* Option added to output WRMM results to MS Access database.

The Water Resources Management Model (WRMM) is a large computer model, developed originally as a planning tool for surface water resources utilization, with a river basin being the fundamental unit of study. It computes a steady state water balance over a sequential period of user-defined timesteps, which are multiples of one day (i.e. the minimum timestep is one day).

For each timestep the water balance is calculated in accordance with allocation priorities set by the user. These priorities are specified by a penalty point system and a Linear Programming algorithm is used to minimize the overall system penalty. This "allocation every timestep" feature uniquely empowers the modelling of water supply and demand where demands have priorities under licences e.g. first in time, first in right. In any timestep when total supply is less than total demand, the lowest priority demand (most junior licence) is cut off first - then the next lowest, and so on.

The model enables easy and repeated analysis of the response of the river basin to differing combinations of water supplies, demands and water management structures.

Use of the model has evolved in two forms:
(a) Basin Planning, which utilizes many years of historical supply and demand data to project future conditions, allowing the assessment of long term water use alternatives;
(b) Operational Planning, which evaluates the short term future (e.g. next few days or weeks) consequences of different operational strategies.

The model was written originally in Fortran, now translated to C. The ‘C’ code is compiled under the Microsoft Visual C++ compiler, Version 6 and the executable will run on any microcomputer, under the Microsoft Windows operating systems.

The WRMM was developed by, and remains the property of, the Department of Environment, Government of Alberta, Canada. Since 1981, when it was first developed, the model has undergone considerable technical improvement and computer-enhancement. It has been used in Alberta and other jurisdictions for approximately 20 years. It is available free of charge and the Documentation and Program Files may be downloaded as indicated on the left.