A grid based physically distributed model analyzes rainfall-runoff using physical parameters and grid-typed
spatial and hydrological data. This study have developed a real time runoff modelling system using GRM RT(Grid
based Rainfall-runoff Model Real Time) which is a real time flow analysis module in GRM, a grid based physically
distributed rainfall-runoff model. Weather radar data received in real time are calibrated by using real time AWS
from Korea Meteorological Administration(KMA), and they are applied to real time runoff modeling. And the runoff
model is calibrated by using observed discharges from a water level gauge in real time. This study have designed
and implemented the databases necessary to construct the real time runoff modelling system, and established the
process of a real time runoff modelling. And the performances of the developed system have been evaluated. The
system have been applied to Nerinheon watershed located in the upstream of Soyanggang Dam and the application
results are evaluated.