You decide to try to make an agreement with Neshbar. You send a team of diplomats to their capital city. They are initially reluctant to help, since the drought has been causing problems there as well. However, they are well aware that a civil war in Rashijan could lead to unrest in their own country, so to increase the security of the entire region, you eventually reach a compromise. You agree on maximum water withdrawal standards that allow Neshbar to use a certain percentage of the river's flow, leaving a sufficient amount for Rashijan's use.
Within a month of the signing of this agreement, the Mahnaz River filled to a usable level again, easing some of the tension.