Development, calibration and evaluation of two mathematical models for pollutant transport in a small river

The present research has two main objectives (1) to build two models for concentration prediction in a stream subject to a pollutant release and (2) to investigate options for estimating the parameters of the models. The models rely on the fundamental advection–dispersion equation and were developed, calibrated and evaluated using tracer data from experiments conducted in the Murray Burn in Edinburgh, UK. During the evaluation by comparison against field data both models were able to predict the main features of the observations at the first three monitoring sites, but results at the final site were less good. These types of models rely very much on the ability to make good estimates of velocity and dispersion coefficients along the stream. Although these parameters could be estimated using tracer experiments, it would be easier if they could be estimated from other hydraulic data such as the water flow rate and the channel characteristics. For the Murray Burn such models for parameter estimation were developed in the form of non-linear relationships with flow rate. This approach could be used to calculate the parameters for other similar streams, if the coefficients in the equations were similar. Alternatively, further work would be needed to explore how these coefficients vary between streams.