Release Level	5.0
Release Date	2005 06
Revision Level	1.0

RRM Rainfall-Runoff Model

The entry point is a selector of scenarios, which can be sorted and filtered by several properties such as name, author, modification date, or location.

Another option at the level of the scenario selection is the possibility to create a new scenario with an empty template. To facilitate and simplify the generation and editing of new scenarios, it is also possible to copy an existing one and modify it incrementally under a new name.

Editing a scenario for the rainfall-runoff model involves four major components:

• Basic scenario (meta) data
• choice of the time series data for rainfall and temperature, optional flow data for comparison (also used in the automatic calibration option);
• setting the basin characteristics and model parameters;
• defining basin geometry.

• Basin characteristics such as size, channel characteristics, drainage density etc.;
• Specific model parameters including the initial conditions;
• Land use (forest, pastures, agriculture, built up areas, and residual)
• Model constant such as degree day coefficients, which only have to be adjusted to adapt the model to different physiographical or climatic situations.

Prior to running the model, all parameters are automatically checked for completeness, consistency, and plausibility (see below).

A special set of parameters with a dedicated editor describes the basin orography, or area-elevation distribution.

For every 100 meter altitude layer, the user specifies the corresponding area.

While the model is spatially (horizontally) lumped, it is vertically distributed: it uses the elevation distribution of the basin to correct temperature and precipitation values varying with elevation, and keeps track of snow and snow-melt where applicable.

Checking scenarios: attached to the editors for all models, a checking routine to check for

• completeness
• consistency
• plausibility

This routine can be triggered interactively, on demand, or it is run automatically whenever the model should be run to ensure proper inputs and thus meaningful model results.

Model results:

On the main scenario page, the model results are shown as a time series of daily runoff.

Where specified, these data are shown together with the observed runoff data that can also be used for automatic model calibration.

The display shows the simulated runoff together with an (optional) observation data set.
The main results page shows a tabular summary of the main parameters and the overall annual basin water budget, as well as a map of the basin simulated.

Together with the daily results, a monthly aggregate for the main variables:

• inputs (temperature and precipitation)
• output (simulated flow and optional observed flow)

• surface runoff and baseflow;
• soil moisture and evapotranspiration;
• deep percolation and groundwater levels.

Components include

• raw and altitude corrected inputs (precipitation and temperature),
• evapotranspiration,
• inputs to the groundwater system,
• runoff and baseflow contribution,
• the overall mass budget.

Inputs used are the simulated flow together with

• basin morphometry (slope and average slop length,
• soil erodibility,
• agricultural practices,
• erosion control measures