Riverine Freshwater Connectivity Among Major Tributaries in a Large Estuary

Abstract Riverine freshwater plays a central role in estuarine systems by regulating estuarine circulation, stratification, and the transport of waterborne materials. While much attention has been given to exchange between individual tributaries and the main stem, system‐wide freshwater connectivity among multiple tributaries remains understudied. Here, we quantify inter‐tributary freshwater connectivity in Chesapeake Bay using a calibrated three‐dimensional hydrodynamic model and two quantitative metrics: the Percentage Metric, which describes the spatial distribution of freshwater from a supplying tributary across the system, and the Contribution Metric, which quantifies its influence on water composition in receiving tributaries. Model results show that most freshwater constituents are retained within their source tributary and the main stem, while inter‐tributary exchange is generally low but non‐negligible (