S.2 Description

The mass conservation model is configured as follows.

  • General
    • 1 month (745 hours) duration
    • Includes salinity, temperature (and heat calculations), sediment and varying numbers of water quality computed variables
    • 15 minute output
    • 15 minute water quality simulation timestep
    • Designed to mimic a deep lake that cools over an autumnal period
  • Geometry
    • Four three-dimensional flat bottomed columns, with the same bed elevation
    • Lateral cell areas each of approximately 10 km\(^2\)
    • Depth of 21 metres
    • 20 vertical layers of variable thickness, with 17 fixed and 3 sigma (which span the top portion of the water column)
  • Boundary conditions
    • No inflows, outflows or other flow boundaries
    • Meteorological boundaries applied
      • Hourly timestep
      • Typical mid latitude autumnal conditions, with rainfall included
  • Water quality parameterisation
    • Parameters are set to be generally within expected ranges
**WQ Module Mass Conservation Model**

Figure S.1: WQ Module Mass Conservation Model

This setup of essentially stationary water is designed to be challenging for mass conservation. In particular, the exclusion of external flow boundaries (that can reset or overwhelm internal process calculations) is deliberate. These conditions might mimic a low rainfall lacustrine environment.