Effective water management is well recognised as a major issue facing all Australian states. NSW encompasses significant spatial and seasonal variability in hydrological conditions, while supporting Australia’s major populations in urban centres that are highly concentrated along dynamic riverine/floodplain, estuarine and coastal oceanic shores. Trustworthy and accessible information derived from fit-for-purpose models and data offers government a strong and cost-effective information base to inform policy, planning and decision frameworks that is evidence-based and scientifically defensible. Information, resource and expertise sharing through the MaMH will benefit government beyond the resources available within individual agencies. Knowledge is being developed and shared via delivery of a portfolio of Special Projects.