Input requirements

The flexibility of MIKE SHE means that there is no predefined list of required input data. The required data depends on the hydrologic process included and the process model selected, which, in turn, depend on what problem you are trying to solve with MIKE SHE. However, the following basic model parameters are required for nearly every MIKE SHE model:

· Model extent - typically as a polygon,

· Topography - as point or gridded data, and

· Precipitation - as station data (rain gauge data).

Additional basic data is required depending on the hydrologic processes included, and their options:

· Reference evapotranspiration - as station data or calculated from meteorological data,

· Air Temperature - for calculating snowmelt (station data),

· Solar Radiation - for calculating snowmelt (station data)

· Sub-catchment delineation - for runoff distribution

· River morphology (geometry + cross-sections) - for river flow and water level calculations

· Land use distribution - for vegetation and paved runoff calculations

· Soil distribution - for distributing infiltration and calculating runoff

· Subsurface geology - for calculating groundwater flow

If you also want to calculate water quality then additional basic information includes:

· Species to be simulated, and

· Source locations

The data items listed above are the basic input data that define your problem. They are not usually part of the calibration. If we now look at each of the hydrologic processes, and the process models available for each, then we can separate out the principle calibration parameters.

Table 1.1 Principle parameters for MIKE SHE
	Principle calibration parameters	Other parameters
Overland flow (finite difference)	Surface roughness	Detention storage
Overland flow (subcatchment-based)	Surface roughness	Detention storage Slope parameters
River flow	River bed roughness River bed leakage coefficient
Unsaturated flow (finite difference)	Saturated hydraulic conductivity	Soil water contents at saturation, field capacity, and wilting point Soil function parameters
Unsaturated flow (2-layer method)	Saturated hydraulic conductivity	Soil water contents at saturation, field capacity, and wilting point Capillary thickness
Actual Evapotranspiration	Leaf Area Index Root depth	Canopy Interception FAO Crop coefficient Kristensen and Jensen ET parameters
Groundwater flow (finite difference)	Hydraulic conductivity Specific yield Specific storage	Drain level Drain time constants
Groundwater flow (linear reservoir)	Reservoir time constants Reservoir volumes (specific yield, depths)	Interbasin transfers (dead zone storage)
Water quality	Porosity Soil bulk density Dispersivities Sorption and degradation rate constants	Source strength

The parameter list in Table 1.1is not complete. There are many other parameters that can be modified if you are trying to simulate something specific, such as snowmelt. If you do not simulate a process, then a place holder parameter is usually required that will need to be calibrated. For example, if you do not simulate the unsaturated zone and evapotranspiration, then precipitation must be converted to groundwater recharge using the Net Rainfall Fraction and Infiltration Fraction parameters to account for losses to evapotranspiration and runoff.