Research Highlights

Tools for Managing Water Quality

Distribution System Interactions That Affect Water Quality (adapted from an image provided by Montana State University’s Center for Biofilm Engineering, 2005)

Distribution System Analysis, an EPA guide for water utilities, informs drinking water utilities and researchers about the state of the art in managing water quality. This guide includes discussions not only of models and model calibration, but also of the use of tracers and monitors, as well as the growing availability of geospatial data. Case studies are included.

Modeling Water Systems  Models are mathematical or physical approximations of a real-world system. Utilities can use them for simulating not just a distribution system’s hydraulics, but also its likely effects on water quality. Models are often employed for decisions involving capital investment, for developing a master plan, or for optimal placement of sensors. They need to be carefully calibrated, however, to make sure they simulate the particular distribution system as closely as possible.

Tracer Studies  Water can move in very complex ways within a distribution network. The speed of movement, and how mixing occurs in tanks and reservoirs, can vary greatly. To track this movement, utilities can use tracers, such as a chemical, whose concentration can be monitored at various points in the system. Ideally, tracers are used with a water quality-monitoring program that includes sampling at a number of locations.

Monitoring Water Quality  Water quality in a distribution system may vary for a great many reasons, so utilities continually monitor it at multiple locations to ensure that it remains acceptable. Water samples can be collected either manually or automatically. Manual sampling will provide a series of “snapshots”, whereas automated sampling makes a composite of multiple samples over time to provide a continuous profile. An automated monitoring system is designed for a particular distribution network, and can be chosen to monitor appropriate physical, chemical, and/or biological characteristics. The resulting information is used to control treatment processes as well as to warn of contaminants.

Geospatial Technology  Since water distribution systems may cover quite a large area, it is very useful to have geospatial data to pinpoint the precise physical location of a particular feature of the network. Geographic information systems (GISs) can help utilities in their routine operations as well as in coping with emergencies.

Contact: Lucille Garner

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