Operating guidelines are used to allocate storage space and to allocate water to the various users. The several uses to which a multiple purpose reservoir is put are seldom of the same priority; so, the water supplied to the users depend upon the amount available and the season of the year. In order to provide service to high priority users, the low priority users loose their service if it appears that there will be a shortage. The problem of ascertaining when the low priority user should loose service is investigated in this report. The Gould method was modified to allow for seasonal variation of discharge from the reservoir, and to allow for variations of discharge with amount of water in storage. (Author)