bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal start‐up control of injection molding barrel temperature
Authors: Yao Ke , Gao Furong
Published: February 2007

It is desirable to control injection molding barrel temperatures to set‐point with a minimal start‐up time and near‐zero overshoot for productivity and product quality. This paper, based on time optimal control, developed a start‐up procedure leading to the optimal heating up profile with the shortest rising time with small overshoot. The design parameters are obtained automatically through one simple open‐loop test. Experiments show that the proposed control achieves the design purpose under different conditions. POLYM. ENG. SCI., 47:254–261, 2007. © 2007 Society of Plastics Engineers.
Flame retarding effects of nanoclay on wood–fiber composites
Authors: Guo G. , Park C.B. , Lee Y.H. , Kim Y.S. , Sain M.
Published: February 2007

This research article focuses on investigating the effects of nanoclay particles on the flame retarding characteristics of wood–fiber/plastic composites (WPC) using ASTM D635. The processing aspects of nanocomposites with WPC are presented. The processing techniques for controlling the degree of exfoliation and the cost aspect are also described. It turns out that the coupling agent used for wood–fibers is also effective for the exfoliation of clay, and therefore, no additional cost is required. This research indicates that the structure of nanocomposites (i.e., the degree of exfoliation) and the clay content used have a large impact on the flame retardancy of WPC. The flame retardancy is investigated as a function of these parameters. Based on this, a cost‐effective way to improve flame retardancy of WPC is presented. POLYM. ENG. SCI., 47:308–313, 2007. © 2007 Society of Plastics Engineers.
Studies of thermal oxidative degradation of polypropylene impact copolymer using the temperature rising elution fractionation method
Authors: Nakatani Hisayuki , Manabe Norio , Yokota Yoshimitsu , Minami Hiroaki , Suzuki Shoutarou , Yamaguchi Fumitaka , Terano Minoru
Published: February 2007

Thermal oxidative degradation of polypropylene impact copolymer has been studied with its fractions obtained using the temperature rising elution fractionation method. The fractions were analyzed using 13C NMR, Fourier transform infrared and differential scanning calorimetry measurements, and the chemical structure, isotacticity, conformation and melting point were investigated. It is found that these fractions are composed of a homopolymer or a polymer blend of polypropylene, polyethylene and ethylene–propylene copolymer. The thermal oxidative degradation of each fraction was carried out at 130 °C, and the degradation progress was estimated by the change of molecular weight distribution (from gel permeation chromatography curves). The rate of degradation is found to be dominated by the content of tertiary CH bonds (propylene unit) and the existence of 31 helix conformation corresponding to a crystalline polypropylene part in each fraction. The latter is more evident leading to the degradation reaction path with a lower activation energy. Copyright © 2007 Society of Chemical Industry
WI‐PHI: A weighted yeast interactome enriched for direct physical interactions
Authors: Kiemer Lars , Costa Stefano , Ueffing Marius , Cesareni Gianni
Published: February 2007

How is the yeast proteome wired? This important question, central in yeast systems biology, remains unanswered in spite of the abundance of protein interaction data from high‐throughput experiments. Unfortunately, these large‐scale studies show striking discrepancies in their results and coverage such that biologists scrutinizing the “interactome” are often confounded by a mix of established physical interactions, functional associations, and experimental artifacts. This stimulated early attempts to integrate the available information and produce a list of protein interactions ranked according to an estimated functional reliability. The recent publication of the results of two large protein interaction experiments and the completion of a comprehensive literature curation effort has more than doubled the available information on the wiring of the yeast proteome. This motivates a fresh approach to the compilation of a yeast interactome based purely on evidence of physical interaction. We present a procedure exploiting both heuristic and probabilistic strategies to draft the yeast interactome taking advantage of various heterogeneous data sources: application of tandem affinity purification coupled to MS (TAP‐MS), large‐scale yeast two‐hybrid studies, and results of small‐scale experiments stored in dedicated databases. The end result is WI‐PHI, a weighted network encompassing a large majority of yeast proteins.
Snow‐cover in th British Isles in January and February of the severe winters of 1940, 1941 and 1942
Authors: Lewis Lilian F.
Published: February 2007

The occurrence of snow‐lying at the morning observation hour has been reported at a number of stations in the British Isles since 1912 and at a larger number since 1914. By 1940 the number of stations recording this element had increased to approximately 300 in Great Britain alone. Thus the net‐work of stations is now fairly close. The majority of the observing stations are on moderately low ground, that is below 500 ft. above m.s.l. Variations in the duration of snow‐cover in the British Isles are great from year to year and in many of the winter months of the present century the number of days of snow‐lying on low ground has been few. The three consecutive winters of 1940, 1941, and 1942 were, however, unusually severe; the snowfall was considerable and the number of days of snow‐lying comparatively large. In this paper maps showing the distribution of the number of days of snow‐lying for each of the six months January and February, 1940, 1941 and 1942 are given and the different distributions are discussed in relation to the mean temperature, the amount and frequency of snow‐fall and the period of the month at which the snow occurred. In conclusion the entire absence of days with snow‐lying at the majority of stations, in February, 1943, is noted.
Variations in wind velocity near the ground
Authors: Carruthers Nellie
Published: February 2007

