A Targeted Approach for Mapping Groundwater Discharge to Surface Water and Fish Thermal Refuge in Four Lake Ontario Tributaries

A Targeted Approach for Mapping Groundwater Discharge to Surface Water and Fish Thermal Refuge in Four Lake Ontario Tributaries | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Hydrological Processes This is a preprint and has not been peer reviewed. Data may be preliminary. 27 November 2025 V1 Latest version Share on A Targeted Approach for Mapping Groundwater Discharge to Surface Water and Fish Thermal Refuge in Four Lake Ontario Tributaries Authors : Josh Woda 0000-0002-2932-8013 [email protected] , Neil Terry , David Kelley , Jason Finkelstein , Christopher Gazoorian , and James McKenna Authors Info & Affiliations https://doi.org/10.22541/au.176426294.41611689/v1 Published Hydrological Processes Version of record Peer review timeline 368 views 160 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract The duration, magnitude, and frequency of heatwaves are predicted to increase in the coming decades, a combination that can reduce the survival of many fish species. Across the world, there is broad interest in identifying thermal refuge for heat-intolerant fish species and exploring opportunities to enhance or protect these areas. Because deeper groundwater maintains a relatively constant temperature, groundwater-influenced areas along streams can provide cool-water refuge for fish during periods of extreme heat. A targeted approach was developed for identifying existing cold-water zones and areas of substantial groundwater discharge in four high priority Lake Ontario tributaries. Our approach included: (1) predicting where groundwater discharge is most likely with a simple geospatial model and (2) using model predictions to select field sites for intensive high-resolution study, including ground-based mapping of groundwater features (springs, seeps, tributaries) as well as drone-based optical and thermal infrared surveys. Results from field sites were used to both verify model performance and map different types and aerial extents of thermal anomalies. Geospatial modeling successfully predicted regions of widespread groundwater upwelling, later verified and mapped by field and drone surveys. Comparison of model and field survey results further highlighted specific geospatial layers, such as soil/bedrock types and topographic wetness index, as being particularly useful for predicting groundwater influence on streams in the study area. In addition, a comparison of geospatial model results with a model of fish abundances along the studied streams showed strong correlations (Spearman’s ρ as high as 0.93) for many heat-intolerant fish species over a wide geographic area. The approach developed in this study can be applied to other watersheds to highlight areas of probable groundwater discharge and could be used by fishery and water resource managers to support cold-water fish habitat management decision-making and resource conservation. Supplementary Material File (thermal_mapping_paper_jcw_hp.docx) Download 4.46 MB Information & Authors Information Version history V1 Version 1 27 November 2025 Peer review timeline Published Hydrological Processes Version of Record 2 Mar 2026 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Hydrological Processes Keywords cold water fish groundwater groundwater discharge modeling springs thermal refuge Authors Affiliations Josh Woda 0000-0002-2932-8013 [email protected] US Geological Survey New York Water Science Center View all articles by this author Neil Terry US Geological Survey New York Water Science Center View all articles by this author David Kelley US Geological Survey New York Water Science Center View all articles by this author Jason Finkelstein US Geological Survey New York Water Science Center View all articles by this author Christopher Gazoorian US Geological Survey New York Water Science Center View all articles by this author James McKenna Great Lakes Science Center View all articles by this author Metrics & Citations Metrics Article Usage 368 views 160 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Josh Woda, Neil Terry, David Kelley, et al. A Targeted Approach for Mapping Groundwater Discharge to Surface Water and Fish Thermal Refuge in Four Lake Ontario Tributaries. Authorea . 27 November 2025. DOI: https://doi.org/10.22541/au.176426294.41611689/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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