Approximately 65 major tributaries link the lower Hudson River to its terrestrial watershed through 3,600 total river miles. At least half of these are blocked by natural geomorphic features making them largely inaccessible for most migratory species. The remaining creeks that once provided critical spawning habitat for migratory species are now largely blocked by obsolete dams, that not only deny biotic connection with the mainstem Hudson, but also disrupt the hydrologic function of these river systems. When examining the gross primary production (GPP) of the United States, the East Coast is vastly more productive than the West Coast for several reasons. For example, the Northeast is dominated by deciduous broad-leaved trees that are adapted to temperate, mesophilic climate and annually shed their leaves to introduce an immense amount of allochthonous carbon to the Hudson River watershed and estuary. The goal of this project is to measure the ecological value of tributaries to the Hudson River Estuary through the lens of biological productivity at multiple trophic levels. A secondary goal is to investigate how stream barriers and other human influences have altered the contribution of tributaries to the Hudson River over time.