Green Infrastructure (GI) is becoming increasingly recognized as an important opportunity for addressing the complex challenges of water management. The GI approach refers to the natural or semi-natural systems that provide services for water resources management with equivalent or similar benefits to conventional (built) “grey” water infrastructure. This guide addresses one of the main barriers to widespread adoption of GI solutions: a general lack of awareness of the solutions and associated cost benefits. The illustrative case studies in this guide provide examples of GI options that address water management challenges, while delivering a number of significant co-benefits. These include reafforestation and afforestation., wetland conservation and construction, levee setbacks, flood bypasses and coastal protection, as well as a number of urban oriented option such as green roofs and permeable pavements.