Regulated river flows provide dynamic resources (e.g. water, nutrients, carbon) and disturbances (e.g. scouring, drowning) to waterways. Water resources are provided to plants via soil moisture that is influenced by the flow regime. The delivery of water for environmental benefits in regulated waterways is one management tool to reduce the risk of plant mortality due to drying, stimulating germination and to increase the available resources for plant growth and reproduction. Despite these objectives, there is little known about the efficacy of flow events in the provision of soil moisture content in Australian river systems and what factors are critical to achieving desired outcomes. We conducted a series of studies to evaluate the soil moisture dynamics in a river bank and how these influence vegetation. Firstly, we installed 16 soil moisture loggers at sites within three Victorian rivers to continuously track soil moisture over multiple years at different soil depths. Secondly, we collected root data of a woody species (Eucalyptus camaldulensis) and herbaceous species (Juncus amabilis) at different bank elevations to examine the interaction between soil moisture and root growth. We found that environmental flows and rainfall both provide important soil moisture in shallow soil profiles. Plants growing closer to the baseflow water margin had shorter and more branched root structures, while plants at higher bank positions had longer roots with few branches to search out water. Environmental flows may have a critical role in enabling the survival and early establishment of plants above the baseflow water margin. Flow delivery to achieve this outcome needs to be carefully timed and delivered in drier climate years.