Information about wind velocity is generally obtainable in the form of mean hourly velocity and highest velocity in a gust at the level of the recording anemometer which, where possible, has an effective height (judged by the quality of exposure) approaching an agreed standard of 10 m. (33 ft.). For various purposes, estimates of both mean velocity and gustiness at other heights and in other exposures are often required. A summary is given here of relevant literature, in preparation of which I am much indebted to Dr. C. E. P. Brooks, both for his wide selection of works on the subject and for his helpful discussion and criticism.

The article deals first with variations in mean velocity with increase of height above the ground, and then with gustiness and its relation to change of mean velocity and height. Next, seasonal and diurnal variations in gustiness are considered and the effect of changes in direction of the mean wind. A general approximate law for variation of wind velocity with height is suggested and tables are given for estimation of velocities at other than the height of observation; the article concludes with a paragraph on range of wind velocity.

The wind velocities here considered are those in the lowest layers of the atmosphere, extending from ground level to a height of about 500 m. Where possible measurements of height are given in metres, velocity in metres per second, and temperature gradient in degrees Fahrenheit per metre (an upward increase is regarded as positive), these units being those of most frequent occurrence in the literature examined.
Thermal characteristics of a hertfordshire frost‐hollow
Authors: Hawke E. L.
Published: February 2007

Records of temperature over a 13‐year period in a Hertfordshire valley which has been described as possessing the most “continental” thermal climate yet investigated instrumentally in the British Isles are summarised, discussed, and compared with data from other stations. Among the facts brought to light are that only two of the 156 calendar months from 1930 to 1942 passed without ground frost on the valley floor; that screen frosts occur even in July and August; and that the mean night minimum temperature is at or below 32°F. for about three‐fifths of the year on the grass and for about two‐fifths of the year in the screen. Three examples of a diurnal range slightly exceeding 50°F. are examined in the light of Fourier analysis; statistical evidence is advanced to show that the probable limiting value for such ranges over a long series of years may be put at not less than 55–56°F. Thermograms are reproduced illustrating the greatest recorded daily variations, as well as the effects of katabatic winds and turbulence in the valley.
Investigation of heptakis(2,6‐di‐O‐methyl)‐β‐cyclodextrin inclusion complexes with flavonoid glycosides by electrospray ionization mass spectrometry
Authors: Yu Zhan , Cui Meng , Yan Cunyu , Song Fengrui , Liu Zhiqiang , Liu Shuying
Published: February 2007

The non‐covalent complexes between three flavonoid glycosides (quercitrin, hyperoside and rutin) and heptakis(2,6‐di‐O‐methyl)‐β‐cyclodextrin (DM‐β‐CD) were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICR‐MS). The 1:1 complexation of each flavonoid glycoside (guest) to the DM‐β‐CD (host) was monitored in the negative ion mode by mixing each guest with an up to 30‐fold molar excess of the host. The binding constants for all complexes were calculated by a linear equation in the order: DM‐β‐CD:quercitrin > DM‐β‐CD:rutin > DM‐β‐CD:hyperoside. A binding model for the complexes has also been proposed based on the binding constants and tandem mass spectrometric data of these complexes. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental and theoretical investigation on binary semiconductor clusters of B/Si and Al/Si
Authors: Sun Zhang , Yang Zheng , Gao Zhen , Tang Zichao
Published: February 2007

ASi (A = B and Al; n = 1–6) binary cluster anions were generated by laser ablation of samples composed of mixtures of Si and A (A = B and Al), and studied in the gas phase by tandem time‐of‐flight mass spectrometry. Some abundant ions are present in the mass spectrum, indicating that the clusters with these ions have stable structures. The structures of ASi clusters were investigated theoretically by the density functional theory (DFT) method and the energetically lowest‐lying structures were obtained. The binary clusters BSi and AlSi, with the same number of n, share different geometric structures except for ASi with n = 1 and 6, which have the same geometric structures in the ground state. For all the anionic clusters ASi, the lower spin state is lower in energy than the higher spin state in their optimized structures except for the linear ASi− anions, for which the triplet state is lower in energy than the singlet. Calculations of the bonding energy (BE), energy gain (Δ) and HOMO‐LUMO energy gaps confirm that the cluster ASi has a very stable structure, which agrees well with the experimental results. Copyright © 2007 John Wiley & Sons, Ltd.
Discontinuity of trichopteran (caddisfly) communities in regulated waters of the clearwater river, Idaho, U.S.A.
Authors: Munn Mark D. , Brusven M. A.
Published: February 2007

Riverine trichopteran (caddisfly) communities were sampled seasonally at eight locations over a two‐year period to determine if a multiple‐level release hydroelectric dam created a faunal discontinuity along the longitudinal profile of the Clearwater River in northern Idaho. The confluence of a non‐regulated river with a regulated reach provided an unusual opportunity to examine the recovery of community parameters in a semi‐regulated river.

