Introduction
Water supply and wastewater collection and treatment systems are basic infrastructural needs of communities worldwide, playing a key role in public health and in the elimination of disease. Sources of drinking water include rivers, lakes, reservoirs, groundwater, estuaries and coastal waters. By far the most common freshwater sources are the surface sources (rivers and lakes), as illustrated in Fig. 1.1, although, on the European mainland, groundwater is used extensively.
In addition to being a source of drinking water, natural water is a valuable resource, put to many beneficial uses: hydropower (electricity generation), fisheries, agriculture, industry, recreation and amenity. Thus, the engineering associated with water resources management and use is multi-faceted. The sectoral use of water in the European Union is presented in Fig. 1.2.
Water engineering encompasses the following activities: the provi- sion of water supplies, hydropower development, wastewater disposal, flood relief and river drainage schemes. The engineering of water supplies includes demand assessment, source evaluation, design of collection/intake works, treatment works and distribution systems. Hydropower engineering includes power yield assessment, pumped storage schemes and the associated impoundments (dams and reser- voirs). Wastewater engineering concerns the design of wastewater collection systems, the evaluation of the degree of treatment required, the design of treatment works and outfall pipes, the issuance of licences for wastewater discharges, pollution control and management of river quality. Flood relief and river drainage schemes are designed and