A Review of the 1995–96 Drought in the North West

As environmental regulator, the Environment Agency seeks the best balance between essential needs of water supply and the environment, whilst taking into account costs and benefits; nowhere is this balance more focused than in the management of droughts. The drought of 1995–96 was the most severe on record in the North West, and presented a major challenge to both the water company and the Environment Agency in safeguarding essential water supplies and minimizing the risks to the environment.
This paper describes the management of the drought from the Agency's perspective.     

Performance of the Burwarton Estate Waste Stabilization Ponds

The Burwarton Estate waste stabilization ponds, near Bridgnorth, Shropshire, serve a population of 150. There are three ponds in series: a facultative pond, and two equal maturation ponds, followed by two parallel and alternately used constructed wetland ditches. This paper describes the design of the ponds and reports upon their performance during the first two years of operation.     

Post-Implementation Appraisal of a Two-Stage Channel in the River Roding, Essex

T he performance of a two-stage river channel is examined from a combination of collected field data on the River Roding and a hydraulic model study. Particular attention is paid to the vegetation on the upper channel berm, including its seasonal effect on hydraulic resistance and the problem of channel maintenance. Recommendations are made with respect to (a) increasing the present capacity of the River Roding, and (b) the future design of two-stage flood channels intended to meet stringent environmental standards.     

Upgrading of Sewerage Assets to Comply with New Legislation: A Lothian Regional Viewpoint

The EC bathing water Directive and the recent EC urban waste water treatment Directive have provided, and will continue to provide, a strong stimulus for the provision of environmental improvement through the upgrading of sewerage assets. The positive response by Lothian Regional Council to necessary improvements in the last fifteen years, and the proposed improvements in the next fifteen years, are reviewed against the background of financial constraints. It is suggested that parts of the urban waste water treatment Directive relating to estuarial and coastal discharges are not appropriate or necessary in the context of conditions in Lothian Region.     

Impact in Scotland of UK and EC Sewage Legislation

The EC Directive (91/271/EEC) concerning urban waste water treatment has far-reaching financial and technological implications for local authorities in Scotland which are responsible for sewerage. Increased capital consent limits and additional financial assistance from central government are essential if the requirements of the legislation are to be met.
Although the Directive is welcomed in general terms, the sections of the legislation dealing with the identification of sensitive waters and the provision of primary treatment for coastal discharges to less sensitive waters are of limited environmental significance in Scotland.
The elimination of sewage sludge disposal at sea will create severe difficulties for Scottish authorities as a high percentage of sewage sludge is currently disposed of at sea. Each of the main alternative disposal options presents environmental, financial and technical problems and, in the case of incineration, the certainty of widespread unpopularity with the public.     

Waste Stabilization Ponds: A Viable Alternative for Small Community Treatment Systems

Waste stabilization ponds are widely used in many European countries, such as France and Germany, for the treatment of wastewater from mainly small communities. There would seem to be no reason why they should not also be a suitable treatment process for populations of under 2000 in the UK. The relative advantages and disadvantages of ponds are compared to other small community treatment systems, such as rotary biological contactors, biological filters and reed-bed systems, particularly in relation to effluent standards with respect to algae, nutrient removal and relative costs.     

NATURAL SEWAGE TREATMENT IN THE UK: SELECTION GUIDELINES

The design of septic tanks, constructed wetlands, waste-stabilisation ponds and rock filters is detailed, and their applicability in the UK is discussed. Septic tanks are a suitable primary treatment system for villages with a population of less than 500. Constructed wetlands, which are secondary or tertiary treatment units, have the disadvantage that their plants do not play any significant role in their performance, except for nitrogen removal. Secondary facultative waste-stabilisation ponds, with pre-treatment in septic tanks and post-treatment in rock filters, provide primary, secondary and tertiary treatment and can produce high-quality effluents. The costs of these processes for small rural communities in the UK are compared.     

Managing and Engineering Rivers for the Benefit of Man

F rom earliest times flood, famine and drought have been scourges of mankind. River engineers alleviate floods, drain the land for agriculture, and conserve water resources. They construct engineering works, guide planners and developers, and provide warnings to minimize damage caused by storms over catchments and coasts. As the country becomes more developed, problems of reconciling conflicting interests require a flexible approach. This paper examines ways of providing the basic services in a climate of increasing public clamour for wildlife and landscape protection, and recreation.     

Abbeystead Outfall Works: Background to Repairs and Modifications – and Lessons Learned

The explosion at the Abbeystead valve house in May 1984, with its attendant loss of life and injury, forcibly drew the attention of the public to the dangers of methane and other natural gases. It also reaffirmed to the water industry and engineering professions the pervasive nature of the gas and the need to take appropriate measures in the construction, design and operation of any scheme which involves a possible methane presence. The investigations into the source and mechanism of the methane gas ingress, and the design of the permanent repairs and modifications to the scheme, have illustrated many of the risks and problems associated with methane and the measures for dealing with them.
The paper describes the essential repairs and modifications which had to be carried out, the main lessons learned, and the recommendations which are felt to be applicable to new and existing water schemes where methane may be present.