Trinity River Restoration Program // River Riffle Newsletter - April Edition
Abel, Jennifer K
River Riffle Newsletter - April (click to read online)
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Current Conditions: B120 Water Year 2026 Determination is “Dry”, download the Flow Notice
- Program Updates: Sediment and Wood Augmentation - Steel Bridge Habitat Enhancement Project
- Featured Article: In case you missed it: Spring Quarterly TMC Meeting Recap
- Trinity River Watershed Animal Spotlight: The Common Merganser (Mergus merganser)
- Upcoming Meetings and Events: Science on Tap and more!
- Reading, Listening & Watching
Current Conditions
Water Year 2026
B120 Water Year Determination and Flow Notification
The California Department of Water Resources 50% Exceedance Forecast B120 declaration was published on Apr. 9 as “Dry” with the determination of inflow at 1,015,000 acre feet - just 10,000 acre feet shy of "Normal".
The hydrograph developed by the Program with the "Dry" water allocation for the Spring Snow Melt Peak and Recession period commenced on Apr. 15. Click to view or download the schedule.
The schedule was finalized with a change order released by Central Valley Operations on April 14. If you would like to receive those emails please follow this link: Subscribe to E-mail Alerts
Program Updates
Sediment and Wood Augmentation
Dams disrupt the natural movement of water, rocks, and wood downstream resulting in a lack of loose, well-sorted sediment and the structural complexity that salmon and steelhead need to successfully spawn, protect their eggs, and rear once hatched. To make up for the loss of these materials below Lewiston dam the Program augments sediment and wood in areas identified as depleted.
Wood and sediments can interact with the river across three scales; first by encouraging geomorphic change that scour pools and sort sediments, second, to provide habitat, and third to create hydraulic forcing at elevated flows. To accomplish these goals, the TRRP and it's partners placed sediment and wood at the BLM River Access on Steel Bridge Road this spring.
Featured Article
Spring Quarterly TMC Meeting Recap
The Spring Quarter meeting of the Trinity Management Council brought together agency and tribal leaders to review advancements in restoration, science, operations, and community engagement shaping the Trinity River Restoration Program. From updates on staffing, financial systems, and rehabilitation projects to emerging science initiatives, hatchery modernization, watershed restoration, and key decisions on flows, research, and fish‑passage infrastructure, the session highlighted both the progress achieved and the important work ahead. Click to Read More
Trinity River Watershed
The Common Merganser (Mergus merganser)
Ever wondered how those graceful ducks you spot along the Trinity River hold relationship with juvenile chinook salmon? Meet the Common Merganser — a migratory bird whose excellent predation skills and extended presence might reveal secrets about how flow management influences the delicate balance between predator and prey. These winter and spring visitors thrive in areas shaped by previous slow-water winter management, and their appetite for salmon fry has sparked new research into how river conditions affect this dynamic. Click to Read
Upcoming Meetings and Events
For a full list of events, click to view the TRRP Calendar.
Apr. 22, 6pm - Science on Tap
Trinity County Brewing Co. - Weaverville
Join research geologist, Andy Calvert, Ph.D. of the USGS for an evidence‑based exploration of volcanic processes in the Western United States, focusing on the tectonic and eruptive history of the Mt. Shasta and Medicine Lake region. This presentation will outline how geologic mapping, argon geochronology, and volcanic stratigraphy reveal over a million years of magmatic evolution and hazard potential within the Cascade Arc. Event Details
Apr. 24, 3:30pm-7:30pm - Earth Day Sustainability Walk & Tree Planting
Lewiston Community Park & Gym
Join us and other community organizations for an Earth Day event sponsored by the Lewiston Community Association. The event will host informational booths, snack vendors, contests, crafts and a 7:30pm movie showing of the Lorax. We look forward to sharing information about riparian plants and restoration initiatives within the Lewiston area. Event Details
Apr. 25, 10am-2pm - Trinity County Plant & Seed Exchange
Young Family Ranch, Weaverville, Ca. - 260 Oregon St., Weaverville, CA
So much fun at the 2026 Plant & Seed Exchange! Whether you’re a seasoned gardener or just getting started, this is a great chance to share seeds, swap plants, learn about native species, and connect with fellow plant lovers in our community.
Weaverville Summer Day Camp, Registration Now Open!
Young Family Ranch - Weaverville
Join the Trinity County RCD for three weeks of outdoor fun and hands-on learning, July 6–24, at the historic Young Family Ranch in Weaverville. Designed for kids ages 8–13, campers will explore nature, connect with community partners (like us!), and dive into hands-on activities, including field trips to the Trinity River, Canyon Creek, North Fork, Stuart Fork, and the Trinity Alps. Event Details
June 17 & 18 - All Day Quarterly TMC Meeting
Reading, Listening, Watching
The Iaqua Oak and the Future of Old Trees
By: Michael Kauffmann | Apr. 4, 2026
Recently, Michael Kauffmann - educator, author and ecologist - visited one of the largest canyon live oaks. He measured and mapped it— not just to record its size, but to better understand its story. Continue Reading ...
Water quality enforcement penalties boost Salinas River beaver renaissance
California Water Boards | Ebb and Flow | Apr. 8, 2026
Nature's furry water engineers, are making a comeback on a major Central Coast waterbody with help from the California Water Boards and a group of dedicated educators and volunteers. Continue Reading...
March brought dramatic snow loss in the Trinity Alps
Watershed Training and Research Center | Facebook | Apr. 8 2026
Ben Letton, one of the WRTC surveyors had this to say about the most recent survey, "We were hoping to measure feet of snow at this time of the year but ended up only measuring inches of snow at Bear Basin and Red Rock snow courses. Unfortunately, very little snow for the end of March.” Continue Reading...
Record 30,000 Endangered Central California Coast Coho Salmon Return to Mendocino Coast Rivers
NOAA Fisheries | West Coast | Mar. 26 2026
Back-to-back record spawning seasons suggest that reconnecting tributaries and restoring salmon habitat is supporting Central California Coast Coho population growth. NOAA has funded more than 100 restoration projects on the Mendocino Coast. Continue Reading...
Contact Us
Call Us: 530-623-1800 Email Us: in...@trrp.net
