SOP for Flood Forecasting & Early Warning - UNESCO Islamabad

c. Continue moving in the northerly direction under the effect of a strong westerly wave over the
plains of Lahore/Gujranwala Divisions to finally ending up over Rawalpindi/Hazara Divisions.
The upper catchments of Chenab, Jhelum and Indus rivers come under its influence.
Extremely heavy rains may occur over Mangla and/or Tarbela catchments under this situation,
depending upon the final position of the depression causing extremely heavy floods
(Category-III), as shown in Annex-4. The probable maximum flood (PMF) is an extreme case
of Category-III flood. These are the most threatening floods for Mangla reservoir, a typical
example of such floods was the 1992 flood. Forecasting of such floods at least 24 hours in
advance should pose no problem, specially when 'S' band weather radars at Lahore and Mangla
are available for system identification. Close coordination between FFD and WAPDA shall be
necessary for the safe routing of such floods through the Mangla reservoir. WAPDA, after
1992 catastrophic flood in Jhelum & Chenab rivers has devised an SOP for the routing of
category I, II & III situation to safely pass the high inflows in Mangla. The SOP for Mangla is
annexed as (5A, 5B, 5C).
The meteorological factors linked with each situation are generally well known and 24-hours
advance prediction should be quite possible in each case. In fact tracking of the depression is
commenced from the Bay of Bengal and its position is reported on continuous basis in the
daily flood forecast bulletin issued by FFD. Once a depression reaches Rajasthan, an extremely
close watch is started using meteorological charts, and satellite cloud pictures. As the
depression advances towards Pakistan and comes within the meteorological range of the
Lahore Radar, an intensive watch would be started and color coded Met Alerts are issued as
applicable.
1.5 Flood Management Process
(i) Flood management process in Pakistan is multi-functional involving a number of different
organizations. The very first step in the process is the issuance of the flood forecast/warning. This
function has been assigned to the Pakistan Meteorological Department (PMD) since the basic
cause of the floods in Pakistan is the rainfall which can be best predicted and monitored by PMD
utilizing the satellite cloud pictures and the quantitative precipitation measurement radar data, in
addition to the conventional weather forecasting facilities. For quantitative flood forecasting the
hydrological data is obtained (through the Provincial Irrigation Department and WAPDA.
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