Hänggi, Pascal. (2005): Hydrometeorological analysis of the Hilkot catchment, Pakistan. Diplomarbeit phil.-nat.
Fakultät Universität Bern. Publikation Gewässerkunde Nr. 350.
The main aim of this study, which was carried out within the PARDYP Project, was to provide a hydrological
and meteorological analysis of the Hilkot catchment in Pakistan.
In a first step the characterisation of the different components of the water balance and their interaction was
Precipitation as the most important parameter of the water balance was characterised by analysing the areal
precipitation, the seasonal distribution, the variability, the intensity and the amount of precipitation falling as
snow. According to this data the precipitation in the Hilkot is mainly dominated by westerlies in winter and by
the monsoon circulation in summer. In the former season the variability is very high, whereas it is low in the
latter. The surrounding mountains were found to be crucial for the amount of precipitation received in this area.
The runoff of the Hilkot watershed was characterised by analysing the discharge main numbers (e.g. yearly
amount of discharge height) and the seasonal discharge distribution and variability. In addition, the amount of
base flow out of the total stream flow was calculated. It was demonstrated that the discharge variability is
controlled by the seasonal precipitation in summer and winter, whereas from spring on the variability is
additionally strengthened by the influence of snowmelt. The amount of base flow was quantified to a fifth of the
total amount of stream flow per year. Unfortunately the available water level data are influenced by taking out of
water. This fact was considered in the interpretation of the analyses.
The characteristics of evaporation in the Hilkot catchment were shown by examining the potential evaporation
and actual evapotranspiration. It is known that the measurements made by the US class A pan do overrate the
evaporation. Therefore, in a first step monthly correction factors were produced by adjusting the monthly pan
evaporation sums with calculated potential evaporation. Additionally, for the real evaporation rate the yearly
actual evapotranspiration was calculated.
As a result the water balance for the Hilkot catchment, which is for the period 2000 to 2004, was set.
In a second step a water limitation and drought analysis was accomplished to analyse the presumed problem of
The water limitation analysis was carried out by comparing the naturally available water with the water demand
in the catchment. It was shown that the water supply in the Hilkot catchment is chronic short. This shortage
exists because the water demand is bigger than the availability.
The drought analysis has shown that totally over one third of a year the weather in the Hilkot catchment shows
meteorological drought conditions. Especially the month of October was detected as being predestined to have
meteorological drought conditions.
Because of influenced discharge data the following hydrological drought analysis was only implemented as a
sample for hydrological drought analyses. In this case the low flow parameters threshold, duration and water
deficit were analysed as a sample for the period November to January.
Pascal Hänggi, 2005.