As a subject of eighteenth-century technical illustration, hydraulic systems prompt especially complex design strategies in the work of Giovanni Battista Piranesi (1720-1778). In ways rarely seen or explored outside of rare book libraries, connections between word and image permeate his individual images and his entire body of work. Within his vast output of nearly 1000 images across about 20 published archaeological and architectural studies, Piranesi produced roughly 100 layered images, some with ten or more  individual “pages” within a single visual frame. Many of these complex images depict features of hydraulic systems. Like his more well-known views of Rome’s architectural marvels, they are littered with informative captions and elaborate cross-references. Drawing on new approaches to Piranesi as a maker of books rather than primarily an engraver of images, and motivated by the historical study of information display, this essay argues that Piranesi makes his graphical representations of water management legible by testing the technologies of the printed book, specifically the annotated image and the cross-reference. In Piranesi’s hands, the ordering of nature generates an expansive and possibly excessive use of bibliographic logic.