Integrated Catchment Management Planning

Catchment management plans represent the National Rivers Authority's vision for the water environment. With the National Rivers Authority being organized by hydrological regions, the catchment is seen as the natural management unit, and catchment plans offer the means to integrate the Authority's work programme with those of other agencies. Catchment plans summarize relevant data and include an agreed action programme to optimize catchment uses, produced after wide consultation; they complement local authority statutory plans, are current for five to ten years, and will be reviewed regularly during this period. The catchment planning process is seen by the National Rivers Authority as a medium for promoting discussion, resolving conflict, assigning priorities, and setting targets by which progress on key issues can be monitored.     

The Roadford Scheme: Minimizing Environmental Impact on Affected Catchments

Roadford reservoir, located in the River Tamar catchment and commissioned in 1989, operates in conjunction with two other reservoirs and increased abstraction from six rivers in North and South Devon. The scheme affects the flow regime in all rivers, as well as their water quality, ecology and, particularly, their important salmon and sea trout fisheries. The paper describes how the detailed operating rules for the scheme have been designed to minimize the impact on the environment by means of changes to the flow regime, without jeopardizing the yield of the scheme. The complex operating rules include the zoning of the reservoir storage, varying prescribed minimum flows, spate sparing rules, and special releases for fisheries purposes. A programme of environmental monitoring will allow further refinement of the operating rules.     

The Influence of Water-Column Mixing on Dissolved-Oxygen Concentrations and Saline Stratification in the River Tawe Barrage, Wales, UK

The Tawe barrage was an early amenity barrage, and studies after its construction showed a deterioration in water quality within the impounded area. The main concern was the effect of low dissolved-oxygen concentrations upon the migrating salmonids during their passage upstream. An aeration/mixing system was chosen in a combination of diffusers and a propeller, which has proved to be capable of maintaining satisfactory water quality. However, additional diffusers need to be installed to (a) achieve a satisfactory concentration of dissolved oxygen at all points in the river and (b) complete the full scheme.     

SOUTH-EAST HOUSING DEVELOPMENT — THE QUEST FOR SUSTAINABILITY: WATER AND SEWERAGE NEEDS

In March 2000, a document entitled Draft Regional Planning Guidance for the South East was published with the primary aim of providing a regional framework for the preparation of development plans to the year 2016.
This paper discusses the potential effects for the water industry of SERPLAN's predicted levels of housing growth on water resources, sewage treatment and the environment. The need for sustainable development with the competing pressures of water-resource limitation, changing regulation, increasing demand and the environment, are discussed. Thames Water's scale of operations is described together with the range of measures aimed at managing the reasonable demands of customers, consistent with achieving sustainable growth. Basingstoke is described as a wastewater case study, highlighting the problem in fulfilling the sewerage undertaker's statutory duties in (a) meeting already stringent effluent-treatment standards which are necessary to maintain and improve river quality, and (b) providing the necessary infrastructure for an area which is earmarked for continuing development.