames River (Ontario), supplemental stocking from local hatcheries, construction of a fishway, and creation of additional spawning habitat. Walleye migrating from Lake Erie are currently hindered from reaching 90% of potential riverine spawning habitat by a dam 7 km upstream. Although increased walleye catch rates were reported following construction of a fishway in 1995, recent assessment has shown that access is still severely restrained. Catch rates of young-of-the-year walleye during fall surveys have increased notably since 1999, coincident with direct transfers of mature adults over the barrier. Recent successful year classes have contributed to a population dominated by young (< 5 y) fish. Genetic analyses show that fish culture contributed between 3% and 25% to five recent year classes of Grand River walleye. Facilitating access to spawning habitat above the Dunnville dam may be the most effective way to increase the productivity of this stock, with consequent strengthening of walleye fisheries and the fish community in the eastern basin of Lake Erie.

Hierarchical structure of stream ecosystems: consequences for bioassessment

It has long been recognized that communities and their ecosystems are structured at several, nested spatial scales. But identifying the appropriate scale(s) to collect, analyse and interpret data to answer specific questions about ecosystems has been a vexing problem for ecologists. We collected observations of the benthic invertebrate community and its environment in 10 primarily agricultural tributary streams of the Thames River in southwestern Ontario, Canada. Within each stream we sampled two reaches, in each reach we sampled three riffles, and in each riffle we took three kick samples of invertebrates and characterized the substrate environment. We also characterized the habitat at each of the 20 reaches (10 streams × 2 reaches/stream). Most of the variability in the stream invertebrate community structure (as described with taxonomic richness and the biotic index of tolerance, as well as by the Bray-Curtis distance of the community composition from the mean at a spatial scale) was at larger spatial scales of among streams and between riffles. Much of the substrate and habitat variation was also at the larger spatial scales, as were correlations between the biota and the environment of the benthic invertebrate community. We concluded that for the purposes of bioassessment, characterization of one reach per stream is sufficient, at least in this context, for describing a stream and evaluating its health.

Inuit Diasporas: Frankenstein and the Inuit in England

first edition of Frankenstein, the Isabella and Alexander set forth from England on a journey of exploration to the North Pole, carrying a Greenlandic Inuit from Disko Island by the name of John Sackhouse. Sackhouse, who had previously stowed away on a whaler from Greenland to Scotland, would serve as the translator on this voyage, enabling communication with the Inuit people along the way. While the Isabella and Alexander were searching for a Northwest Passage across northern America, the Dorothea and Trent headed ‘across the north pole’, hoping to meet the Isabella and Alexander at the Bering Strait. At the time, it was believed that the North Pole was ‘free of ice’, making a meeting like this possible. Mary Shelley, an avid reader of the Quarterly Review between 1816 and 1820, followed speculations surrounding these journeys in preparation for writing Frankenstein. Frankenstein, in fact, could be said to capitalize on the suspense and widely popular appeal of these journeys. Perhaps not coincidentally, the release of her novel appeared to be timed to coincide with the advent of these infamous expeditions to the North. Besides being captivated by the expeditions themselves, the English public had long been fascinated by Greenlandic Inuits and Eskimos. I would argue that, in Frankenstein, the creature himself came to represent these inhabitants of the North, as well as the threat of their arrival in England if increased communication were to occur. Just as John Sackhouse had once arrived as a stowaway on British shores, so Frankenstein’s creature is a stranger who must be incorporated in – or rejected from – European culture. In the novel, the ‘birth’ of the creature in Europe could be said to represent cultural fears of the invasion of the ‘primitive’ in ‘civilized’ society, or the arrival of the colonized, in search of revenge, on the shores of the colonizer. Since the late sixteenth century, ‘Esquimaux Indians’ from Greenland to Alaska had been captured by British explorers and carried back to England, where they were generally presented as novelties to the King or Queen. In 1576, Martin Frobisher captured a Greenlandic Inuit who was later described in London as ‘such a wonder unto the whole city and to the rest of the realm that heard of it’ (Oswalt, 27). In 1578, Eskimos captured off Baffin Island were given permission by the Queen to hunt swans on the Thames River. In 1605, an Inuit performed before the King and Queen of Denmark, racing their traditional kayaks against a Danish boat. By the late eighteenth century, discussions of these ‘Esquimaux Indians’ peppered the pages of books and journals ranging from the Quarterly Review to John Pinkerton’s famous collection, A General Collection of the Best and Most Interesting Voyages and Travels in all Parts of the World. Karen Piper

Effectiveness of best management practices in improving stream ecosystem quality

Implementation of best management practices (BMPs), such as improved manure storage, buffer strips, and grassed waterways, through government funded conservation programs is a common approach for mitigation of the impacts agricultural activities have on the surrounding environment. In this study, we tested the ability of these practices to meet the environmental goal of improved stream quality at a “micro-basin” scale in the Upper Thames River Watershed, southern Ontario, Canada. Micro-basins were first and second order basins, averaging 400 ha in area, representing gradients of land cover, geomorphology, and participation in conservation programs. At the outflow of each micro-basin the benthic macro-invertebrate community was sampled, water chemistry measurements completed, and habitat quality assessed. Results showed micro-basins with relatively high levels of BMP implementation consistently demonstrated improved stream ecosystem quality over the majority of micro-basins with low or no implementation. Streams in the Upper Thames River basin appeared to exhibit a threshold effect, where with several BMPs in the same basin an improvement in stream ecosystem quality is visible. In addition to the BMPs implemented through government funded conservation programs, the observed ecosystem improvements are probably due to increased environmental awareness and improved management by farmers.

