J. Lange et al., Modelling high magnitude events in large arid catchments - a field based approach in Nahal Zin, Israel, IAHS-AISH P, (248), 1998, pp. 561-567
A physically-based distributed rainfall-runoff model was applied to the 140
0 km(2) catchment of Nahal Zin, Israel, to study the major processes govern
ing the development of big floods. Both runoff generation in the headwater
surfaces and Bow losses along the channel network were studied using spatia
l distribution. In this way physically-based input parameters can be incorp
orated into the model and no calibration is needed. The study concentrated
on the rocky headwaters of the catchment and on one big flood using a GIS f
ramework to combine map-derived information, images of rainfall radar, air
photos and results of an extensive field survey. A modular model structure
was chosen to facilitate the stepwise simulation of the dominant hydrologic
al processes. In the upper rocky headwater catchment with its narrow channe
ls simplifying assumptions were possible. The simulation yields results whi
ch compare reasonably with measured peak discharges. Multiple peaks by trib
utaries and the downstream decrease of floods can be described realisticall
y. Sensitivity tests show the outstanding importance of a correctly calibra
ted rainfall radar as model input.