
As elsewhere in the UK, a number of different methods for estimating surface water yield have been used in Scotland and Northern Ireland in past years. The clients identified the need to develop a consistent methodology which could be used by the various organisations with water resource responsibilities in the two countries. They elected to use a conceptual catchment model founded on physical principles but required it to take account of all available scientific knowledge relating to processes of particular relevance to the region (e.g. snowmelt, evaporation from peat etc.). They also required the hydrological model to be linked to a water resource simulation model. The whole package was to be developed and proved using data from five diverse test catchments
The Company, together with OSS, was in a good position to bid for the project having in-house experience of software development in two key areas – catchment rainfall-runoff models and water resource system simulation. The HYSIM model would need some adaptation to accommodate recent scientific thinking and the RESSIM model applied in England would be developed further, with powerful new facilities enabling users to mould specific implementations, and renamed AQUATOR.
The Project is completed. Rainfall and stream flow data for five test sites (which include, inter alia, Loch Lomond and the Dee catchment) have been collated and HYSIM has been calibrated to them. A method of estimating monthly PE sequences from 1918 to 1998 anywhere in the region has been developed. The resources of all river basins have been analysed using AQUATOR. The client and its consultants have continued to use both HYSIM and AQUATOR.