A marked discontinuity in the caddisfly community occurred in the regulated reach immediately below the dam, reflected by greatly reduced diversity and abundance values, and by shifts in functional relationships. These faunal changes are primarily attributable to the modified temperature, discharge, and food resources induced by river regulation. The non‐regulated river exerted a major mitigative effect on the trichopteran fauna below its confluence with the regulated reach, despite maintenance of semi‐regulated conditions. Trichopteran community parameters approached near normal levels concomitant with partial reductions in flow fluctuations, and partial recovery of temperature and food resources. In addition, the non‐regulated river provided an important colonization pathway for riverine species to enter the semi‐regulated lower reaches.
Channel sedimentation within the urbanized river Tame, U.K.
Authors: Thoms M. C.
Published: February 2007

This study examines the distribution and composition of fine sediment within the gravel‐bed substrate of the channelized River Tame, within and below the Birmingham conurbation, United Kingdom. A freeze coring technique was employed to collect undistributed volumetric samples, to a depth of 30‐40 cm, providing information not only on the gross deposit but also on the vertical structure of the river bed in terms of textural and geochemical properties.

The urbanized substrate differs from that of the natural river, both in terms of the volume of matrix sediment present, which is less than ‚expected’︁, and in the size characteristics of the coarse framework and finer matrix components. Moreover heavy metal concentrations within the urbanized matrix sediment are up to 3000 times greater than background levels and maximum concentrations are shown to occur at a depth of more than 15 cm within the substrate.
Environmental issues of the three gorges project, China
Authors: Changming Liu , Dakang Zuo
Published: February 2007

This paper reviews several issues relating to the potential environmental impacts of a planned high dam at Three Gorges on the main course of the Changjiang (Yangtze River).
Characteristics of seston in a regulated Appalachian Mountain river, U.S.A
Authors: Kazmierczak R. F. , Webster J. R. , Benfield E. F.
Published: February 2007

Six size classes of seston were collected seasonally from the New River, Virginia, U.S.A., during three flow regimes: low flow, discharge changes resulting from daily cycles of hydroelectric power generation, and naturally occurring storm discharge cycles. Seston concentration and particle shape, density, and settling velocity were measured for all size classes, seasons, and flow regimes. Seston concentration, density, and settling velocity varied significantly with size class, season, and flow regime. Total concentrations ranged from a low of 0.47 mg litre−1 during autumn base‐flow to a high of 92.6 mg litre−1 during a winter storm. Mean seston densities ranged between 1.60 and 2.02 g cm−1, which is much lower than previously published measurements for rivers, suggesting that seston in the New River may be mainly organic‐inorganic aggregates. Mean seston settling velocity was lowest during low‐flow and hydroelectric discharges (0.10 cms−1) and highest during storms (0.19 cms−1). Seston particle shape varied significantly only with size class. The inability of a commonly used transport equation to predict transport during most discharge conditions suggests that, in some systems, seston concentration and transport may be less a function of discharge and power than of long‐term seasonal and short‐term discharge cycle effects on the density and size characteristics of seston.
Modification of temperature behaviour through regulation of a British river system
Authors: Webb B. W. , Walling D. E.
Published: February 2007

The effects of flow regulation on temperature behaviour in the River Exe, Devon, U.K. have been studied, and attention is given to the local impact of impoundment and its downstream persistence. Temperature levels and seasonal thermal regime are considered as well as diel temperature fluctuations and temperatures during extreme weather conditions. Variations in temperature during individual reservoir releases have also been monitored. The impact of impoundment has been to make the stream environment immediately below the dam more homothermous so that temperatures rearely rise above 17·5°C or fall below 2·0°C, and monthyl average diel ranges are < 3 and < 1°C in summer and winter months respectively. In contrast to other reservoirs in Britain and abroad, this effect has been largely caused by increased groundwater flow downstream from the reservoir following impoundment. Regulation has also affected downstream temperature behaviour and has moderated the thermal regime of the Exe mainstream. This influence is generally restricted to a distance of up to 20 km from the dam, but in conditions of hot weather and low flows it may extend to almost 40 km from the impoundment.
River regulation by seasonal groundwater abstraction: The case of the River Itchen
Authors: Giles D. M. , Lowings V. A. , Midgley P.
Published: February 2007

This paper describes the development of groundwater to regulate the flows of the River Itchen in Southern England. The permeable chalk geology of the river catchment makes the use of natural groundwater storage more cost effective than conventional surface reservoirs. The principles of groundwater regulation and the construction and testing of the first two schemes are described. Flow extension and mathematical modelling have been used to assess yields and assist with operational decisions. The paper concludes that groundwater regulation is a viable alternative to reservoirs in permeable catchments and further schemes are planned.
Channel change and sediment transport in regulated U.K. rivers
Authors: Carling P. A.
Published: February 2007

The history of investigations of channel change consequent upon river regulation is traced from the late 1960s until the present. The associated sediment transport and depositional processes are also reviewed. Conveniently the approaches adopted historically have fallen into three basic groups, these are: (1) analyses of the changes in channel networks as evident in adjustments to hydraulic geometry related to catchment area; (2) analyses concerned with sediment transport processes and channel adjustments at the reach scale (typically utilizing regime‐type concepts), and finally; (3) more recent attempts at an integrated approach utilizing holistic concepts of channel change over extended time periods.

