Just as we experience atmospheric heat waves, our rivers and streams face their own version of these extreme events—periods of unusually warm water that can stress aquatic life and alter ecosystem health. New research shows that these riverine heat waves have become twice as common across the nation over the past 25 years, often coinciding with periods of low water flow or drought.

Using extensive temperature datasets from monitoring stations across the western U.S., Jonathan Walter investigates how and why these warming events occur simultaneously across different watersheds. Recent findings reveal that large-scale climate patterns drive regional heatwave patterns. Local river networks and water management decisions also influence which waterways might provide cool refuges during hot periods. This information is critical for protecting aquatic species that depend on these temperature-safe havens for survival.

Why This Matters

This research has important implications for California's water management strategies. When heat waves occur at the same time across multiple waterways, fish and other aquatic species lose access to the cool refuges they need for survival. By improving data collection networks and developing better prediction tools, water managers can make more informed decisions about environmental water releases, habitat restoration priorities, and conservation strategies—especially as climate change continues to intensify these warming events.

Agenda

• Welcome and introduction (10 mins)
• Presentation (35 mins)
• Facilitated discussion (15 mins)
• Additional Q&A time (30 mins)

About the Speaker

Jonathan Walter is an aquatic ecologist at the University of California Davis’s Center for Watershed Sciences. He uses data science and mathematical models to tackle pressing challenges in California’s rivers, streams, and aquatic ecosystems. His research bridges the gap between advanced analytics and practical water management, helping agencies and communities make more informed decisions about their water resources. Walter’s current projects include studying fish population stability in central California, tracking the movement patterns of imperiled sturgeon species, and developing early warning systems for extreme events like heat waves and harmful algal blooms in our waterways.

About the Center for Watershed Sciences

The Center for Watershed Sciences is a research center at the UC Davis Institute of the Environment that is dedicated to the interdisciplinary study of critical water challenges, particularly in California, focusing on environmentally and economically sustainable solutions for managing rivers, lakes and estuaries.

To learn more about future events and current projects from the Center for Watershed Sciences visit their website: https://watershed.ucdavis.edu/