Water Quality and Standards

4.8 Other Statutory Requirements

The UWWTD, Bathing Waters Directive and some of the other directives referred to earlier all have discharge consent standards associated with them. These discharge consents are set by SEPA under the Control of Pollution Act 1974 (COPA). SEPA is also working with the water authorities in reviewing consents where monitoring has identified poor and grossly polluted waters and where action is required to protect excellent and good quality waters. SEPA has published targets for the improvement of Scotland's aquatic environment by 2000 and provisionally 2005.

SEPA's targets for improving the aquatic environment by 2000 and 2005 are based on its assessment of the work required to improve the water quality of rivers, estuaries, lochs and coastal waters. This may require water authority discharge consents to be made more stringent to allow for these improvements. The overwhelming majority of these consents relate to the investment programmes the water authorities already have in place to meet the requirements of the directives discussed above. The predicted improvements up to the year 2000 are based upon investments already agreed with dischargers or are part of existing pollution control initiatives. These targets for 2000 have also been agreed with the Scottish Executive and are set out in SEPA's current Corporate Plan. The costs of meeting these targets has been agreed by the water authorities and SEPA. SEPA will discuss the targets for 2005 with dischargers in the public and private sectors. Following this consultation and wider discussion the targets, adjusted if appropriate, will be forwarded to the Scottish Executive for approval as part of a SEPA Corporate Plan.

Uncertainties. Final targets for 2005 have yet to be agreed by the Scottish Executive, and some aspects of their expenditure implications for water authorities have still to be clarified.

Quality of Coastal Waters

(Charts reproduced courtesy of SEPA)

4.9 Improved waste water treatment: costs and benefits

The estimated capital cost (in £m) of the investments to comply with the Directives (Urban Waste Water, Bathing Waters, Freshwater Fish Waters, Shellfish Waters and Sewage Sludge) together with the cost of complying with any other SEPA consents in Scotland is:

Beyond the next two years, further expenditure to meet the requirements of the Directives and COPA generally will amount to some £400m. If environmental protection standards are further enhanced in future, this would imply additional capital expenditure.

In addition to this investment programme, the water authorities are progressing a number of schemes using the Private Finance Initiative . A total of 9 schemes are being obtained in this way, with an equivalent capital value of over £650m, principally to meet the requirements of the UWWTD. These schemes will not be financed from the authorities' capital resources but will come from revenue expenditure.

Benefits of improved waste water treatment. Water authority investment in this area will make a major contribution to the elimination of poor and grossly polluted inland waters, estuaries and coastal waters. This provides benefits in respect of increasing water resources for abstraction (e.g. for potable and industrial supplies), for recreational use (e.g. the return of salmon to the River Clyde), for use by the public (e.g. recreational use of coastal and inland waters), and for development of tourism. Compliance with the Urban Waste Water Directives will bring benefits in environmental quality for rivers, estuaries and coastal waters. Meeting mandatory and guideline standards for Bathing Waters reduces risks to public health and should have positive effects on tourism. The benefits to the shellfish industry and the customer are that water quality at sites used to harvest shellfish is protected and where necessary improved. This helps to protect the environment and public health. The approach to sewage sludge pursued by the water authorities should help reduce the adverse environmental impact of dealing with this form of waste.

4.10 Infrastructure renewals (asset maintenance)

The water authorities have a duty under the Sewerage (Scotland) Act 1968 to provide public sewers to effectively drain their areas of domestic sewage, surface water and trade effluent and to make provision for treatment of that sewage. The UWWTD also requires the establishment and maintenance of effective sewerage systems (see section 4.1 above). The problems associated with an ageing sewerage infrastructure, most of which is as old as the developments it serves, are similar (but possibly not as severe) as the problems of an ageing water distribution system. Many old sewers are built of intrinsically durable materials (such as stoneware) but they can suffer from accelerated damage from such things as modern traffic loadings. The size of some of these pipes can also often be inappropriate for modern conditions. The introduction of sewer system network analysis systems capable of detailed hydraulic analysis to assess their performance affords an opportunity for integrated sewer network management. This should consider all of the inputs and outputs and should provide informed cost effective solutions to a range of issues, some of which will be statutory. The operation of overflows can be controlled and the visual environmental impact reduced by the careful management of the system, by making full use of in-sewer storage and by the provision of appropriate screening, but at the same time not risking system backup which can result in waste water flooding above ground.

There is also a problem with sewerage systems utilising combined man holes for separate foul and surface water sewers. Such manholes provide the opportunity for foul sewage to contaminate surface water. There are many sewerage systems that suffer this problem. For example, in East Kilbride West of Scotland Water has a major investment programme to address the deficiencies in the system which result in public health concerns and pollution of controlled waters.

Sustainable Urban Drainage Systems When new development takes place, environmental problems can be caused by the design of the drainage system. The combination of increased amounts of hard surface areas and pipes draining directly into rivers can lead to increased environmental problems, where inputs of rainwater are sudden and uncontrolled. Sediment removal and erosion of riverbanks can damage the natural river habitat system. After periods of drought, the flushing effect of rainfall can lead to significant amounts of oils, particles and dissolved metals entering the natural water environment and causing degradation of the water courses.

SEPA is working with local authorities, water authorities and developers to promote sustainable urban drainage for all developments. This will lead to publication of a manual to provide guidance which covers Scotland's particular circumstances. The manual will promote the use of natural treatment systems such as swales, ponds and trenches to allow these developed areas to retain their natural drainage characteristics and keep diffuse pollutants out of watercourses.

Water authorities also plan to make full use of appropriate Information Technology systems to develop integrated network management models.

There is demand for extensions to the public wastewater system where there are development constraints, or where the environment is particularly threatened by the current provision of private systems. Because of the resource pressures of meeting statutory deadlines, the authorities have limited programmes in this area, addressing only the highest priority cases.

A typical Sustainable Urban Drainage System - a swale draining surface water from a new development
(Photograph Courtesy of SEPA)

SEPA and the three water authorities are also trying to develop a prioritised programme of first time sewerage (ie connecting properties that presently have an inadequate private sewerage system to the public sewerage system), based on addressing clearly identified environmental pollution and public health issues.

For sewer network refurbishment / renewal and new developments etc, the estimated capital costs (in £m) is:

Infrastructure renewal is a constant expenditure to maintain the capacity of a sewerage network to safely remove waste water to the treatment works. The authorities will need to maintain this expenditure at around £50m each year.

Benefits Sewer flooding problems will be resolved, the need for CSOs could be reduced or eliminated, there will be fewer sewer collapses and fewer capacity problems that hinder development and the aesthetic environmental impact would be reduced.

Uncertainties All three water authorities are developing asset management plans but until these are developed further there will only be a limited amount of information on infrastructure and hence on the costs to maintain or improve it. The extent and timing of works for future developments for housing and industry is based on past trends which may or may not be accurate.

Demand for sewerage extensions may increase due to SEPA's improvement programme or development pressure. Other areas of uncertainty include environmental improvements beyond statutory requirements and Sustainable Urban Drainage Systems.

*1. In 1996, SEPA reviewed the river classification scheme to reflect a wider view of what constitutes good quality.

*2. The estuary classification scheme was revised in 1995 to include additional measures of environmental quality.