A major conclusion drawn from this review is that each reservoir‐catchment system is unique, producing singular responses that cannot easily be integrated into a basic general model except at a facile level. The continuing lack of complete theoretical models of channel adjustment is a hindrance in predicting regulation effects and may be related to limited understanding of such factors as sediment supply dynamics and bank collapse mechanisms. Emphasis is placed on: the importance of the aggregational as well as the well‐known degradational response of channels below dams; the recognition of suitable temporal frameworks; the potentially destabilizing effect of rare large floods; and the local effects of unregulated tributary inflows. In addition more sophisticated theory and analysis needs applying to the transport and subsequent deposition of suspended sediments in gravel‐beds whilst the three‐dimensional facies relationships of regulated river alluvial suites need clarification in the light of recent initiatives concerning the sedimentary architecture of other alluvial systems.
Compensation flows in the UK: A hydrological review
Authors: Gustard Alan
Published: February 2007

A survey of United Kingdom reservoirs identified the development of compensation flow policy from the early 19th Century to the present day. Details on the level and pattern of releases below 261 impounding reservoirs provided the basis for assessing the spatial and temporal variation in compensation flows and the impact of impoundment on downstream flow regimes. By standardizing compensation releases by the natural pre‐impoundment mean discharge, release patterns from reservoirs with a wide range of both catchment area and climate could be compared. Analysis of the change in flood and low flow frequency following impoundment enabled the impact of reservoir regulation to be evaluated at the regional scale. For individual reservoirs the natural downstream increase in river flow provides a basis for determining the length of river reach which is sensitive to regime changes. The majority of present day compensation discharges were set to satisfy river interests which no longer apply or were based on inadequate hydrological or biological information. This has led to a wide range of release patterns and it is therefore recommended that the re‐evaluation of existing water resource schemes should include an assessment of the suitability of current release patterns for present day downstream demands and water resource requirements.
Prediction of regulation effects on natural biological rhythms in south‐central African freshwater fish
Authors: Jackson P. B. N.
Published: February 2007

Fish in south‐central African freshwaters are governed by biological rhythms. First, these are associated with the markedly seasonal summer annual rainfall when breeding takes place with an initially high mortality among newspawned juveniles. Second, a longer term rhythm of annual rainfall variability occurs in cycles up to or more than a decade. These cause water levels to vary from exceptionally high levels to near desiccation in endorheic systems.

Studies of the shallow endorheic lakes Mweru Wa'Ntipa (Zambia), Ngami (Botswana), and Chilwa (Malawi) are cited showing that species diversity rapidly increases by colonization from adjacent ‘inocula’ (relict communities surviving in more permanent nearby water bodies, e.g. deep pools in perennial streams) when filling starts. During the drydown phase of the cycle, diversity decreases through lack of annual breeding environment and diminution of water quantity and quality. A few, usually three, species remain longer which, being physiologically hardy or showing phenotypic plasticity, are tolerant of higher salinity, temperature, etc., conditions associated with dry‐out. Despite the lakes' wide geographical separation these taxa in every case are a single species of the tilapia, genus Oreochromis, the catfish Clarias gariepinus, and the minnow Barbus paludinosus, which build up large populations valuable to local fisheries.

Evidence from the Pongolo River, Zululand, regulated by a large dam, shows that fish of downstream endorheic lakes react similarly to artificial water deprivation, with mainly the same taxa persisting. Managed water releases timed to coincide with breeding rhythms largely restore the conditions which previously prevailed. Data from Zambezi impoundments indicate conversely that reaction of previously riverine fish to large man‐made lakes is for previously sparse lentic taxa like Oreochromis to proliferate greatly while lotic forms like Labeo are reduced in number.

