Storage and subsequent release of water is a key function of catchments
that moderates the impact of meteorological and climate extremes.
Despite the fact that many key hydrological processes depend upon
storage, there are relatively few studies that focus on storage itself.
Storage is difficult to quantify due to catchment heterogeneity and the
paucity of data on key catchment characteristics that largely determine
storage, such as soil, hydrogeology, and topography. We adopt a
multi-method approach to estimate the dynamic and extended dynamic
storages using hydrometric data in 69 catchments in the Murray-Darling
Basin in south-eastern Australia. We test relationships between the
derived catchment storages and hydrological and physical characteristics
that potentially control storage. The study catchments tended to have
small dynamic storages relative to the extended dynamic storage;
proportionally the dynamic storages were all less than
10\% of the extended dynamic storage. While storage
estimates produced by the different methods and study catchments varied,
the order in which they ranked was consistent. Correlations between
catchment characteristics and estimates of storage were inconsistent;
however, the results indicated that greater storage is strongly
associated with steeper catchments and smoother hydrographs. This study
highlights limitations in the current methodology to derive storage and
the quality of widely applied hydrometric data. We reinforce the need to
collect data that can validate storage estimates and call for new
approaches that can broadly estimate storage at the catchment scale.