 This agreement established the allowed river levels and how much they could change as a result of the various hydroelectrical undertakings in the watershed that was shared by the three countries.The reservoir began its formation on October 13, 1982, when the dam works were completed and the side canal's gates were closed.Throughout this period, heavy rains and flooding accelerated the filling of the reservoir as the water rose and reached the gates of the spillway on October 27.