General Information¶
Runoff models available in the 1D engine¶
As in MIKE+ and MIKE 11, different surface runoff computation concepts are available in the 1D engine. The following table lists the existing models and the corresponding name in the different interfaces:
Table: Surface runoff computation concepts.
| 1D engine | MIKE+ | MIKE 11 |
|---|---|---|
| NAM | NAM | RDII |
| Time/area | Model A | Urban A |
| Kinematic Wave | Model B | Urban B |
| Linear Reservoir (global) | Model C1 | Not available |
| French Linear reservoir | Model C2 | Not available |
| UHM | UHM | UHM |
Surface runoff computations in the 1D engine can be based on any of these concepts, provided that the necessary data have been specified for each catchment specified in the set-up. Moreover, in one simulation run it is possible to combine different runoff computation concepts for various model areas.
NAM: A lumped, conceptual rainfall-runoff model, simulating the overland-, inter- flow, and base-flow components as a function of the moisture contents in four storages.
Time/area: In the Time-Area the shape of the runoff hydrograph is controlled by the concentration time and by the time-area (T-A) curve.
Kinematic Wave: The concept of this surface runoff model is founded on the kinematic wave computation, which is using the Manning equation.
Linear Reservoir (global): The linear reservoir surface runoff model is founded on the routing through a linear reservoir.
French Linear reservoir: This surface runoff model is an extension of the Global Linear Reservoir model, where two linear reservoirs in series are used for the routing of the runoff.
UHM: The Unit Hydrograph Module includes different loss models (constant, proportional) and the SCS method for estimating storm runoff.
Organisation of runoff model data¶
Use of different runoff models for the same catchment in subsequent simulations may result in very different simulated runoff. This is because each of the models uses different set of input data and model parameters, as well as different runoff computation concept. It is therefore of utmost importance to understand the background for the runoff computations applied in each of the models, as well as the meaning and interpretation of the various data and model parameters.
The runoff model data and model parameters are organised in the following clusters:
- Model-specific catchment data
- Model parameters
The model-specific catchment data comprise different sets for each of the models. These data basically provide further information about the geometry of the catchments and a more or less detailed land use description. Reference to a specific parameter set is also a part of this group.
Model parameters are organised in parameter sets. A parameter set is comprised of all editable parameters needed to execute certain type of runoff computation. Surface runoff computation for an individual catchment is based on the parameters contained in the set associated with the catchment.