Optimization of Sampling Resources

T his paper reports on an investigation into the efficient routing of sample collection in the Lincoln Division of Anglian Water. Samples have to be collected from more than 600 sample points across three functions and at frequencies ranging from daily to once in two years. The organization of this activity is clearly complex.
As a result of the review carried out using manual methods, the additional 15 000 water samples which are required annually are now being collected with no increase in staff resources. The scale of the effort required for this review prevents it from being repeated except at infrequent intervals; yet without frequent reviews the efficiency of routes is eroded as the required pattern of samples changes. A computer system is therefore being developed, offering the prospect of halting the drift away from efficiency and the speedy evaluation of alternative strategies.     

Groundwater Model of Conditions in Liverpool Sandstone Aquifer

T his study considers the groundwater conditions for the period 1948–82 in the Permo-Triassic Sandstone aquifer of the Liverpool area. During this period, significant changes have occurred in the abstraction patterns and a new railway tunnel has been constructed below sea level in Central Liverpool. To understand the flow conditions within the aquifer, detailed studies have been carried out into the aquifer properties, the influence of rivers and tunnels, and the estimation of recharge. It is found that conventional rainfall recharge accounts for only one-third of the total recharge.
Numerical model solutions were used to check the adequacy of the understanding of the flow processes and the solutions have confirmed that the rising water levels in Central Liverpool result from high recharge and a reduction in abstraction. Having validated the model by comparisons with field data, the model was then used to predict the probable future water level changes.     

In Situ Performance Monitoring of an Infiltration Drainage System and Field Testing of Current Design Procedures

Sustainable urban drainage systems offer a sustainable option for the disposal of stormwater runoff - reducing the risks of flooding and pollution of receiving watercourses. However, the adoption of such systems has been slow, with a lack of performance data identified as being one barrier. This paper presents in situ performance data from a perforated concrete ring soakaway which was installed to collect stormwater runoff from a school roof and paved area. Data on rainfall at the site and water depth in the soakaway were collected for a period of twenty months, and a number of rain events were studied in detail. Data from the soakaway were used to test the most recent design procedures for infiltration drainage systems, and it was found that the design equations gave reasonable predictions of system response to rainfall - especially when the observed runoff coefficients were taken into account.     

A Replacement Outfall for Peterhead

The paper describes the design and construction of an outfall into Sandford Bay, Peterhead, on a highly-exposed stretch of the NE coast of Scotland.
The outfall forms part of a drainage system that was installed in the early 1970s to reduce pollution in Peterhead Bay and to accommodate increased flows from oil-related development. It replaces the original outfall, which failed in 1979 due to wave action.
Stability of the new steel-pipe outfall, which was installed by the bottom pull method, is ensured by burial within an excavated rock trench, backfilled and armoured with graded stone.
The exposed location of the site was demonstrated during construction work when bad weather and adverse sea conditions delayed completion by one year.
The paper concludes that the full significance of prevailing sea and weather conditions, and consequently reduced working 'windows', should be taken into account in the planning and programming of outfall work, to reduce the risk of damage to a partially completed and unprotected outfall.     

Hydrophilic antioxidants of virgin olive oil. Part 2: Biosynthesis and biotransformation of phenolic compounds in virgin olive oil as affected by agronomic and processing factors

The biosynthesis of the phenolic fraction of olive fruits during ripening and the transformations occurring in this moiety during virgin olive oil (VOO) extraction are discussed in this paper. The influence of agronomical factors that can significantly affect the phenolic profile of VOO is also discussed. Particularly, it is worth emphasizing the role of genetic factors, cultivation and climatic conditions such as water availability, atmospheric temperature, altitude, health status of the fruits, alternate bearing in the olive, and some processing factors such as crushing, malaxation time and temperature or volume of water added during milling. Among these parameters, special attention has been paid to genetic factors due to the high variability observed among Olea europaea genotypes for all recorded traits. In this context, interesting experimental results have been obtained with cultivated and wild olive trees, and also with segregating populations resulting from olive breeding programs. To the authors' knowledge, reviews evaluating the influence of the main factors that contribute to the profile of hydrophilic phenols have not been previously published. The discussion concerning olive breeding programs is a major and novel aspect to be emphasized considering recent trends to obtain new olive cultivars that confer better organoleptic properties and better quality to VOO.     

THE 1999 CRYPTOSPORIDIUM RISK ASSESSMENT EXERCISE IN ENGLAND AND WALES- A GROUNDWATER OVERVIEW

Regulations Introduced in 1999 obliged water companies In England and Wales to conduct risk assessments of their treatment works to establish whether there was a significant risk from Cryptosporidium oocysts in the water supplied. More than 330 treatment works were identified as being at risk, just over half of which were plants treating groundwater. This paper provides an overview of what water companies themselves identified as the most at-risk settings for their groundwater-based works in terms of aquifer and type of supply. Evaluation of results from the subsequent continuous monitoring regulatory regime that came into force on many of these supplies could validate the primarily qualitative nature of the initial assessments of at-risk settings. There would also be public health benefits from confirmation of whether currently-employed risk assessment methods are well-founded because similar procedures could then be applied with confidence to the many small private supplies In Britain.     

DYNAMICS OF SEDIMENT-ASSOCIATED METALS IN A HIGHLY URBANISED CATCHMENT: BRADFORD, WEST YORKSHIRE

Urban watercourses are potential hazards because of their rapid flow changes, poor water quality and contaminated sediments. This study is a preliminary field investigation into fine sediment-associated metal contamination and its transport dynamics in a highly urbanised catchment in West Yorkshire, UK. Spatial and temporal changes in the concentration of channel-bed sediment-associated metals are investigated, and the fluxes of selected suspended sediment-associated metals, during an extreme high flow event, are determined. Channel-bed sediments were more contaminated at the most heavily urbanised sites. Data suggest that contaminated bed sediments could accumulate and possibly become increasingly contaminated between high-flow events, prior to being flushed from the system. Fluxes of contaminated suspended sediments were very high at the peak of the high flow event. The spatial and temporal dynamics of contaminated fine sediment which were identified in this study could inform planners with regard to future monitoring strategies.     

The Use of Chemicals in Agriculture

This paper examines the use of agrochemicals in modern agriculture and horticulture. It begins by reflecting on the uncertainties of agricultural and horticultural production prior to the use of synthetic chemicals, then discusses the improved quantity and quality of output which is possible using agrochemicals. The social, environmental and agricultural hazards attendant upon chemical use are also considered. Provided that proper safeguards are observed, the use of agrochemicals is a sine qua non for the majority of farmers and growers in the UK.     

The Use of Different Conveyance Calculations for Modelling Flows in a Compact Compound Channel

Flow measurements have been taken for steady and unsteady flows on a reach of a river having a compact compound channel. The 'single channel', 'divided channel' and 'lateral' distribution methods have been used to calculate conveyances for use in a one-dimensional unsteady flow model of the reach. Comparisons with measured flows show that the divided channel method and the lateral distribution method both underestimate floodplain flow depths. The lateral distribution method gives the closest accuracy in the relative depth range 0.15 ≤ Yr < 0.40. For large flow depths the single channel method becomes more accurate and slightly over-estimates flow depths.
The accuracy of unit width discharge distributions, calculated from the lateral distribution method are assessed by comparison with observed distributions for overbank flows.