Summary - Response of Flood Events to Land Use and Climate Change - page 233

already occurred. The results of the hydrodynamic section are very important as
basic information for policy making, decision support and flood hazard planning in
the Barcelonnette area. Additionally, this research gave a comparative overview of
the major challenges faced when dealing with flood hazards. It provided a
methodology to investigate the probable climate change and land use change from
the past until the present in the Barcelonnette area. The results of the time series
analysis between 1961 and 2009 showed that the highest precipitation occurred in
1977. Therefore, this year was selected for comparison with the 2008 flood.
Monthly data for precipitation discharge and temperature was analyzed for both
years. By investigating all achieved results from the time series analysis, it could
be concluded that: (a) the amount of precipitation for almost all months in 1977
was more than in 2008. In general, precipitation shows a decreasing trend at the
end of the period (1961-2008); (b) the temperature for almost all months in 2008
increased from 0-4 C; (c) maximum discharge in 2008 was more than in 1977.
To confirm these results, the ''Mann-Kendall'' method was applied to detect
possible influence of climate change in the area. From all achieved results, it could
be concluded that although there is a significant downward trend in precipitation
and, inversely, an upward trend in the maximum temperature, the distribution of
discharge in the channel was normal and no trend was distinguished in the flow
discharge at the Barcelonnette station. The analysis of average monthly
precipitation between 1961 and 2009 showed that the maximum rainfall
occurred in spring and autumn and the maximum peak was recorded in May,
June, October and November. Based on observed data at the Barcelonnette station
from 1961 to 2009, the maximum temperature occurred between May and
September. During the same period, a monthly investigation into discharge
showed that lower discharge happened from December to March, while the
maximum amount of water occurred from April to July. These results pushed
the research to find other triggering factors which affect on normal discharge
distribution in the channel. In light of this, the available daily basis analysis for
maximum snow depth, maximum discharge, precipitation and maximum
temperature between 1995 and 2005 was also analyzed in this research. The
results showed that during the summer the rate of snowmelt had a direct impact on
the rivers' peak discharge. In both flood events in 1957 and 2008, it was also
reported that the rate of snowmelt was higher than the average of other years. From
the investigated results of land use change, it was realized that urban areas have
increased about *+140 % and arable land has had a decreasing trend (*-54 %)
from the past until the present. Forests also represented an increasing trend
(*12 %), inversely due to channelization and human activity, and the channel has
also decreased (*-37 %) over time. Based on all achieved results, it's concluded
that: (a) a decreasing trend in precipitation and an increasing trend in temperature
and seasonal changes seem to be a sign of climate change (especially since
increasing temperatures lead to more snowmelt during spring); (b) the results of
cross-correlation for water depth and discharge also showed that there is a strong
backward negative correlation between maximum discharge and snow depth. This
means that when snow packs start to melt, the melted snow will consequently