Since fish stocks are a valuable natural resource, such basic scientific results may be applied with great advantage. The collaboration between engineer, biologist, and management authority can minimize adverse environmental effects and predict better opportunity cost assessments of a projected river manipulation.
Determination of hydraulic parameters for instream flow assessments
Authors: Courot A.
Published: February 2007

Determination of the hydraulic parameters of a stream is the first stage in the instream flow incremental method (IFIM). Two different modellings have been applied to simulate the hydraulic conditions (i.e. depth and velocity) of the Orne river at Rabodanges in order to assess the changes in fish habitat with the flow. One process consists of representing the reach examined by a few sections (the pilot sections), the other is a conventional flow model. The accuracy of both types of model has been calculated by comparison with depth and velocity data available for four different rates of flow. As regards the flow model, the accuracy of depth calculations is average (16 per cent) but decreases for low rates of flow. Velocity values are less accurate (24 per cent). Concerning the pilot sections method, the degree of accuracy of velocities should be improved (80 per cent) but the accuracy of depths is interesting (7 per cent). The representation of the flow conditions the accuracy of per cent usable area (PUA). For brown trout juveniles and fry the accuracy on PUA is of the same order of magnitude as the degree of accuracy of depth. The inaccuracy on velocities due to the method is not totally reflected in the PUA values, the probability‐of‐use curves of the species considered can act as a filter for errors linked to the method followed for assessing hydraulic parameters.
The Orinoco river: A review of hydrobiological research
Authors: Vásquez Enrique
Published: February 2007

The Orinoco River is one of the world's longest rivers (2060 km) and in terms of average water discharge (36000 m3 s−1) it ranks third. Seventy per cent of its basin (1.1 × 106km2) is found in Venezuela and the rest in Colombia. Due to the uneven distribution of the population toward the northern coastal areas (97 per cent of the population inhabits 55 per cent of the country with only 16 per cent of the surface waters) plans have been carried out to develop resources in the Orinoco Basin. So far these programs include mining (mainly iron and bauxite), oil exploration and extraction from the Orinoco Oil Belt, industry, river transport, and hydroelectric exploitation. Development of the latter has involved the construction of two dams on the Caroní River (the most important blackwater tributary of the Orinoco) and two more are planned on this same river. Hydroelectric projects are also being considered for the Orinoco River. Physicochemical and biological characterization has been regarded as of major importance to establish base‐line information to detect and quantify possible alterations in this river which is considered to be in a pristine state. Systematic hydrobiological research has recently been carried out in the river, some of its major tributaries, and floodplain lakes, and a fair amount of knowledge has emerged mainly from its lower section.

Phytoplankton studies have revealed the presence of over 400 species of algae. Zooplankton research has identified 116 taxa of rotifers and 58 taxa of cladocerans. In general plankton densities negatively correlate with water level. Diatoms were observed to predominate in the Orinoco River while Cyanophyta predominate in the studied floodplain lakes. Seventeen aquatic macrophyte species have been recorded in the lakes of the Orinoco with high densities of Eichhornia crassipes, Oxycarium cubense, and Paspalum repens. Rooted emergent and floating‐plant cover tends to increase rapidly during high water.

Some 318 species and subspecies of fish have been reported for the Orinoco Basin, even though this number is far from complete. Preliminary data have revealed different species associations among relatively close lakes with biomasses ranging between 30 to 900kg ha−1 displaying considerable variations in diversity and species richness. Fisheries along the Orinoco are mainly of a multispecific nature and their overall potential has been estimated as being in the order of 45 000t yr−1.

In general, management plans have taken into consideration the multispecific potential of the Orinoco Basin but indicate a lack of sufficient knowledge of the physical, biological, and social aspects involved. Furthermore development plans tend to precede the generation of this basic knowledge, thereby increasing the risks of conflict among the various users of the resources involved.
River fisheries in Brazil: A review
Authors: Jr. Miguel Petrere
Published: February 2007

Riverine fisheries in Brazil are reviewed. There is a broad description of the environment and the fish, and arguments for the high diversity of fish fauna diversity are examined. The country is divided into five large river basins and the fisheries are described in relation to the main fish species caught, the main gear employed, and the fishing strategies. Exotic species introduction is discussed along with strategies for fish stock management. Effects of dams on resident fish stocks and consequences for the small scale fisheries are discussed and compared with the effects of pollution.
Long‐term nitrate trends in the river trent and four major tributaries
Authors: Josæ P.
Published: February 2007

Nitrate levels which have been rising in many British rivers for at least thirty years have become of particular interest since Britain adopted the EC Drinking Water Directive. The literature examining nitrate trends in the rivers of the U.K. and Eire is reviewed. Long‐term nitrate concentration trends are derived for eight sites in the River Trent drainage system. These include sites on two rural tributaries, two urbanized tributaries, and the main river. Currently, mean annual concentrations for these sites range from about 4.0 mg1−1N in the rural catchments, to 12.4 mg 1−1 N in the urbanized tributaries, and to between 8.7 mg 1−1N and 11.0 mg 1−1 N along the mainstream. Moreover rates of increase of nitrate concentration of approximately 0.06 mg 1−1 N yr −1 in the rural catchments, contrast with values up to 0.20 mg 1−1 N yr −1 in the two urbanized tributaries and River Trent. Long term nitrate loads have been calculated for the River Trent at Nottingham using a discharge weighted mean interval method. This method probably provides the best available estimate of nitrate loads calculable from irregular data of variable sampling frequency for lowland rivers. Annual nitrate loads varied between 10700t yr −1 and 29 800t yr −1 over the period of record. A rate of increase in nitrate load of 455 t yr −1 was obtained. The increases in nitrate concentrations and loads within the Trent basin are matched by similar rates of increase in other European catchments.
Long‐term effects of navigation dams on a segment of the upper Mississippi River
Authors: Grubaugh J. W. , Anderson R. V.
Published: February 2007

