Sugarcane farmers in many districts are considering on-farm water storages (OFWS’s) as a means of countering ongoing water shortages. OFWS’s are attractive because they can be used to capture runoff and tailwater, and for the temporary storage of surplus water from other irrigation sources (eg allocation, out of allocation, water harvesting etc), thereby providing increased flexibility in managing limited water supplies. The decision to invest in such storages is, however, complex and multi-facetted, requiring assessment of a range of biophysical, economic, legislative and social factors. Computer-based simulation models can potentially capture many of these factors and their interactions, and hence, can play a useful decision support role. In this paper, we describe and demonstrate a new software package (Dam Ea$y) that couples biophysical and economic modelling tools, in a way that enables analysis of various scenarios regarding investment in OFWS, and the likely benefits and costs of such investments.