sentences:  Each of these models has been developed using object-oriented techniques, a programming approach commonly applied in commercial software development but only relatively recently adopted in numerical modelling for scientific analysis.ZOOMQ3D and ZOOPT have been developed through a tri-partite collaboration between the School of Civil Engineering of the University of Birmingham, UK, the British Geological Survey and the Environment Agency of England and Wales.The distributed recharge model ZOODRM has been developed by the British Geological Survey.