Navigation dams on the upper Mississippi River have altered the long‐term relationship of river stage to river discharge. Analysis of the 34‐year pre‐dam and 74‐year post‐dam data sets indicated that the completion of Lock and Dam 19 in 1913 increased river width and volume behind the dam. The immediate impact was a higher mean river stage less influenced by changes in river discharge. The dam's long‐term impact was to increase sedimentation causing a steady loss of both river width and volume that resulted in stage/discharge relationships approaching those of the pre‐dam era. The present condition of higher mean river stage coupled with greater stage fluctuation is a major factor in the increased recurrence and duration of floods on the upper Mississippi River in recent decades.
Aquatic invertebrate surveys as a water quality management tool in the Anglian Water region
Authors: Extence C. A. , Ferguson A. J. D.
Published: February 2007

The benefits of utilizing biological data in managing water quality are discussed, and the drawbacks and restrictions of traditional methods used to summarize and present biological results, are briefly outlined. Recent work in the Anglian Water region has led to the development of the Lincoln Quality Index, and this method overcomes some of these problems, enabling biological data to be usefully incorporated into environmental management programmes. Examples are given to show how the technique can assist in detecting and determining the significance of intermittent and shock pollution loads. The impact of deteriorating sewage effluent quality is also considered in some detail. The adoption of the Lincoln Quality Index method offers the opportunity for substantial cost savings, as well as allowing water quality surveillance programmes to be undertaken with increased flexibility. Areas where further work would be beneficial are finally identified.
Prediction of invertebrate communities using stream measurements
Authors: Wright J. F. , Armitage P. D. , Furse M. T. , Moss D.
Published: February 2007

An account is given of the development of a computer‐based system for prediction of the invertebrate fauna to be expected at unpolluted sites using environmental features. The variables for use in prediction and the flexibility of the output, with respect to taxonomic level, are demonstrated using an early version of the system which has been tested within the water industry. The practical value for river management of predictions of species, families, and biological indices is elaborated. In addition, the relevance of the system throughout Great Britain for setting target values of a biological index is demonstrated.

A new version of the prediction system has recently been developed. It has application over a wider range of river systems and incorporates additional options for prediction, as requested by the Water Industry. Further developments of the system to make it more efficient for operational use are now under active consideration.
Assessment of the value of rivers for Otters (Lutra lutra)
Authors: Andrews Elizabeth
Published: February 2007

The British otter Lutra lutra L. requires good water quality, an adequate supply of fish and certain types of vegetation or cavities (holts) adjacent to water bodies for resting and breeding sites. In the U.K. otters and their holts are legally protected.

Trained surveyors are needed to confirm the presence of otters on a river as the animals are rarely seen, but their tracks and droppings (spraints) may be detected. To evaluate a river for otters, information is required on water quality, fish species and biomass, as well as available habitat. Pioneer evaluation work based on the River Corridor Survey techniques has been done on Welsh rivers with good otter populations. Riparian vegetation, especially trees, is shown to be particularly important. This work is now being extended to areas on the margins of otter distribution such as the lower river Wye in England and Wales. Such surveys provide important management information for water authorities and give opportunities for enhancement work to benefit this animal.
Modelling water quality of a reregulated stream below a peaking hydropower dam
Authors: Zimmerman Marc J. , Dortch Mark S.
Published: February 2007

This paper describes CE‐QUAL‐R1V1, a dynamic, one‐dimensional, stream water quality model capable of simulating branched riverine systems with multiple hydraulic control structures, such as weirs, reregulation dams, and navigation locks and dams. We provide examples of potential water quality impacts associated with operations alternatives for a reregulation dam proposed for construction downstream from Buford Dam on the Chattahoochee River near Atlanta, Georgia, in the southeastern United States. Model calibration, confirmation, and application are examined. The model is calibrated for stage, transport, temperature, dissolved oxygen, carbonaceous biochemical oxygen demand, ammonium‐N, and nitrate‐N. Results indicate that release operations which maintain cool temperatures in summer may cause undesirable decreases in dissolved oxygen and increases in dissolved iron in autumn. Flexibility in release scheduling is recommended to avoid unnecessary problems.
Comparison of macrobenthos in braided and channelized sectors of the Drôme River, France
Authors: Peeters E. T. H. M. , Tachet H.
Published: February 2007

The influence of braided pattern on macrobenthic communities was studied in the Lower Drǒme River (France). The qualitative differences between embanked and braided sections are weak. The sessile species (for example Psychomyia pusilla) are more frequent in the embanked section whereas the drifting species (for example Baetis fuscatus) are more frequent in the braided section. The density of macroinvertebrates in the latter, especially in the secondary channels, is higher than in the embanked section, but the diversity remains low because the location of the channels changes at each extreme flood.
Sediment deposition in cutoff meander bends and implications for effective management
Authors: Douglas Shields F. , Abt Steven R.
Published: February 2007

Cutoff bends along modified, stabilized streams often constitute a valuable recreational, ecological, and aesthetic resource. However, their resource value rapidly declines as they fill with sediment, and new cutoff bends do not form to replace them in highly managed rivers.

