Irrigation, flood protection and road development in Lao P.D.R. has led to construction of numerous water regulation structures on the floodplains of the Lower Mekong Basin. Movements of fish (and other aquatic animals) between rivers and floodplains is subsequently restricted, or may be entirely prevented, and this has led to severe declines in fish production in many areas. Developing robust fish passage outcomes requires an integrated and long-term approach. Implementing a strategy that sought to identify the scale of riverine development, develop a widely applicable solution and also capture social and economic benefits was a sound approach that had wider support from government and investment agencies. Subsequent research in Lao P.D.R. demonstrated that fish-passage technology has the potential to enable movement of migratory fish past these low-level (less than 6 m) barriers. Consequently, fisheries agencies were interested in increasing capacity to design manage and operate fish passage facilities on new and existing low-level water control structures in order to ensure the long-term sustainability of fish resources. To raise the importance of the issue with other water users, it was important that barrier mapping had been undertaken at the same time to increase the spatial understanding of existing infrastructure development. This led to active collaboration with engineering and development agencies to include fish passage restoration in ongoing irrigation development projects. Combining this information with an inventory of planned construction would provide a powerful tool for future investment opportunities.