Routing is a simplified hydraulic calculation. Normally, simulation of how a flood wave or a hydrograph propagates along a branch is based on a solution of the St. Venant equations, which requires cross section information. However, if such is not available routing may be an alternative. There are per default no water levels calculated in routing branches. The concept of routing is basically transformation of a hydrograph, i.e. using the inflow hydrograph at the upstream end of a branch (provided either as a boundary condition or coming from the upstream node of the branch) as input routing calculates the outflow hydrograph as function of various user-defined routing elements with specific characteristics and hence able to transform an inflow to a different outflow with e.g. different peak value and adjusted shape of the hydrograph. Typically such a routing element represents a reach of a river or a flood control device such as a reservoir or a hydraulic control structure.
To allow for the insertion of routing components into a branch the branch type must be defined as either “Kinematic Routing” or “Routing”. See section 2.2.2 Branches (p. 60).
Any number and combination of routing components are allowed. If no routing components are inserted in a routing branch, the outflow will equal the inflow. The order of the routing components are determined by the chainage of the components. However, additional inflow can also be added as the runoff from a catchment.
A routing component is any of the data types described in the following sections.The order of the routing components are determined by the chainage of the components.
Routing can be combined with normal hydrodynamic simulation such that in some branches routing is applied while in others hydrodynamic simulation is done. The only requirement is that at the upstream end of a routing branch there should either be no other branch connected, or only branches which are routing branches as well.
In order to make a hydrodynamic simulation, MIKE 11 requires a cross section file and a HD parameter file, i.e. if routing is applied in all branches then it will be required to create an empty cross section (.xns11) and a HD parameter file (.HD11) with e.g. default values, and reference made to these in the simulation editor.
If the upstream end of a routing branch has no connection to other branches a discharge boundary condition is required at this location. This also applies if inflow is only to be supplied as catchment runoff. In such case a dummy discharge boundary condition with Q=0 must be specified.
Note: The following sections describe a number of different Routing options in MIKE 11. However, it is important to note that only the ‘Kinematic Routing option (section 2.4.6) is included in a ‘standard’ MIKE 11 license.
Other options described (sections 2.4.1 through 2.4.5) are only developed as part of a dedicated MIKE 11 Japanese version and as such only visible and possible to activate for users who have purchased the required modules in their MIKE 11 license. If the required modules are not present in the license, these dialog entries will not appear when opening the Tabular View of the Network Editor.
