1,515 research outputs found
Assessing the importance of river bank erosion for fine sediment delivery to Bassenthwaite Lake
No full textAvailable evidence from lake sediment core records and short-term sediment flux sampling programs has suggested increased fine sediment deposition and suspended sediment transfers to Bassenthwaite Lake, Cumbria, U.K over recent decades. This increase in sedimentation has been associated with a decline in water quality in the lake which is thought to have had serious consequences for the population of the vendace (Coregonu albula), which also declined markedly during the 1990ร and into the 21 St Century. Recent studies of sediment delivery risk in the catchment have suggested that there are potentially large sediment sources in the lowland river network, especially the River Derwent between Derwent Water and Bassenthwaite Lake. The aim of this research is to describe the characteristics of fluvial suspended sediment transfers to Bassenthwaite Lake through direct monitoring of the River Dement and Newlands Beck (at the head of Bassenthwaite Lake) in order to assess the potential contribution of river bank erosion on the lowland River Derwent to fine sediment delivery. Three suspended sediment monitoring stations at Portinscale and Low Stock Bndge on the River Derwent and at Newlands Beck Bridge are used to assess changes in sediment transport along these important river reaches. The potential contribution of river bank erosion to fluvial sediment delivery was assessed by river bank mapping and surveying of erosion features on the 5.7km reach of the River Derwent between Derwent Water and Bassenthwaite Lake, along with a detailed study of morphological change on three river banks near Low Stock Bridge using a terrestrial laser scanner. The main findings of this project suggest that the River Derwent dominates suspended sediment transfers to Bassenthwaite Lake. The fine sediment load transported on the Derwent is over five times greater than that of Newlands Beck and the mean suspended sediment concentration on the lower Derwent is 56% higher than that on Newlands Beck. Specific catchment sediment yields for the River Derwent and Newlands Beck, based on effective drainage area, are 50.871 km(^2) a(^-1) and 35.721 km2 a(^-1) respectively. A high proportion of all suspended sediment transfers in the lowland Bassenthwaite Lake catchment were observed to occur in high-magnitude, low-frequency flow events, with approximately two- thirds of total suspended sediment transport occurring in just over 10% of the time. There is also direct evidence for increased fine sediment supply on the lowland River Derwent, as an estimated 1,158 ta(^-1) increase in the overall sediment load was observed on the 3.7 km reach of the Derwent between Portinscale and Low stock Bridge. Hysteresis analysis and analysis of suspended sediment transfers during high flow events on the Derwent support this hypothesis. Overall, 21.1% of all river banks on the River Derwent were assessed as eroded, with 9.4% of banks undergoing active river bank erosion. Therefore, it is suggested that river bank erosion is a significant fine sediment source in the lowland Bassenthwaite catchment, and that it is responsible for a large proportion of sediment inputs on the lowland River Derwent (c. 18.9%), and ultimately to Bassenthwaite Lake
Derwent lighthouse & Mt Wellington [picture].
No full textCondition: Good.; Photographer is uncertain. Possibly E.W. Searle.; Part of the collection of photographs compiled by Australian photographer E. W. Searle while working for J. W. Beattie in Hobart during 1911-1915.; In the title from caption in white ink below the photograph, the letters 'v' and 'r' are upper case.; "957. Beattie-Hobart."--Inscription on lower right corner.Derwent lighthouse and Mt WellingtonThe Iron Pot, Derwent RvrThe Iron Pot, Derwent Rive
Rev. Derwent Coleridge, ca. 1860\u27s
No full textRev. Derwent Coleridge, ca. 1860\u27s, col. Derwent was a child of Samuel Taylor Coleridge. distinguished scholar and author. In 1864 he accepted from Bishop Tait the rectory of Hanwell. Finding the parish church a long way from the population, he set to work to build a new one in the midst of them, and it was consecrated on the last day of 1879, when he was in his eightieth year.https://mds.marshall.edu/marshall_regional_photograph_collection/1423/thumbnail.jp
The floods of the Lake District - Part I
No full textThis report summarises the annual rainfall of the River Derwent catchment area and examines the floods of 1931 and 1932. The author uses data from the Meteorological Office to examine if the floods were extraordinary and takes into account local lakes in reducing the magnitude of the flood. Areas that are presented in more detail are Bassenthwaite Lake, Thirlmere, Cockermouth, Keswick, Newlands and Coledale Beck. (PDF contains 38 pages
Radiative forcing from aircraft NOx emissions: Mechanisms and seasonal dependence
