Building a MIKE Hydro River model

Integrating a MIKE SHE and a MIKE Hydro River model is not very different from establishing a stand-alone MIKE Hydro River HD model and a stand-alone MIKE SHE model. In principle, there are three basic set-up steps:

1.       Build a stand-alone MIKE Hydro River HD hydraulic model and make a performance test and, if possible, a rough calibration using prescribed inflow and stage boundaries. If needed, you can specify a default groundwater table (e.g. MIKE SHE’s initial groundwater level) and leak­age coefficients for any leakage calculations.

2.       Build a stand-alone MIKE SHE model that includes the overland flow component and (optionally) the saturated zone and unsaturated zone components. An SZ drainage boundary can be used to prevent exces­sive surface flows in low lying areas and the river flood plain.

3.       Couple MIKE SHE and MIKE Hydro River by defining branches (reaches) where MIKE Hydro River HD should interact with MIKE SHE. Modify your MIKE SHE and MIKE Hydro River models so that they work together properly. For example, by removing the specified groundwater table in MIKE Hydro River and adjusting your SZ drainage elevations if you used these in Step 2.

In the above scheme, the first step in coupling MIKE Hydro River to MIKE SHE is to create a normal MIKE Hydro River HD model without coupling it with MIKE SHE. In this regard, a few things should be emphasised:

·         In a normal MIKE Hydro River model only the river chainage (dx) is important for the results. Geographic positioning of river branches and cross-sections are only important for the graphical presentation. When interfacing MIKE Hydro River to MIKE SHE geographic positioning is crit­ical, as MIKE SHE needs information on the river location.

·         A reasonably high number of river cross-sections should be included to ensure that the river elevations are reasonably consistent with the sur­face topographic features.