Citizen science reveals unexpected solute patterns in semiarid river networks

PLoS One. 2021 Aug 19;16(8):e0255411. doi: 10.1371/journal.pone.0255411. eCollection 2021.


Human modification of water and nutrient flows has resulted in widespread degradation of aquatic ecosystems. The resulting global water crisis causes millions of deaths and trillions of USD in economic damages annually. Semiarid regions have been disproportionately affected because of high relative water demand and pollution. Many proven water management strategies are not fully implemented, partially because of a lack of public engagement with freshwater ecosystems. In this context, we organized a large citizen science initiative to quantify nutrient status and cultivate connection in the semiarid watershed of Utah Lake (USA). Working with community members, we collected samples from ~200 locations throughout the 7,640 km2 watershed on a single day in the spring, summer, and fall of 2018. We calculated ecohydrological metrics for nutrients, major ions, and carbon. For most solutes, concentration and leverage (influence on flux) were highest in lowland reaches draining directly to the lake, coincident with urban and agricultural sources. Solute sources were relatively persistent through time for most parameters despite substantial hydrological variation. Carbon, nitrogen, and phosphorus species showed critical source area behavior, with 10-17% of the sites accounting for most of the flux. Unlike temperate watersheds, where spatial variability often decreases with watershed size, longitudinal variability showed an hourglass shape: high variability among headwaters, low variability in mid-order reaches, and high variability in tailwaters. This unexpected pattern was attributable to the distribution of human activity and hydrological complexity associated with return flows, losing river reaches, and diversions in the tailwaters. We conclude that participatory science has great potential to reveal ecohydrological patterns and rehabilitate individual and community relationships with local ecosystems. In this way, such projects represent an opportunity to both understand and improve water quality in diverse socioecological contexts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Citizen Science*
  • Ecosystem*
  • Nitrogen
  • Phosphorus
  • Rivers*
  • Water Quality


  • Phosphorus
  • Nitrogen

Grant support

This work was supported by the Utah Division of Wildlife Resources through the Watershed Restoration Initiative program and National Science Foundation (award numbers EAR-2011439 and EAR-2012123) to BWA. Additional support was provided to BWA, ZTA, and NCH by the Sant Family Foundation through the Roger and Victoria Sant Endowment and the Provo River Watershed Council. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.