Rivers can be both givers of life and takers of life. Investments that provide protection against flooding are often beneficial during normal or low flows. Investments such as storage reservoirs are long lived, separating construction and management operations. With international rivers, the absence of enforcement mechanisms may preclude infrastructure collaboration. Where physical infrastructure is in an upstream nation, downstream impacts may be ignored after the structure has been completed. Using a game theoretic model, it is shown that downstream cooperation may only be rational when flooding is the primary downstream impact. A stylized arid developing region and humid developed region are compared. Potential gains from collaboration are greatest in arid regions, but may be difficult to achieve. There may be little scope for capturing the gains from basin level management if economic integration does not extend beyond water issues.