The impact of urbanisation on integrated
catchment hydrology and water resources, West Bank and Israel
a trilateral research project funded by
the German Science Foundation (DFG)
Large Scale
Rainfall-Runoff Modelling
The field results were used to directly determine parameters of a physically based, non-calibrated rainfall-runoff model for the 250 km2 catchment of Nahal Natuf. On natural, non terraced slopes runoff generation was quantified according to the results of the sprinkling experiments, on urban areas all rainfall was assumed to turn into immediate runoff.
To illustrate the impacts of urban development three different model runs for one high magnitude flood (1991/1992) were performed. The first totally disregarded the urban areas, the second included only those visible on airphotos of 1967, the third included those of a 1994 land use map.
A catchment-wide urbanisation of 7.7% (1994) resulted in a simulated 16% increase in runoff peak and a 35% increase in runoff volume. Due to the high model uncertainty (± 40 % in the simulated peak), these results must be treated with caution and depend on event and catchment characteristics. Still the model helps to detect possible shortcomings in hydrometric streamflow data and proves, on a regional scale, the negative impacts of urbanization in an area with restricted water resources.