A PROCEDURE FOR STATE UPDATING OF SWAT-BASED DISTRIBUTED HYDROLOGICAL MODEL FOR OPERATIONAL RUNOFF FORECASTING
 
D. Divac, N. Milivojević, N. Grujović, B. Stojanović, Z. Simić
 
Abstract
 
The foundation of operational management of river flows (regarding water resources
exploitation, hydropower potential use, flood management, etc.) is accurate and reliable runoff
forecast. The systems for operational management support are based on
hydrological/hydrodynamic simulation model that uses data on up-to-date states of catchment
and prognostic values of model forcing (e.g. precipitation) for prediction of water levels and
flows in streams and reservoirs. The best estimate of model forcing (temperature, quantity and
distribution of precipitation, etc.) derived from ground measurements and remote sensing is
crucial for success of simulation model use. This paper discusses the application of “data
assimilation” procedure for updating simulation model state variables using mainly model
forcing data. The term itself relates to a set of mathematical methods designed for use of
measured data and differences between simulated and measured values in up-to-date model
state estimation and forecast of future states in physical systems. These methods allow for better
parameterization, structural and sensitivity analysis of the model, as well as design of more
efficient observation networks and improving forecasts and quantitative measures of their
reliability. The paper presents an approach to operational use of SWAT-based rainfall/runoff
hydrological model, using an algorithm for rainfall distribution estimation based on data from
few automated weather stations. The implementation of presented algorithm in “Drina” hydroinformation
system confirms the sensitivity of the simulation model to forcing data, and
provides improvements of the runoff forecasting, bringing the mentioned model into operational
use.