The purpose of the Resource Management Act is to achieve sustainable management. However the development of alternatives is primarily the responsibility of applicants. In practice this usually leads to proposals that maximise the interests of applicants and result in adverse effects at the margins of acceptability. This paper describes the application of collaborative approaches to two controversial storage proposals in Canterbury – a dam on the Orari River and the Hurunui Water Project (a storage on the South Branch of the Hurunui River and control gates on Lake Sumner). Both processes led to the development of different alternatives which were superior in terms of sustainable management, lower impacts and greater community acceptance – respectively an off-river storage taking high flows from the Rangitata River, and, a series of storages on the Waitohi River, a tributary to the Hurunui. The use of collaborative processes as an alternative to RMA processes to resolve issues was initially resisted by applicants. However there has been a high level of acceptance of the value of collaboration after innovative alternatives were developed. Some of the key learning outcomes from this approach include: the value of collaborative engagement with affected communities outside of adversarial RMA processes; the improvements in alternative generation from collaboration if affected communities can meaningfully participate in decisions on alternative selection; and, the limitations of RMA processes in achieving sustainable management.