Modern water quality monitoring programs often include some field measurements that are measured at the time and location of water sample collection. Field measurement, as opposed to laboratory measurement, may be used if the analyte is unstable once removed from the water body or simply because such measurements are more cost effective or convenient to determine in the field. Typical field-measured water quality parameters include pH, specific conductivity, dissolved oxygen (DO), redox potential, and temperature, which may be assayed using individual or multiparameter portable instruments. Depending on the goals of a specific water quality monitoring program, other measurements (for which field test kits are available) may also be performed. Test kits covering a wide range of water quality parameters are commercially available. However, these are generally less sensitive with less rigorous quality control than those commonly performed in an analytical laboratory. With the advent of powerful microcomputers, novel software, data loggers, wireless communication networks, and new robust sensor designs, devices for autonomous realtime or near real-time field measurements have also been developed. These systems can be placed near or into a given water body and are programmed to conduct water quality tests automatically on a prescribed schedule or when triggered remotely. After connection to a wireless network, real-time measurements are instantly relayed to a central location for immediate operational decisions in response to water quality changes.

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