Using groundwater flow models requires a proper setting of parameters. Obtaining optimal settings based on measurements is possible, using the OpenDA data-assimilation tool.
Hydrological consultant Harry Boukes demonstrated this, using pressure data from well pumps. He studied how switching one pump on or off influences the pressures in nearby wells. From this data, he managed to determine kD, c and S values for a MODFLOW model of the area. To determine these parameters, he used the OpenDA data-assimilation tool. OpenDA is free open source software that can be used for model calibration but also for other types of combinations of data and models. VORtech helped Harry with the coupling of OpenDA to MODFLOW. Given our in-depth knowledge of OpenDA, this was only a few days work.
Harry Boukes noted that OpenDA is capable of finding very good estimates for the parameters such that the observed time series are reproduced accurately. But not only the quality of the parameter settings is good. OpenDA also proved to be very efficient, finding a good solution in much less times than other tools that have been used in the past. The only drawback of OpenDA is that it is somewhat difficult to use for someone with limited experience in the field. Harry Boukes and VORtech are now looking into options to build a proper user interface around the tool so that it can be used by other hydrological modelers as well.