No full textA chemistry-climate model has been applied to study the radiative forcings generated by aircraft NOx emissions through changes in ozone and methane. Four numerical experiments, where an extra pulse of aircraft NOx was emitted into the model atmosphere for a single month (January, April, July, or October), were compared to a control experiment, allowing the aircraft impact to be isolated. The extra NOx produces a short-lived (few months) pulse of ozone that generates a positive radiative forcing. However, the NOx and O3 both generate OH, which leads to a reduction in CH4. A detailed analysis of the OH budget reveals the spatial structure and chemical reactions responsible for the generation of the OH perturbation. Methane's long lifetime means that the CH4 anomaly decays slowly (perturbation lifetime of 11.1 years). The negative CH4 anomaly also has an associated negative O3 anomaly, and both of these introduce a negative radiative forcing. There are important seasonal differences in the response of O3 and CH4 to aircraft NOx, related to the annual cycle in photochemistry; the O3 radiative forcing calculations also have a seasonal dependence. The long-term globally integrated annual mean net forcing calculated here is approximately zero, although earlier work suggests a small net positive forcing. The model design (e.g., upper tropospheric chemistry, convection parameterization) and experimental setup (pulse magnitude and duration) may somewhat influence the results: further work with a range of models is required to confirm these results quantitatively
The rhetoric of disfigurement in First World War Britain
No full textDuring the First World War, the horror of facial mutilation was evoked in journalism, poems, memoirs and fiction; but in Britain it was almost never represented visually outside the professional contexts of clinical medicine and medical history. This article asks why, and offers an account of British visual culture in which visual anxiety and aversion are of central importance. By comparing the rhetoric of disfigurement to the parallel treatment of amputees, an asymmetrical picture emerges in which the ‘worst loss of all’—the loss of one’s face—is perceived as a loss of humanity. The only hope was surgical or, if that failed, prosthetic repair: innovations that were often wildly exaggerated in the popular press. Francis Derwent Wood was one of several sculptors whose technical skill and artistic ‘wizardry’ played a part in the improvised reconstruction of identity and humanity
Quantifying and Characterizing Metal Concentrations in Derwent Estuary Sediments using Portable X-Ray Fluorescence Spectrometry
No full textThe Derwent Estuary is highly enriched in potentially toxic elements such as Zn, Pb, Cu, As, Hg and Cd. This occurred due to inputs from historical industrial activity adjacent to the river, predominantly prior to strict environmental protection procedures introduced in the 1970s. Contaminants are now buried at shallow depths within the sediment profile, in one or two highly concentrated layers decreasing in concentration away from an electrolytic zinc refinery, regarded as the main source of the contaminants. Enriched metals (Zn, Pb, Cu, Cd and As) in the estuary were estimated from data collected from 37 sediment cores using a portable X-ray fluorescence spectrometer, validated against mass spectrometer analyses. The thickness of the metal and metalloid enriched layers ranges from 32.5 cm to 107.5 cm, with an average thickness of 63 cm. Sedimentation rates based on this layer and the time since the start of zinc processing are approximately 0.46 cm/year. Recent trends in sedimentation based on the thickness of sediments since maximum metal and metalloid concentrations produced rates between 0.17 – 1.64 cm/year. Based on these sedimentation rates, the average time it will take for surface sediments to return to background metal and metalloid concentrations is approximately 123 years
Predicting calyptrate fly populations from the weather, and probable consequences of climate change
No full text1. Calyptrate flies include numerous species that are disease vectors and have a high nuisance value, notably Musca domestica. Populations are often associated with livestock farms and domestic waste disposal facilities such as landfill, where the accumulating organic matter provides suitable breeding conditions for a range of species.2. We examined the relationship between fly numbers and weather conditions using a 4-year data set of weekly fly catches from six sites in southern UK, together with meteorological data. The first 3 years were used to develop predictive models, and these were then used to forecast fly populations in the fourth year. The accuracy of these predictions was assessed by comparison with the actual fly catches for that year. Separate models were developed for M. domestica, Calliphora spp. and all calyptrate flies combined.3. Predictions based only on humidity, temperature and rainfall were strongly correlated with observed data (r(2) values ranged from 0.52 to 0.84), suggesting that fly population changes are largely driven by the weather rather than by biotic factors. We can forecast fly populations so that control measures need only be deployed when weather conditions are suitable for a fly outbreak, reducing the need for prophylactic insecticide use.4. Climate change was simulated using the most recent predictions of future temperature increases. Our models predicted substantial increases in fly populations up to 244% by 2080 compared with current levels, with the greatest increases occurring in the summer months.5. Synthesis and applications. Models developed use weather data to predict populations of pestiferous flies such as M. domestica, which may prove valuable in integrated control programmes. These models predict substantial increases in fly populations in the future under likely scenarios of climate change. If this occurs we may expect considerable increases in the incidence of fly-borne disease