Potable water and sanitation in Tenochtitlan: Aztec culture

A source of clean drinking water is essential, and the Aztecs were quite advanced in providing it. While London still drew its drinking water from the polluted Thames River as late as 1854, the Aztecs brought potable water to Tenochtitlán from springs on the mainland by means of the aqueduct built by Nezahualcoyotl between 1466 and 1478. A second aqueduct was constructed in 1,499–1,500 by the ruler Ahuizotl when the first aqueduct became inadequate. Although the Aztecs had no citywide drainage system, and much of the wastewater ended up in the lake surrounding the city, they had a system to handle human waste by means of privies in all public places and many private dwellings from which excrement was collected in canoes. The excrement was applied as fertilizer to chinampas (floating parcels of land) or sold in the market to be used for tanning animal hides. Urine was collected in pottery vessels to be used later as a mordant for dyeing cloth. The Tenochtitlán environment was obviously healthy for its time, especially in comparison to European cities. Public and personal hygiene contributed to minimize the incidence and severity of illnesses.

Improved K-Nearest Neighbor Weather Generating Model

A major limitation of K -nearest neighbor based weather generators is that they do not produce new values but merely reshuffle the historical data to generate realistic weather sequences. In this paper, a modified approach is developed that allows nearest neighbor resampling with perturbation of the historic data. A strategy is introduced that resamples the historical data with perturbations while preserving the prominent statistical characteristics, including the interstation correlations. The approach is similar in spirit to traditional autoregressive models except that the new values are obtained by adding a random component to the individual resampled data points. An advantage of the approach is that unprecedented precipitation amounts are generated that are important for the simulation of extreme events. The approach is demonstrated through application to the Upper Thames River Basin in Ontario. Daily weather variables (maximum temperature, minimum temperature, and precipitation) were simulated at mu...

Spatial Distributions and Temporal Trends in Sediment Contamination in Lake St. Clair

The sediments of Lake St. Clair were surveyed in 2001 for a range of compound classes including metals (such as total mercury and lead), polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, organochlorine pesticides, polycyclic aromatic hydrocarbons, and short- and medium- chain chlorinated paraffins, in order to evaluate the spatial distribution and temporal trends of contamination. Concentrations of contaminants were generally low compared to the lower Great Lakes (Erie and Ontario), and were typically below the Canadian Sediment Quality Probable Effect Level (PEL) guidelines. The only exceptions were for mercury and DDE, where concentrations exceeded their respective PEL at one of the thirty-four sites sampled. With the exception of mercury, it was difficult to interpret spatial trends in contaminant concentrations due to these low levels, although relatively elevated concentrations of several contaminants were found in L’Anse Creuse Bay and at the outflow of the Thames River. In the case of mercury, historically-contaminated sediments in the St. Clair River associated with chlor-alkali production appeared to contribute to loadings to Lake St. Clair. There have been substantial reductions in sediment contamination in Lake St. Clair over the past three decades, as determined through sediment core profiles as well as through comparison of current data to those from historical surveys conducted in the early 1970s. These results indicate that management actions to reduce contaminant loadings to Lake St. Clair have been generally successful.

Impacts of Changing Climatic Conditions in the Upper Thames River Basin

This paper presents the application of the inverse approach in the study of high and low flows due to changing climatic conditions in the Upper Thames River basin, southwestern Ontario. The inverse approach is an alternative to statistical downscaling of global circulation model outputs, typically used in climate change studies. At the core of the inverse approach is a weather generator model that uses locally observed climate data, together with outputs from global circulation models, to generate an arbitrary long record of regional climatic conditions. A base case and two climate scenarios are produced by a weather generator, whose output is used as input into: (a) an event hydrologic model (for high flows); and (b) a continuous hydrologic model (for low flows). Changing hydrologic conditions are identified through frequency analysis for both flood and low flow hydrographs (obtained as outputs from hydrologic models). Changes in local water resources management practices, guidelines and design standards are recommended on the basis of the analysis of altered climates and their impacts on the hydrologic flow regime.

Increase of Flood Risk due to Urbanisation: A Canadian Example

There has been increasing concern among the government officials who deal with emergency preparedness and natural disasters that increasing urbanisation is enhancing the risk from river flooding in urban areas. This study concerns such a risk for the City of London in the province of Ontario in Canada. It has been shown that between 1974 and 2000 there has been a considerably elevated risk from floods due to heavy urbanisation in the watershed of the Upper Thames River, of which the City of London is a part. Databases were prepared making use of satellite remote sensing technology on landuse classification and this information was integrated with meteorological and hydrological data records and analysed to obtain a quantitative estimate of the potential risk from river floods to London.

