Watershed Dynamics and Evolution Science Focus Area Theme 3: Network Function–Understanding the Role of Heterogeneous Land Cover and Hydrologic Regimes on Stream Hydro-Biogeochemical Function Within and Across Mid-Order Watersheds


Marie Kurz1* (kurzmj@ornl.gov), Natalie Griffiths1, Matthew Cohen2, Lydia Zeglin3, Jesus Gomez-Velez1, Dan Lu1, Saubhagya Rathore1, Scott Painter1, Elizabeth Herndon1, Scott Brooks1, Eric M. Pierce1


1Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN; 2School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, FL; 3Division of Biology, Kansas State University, Manhattan, KS



Anthropogenic activities are altering watershed hydrology and land use and land cover with cascading effects on the storage, processing, and transport of water, nutrients, carbon, sediments, metals, and contaminants from watersheds. Theme 3 of Oak Ridge National Laboratory’s Watershed Dynamics and Evolution (WaDE) SFA seeks to resolve the network-scale organizational controls on the emergent patterns and regimes in stream function along and across mid-order stream networks with heterogeneous land cover. Stream metabolism will serve as a key indicator of ecosystem function given its fundamental role in carbon and nutrient cycling and dependency on multiple parameters that are controlled by watershed structure, land cover, and hydrologic state. Specifically, Theme 3 will evaluate how stream metabolism and associated measures of stream function vary along the network and reflect connectivity between the stream and a mosaic of different land covers. This objective requires an understanding of (1) how complex interactions between watershed structure, land cover, and hydrologic state control emergent patterns in stream metabolism; (2) how these network-scale patterns align with fine-scale understanding of process dynamics; and (3) what resolution of system characterization is needed to accurately predict stream metabolism at any given scale.

This presentation will provide an overview of (1) the project-wide approach for determining representative clusters of mid-order watersheds within the Tennessee River Basin and selecting three increasingly divergent watersheds across which to systematically translate, apply, and refine the process understanding and modeling capabilities gained over the next 10 years; (2) the Theme 3 network-scale investigations planned over the next 3 years; and (3) how these investigations integrate with parallel activities focused on:

  • Water and solute mobilization and export from uplands with heterogeneous land cover (WaDE SFA Theme 1).
  • Resultant feedbacks between flow, solute concentrations, and the resistance and resilience of stream function in stream corridors (WaDE SFA Theme 2).
  • Development of a virtual watershed capability (WaDE SFA Modeling Crosscut).