The aim of the TELFLOOD project is to improve methods for hydrological forecasting in steep

catchments. The hydrological modelling task of SMHI has been to improve the HBV model and to

develop and test routines for model updating and forecasting.

A new response routine, based on the variable contributing area concept, has been developed and

proved to be successful in several experimental basins in Sweden, Italy and Ireland

. The technique

uses the contributing area in a way that is consistent with the procedure for soil moisture accounting

and does not require further free parameters. Model improvements are significant to the standard

HBV-96 version, in particular as concems minor floods after dry periods.

A new updating routine, based on state corrections of the storages of the HBV model, was

developed and tested. For some events it proved to be more efficient than the standard method

based on input corrections.