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Worldwide Hydrobiogeochemical Observation Network for Dynamic River Systems (WHONDRS)



The Worldwide Hydrobiogeochemical Observation Network for Dynamic River Systems (WHONDRS) is a consortium of researchers and other interested parties that aims to understand the hydrologic, biogeochemical, and microbial impacts of sustained high-frequency water level fluctuations in river corridors from local to global scales. By galvanizing a global community around understanding these impacts, WHONDRS ultimately aims to provide the scientific basis for improved management of dynamic river corridors throughout the world.

Benefits of Joining WHONDRS

The success of WHONDRS hinges on broad involvement, and we invite interested parties to contact us to evaluate potential collaboration. WHONDRS partners will have the opportunity to:

  • Join a global effort to understand how major ecosystem drivers, such as dam operations, influence the holistic functioning of dynamic river corridor ecosystems.
  • Access WHONDRS-developed infrastructure and methods such as a streamlined sensor package, sample collection/analysis and quality assurance protocols, modeling approaches, and data management/storage that can be applied to any field system that is part of the network.
  • Generate hydrobiogeochemical data in river corridor systems that are of interest to WHONDRS partners, while also contributing to global understanding.
  • Share locally collected data and insights with the global community, whereby all data will be georeferenced, publicly available, and visualized through the WHONDRS website.

WHONDRS Motivation

Long-term exposure to high-frequency (< 24 hour) river water level (i.e., stage) fluctuations has myriad influences on the structure, function, and health of river corridor ecosystems. Studies examining these influences often focus on the impacts of hydroelectric dam operations on fish and invertebrate ecology. This work has revealed impacts such as fish mortality and precipitous declines in invertebrate diversity due to dam-driven stage fluctuations. There is also a growing interest in the biogeochemical and hydrologic influences of high-frequency stage fluctuations, but these influences are poorly studied relative to ecological impacts. In addition to dam operations, other factors can drive high-frequency stage fluctuations, such as tidal dynamics in coastal rivers and diel freeze-thaw cycles in glaciated systems, making the phenomenon of sustained high-frequency stage fluctuations globally ubiquitous.

Hydrology, biogeochemistry, and microbiology are intrinsically linked and constitute the 'hydrobiogeochemistry' of a river corridor system and can be strongly influenced by high-frequency stage fluctuations. For example, stage fluctuations can increase the flux of surface water through belowground sediments (i.e., through the hyporheic zone). High levels of microbe-driven biogeochemical activity in the hyporheic zone can transform pollutants such that the elevated flux of surface water through the hyporheic zone has the potential to improve water quality. On the other hand, increased fluxes of river water through the hyporheic zone can change thermal regimes of both the hyporheic zone and river, potentially improving or degrading ecosystem health. Integrated understanding of river corridor hydrobiogeochemistry is therefore needed to inform predictions of ecosystem health impacts of sustained high-frequency stage fluctuations.

High biogeochemical rates within the hyporheic zone result in this zone having outsized influences on important river corridor ecosystem features such as water quality and habitat suitability. Given the important role played by the hyporheic zone and the direct effect of high-frequency stage fluctuations on its hydrobiogeochemical dynamics, it is the focus of WHONDRS science. Please see the Science Drivers section for additional details, including additional scientific scope beyond the hyporheic zone.

Impact of high-frequency stage fluctuations on hydrology, biogeochemistry, and microbiology, which are the foci of WHONDRS. Insets show a cross section of the subsurface below a river (i.e., the hyporheic zone) associated with different river stages, where green and blue water represent groundwater and river water, respectively. When the river is low (left inset) groundwater brings microbes (brown cells) into the hyporheic zone, which may alter biogeochemical function. Low river levels also cause the water in pores to drain, which can spatially isolate organic carbon (green clumps) from microbial cells. Enzymes (black and red) excreted into the environment by microbial cells continue to degrade particulate carbon into molecules that can be consumed by microbes, yet accumulate due to being isolated from microbial cells. A rise in river level (right inset) causes groundwater-surface mixing, releases organic carbon, changes the types of microbes found in the hyporheic zone, and can stimulate biogeochemical function. These hydrobiogeochemical dynamics are ultimately driven by high-frequency stage fluctuations, and were inferred at the original WHONDRS field site along the Columbia River. One key question is how these dynamics play out in different parts of the world across river corridors that experience high-frequency stage fluctuations, but that demonstrate different sediment characteristics and different biogeochemical and microbial features. (Note: inset panels derived from Stegen et al. 2016, doi: 10.1038/ncomms11237)

While our understanding of dynamic river corridors is increasing, there is still significant uncertainty in the hydrobiogeochemical impacts of sustained high-frequency stage fluctuations, and such influences are omitted from current ecosystem and Earth system models. This uncertainty and lack of model-based representation undermines our ability to predict feedbacks among the operation of energy-water systems, water quality, and the health of dynamic river corridors under future environmental conditions.

Founded in 2017, the Worldwide Hydrobiogeochemical Observation Network for Dynamic River Systems (WHONDRS) aims to overcome these limitations in knowledge and to enable robust representation of hydrobiogeochemical dynamics in predictive river corridor models. To do so, WHONDRS partners with researchers and other interested parties around the world. WHONDRS partners use standardized instrumentation across globally distributed field sites to systematically collect and synthesize hydrobiogeochemical data in river corridor ecosystems impacted by high-frequency stage fluctuations. WHONDRS also provides a repository for collected data, which undergo rigorous quality assessment and are publicly accessible.

Science Drivers

While the primary scientific focus of WHONDRS examines the impacts of high-frequency stage fluctuations on hyporheic zone hydrobiogeochemistry, this is not the exclusive focus. WHONDRS is also interested in impacts to thermal regimes, nutrient export, primary producers, and physical dynamics of river corridor ecosystems.

WHONDRS investigates impacts of sustained high-frequency stage fluctuations at local to global scales

  • The magnitude of hydrologic exchange between surface water and the hyporheic zone
  • River water and hyporheic zone thermal dynamics
  • Organic carbon character in river water and the hyporheic zone
  • Microbiology of the hyporheic zone
  • Biogeochemical reaction potential of the hyporheic zone
  • Riparian vegetation and periphyton distributions
  • Total nutrient export from rivers to coastal environments
  • Sediment transport, accumulation, and scouring dynamics

WHONDRS is taking a staged approach to addressing these issues, with an initial focus on hydrologic exchange, thermal dynamics, and organic carbon character.

By addressing these scientific drivers, WHONDRS will fill important knowledge gaps linking high-frequency stage fluctuations to river corridor ecosystem function and health. By galvanizing a global community around these challenges, WHONDRS ultimately aims to provide the scientific basis for improved management of dynamic river corridors throughout the world.


WHONDRS is expanding our field locations and encourages institutions or individual researchers interested in participating to contact us at , follow us on Twitter @WHONDRS, and join our LinkedIn Group. The original WHONDRS field site is along the Columbia River in southeastern Washington State, USA, and is coordinated by the DOE-funded Science Focus Area (SFA) project on Subsurface Biogeochemical Research (SBR) at Pacific Northwest National Laboratory (PNNL).


Research Activities

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