PRACTICAL METHODOLOGY FOR DETERMINING THE SIGNIFICANCE OF IMPACTS ON THE WATER ENVIRONMENT

There is currently limited guidance available in the UK for predicting the significance of the impacts of developments on the water environment. This may be partly due to the disparate nature of the components of the water environment, which are covered by a range of scientific and engineering disciplines. This paper reviews the current status of Environmental Impact Assessment for the water environment in the UK and identifies key methodologies and guidance. Proposals are made for a more detailed approach to determining the significance of impacts on rivers, stillwaters (lakes and ponds), groundwater and floodplains, building on methodologies previously developed for highways schemes. Account is taken of the Environment Agency's ongoing work to classify water features to meet the requirements of the Water Framework Directive.     

National Rivers Authority National Strategy and Planning for the Future

The protracted drought from 1988 to 1992 has focused attention upon the availability of water sources in England and Wales. The drought was most severe in the east and south-east parts of England, which also coincides with the areas having (a) the least available water resources, (b) the greatest forecast increase in demand, and (c) the majority of low-flow problems due to excessive authorized abstraction. Even with increasing attention being paid to demand management, there is a need to develop further water-resource schemes. Once local options have been developed it is likely that inter-basin transfers will be required.     

LAND USE AND FLOOD RISK THROUGH CATCHMENT FLOOD-MANAGEMENT PLANS

Catchment Flood Management Plans involve a high-level assessment of current flood risk and attempt to demonstrate how this risk could change with time. An influencing factor will be the changes to rural and urban land use on catchment hydraulics. By assessing a range of land use and urban-growth scenarios catchment wide, a 'catchment flood management plan' can demonstrate the cumulative effect on downstream flood-risk areas. 'Catchment flood management plan' methods also indicate how long-term land-use and climate changes can expose new areas to more frequent flooding. Techniques to assess these issues, up to a 50-year horizon, have been established as part of these pilot studies. In addition to briefly describing how land-use concerns are integrated into such concepts, this paper outlines how flood-management planning must evolve as a dynamic tool, to fulfil an on-going requirement for future development assessment.     

WATER, SEWERAGE AND DRAINAGE INFRASTRUCTURE FOR PALESTINIAN REFUGEE CAMPS IN LEBANON

Many of the Palestinian refugee camps in Lebanon were originally established as tented encampments during the period 1948–1955. Half a century later, with high population densities and limited vehicular access, they remain largely separate from adjacent Lebanese communities, with infrastructure and welfare services mainly provided by the United Nations. Water supply, sewerage and stormwater-drainage systems have been developed on a piecemeal basis, are frequently in poor condition, and are inadequate to cops with expanding populations. A project for the design of new systems was commissioned to serve a total population of about 250 000 by the year 2020. The new facilities have had to take account of complex networks of narrow pedestrian alleyways that characterise many of the camps.
This paper provides an insight into (a) working within established refugee camps and other economically poor and densely populated communities, and (b) the problems which were experienced in developing feasible solutions for the improvement of infrastructure.     

Application of a Biological Iron Removal Process at Grove Water-Treatment Works

This paper describes the process of biological iron removal with specific reference to the new water-treatment plant at Grove (near Retford), operated by Anglian Water Services. The reasons for selection of a biological-treatment process are discussed together with process design, commissioning experiences, and details of plant performance.
The raw-water data suggested that a biological removal process would be feasible and would offer capital cost savings over a conventional aeration and filtration process. Further investigations were carried out in a pilot plant. A summary of the data which were collected during the performance trials is presented, which demonstrates the successful application of the process.     

Domestic Water Consumption and Its Determination in Rural Guatemala

Development agencies who work in the water sector often implement their aims using projects which provide basic physical infrastructure. The provision of adequate and appropriate water systems and services relies upon the availability of valid design data, such as per capita consumption and peak-flow factors, yet many project designs are based upon broad assumptions or inappropriate data. This paper presents the methods and results from a project to collect domestic water consumption data from rural water systems in Guatemala. General observations on the implications of the results are discussed together with the role which simple data collection can have within development projects.     

Easter 1998 Floods

Prior to Easter 1998, the 1947 floods were the reference events for flood-risk management in many catchments throughout England and Wales. However, Easter flood levels were generally higher than those of 1947 in the river systems draining an area of about 5000 km², bounded by Bedford in the east, Evesham in the west, Peterborough in the north, and Oxford in the south.
The paper describes the background to the floods and the independent review, and outlines the lessons which emerged from the Easter 1998 flood experiences, particularly in relation to flood-plain management, hydrometry and flood forecasting and warning.     

An Assessment of Drainage Best Management Practices in Scotland

The study was carried out to establish the extent to which source-control systems are being used in Scotland. An investigation into the level of knowledge of such systems was also initiated. Over 100 questionnaires were sent to organizations which have been involved in the development of surface-water drainage schemes, and the 43 responses were analysed.
Further work was then undertaken to establish the locations of source-control systems in use. The collated information was utilized and, with the help of the Scottish Environment Protection Agency consent files and correspondence with consultants, a database indicating the locations of sites, was compiled. Information was collected on approximately 79 examples of such systems, currently in use or proposed, in Eastern Scotland.     

GULLANE OUTFALLS, SCOTLAND

This paper describes design and construction of two new sea outfalls discharging from Gullane Waste Water Treatment Works (WwTW) to Aberlady Bay, on the south side of the Forth estuary (Firth of Forth), 25km east of Edinburgh, Scotland. The outfalls were installed by float and lower, using the Flow-Lay® technique, believed to be a first for steel pipes. The paper also describes air transport, beach movement and soil liquefaction and their effect on pipe stability, material and profile.