Real Time Optimal Monitoring Network Design in River Networks

Abstract

The components of a river monitoring network design study would include the selection of the water quality variables, identification of the location of sampling stations and determination of the sampling frequencies. These are primary design considerations which may require a variety of objectives, constraints and solution methods. In this study we focus on the optimal river water quality monitoring network design, which determines the optimal locations of data collection points, based on continuous measurements at these locations for a generic single or multiple contaminant sources. In the proposed model, the locations of sampling sites are determined such that “the contaminant detection time is minimized” for the overall river network while achieving “maximum reliability” for the system performance. In the proposed methodology, a water quality simulation model is used to generate the time series information for the concentrations of the water quality variables at the potential monitoring locations along the river network. Since contamination events may occur at any time within the simulation period in multiple occurrences, dynamic hydrodynamic and fate and contaminant transport analysis of the overall system would be necessary to arrive at the optimal design. For comparison purposes, the proposed model is tested on a simple network that has been studied in the literature. The comparative analysis of the design generated in this study and the outcome presented in the literature is discussed for various contamination scenarios. The results indicate that steady state solutions or solutions that are based on the geometry of the river network may not provide a reliable solution for the network design problem considered here and a dynamic analysis may be necessary to solve this important problem. The results show that the proposed model can be effectively used for optimal design of monitoring networks.