The management of environmental water engages actors from a wide range of domains, from policy makers and managers to academics, from environmental activists to industry and farming groups, as well as members of the broader community. All have opinions and advice for the environmental water manager; this is accompanied by a substantial body of (grey and scientific) literature that use methods and case studies to provide more advice to the environmental water manager. It has become a noisy, and often contested, space. For the environmental water manager, navigating this noisy space can be challenging amidst the day-to-day operational pressures of the role. Scientists engaged to provide advice and evaluate the outcomes of environmental water management, often lack the understanding of the operational context in which the environmental manager works and the broader learning that comes from their experiences. It is rare to hear the voice of the environmental water manager in the literature or the stories that illustrate the suite of knowledge sources that inform their decision making. In this paper, we explore environmental flow management in the Lachlan River, New South Wales, Australia and illustrate the wide range of knowledge and information that is used to underpin the management of water for the environment. We distil learning from many years of working in the catchment to highlight a series of lessons that demonstrate the complexity of the role and the information and knowledge that contributes to decision making. In doing so, we highlight the way that the practise of environmental water management has evolved over time.