Water Quality

Numerical Model Descriptions

The numerical model used in this case study was RMA-11 (Resource Modelling Associates 11). RMA-11 is a finite element water quality model for simulation of three-dimensional estuaries, bays, lakes, rivers and coastal regions. It is capable of simulating one- and two-dimensional approximations of systems, either separately or in combined form. It is designed to accept input of velocity fields from the three-dimensional stratified flow model, RMA-10, and these are used in the solution of the advection diffusion constituent transport equations.  Additional input of constituent sources and sinks are required along with parameters for each constituent.

Constituents that may be represented are:

  • Temperature with a full atmospheric heat budget at the water surface;
  • BOD/DO;
  • The nitrogen cycle (including organic nitrogen, ammonia, nitrite and nitrates)
  • The phosphorous cycle (including organic phosphorous and phosphates).
  • Algae growth and decay  See Figure
  • Cohesive suspended sediment
  • Non-cohesive suspended sediment such as sand.
  • Conservative constituents.
  • Coliforms