Data from repetitive hydrographic surveys of 20 cutoff bends along four rivers in the southeastern United States were examined using conceptual and analytical models in order to provide a more objective basis for bend management. Bend volume was found to be a log‐decay function of cumulative water discharge through the cutoff reach. Regression analyses were used to generate functions to predict the log‐decay constant. The log‐decay constant varied directly with master stream suspended bed‐material concentration and inversely with variables describing the geometry of the upstream entrance of the old bend. Management of cutoff bends should focus on sequencing construction activities and modification of the upstream bend entrance geometry to reduce the quantity of bed material diverted into the bend. Construction of blockage structures to top‐bank elevation in upstream entrances of cutoff bends is recommended for systems with average suspended bed‐material concentrations greater than about 50ppm. Blockage or modification of entrance geometry of longer bends preserves more aquatic habitat longer than similar levels of effort directed toward shorter bends. Maintenance of a hydraulic connection between the river and at least one end of the cutoff bend is recommended.
Endangered fish species of the Danube river in Austria
Authors: Schiemer Fritz , Spindler Thomas
Published: February 2007

The ecological affinity of fish species to different habitat types in the course of their life cycles is investigated in the free‐flowing sections of the Austrian Danube. The results point to the great significance of the degree of hydrological integration between the river and its adjoining waters. In the breeding and fry stage, rheophilic species are bound to the river itself, but the preferred zones show great variations according to both fish age and species. A highly structured shoreline is important in providing a gradient of water current and a spectrum of food sources. Regulated embankments are characterized by an extremely reduced fauna with low population densities of eurytopic species. These results give evidence that the conservation of the characteristic species association is incompatible with the planned hydroelectric power dams in the remaining, free flowing zones of the Danube. The importance of the fish fauna as an indicator group for the condition of large river systems is discussed from the conservation point of view.
Relationships between actinomycete populations and organic matter degradation in Lake Mulwala, southeastern Australia
Authors: Boon P. I.
Published: February 2007

This communication examines the proposal that actinomycete populations, and thus the occurrence of taste and odour problems in potable water supplies, are related to the input of organic matter to reservoirs. The number of actinomycetes in Lake Mulwala, a man‐made lake in southeastern Australia, ranged from 2–80 ml−1 in the water column, and 2.7–12 × 104cm−3 in the sediments. Population densities in the water column and sediments were greatest in winter and summer, respectively. They were not highly correlated with protein or polysaccharide degradation. The weak relationship between actinomycete numbers and the rate of organic‐matter breakdown was probably due to metabolic inactivity of the bacteria, since actinomycetes in the sediments occurred mainly as spores rather than as vegetative cells. Limiting the input of organic matter, for instance by the removal of fringing vegetation, will have little effect on actinomycete populations in this reservoir.
Water mangement and ecological perspectives of the upper rhine's floodplains
Authors: Dister Emil , Gomer Dieter , Obrdlik Petr , Petermann Peter , Schneider Erika
Published: February 2007

The diverse Upper Rhine floodplains (with regard to geomorphology, hydrology, vegetation, and fauna) have undergone far‐reaching changews over the last 170 years, intensified from 1955 to 1977, especially as a result of water engineering measures.

Far‐reaching and serious distrubances of the ecological balance (flood problems, lowering of the water table, etc.) and the drastic reduction of biotic communities, as well as the increasing demands of society, call for a newly oriented policy with regard to the future development of the Upper Rhine floodplains. This should be based on a critical review of the recent history of the landscape and a recognition of the ecological importance of these floodplains.
River engineering in national parks: The case of the river Wharfe, U.K.
Authors: Hey R. D. , Winterbottom A. N.
Published: February 2007

River engineering works have recently been carried out on the upper River Wharfe (U.K.) in order to reduce the flood risk and resore land drainage beween Hubberholme and Kettlewell. As the river is located in a National Park, great care had to be exercised to limit the degree of interference and to ensure that an environmentally acceptable solution was adopted.

Increased flood risk can be partially attributed to afforestation in the headwaters of the Wharfe. Improved drainage prior to planting has lead to an apparent increase in the mangitude and frequency of flooding and an increase in sediment yield.

The works were to remedy both problems and were designed in consultation with a range of conservation and amenity organizations. First, a bed load trap was constructed on the Wharfe to curtail the sediment supply to the flood prone reach and prevent further aggradation. Second, limited dredging was carried out near tributary junctions to improve land drainage on the floodplain. Third, the dredged material was used to form the core of the raised banks.