Studies on heavy metal toxicity and accumulation in the catchment area of the Derwent Reservoir
No full textA three year long study has been carried out of the distribution of zinc, lead and cadmium within the water, sediments and submerged plants of the Derwent Reservoir and its catchment These studies have been extended to include detailed field investigations of the accumulation of heavy metals by Lemanea fluviatilis, an alga common in the R. Derwent Further field and laboratory investigations have been carried out of the tolerance to zinc of Stxgeoclonxum tenue. Elevated concentrations of zinc, lead and cadmium were shown to be present, in the water and sediments of the R. Derwent at its point of entry to the Derwent Reservoir. These metals were derived mainly from Bolts Burn, a polluted tributary. This latter stream was found to receive inputs of heavy metals from clearly defined sources within an active fluorspar mine. Although old mine workings were present within the catchment, these had a relatively small effect on the composition of water in Bolts Burn and the R. Derwent. Detailed investigations of the composition of stream and river water enabled various aspects of the behaviour of different fractions of metals to be described and compared in polluted and non-polluted reaches. The concentrations of zinc, lead and cadmium within the water, sediments and submerged plants of the Derwent Reservoir were found to be high when compared with data from other published studies. The pollution of the reservoir with these metals may therefore be regarded as serious. Surveys of the distribution of heavy metals in the water column were carried out at different stages in the filling cycle of the reservoir. These, together with surveys of the composition of sediments and submerged plants, enabled several of the major factors influencing the distribution of metals within the reservoir to be determined. Studies of the accumulation of heavy metals by 47 populations of Lemanea fluviatilis indicated that the alga is a potentially useful 'monitor' of pollution by zinc, lead and cadmium in flowing waters. Although the enrichment ratios for these metals were not constant over a range of concentrations in the water, clear linear relationships were apparent between the concentrations of each metal in the water and in filaments of Lemanea. Intensive sampling from a single population in the R. Derwent demonstrated that a proportion of the zinc content of filaments was sensitive to short term fluctuations in the zinc content of the surrounding water. The results of a series of transplant experiments are also reported. Stigeoclonium tenue was found to be abundant in several streams carrying relatively high concentrations of zinc in the water A study of populations isolated from 35 reaches demonstrated that material growing in higher concentrations of zinc in the field had an enhanced tolerance to zinc. This tolerance was stable during long term culturing, and appeared to have a genetic basis. Assays of populations from harder waters suggested that high concentrations of calcium acted to reduce the toxicity of zinc in the field. Further studies performed in the laboratory demonstrated that increases in pH and the concentrations of magnesium, calcium and phosphate all acted to reduce the toxicity of zinc to Stigeoclonium tenue. However, the effects of these factors on toxicity were found to differ between a zinc sensitive population and a zinc tolerant populatio
Tropospheric ozone and El Niño–Southern Oscillation: Influence of atmospheric dynamics, biomass burning emissions, and future climate change
No full textWe investigate how El Niño Southern Oscillation (ENSO) influences tropospheric ozone and its precursors in a coupled climate-chemistry model. As shown in similar studies, tropospheric column ozone (TCO) decreases in the central and east Pacific and increases in the west Pacific/Indonesia in response to circulation and convective changes during El Niño conditions. Simulated changes in TCO for “peak” El Niño events in the central and east Pacific are in good agreement but are underestimated in the west Pacific compared to previous observational and modeling studies for October 1997. Tropospheric column-average NOx decreases over Indonesia and generally over South America as a result of suppressed convection and lightning over these land regions. NOx and HOx changes during El Niño modify ozone chemical production and destruction. When we include annually varying biomass burning emissions in our model simulations we find that these emissions peak over Indonesia 1–2 months in advance of the peak elevated sea-surface temperatures (SSTs) and hence the “meteorological” El Niño. We underestimate the strength of the TCO increase due to El Niño–related dry conditions over Indonesia in October 1997 compared to observations. We also examine how future mean and variability changes in ENSO, as simulated in the HadCM3 climate model, impacts tropospheric ozone. A mean future El Niño–like state is simulated in the tropical Pacific in HadCM3, but this has no discernable impact on the future TCO trend in this region. However, we do simulate increased variability in precipitation and TCO related to ENSO in the future
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