Lake Almanor’s Recovery After the Dixie Fire: What the Water Is Telling Us

Who Is the Lake Almanor Watershed Group?

The Lake Almanor Watershed Group (LAWG) is a grassroots, citizen-led initiative that has been monitoring the health of Lake Almanor and advocating for sustainable land and water management since 2009. Originally formed in 2005 by the Plumas County Board of Supervisors as part of early watershed planning efforts in the basin, LAWG worked at the intersection of rural Sierra Nevada communities and water conservation, recreation, and science. Their legacy and impact helped spur the formation of the South Lassen Watersheds Group (SLWG) — a collaborative effort that supports community-based natural resource management across 1,000,000 acres.

Each year, volunteers, scientists, and community members continue to collect water quality data from different parts of the lake and nearby streams to better understand how conditions are changing over time. Think of it like a regular health check-up for the lake.

What Does the Annual Water Quality Report Track?

The annual monitoring report covers a range of indicators that together paint a picture of lake health:

• Water temperature
• Oxygen levels in the water
• Water clarity
• Nutrients and algae
• Tiny organisms that support the lake’s food web

These measurements — especially when collected over decades — help tell an important story about the overall health of the lake and its watershed. Long-term data is what separates a snapshot from a trend.

How Did the Dixie Fire Affect Lake Almanor?

This year’s report focused heavily on how the lake is recovering after the 2021 Dixie Fire, one of the largest wildfires in California history. The fire burned extensively across the Feather River watershed, dramatically changing the land that drains into the lake. The 2021 LAWG water quality report documented that, even before major post-fire runoff impacts, Lake Almanor was already experiencing dry-year conditions, including lower oxygen levels in deeper water during the summer, and added stress on cold-water fish habitat.

The most significant post-fire impacts were not observed until 2023, when heavy runoff transported large amounts of ash, soil, and debris from the watershed into the reservoir. This led to a noticeable decline in dissolved oxygen in portions of the lake, particularly in deeper areas, and marked the peak of post-fire water quality impacts. When oxygen levels get too low, fish and other aquatic life become stressed, and it signals that the lake ecosystem is struggling.

By 2024, monitoring data showed the beginning of recovery. Much of the material that entered the lake during the high-runoff period had been flushed through the system, and spring measurements showed oxygen levels returning closer to normal. While these results were encouraging, they also set the stage for continued monitoring in 2025 to better understand how conditions were stabilizing over time and whether recovery trends would continue.

To learn more about how wildfire affects watershed health across the Sierra, visit Sierra Institute’s work on forest resilience and watershed restoration.

What Does the 2025 Monitoring Data Show?

The good news: the 2025 monitoring results show continued encouraging signs of recovery.

LAWG found that oxygen levels had largely returned to near-normal conditions by spring 2025. The report also documented healthy and diverse algae and plankton communities in both spring and fall — important indicators, since these tiny organisms are a foundational food source for fish and other aquatic life.

These findings align with observations from local fishing guide Captain Rob, who has noted signs of recovery in Lake Almanor’s fish populations in recent years. He shared that fish previously observed with signs of poor body condition have become less common and that fish are now more widely distributed throughout the lake, suggesting improving conditions following post-fire impacts.

That said, some challenges remain. During increasingly hot summer months, warm surface water traps cooler water deeper in the lake, reducing oxygen at expected depths and making conditions more limited for cold-water fish species. Warmer temperatures in 2025 also contributed to a slight increase in blue-green algae growth in some areas — a trend worth watching in the years ahead.