Luke de Vial (Wessex Water) first described how, prior to adopting MISER, short-term planning was carried out using spreadsheets with estimated yields, no schematics and much individual judgement. Long-term planning used to be based on individual source yields, resource zone level demands, without taking into account : infrastructure constraints; conjunctive use; time-dependent ground-water yields; and the need for consistency with the short-term plan and its assumptions.
Luke then described how MISER had become central in Wessex water management emphasising that there is now "one model and one team" applying MISER to both long-term planning for Draft Water Resources Plan and short-term planning of monthly production. The model resolution is now at the DMA level with 575 demand nodes.
Wessex run MISER with a monthly time-step for short-term production planning up-dated for:
forecast rainfall, i.e. early in the year assume single dry summer, from summer onwards assume a dry winter will follow.
use of sources to date to ensure balance of annual licences
current reservoir levels
current groundwater levels
current river flows
The outputs are linked to a spreadsheet summary which is used as the basis for the monthly Production and Distribution Manager’s meeting.
The same model is used for long-term planning with appropriate inputs:
demand forecasts, including increases to reflect outage headroom requirements
design drought (1975-76) extended to incorporate full licence year
short-term operational constraints removed
The model is used to investigate and quantify alternative operational solutions and the results are then transferred to the Water Resources Plan tables.
Luke went on to describe how Wessex have used the ‘mini max/maxi min’ functionality of MISER to calculate:
the capacity of new infrastructure in long-term planning
the maximum transfer capacity required to meet demands with licence constraints
the size of a new reservoir
Finally, Luke described how simplified groundwater modelling can be incorporated into MISER to reflect observed relationships between level and yield. He concluded with some valuable suggestions for future developments.
