Despite Historic Rainfall, Trinity Lake Remains Dreadfully Low. Here’s Why.

As of April 1st, most reservoirs in California are at, over, or near their historical average capacity. But there’s a glaring exception: Trinity Lake, situated in the far north of California. According to the Department of Water Resources, Trinity Lake is only at 51% of its historical average capacity and 37% of capacity overall.
Why is Trinity Lake filling at a slower rate than other reservoirs? Jeffrey Mount, Senior Fellow with the Public Policy Institute of California Water Policy Center, believes that the state’s northernmost region has received less rainfall relative to other parts. Furthermore, Trinity Lake relies heavily on snowpack for water, unlike Shasta, which mostly depends on rainfall. Much of the snowfall may not melt and flow into the reservoir until late spring or summer.
The U.S. Drought Monitor reveals that the northernmost parts of California, including Siskiyou, Modoc, Lassen, Shasta, and Trinity counties, still experience “moderate drought” conditions, with interior parts remaining “abnormally dry.” While Governor Gavin Newsom rolled back some drought restrictions, he didn’t revoke the drought emergency proclamation due to persistent dryness in specific regions.
These dry areas tend to be naturally arid. The northeast corner of California is a known rain shadow, while the southeast – where drought also persists – is desert. The southeast corner receives most of its precipitation from summer monsoon rains rather than winter storms. Inyo, San Bernardino, Imperial, and Riverside counties remain in “moderate drought,” with parts of Inyo and San Bernardino experiencing “severe drought.”
The atmospheric rivers that hit California since December have primarily focused on the Bay Area and Central Coast, with some reaching the Los Angeles region. However, few have been directed at the Klamath Basin, where Trinity Lake is located. This year, most atmospheric rivers have shifted a couple of hundred miles south, leaving the far north less wet than usual.

While some areas of California may no longer be classified as being in a drought, they will still face long-term water supply problems. The Drought Monitor may not accurately reflect California’s situation, as it doesn’t account for groundwater conditions and the state’s water transportation. As Jay Lund, Vice Director of the UC Davis Center for Watershed Sciences, points out, “water scarcity is enduring.” Groundwater recovery in the San Joaquin and Sacramento valleys may take years, and the Klamath Basin still faces ongoing water use conflicts between agriculture and ecosystem preservation.
As it stands, a single wet year won’t be enough to compensate for the cumulative loss of precipitation experienced since 1997. It will take more than one wet year to truly break free from the drought’s grasp and its impact on ecosystems and water systems.
If the author had done any research of daily intakes and releases they would have noticed on most days intake = releases. And for some days releases exceeded intakes. Oh no! Climate change. Maybe incompetent is a better explanation?
Totally they are high thinking it’s drought
Trinity Lake is a snowmelt reservoir. It was constructed as a snowmelt reservoir. It has always been a snowmelt reservoir. Trinity Lake does not fill with rainwater, like Shasta or Oroville. Why not? Because rain doesn’t fall at that location during the winter. Snow does. This is not new. This is not unique. This is not climate change. Trinity Lake will fill with water AFTER the snow melts. As it always has.
Trinity reservoir’s water storage is enhanced by both rainfall and snowmelt. It’s been a chilly and snowy winter here in NW California/Southern Oregon and snow depths and SWE at higher altitudes are good but rainfall at lower altitudes are in many cases behind historical averages. The snowmelt will bring up Trinity Reservoir’s level but attaining full pool is questionable to my mind.
Rain falls at lake level along with snow. March to June is the thaw and because of 1500cfs to as much as 4000cfs being released In a new winter variable flow started by trinity river restoration back on Feb.15th any thing above 400cfs has been lost. The annual spring release will start April 16th right after the end of the new winter flow on April 14th. On average 1600cfs per day has been lost thats 2 full months of early spring run off that can’t be recovered. By the way it’s a 70/30 split of snow and rain that fills that lake.
Nope it won’t fill lol. You can’t let out more than what’s coming in it just doesn’t work that way. Been the same problem for years.
Then why would it only be at 51% of historical average at this time?
Trinity reservoir’s water storage is enhanced by both rainfall and snowmelt. It’s been a chilly and snowy winter here in NW California/Southern Oregon and snow depths and SWE at higher altitudes are good but rainfall at lower altitudes are in many cases behind historical averages. The snowmelt will bring up Trinity Reservoir’s level but attaining full pool is questionable to my mind.
Trinity has been releasing water all winter to keep the levels down while doing maintenance work on equipment. Read more here: https://www.siskiyou.news/2023/03/12/water-from-trinity-lake-is-being-drained-for-repairs/
Here is a good web site to track water in and water out:
https://cdec.water.ca.gov/reportapp/javareports?name=RES
I have been watching Trinity also and it seems they are always letting more water out than is coming in. Looks like it joins the Klamath River and ends up in Requa by the Sea. Not sure why the outflows are so high compared to inflows? Power generation? Fish spawning?