The engineering works were carred out between 1985‐87. Since completion in August 1987 the flood banks have been overtopped only twice which compares with the previous record of thirty‐two times per year. No significant erosion or deposition has occurred and the gravel trap is performing according to expectations; being half full after two and a half years of operation. Although stocks of mature trout were displaced by bed workings, there are now signs of a recovery.
Restoration of fish communities of the rhine river two years after a heavy pollution wave
Authors: Lelek Anton , Köhler Christian
Published: February 2007

The Rhine may provide a classical example of faunistic changes due to Man‐made stress. Formerly a salmonid river, it was transformed into a ship‐canal. Steadily increasing pollution culminated in the 1960s and 1970s. An improvement of water quality in the 1980s was followed by an increase in abundance of several species and faunal diversity. Originally 47 species inhabited the Rhine; at present 40 indigenous and 15 introduced species live in the river, seven have vanished or have not been observed so far. Recent setabacks, like the Sandoz Accident in 1986 failed to eliminate any taxon. Protection of the indigenous fauna is to be linked with conservation of remaining environmental diversity, ecotechnical improvements, and new strategies in fishery management, which do not merely support only economic species.
Changes in plankton communities in regulated reaches of the lower river rhine
Authors: de Ruyter van Steveninck E. D. , Admiraal W. , van Zanten B.
Published: February 2007

The Dutch section of the Lower Rhine is highly modified by regulating measures, such as the construction of weirs and the closure of estuarine river mouths, which seriously affect sedimentation of suspended material. During 1987 the fate of plankton communities in this part of the Rhine was investigated. Water samples were taken fortnightly at the German‐Dutch border and in the main branch of the Rhine, just before it debouches into the North Sea. Dry weights of suspended matter, bacterial numbers, phytoplankton biomass (as chlorophyll a) and zooplankton composition and biovolumes were determined, and, at two occasions, phytoplankton composition and biovolumes as well. Supended matter and bacteria disappeared during transport in the Rhine Delta. phytoplankton biomass (primarily diatoms) showed typical spring and summer peaks and also decreased in the investigated river reach. In contrast, zooplankton developed a higher biomass due to an increase in the numbers of rotifers, crustaceans, and molluscan larvae, whereas arcellas and ciliates decreased in numbers.

It is concluded that the Rhine, after flowing more than 800 km, meets in its delta the proper conditions for a true plankton community to develop: settling and trophic interactions become of increasing importance in determining the structure of plankton communities.
Effects of fluctuating levels of lake superior on morphological adjustments in the neebing‐mcintyre floodway, thunder bay, Ontario Canada
Authors: Rasid Harun , Phillips Brian A. M.
Published: February 2007

The Neebing‐McIntyre Floodway, a relatively straight, trapezidal flood‐control channel, was constructed in 1983 to dispose of the combined flows of the Neebing and the McIntyre rivers into Lake Superior. Because of its location in a transitional fluvial/lacustrine environment, related processes had direct and indirect impacts on its morphological readjustments. During the post‐construction period (1983‐88) the combined peak flows of the Neebing and the McIntyre rivers never exceeded the two‐year design floods for the floodway, resulting in relatively low stream power and sediment transport rates. The average rate of sedimentation in the new channel (1100 m3 y−1) was thus much lower than the designers' estimated volume (11 800 m3 y−1). These low‐flow events coincided with high water levels in Lake Superior in 1985‐86, reinforcing the normal backwater effect in the floodway and further dampening its stream power. During this event the floodway behaved hydraulically almost like a reservoir, with fluctuating water levels and wind‐generated waves as the principal geomorphological agents of bank erosion. Estimates based on volumetric surveys indicate annual rates of bank erosion ranging from 0.03 to 0.16 m3 m−1 of bank length, with an average annual rate of 0.1 m3 m−1. The bank materials are composed of highly erodible sandy loam and loamy sand, which have a tendency to disperse and liquefy relatively easily. There are no significant spatial variations in erosion rates along a given bank but contrasts in the magnitude of erosion between the north and the south banks can be related to the relative exposure of a bank to average wind velocities, total duration of winds and the effective wind‐wave fetches.
Interactions between geomorphological processes, benthic and hyporheic communities: First results on a by‐passed canal of the french upper rhône river
Authors: Chatelliers M. Creuze Des , Reygrobellet J. L.
Published: February 2007

On the basis of data collected from several previous studies on the Miribel Canal, a by‐passed section of the Upper Rhône river near Lyon (France), an ecological methodology, based on geomorphology and dealing with both benthic and hyporheic layers of the river bed, has been set up and tested at the scale of the whole reach. The methodology allowed the description, by single spatial survey of, a “functional profile” of the canal incorporating both hydrological and faunistic fluxes. The ecological importance of riffles is emphasized and the results indicate that, even in this kind of disturbed channel, geomorphological processes (degradation/aggradation…) act as ecological constraints, especially in the hyporheic layers where they determine community structure by influencing groundwater circulation. The methodology proved to be a good tool over different scales for ecological studies of fluvial systems.