39-4 A Synthesis of Water Temperature Signatures of Streams in the Continental United States

Session: Functions of River Corridors, Floodplains and Wetlands

Presenting Author:

Authors:

Abstract:

Water temperature is a governing factor for almost all physico-chemical equilibria in the natural environment. Stream thermal responses provide insight into key hydrologic processes and human influences, such as groundwater recharge, sensitivity to atmospheric temperatures, thermal shocks from transient inputs (snow melt in the winter and superheated surface runoff in the summer), land use change, and reservoir operation. Quantifying thermal regimes in stream environments can offer an unusually clear picture of the health and stability of stream ecosystems. 

We designed a structured framework to quantify river thermal regimes and identify dominant underlying processes using water temperature signatures, defined as a set of quantitative metrics derived from water temperature time series that reflect the influence of environmental conditions and hydrologic processes. We develop ‘RivTemp CONUS,’ a large-scale dataset linking USGS high-frequency river temperature records (1800+ sites, 9 million+ records) with NOAA air temperature observations and comprehensive watershed attributes across the conterminous United States (CONUS). We then leverage contemporary statistical and mathematical models to assess alterations in river thermal regimes across the CONUS, quantifying their correlations with natural and anthropogenic drivers, and conclude by inferring underlying watershed processes. Models employed for analysis include thermal sensitivity plots, Mann-Kendall (MK) trend tests, sinusoidal model fitting, and various spatial-temportal statistical models.

The framework was used to evaluate the effect of legacy sediment removal as a novel floodplain-wetland restoration practice in the Chesapeake Bay Watershed. Using this approach, we quantify notable measures of restoration success in cooling trends (~3°C per decade) that distinguished the site of interest from other regional controls. Additionally, our framework reveals the capacity of such restoration practices to daylight local springs, enhance groundwater recharge, and reduce thermal sensitivity across the floodplain. 

Ultimately this research synthesizes current research on thermal signature analysis and clearly defines novel metrics of quantitative hydrological analysis capable of informing policy action towards protecting streams in targeted and effective ways.

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.