A Study of High Frequency Water Quality Observations in the Little Bear River Utah, USA,

Process-based understanding of short and longer-term behavior of catchments is important to our ability to predict hydrologic system response. The time scale of many processes is on the order of minutes to hours, not weeks to months, and understanding the linkages between catchment hydrology and hydrochemistry requires measurements on a time scale consistent with these processes. We present a study of continuous, high frequency water quality observations within the Little Bear River Utah, USA, with the overarching goals of improving understanding of the hydrologic and hydrochemical response of the watershed, the timing, duration, and sources of water quality constituent fluxes, and development of the observing infrastructure and cyberinfrastructure needed to better quantify these fluxes. We installed high frequency water quality and discharge monitoring instrumentation at seven locations within the Little Bear River, along with 4 continuous weather and soil moisture monitoring stations. We developed and implemented the cyberinfrastructure required to manage the data from sensor to publication using components of the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System. We describe our sensor network design, cyberinfrastructure, and data collection procedures and provide results from our analyses that demonstrate how the scope and resolution of high frequency sensor data enable identification of trends and analysis of hydrologic and hydrochemical behavior that could not be observed by more traditional water quality monitoring. Using continuous, high frequency data from multiple sites, we demonstrate the dynamic hydrologic and hydrochemical response in the Little Bear as well as the importance of sampling frequency in the estimation of water quality constituent fluxes. We also examine the importance of early spring snowmelt in contributing to annual loads of total phosphorus and total suspended solids and differences in ecological responses across sampling sites as measured in dissolved oxygen time series