There are three scenarios of cultivated area to be
used as input data for calculating water requirement
and net benefit, as shown in Table III; the cultivated
areas in the wet period for scenarios 1, 2 and 3 are
based on actual data or 93% in scenario 1, a smaller
percentage than actual or 80% in scenario 2, and a larger
percentage than actual or 100% in scenario 3. In the
dry period, about 14% of planned irrigated areas are
used for each scenario because of the marketing policy
and other reasons mentioned above. The results of the
optimal upper and lower rule curves of each scenario
are compared with those obtained using the standard
operating policy (SOP). In the SOP, the water storage
will be released once a month to meet the demand. If
the reservoir storage is not sufficient to meet the demand,
then the reservoir will be emptied. If the reservoir storage
is above the maximum storage capacity, then the excess
storage will be spilled and the reservoir is full. Especially
in scenario 1, the results are additionally compared with
the HEC-3 simulated results obtained from the RID.