| The influence of land use
changes on flood occurrence and severity in the Bisagno River (Thyrrenian
Liguria, N.W. Italy is investigated using a Monte Carlo simulation approach (Rulli
and Rosso, 2002). High resolution land-use maps for the area were reconstructed
and scenario simulations were made for a pre-industrial (1878), an intermediate
(1930) and a current (1980) year. Land-use effects were explored to assess the
consequences of distributed changes in land use due to agricultural practice and
urbanisation. Hydraulic conveyance effects were considered, to assess the
consequences of channel modifications associated with engineering works in the
lower Bisagno River network. Flood frequency analyses of the annual flood
series, retrieved from the simulations, were used to examine the effect of
land-use change and river conveyance on flood regime. The impact of these
effects proved to be negligible in the upper Bisagno River, moderate in the
downstream river and severe in the small tributaries in the lower Bisagno valley
that drain densely populated urban areas. The simulation approach is shown to be
capable of incorporating historical data on landscape and river patterns into
quantitative methods for risk assessment.
Keywords: flood, simulation, distributed model, land-use changes,
channel modifications, historical data |