The case study was made in the area of Kiru Valley, Tanzania, in order to study the conflicts over the water in the river Dodumera, and also to understand how the villages Mawemairo, Matufa and Mapea have been affected by the construction of the IFAD irrigation scheme. The aim was to connect the conflicts in the area with a general view of how water can create such conflicts. The method used in the case study was semi-structured interviews. The results from the interviews made with farmers and officials in Kiru Valley was analysed through general theories about water conflicts and theories about governing common-pool resources, such as Ostrom’s eight principles and the theory the Tragedy of the Commons. The analysis was also made through the IFAD poverty reduction strategy programme (PRSP). The conclusion made on the basis of this analysis was that the IFAD project, in Kiru Valley, was in correlation with the PRSP and an attempt to reduce poverty in the two villages Mawemairo and Matufa. The project has been very successful and has contributed to an increase of livelihood and development in the villages. However, the scheme has also affected other villages, such as Mapea. The scheme has contributed to a decrease of water availability in the Dodumera River for Mapea. Nowadays they only rely on rain-fed irrigation. The conflicts have been affected by the scheme, not so much in the quantity of the conflicts but more in the target of the conflicts. Before the construction of the scheme the conflicts was directed at the big-scale farmers, now they are directed at the scheme. On the other hand, the scheme has helped reducing the conflicts between the farmers in Mawemairo and Matufa. There are solutions to conflicts and water scarcity, such as more efficient irrigation techniques and Ostrom’s principles on governing the common-pool resources.