Calculate stable water level use case (Water Overlay)

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For water management purposes it can be relevant to know how water will stabilize throughout the system. This can be in a default situation, where there is a nominal amount of water in- and outflow. This can also be in a situation where the system is under duress, such as with a consistent amount of rainfall. There are multiple possible definitions of a stable water system, but a common characteristic is that the inflow and outflow match up, leading to either a consistent amount of water in the system or a predictable water rise/fall at points of measurement.

For the purposes of this scenario, a simple hydrological model will be assumed, with an inflow of water from an upstream source and a downstream means for water to leave the water system.

Requirements

Before implementing this use-case, make sure you have a basic water model set up. For the specified scenario, the rainfall overlay is recommended, although any variant will work.

Also ensure the following in your project, if possible:

  • The hydrological system has appropriate inflows and outflows.
  • The hydrological system has a SURFACE_LAST_VALUE result type, either as main result or as a child result type.
  • The simulation is set up to output a reasonable amount of timeframes. For a stabilization case, one timeframe per 12 hours of simulation time is reasonable.

Steps

The use-case can be implemented through the following steps.

How to determine stable water levels:
  1. Configure a base hydrological system.
  2. Ensure the overlay is (re)calculated.
  3. Inspect the "Surface last value" result overlay.
  4. In the location where water should stabilize, place a point measurement using the measurement tool.
  5. If the line in the graph becomes horizontal, that's the time and level at which the water is stable.

Notes

  • A possibility for water to stabilize is most likely if the water inflow is constant, but the outflow increases as water in the system increases. A Weir at the outflow side of the water system can effectuate this.
  • It's possible that the water does not stabilize, if the water flows in faster than water can leave the water system.
  • It's possible that the water in the water system is effectively exhausted before stability is reached, if water flows out faster than water enters the system.