Optimized selection of river sampling sites

A method for optimizing the selection of river sampling sites is presented. Procedures using a geographical information system (GIS), graph theory and a simulated annealing algorithm are described. Three case studies are presented which demonstrate the use of the methodology in (i) a simple regulatory monitoring situation, (ii) a situation where possible sampling sites are severely restricted and (iii) for monitoring an impounding catchment with problem inflows. Optimization of sampling site location by simulated annealing is shown to be adaptable to a variety of practical situations and to perform better than the algorithmic method previously published by Sharp (1971) [Sharp, W. E. (1971) A topologically optimum water sampling plan for rivers and streams. Water Resources Research 7(6), 1641–1646]