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Assessing the State of Hydrologic Science in the Upper Klamath Basin—A Comprehensive Review of Data, Tools, and Models

Scientific Investigations Report 2026-5139
Water Resources Mission Area—Water Availability and Use Science Program
By: , , , and 
https://doi.org/10.3133/sir20265139

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Abstract

Water demand in the Upper Klamath Basin (UKB) from various stakeholders and ecological needs often outstrips available supply, leading to persistent management challenges. This study reviews the state of hydrologic science within the UKB as of 2025—specifically, the tools, data, and models available for assessing five key components of the water system: (1) surface water; (2) precipitation; (3) evapotranspiration; (4) groundwater; and (5) water use. The UKB water supply is critical for Native American communities, regional agriculture, and federally listed fishes and faces challenges from competing needs, climate variability, and operational/regulatory requirements. We assess existing datasets, regional and national models, and historical studies to understand the available resources and identify gaps that may hinder integrated water assessments and management. Our findings indicate areas where improvements in data collection and model precision could improve the accuracy of water-availability forecasts and support water-management practices. This review can inform near-term forecasting, assist in optimizing water-resource data collection and management strategies, and support regional water-availability assessments of the basin.

Plain Language Summary

The Upper Klamath Basin (UKB), located in southern Oregon, includes Upper Klamath Lake and its tributaries. Upper Klamath Lake forms the headwaters of the Klamath River, which flows into northern California. The UKB is essential to the region’s ecology and serves as the main water source for the surrounding area. The water resources of the UKB are used in various ways, including irrigation for agriculture, domestic and industrial use, and commercial and recreational fishing. Over time, these competing demands have contributed to increased water stress in the UKB, complicating water allocation and contributing to more variable lake levels. Accurate lake-level forecasting is needed to inform management of lake water, but these competing demands also complicate efforts to forecast lake levels. This report offers an overview of the historical and current tools and methods used to monitor and forecast hydrological conditions in the UKB. The report highlights key factors affecting water availability, such as groundwater and surface-water dynamics, climate-related effects, precipitation patterns, and evapotranspiration (the combined water loss to the atmosphere through evaporation from surfaces and transpiration from plants). The tools and methods used to monitor the UKB include statistical techniques, computer modeling, field measurements, and high-tech instrumentation, and the report highlights their strengths and weaknesses. This analysis of the state of science in the UKB offers a synthesis of existing tools, models and data to inform future research, data collection, and water-management decisions. The objectives of this analysis are to (1) facilitate the availability of high-quality data to water managers, (2) aid water-management decision-making and UKB stewardship programs, and (3) improve the accuracy of water supply forecasting.

Suggested Citation

Stonewall, A.J., Harden, T.M., Reale, J.K., and Cameron, C.R., 2026, Assessing the state of hydrologic science in the Upper Klamath Basin—A comprehensive review of data, tools, and models: U.S. Geological Survey Scientific Investigations Report 2026–5139, 56 p., https://doi.org/10.3133/sir20265139.

ISSN: 2328-0328 (online)

Table of Contents

  • Acknowledgments
  • Abstract
  • Plain Language Summary
  • Introduction
  • Purpose and Scope
  • Review of Upper Klamath Basin Data, Tools, and Models
  • Upper Klamath Lake Water- budget Uncertainty—Insights on Data Needs
  • Considerations for Future Research
  • Summary and Conclusions
  • References Cited
  • Appendix 1. Summary of Hydroclimatic Gaging Stations for the Upper Klamath Basin
  • Appendix 2. Summary of Upper Klamath Basin Models and Studies
  • Appendix 3. Published Estimates of Upper Klamath Lake Water Balance
Publication type Report
Publication Subtype USGS Numbered Series
Title Assessing the state of hydrologic science in the Upper Klamath Basin—A comprehensive review of data, tools, and models
Series title Scientific Investigations Report
Series number 2026-5139
DOI 10.3133/sir20265139
Publication Date June 16, 2026
Year Published 2026
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Oregon Water Science Center
Description Report: ix, 56 p.
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details