This part of ISO 5667 presents detailed principles to be applied to the design of sampling programmes, to sampling techniques and the handling and preservation of samples of water from natural and man-made lakes. Sampling for microbiological examination is not included. The main objectives are specified in 1.1 to 1.3. 1.1 Quality characterization measurement Measurement of water quality over a long period of time (several years) including the total body of water. 1.2 Quality control measurement Measurement of water quality over a long period of time at one or several defined places in a body of water where water is or may be withdrawn for use. 1.3 Measurement for specific reasons Identification and measurement of pollution, for example fish or bird mortality, or other unusual phenomena (colour or turbidity development, formation of floating layers).