PNNL

Abstract

Water quality is an emergent property of solute interactions with process domains, such as stream corridors, aquifers, and soils. Here, we explore the utility of a “storageexchange reference frame” that partitions a process domain as an “environmental reactor” having both a nonreactive transport compartment and a reactive storage zone.We developed a simulation model of stream corridors with a storage-exchange reference frame and varied the exchange of water and solutes between the channel (transport compartment) and hyporheic zone (reactive storage), and the first-order reaction rate constant governing reaction-rate kinetics in the reactive storage. We subsequently calculated Damk¨ohler indices to quantitatively describe controls on environmental reactive transport. Whole stream Damk¨ohler indices were strongly governed by the interaction of the biogeochemical reaction-rate constant with the hydraulic exchange of water and advective exchange of solutes between the channel and hyporheic zone. Thus, the storage-exchange reference frame is useful for incorporating the effects of linked channel-hyporheic processes in stream corridors and shows promise for extension to other process domains.