Hyporheic exchange is now widely acknowledged as a key driver of ecosystem processes in many streams. Yet stream ecologists have been slow to adopt nuanced hydrologic frameworks developed and applied by engineers and hydrologists to describe the relationship between water storage, water age, and water balance in finite hydrosystems such as hyporheic zones. Here, in the context of hyporheic hydrology, we summarize a well-established mathematical framework useful for describing hyporheic hydrology, while also applying the framework heuristically to visualize the relationships between water age, rates of hyporheic exchange, and water volume within hyporheic zones. Building on this heuristic application, we discuss how improved accuracy in the conceptualization of hyporheic exchange can yield a deeper understanding of the role of the hyporheic zone in stream ecosystems. Although the equations presented here have been well-described for decades, our aim is to make the mathematical basis as accessible as possible and to encourage broader understanding among aquatic ecologists of the implications of tailed age distributions commonly observed in water discharged from and stored within hyporheic zones. Our quantitative description of “hyporheic hydraulic geometry,” associated visualizations, and discussion offer a nuanced and realistic understanding of hyporheic hydrology to aid in considering hyporheic exchange in the context of river and stream ecosystem science and management.

1. Long-term deployment of in-stream data loggers provides valuable information about stream conditions, particularly at times when streams are difficult to sample manually. However, in streams with high water velocities and substantial shear stress, the detachment of loggers from their installation points is a common problem. Thus, successful logger retrieval requires a durable installation method.2. We present a method for data logger installation using rock-climbing hardware that is simple to assemble, economical and minimally invasive. The method is applicable in streams with exposed bedrock or boulders, which serve as attachment points for loggers. Installed loggers are capable of withstanding extreme environmental conditions.After deploying 18 loggers for approximately 15 months in six different streams with snowmelt-dominated hydrographs, we retrieved 16 of the 18 loggers originally deployed. Where loggers were not recovered, hardware failure at installation sites was not likely the cause.4. In addition to application in streams, the use of rock-climbing hardware may be well-suited to securing long-term data logger installations on rock substrates in any extreme environment. K E Y W O R D Sclimbing hardware, data logger, extreme flows, installation, long-term, river, stream, temperature logger | 685 FOGG et al. Methods in Ecology and Evoluঞon