Phosphorus in the river corridor

River corridor protection has been adopted by government agencies and non-governmental organizations to try to control nonpoint nutrient loading to rivers. Yet, river corridor protection and modeling strategies developed on a national basis may not fully account for dynamics that have proven to be important controls on phosphorus in river corridors. These sources of uncertainty may have economic and environmental costs, yet we know of no previous works that have proposed a broad conceptual model of phosphorus dynamics in river corridors. In this review, we develop a conceptual model of phosphorus in the river corridor under natural conditions based on existing research by: (i) evaluating how processes and controls vary among distinct landscape characteristics and among distinct segments within river networks (e.g., in confined channels versus wide valleys); and (ii) determining whether some processes and controls are generally more dominant for some landscape types and river reaches. Finally, we provide an example application of the conceptual model, and identify key areas for future research. The review suggests that phosphorus dynamics in the river corridor, and their controls, may vary substantially across different landscape types and river reaches. However, the conceptual model outlined here illustrates how certain characteristics of landscape type, and abundance, transport, and transformation of phosphorus and reactive compounds, may help to predict important river corridor phosphorus dynamics. Use of this conceptual model can better inform numerical modeling of phosphorus dynamics and management of river corridors.