Results - Response of Flood Events to Land Use and Climate Change - page 209

Fig. 6.77 Average monthly precipitation, discharge and temperature between 1961 and 2009

previous results, monthly precipitation has experienced a minimal decline.
Monthly maximum discharge, on the other hand, is relatively stable. Furthermore,
runoff does not increase with a simultaneous increase in precipitation; and the rate
of changes in precipitation is not necessary equal to the amount of runoff. For
instance, while precipitation dropped from 2007, runoff increased.
As partly conclusion, as mentioned in pervious sections, on the monthly scale,
the results of p values statistical analysis show that only precipitation and maxi-
mum temperature are statistically significant with p values of 0.023 and 0.024 at
significant levels of 1 and 5 %. On the other hand, the p value for discharge
represents non-significant levels of both 1 and 5 %. The Mann-Kendall test
analysis shows there is a negative and downward trend in precipitation and for
maximum temperatures and a positive or upward trend with Kendall's tau of
-0.063 and +0.062, respectively.
So far, all achieved results force the research to focus more on monthly and
daily available data. Figure 6.77 represents the average monthly precipitation,
discharge, and temperature between 1961 and 2009.
Daily analysis (maximum snow depth, maximum discharge, precipitation, and
maximum temperature) between 1995 and 2005 is also shown in Fig. 6.78 . The
results of analysis show that during the summer the rate of snowmelt has a direct
impact on the rivers peak discharge. In both flood events of 1957 and 2008, the
rate of snowmelt was higher than the normal rate in other years.
Bhattacharya [ 1 ] interviewed local people and, according to them, there has
been neither a decline in the amount of snowfall nor have there been more frequent
wetter winters and drier summers, which is a possible indication of climate change
in the area.
The results of cross-correlation (CCF) (snow depth-discharge) also show that
there is a strong backward negative correlation between maximum discharge and
snow depth. When snow packs start to melt this will affect the rate of runoff in the
Ubaye River (Fig. 6.79 ).