The routing method definitions specify the location and properties for routing elements defined at specific locations in the river system. Routing elements are recognized as locations in which a routing procedure is active, that is where change in hydrograph appearance occur.
Multiple routing elements can be defined within the same branch if required.
Specify the location of a Routing element
Branch name. The branch name of where the routing method is applied can be chosen from the drop down list.
Chainage. Chainage at which the routing method is applied. The chainage of a routing element will have effect on the downstream node in the branch where the routing element is defined.
ID. String identification of the routing location.
Three options for routing methods are available These methods are:
· Muskingum: a routing method that requires two parameters to be specified to describe the delay and the shape of the modified hydrograph. These parameters are fixed in time and space.
· Muskingum-Cunge: a modified version of the Muskingum routing method, for which the two parameters are automatically computed based on the diffusive wave model. The parameters are recomputed at each time step of the simulation. Hence, this method doesn't require any additional parameter to be specified by the user.
· No flow routing: the hydrograph is not transformed while passing the current routing element.
When the Muskingum-Cunge method is selected, the two additional parameters below are must also be specified.
Delay parameter. Time for the hydrograph to travel between the selected river node and the next downstream node. Its value may also be estimated as the observed travel time of the flood peak between the nodes.
Shape parameter. A dimensionless factor controlling the shape of the modified hydrograph. This factor depends on the shape of the modelled wedge storage and must be between 0 and 0.5. In natural rivers, it usually has a value between 0 (reservoir type storage) and 0.3, with a mean value of 0.2.
Note: the Muskingum-Cunge method computes the delay parameter and the shape parameter using the flow width and the flow area, and it therefore requires that a cross section exists at the routing location.
