Water quality assessments: a guide to the use of biota, sediments and water in environmental monitoring, 2nd edition

Appendix 10.1 Basic design for sampling programmes General guidance on sampling design (location, frequency, sampling equipment, number of samples) has been given in the relevant chapters for different levels of assessment in rivers, lakes, reservoirs and groundwaters. However, in many water bodies (e.g., complex reservoirs) the issues of where to sample and how many samples to take in order to give representative results for the whole water body, need more than an intuitive choice of sampling design. Nevertheless, the task of deciding the optimum number of samples to take and the most suitable locations in a water body in order to characterise its water quality in a meaningful way, and with the most economic use of resources, can be quite daunting. Statistically based methods of sampling design can help this task and also ensure that the data collected are appropriate for later statistical analysis and interpretation. A full coverage of this subject is beyond the scope of this guidebook but some basic principles are described briefly in this appendix. A full description of the sampling process is given in Keith (1988). Gilbert (1987) also gives a comprehensive account of sampling theory, with many excellent examples based on environmenta