SI17 What Diseases Should We Test For and Which Ones Should We Not Test For

The safety of the blood supply in high income countries has very high standards. New technical developments allow even further improvement of the safety margin, although at very high costs. From the perspective of health care budget at large, the costs for screening the blood supply for viral infectious agents are unprecedented high, compared to the benefit the recipients of blood products may experience. Moreover, the majority of fatal transfusion reactions are due to other causes, like TRALI, haemolytic transfusion reactions and sepsis by bacterial contaminated blood products, as was mentioned in a recently published International Forum [Vox Sanguinis (2006) 90: 207–241]. Fatal viral infections are at present a minority of all fatalities caused by transfusion of blood! What tests can we add in the (near) future to further safeguard the blood supply for infectious diseases? Bacterial testing of all labile blood components, and especially platelet concentrates stored at room temperature may be a sensible approach when these tests become less labour intensive and more sensitive. Prototype NAT tests have shown proof of principle and have great promise to fulfil the above criterions, although many problems have to be solved yet. Improvement of tests to detect donors with malaria parasites is welcomed. When more sensitive tests are implemented, the rejection of a substantial proportion of donors who travelled or stayed in endemic areas may be avoided in the future. With respect to viral screening pressure from the industry is building up to test for HBV‐DNA, offering only multiplex (HIV, HCV, HBV) formatted NAT tests for their second generation automates. If we follow the industry (and I am afraid we do not have much choice), the pool size should be diminished to &lt;8 donors to make HBV‐NAT screening significant. Eventually we may end by testing individual donor samples, as is already the case in some countries like South‐Africa. When sensitive and specific vCJD tests will become available, it is clear that all donors will be screened in the future. Tendencies from the plasma industry to test for Parvo B19 DNA and HAV by NAT should only be done as internal control tests for plasma derivates and not be used as release criterion for labile blood components. What screening tests may be omitted in the future? In countries who have implemented anti‐HBc (anti‐HB‐core) screening HBsAg, like HIV p24 antigen test, may be superfluous when (ID) HBV‐NAT is in place. However, much water has to flow through the Thames River before we dare to omit such an old and reliable screening test as HBsAg ! From a cost benefit point of view all NAT screening tests may be omitted, taking into consideration their low yield to detect extra infected donations. Especially when pathogen inactivation may become state‐of‐the‐art in the future, this option becomes more realistic. Next to screening, it is important that a continuous monitoring system for new infectious agents or variants of old ones, within the population at large is warning the blood transfusion organizations in the various countries for new threats. BOTIA, a consortium sponsored by the European Commission, is an example of such a monitoring system. In conclusion, screening for infectious agents in donor blood will be in the future as dynamic as it was for the last 3 decades.

Chaffin, Sea Of Gray - The Around-The-World Odyssey Of The Confederate Raider Shenandoah

On October 8, 1864, the Sea King slipped down the Thames River and sailed into the Atlantic Ocean. The ship arrived at the island of Las Desertas, where it took on supplies. It also revealed its true name, the CSS Shenandoah. A Confederate commerce raider in the style of the CSS Alabama and Florida, the mysterious ship had orders to attack Yankee whaling ships in the Bering Sea.

Carmen Rabell. Rewriting the Italian novella in counter-reformation Spain. Tamesis, London, 2003; 172 pp.

Se reseñó el libro: Rewriting the Italian novella in counter-reformation Spain.

Suspended sediment and particulate phosphorus in surface waters of the upper Thames Basin, UK

Summary Suspended sediment (SS) and particulate phosphorus (PP) concentrations in surface waters of the upper Thames Basin are reported for the main stem of the River Thames, several of its tributaries, the Cherwell, Dun, Lambourn, Pang and Thame, the Kennet and Avon Canal (that drains to the Dun and Kennet) and an artificial supply reservoir (Wilton Water). For the rivers which are mainly supplied from Chalk aquifer sources, SS and PP concentrations are poorly correlated with flow and there are issues of both biological and inorganic production of SS and PP during the spring and summer months. SS and PP are better correlated with flow when the antecedent conditions are taken into account. Thus, if flows had increased the previous day, then SS and PP concentrations are augmented. Wilton Water and the Kennet and Avon Canal have, on average, higher SS and PP concentrations than the nearby Chalk fed rivers and this probably reflects increased effects of biological activity and calcite (CaCO3) precipitation under more stagnant conditions. For the rivers draining less permeable (clay dominated) catchments, then there is clearer linkage between flow and SS and PP concentrations. This feature reflects the more responsive influence of runoff from the land surface without the confounding issues of seasonally-varying groundwater discharges, intersection of groundwater levels with the ground surface and overland flow that may well characterise the permeable Chalk catchments. SS and PP are linearly correlated across the catchments. For the Chalk catchments and the associated Wilton Water and Kennet and Avon Canal, the PP:SS ratios are similar, ranging typically between 2 and 4 μg/mg. For the clay dominated catchments, the ratios are typically higher at 3–7 μg/mg. The results are considered in the light of process understanding, farming, climate change/climate-variability and the Water Framework Directive.