Erosion Line Journal
May 8, 2025
So fun to have CSU Chico instructor Lilita Wood back on the Erosion Line, this time with a group of 9-11 year olds. Alexander, Gus, Llewyn (who had been here in January!), Rowan, and Rusty worked on a tricky and heavily eroded switchback on Maidu Trail.
Wow, these guys got a lot done. They finished the entire section with time left over to do experiments that involved pouring jugs of water uphill of their motifs. They got to see first have how soil is washed downhill, exposing bedrock. They are invited to come back next spring to see what happened to their section!
May 3, 2025
Aidan and I spent the morning near the top of Manzanita Trail, working on small patches of trail erosion-exposed bedrock. Pretty crumbly stone, took careful work to complete. Congrats to this wonderful person for landing his dream job in bird surveying!
April 23, 2025
Kat, Aidan, and Diego finishing the last horizontal motifs on Manzanita Trail! Six months after starting, with the help of over 65 community volunteers, Erosion Line is complete on this trail. What a milestone!
The last motif on Manzanita Trail!
April 19, 2025
Diego demonstrating great carving technique: finesse, not force. Just delicate tapping while turning the star chisel to drill a clean, small hole into the bedrock.
Eduardo, Diego, and I continued to add horizontal motifs along Manzanita Trail. The stone is dry now, and easy to work. We got a lot done on a gorgeous spring day in Bidwell Park.
April 16, 2025
Chico Junior High School science instructor Kristen James brought her AP Biology class to Erosion Line. They completed a large section of Manzanita Trail and had time to do water experiments. They poured jugs of water over various terrains to see how it effected their motifs, interesting stuff. Next year’s AP biology class will come back to this spot in spring of 2026 to track the progression of erosion. We plan to share this info with City and Bidwell Park leadership to help with Park planning decisions. Thank you, students, for your hard work! And thank you to Aidan for your capable assistance!
April 9, 2025
At last, the volcanic bedrock is dry enough to work again. Mary Jo and two CSU Chico students who attended last week’s class field trip, Diego and Aidan, made plenty of motifs that will allow us to track the rate at which this section of Maidu trail increases in width.
Fun coincidence, Mary Jo’s three year old grand daughter had stopped by Erosion Line a few days prior on her way (with her parents) to summit Monkey Face. She took a short break from her trek to help Aidan make a hole, becoming our youngest volunteer to date! And was very pleased to hear that Grandma was continuing this new family tradition.
April 5, 2025
Aidan finishing the final boulder motif on Manzanita Trail! It’s now possible to track vertical erosion on the entire length of this tail.
March 26, 2025
CSU Chico students from Lilita Wood’s Diversity in Public Lands course standing on the section of Manzanita Trail that they completed in just a couple of hours. All of the visible bedrock and soil in this photo was formerly covered by vegetated topsoil, now exposed by trail erosion. We are planning to have students return in Spring 2026 to record the progression of erosion, using these motifs as reference.
March 22 and 23, 2025
Jessica, Morgana and I continued to make motifs on boulders to track the vertical loss of soil on Manzanita Trail. These motifs are more visible that those carved into horizontal bedrock as they aren’t obscurred by deposits of eroded soil. The motif is on a portion of this boilders that was previously underground. Four inches of topsoil had already eroded away.
March 19, 2025
Liz, Aiden, and I continued up the switchbacks toward the top of the Manzanita trail. In this section of the trail, the flat volcanic bedrock is still covered in soil. We can track erosion by making the motifs on boulders that have been exposed by erosion.
March 15 and 16, 2025
Samuel, Morgana, Jessica, Aidan, and I made big progress on the switchback portion of Manzanita trail, which leads to the top of Monkey Face. On our way up, Morgana used this Erosion Line motif made earlier in the winter to measure about 9″ of horizontal soil loss. It happens fast.
March 12, 2025
Aidan and I were back on Manzanita trail, making motifs on boulders to track vertical soil loss. The volcanic bedrock is still too soft to work.
February 26, 2025
Tay, Megan, and Aidan helped on the lower portion of Manzanita trail today. There is a lot of bald soil here as people pretty much wander at will. Can’t really blame them as signage is confusing and the trail turns into mud soup after storms. But, this trail erosion is alarming; the trail is more than 18′ wide in places. Bare, compacted soil makes a feedback loop that intensifies the erosion process.
We made motifs on small boulders to track vertical erosion and deposition as it happens. And hope future signage and trail improvements will help this area heal.
February 23, 2025
Back on Manzanita trail this weekend, working on the low end of the trail just past the creek crossing with Aidan, Jessica, Morgana, Isai, and Jorge. Those last four all work for California Convervation Corps, where they do emergency response and conservation work and are encouraged to do environmental volunteer work between assignments (like Erosion Line!). All four had recently been in southern California, working on the horrific Eaton and Palisades fire. Big thanks to all of them!
February 22, 2025
This crew has been out here a LOT! So grateful to have your continued help Aidan, Morgana, and Jessica. We’ve gotten so much done! Thank you!
February 19, 2025
On Maidu trail for a blustery day of boulder motifing. Today’s volunteer, Chrys, is a fine art photographer, artist, and grant writer. She offered to help if I apply for a grant to fund Erosion Line!
February 15 and 16, 2025
Aidan, Jessica, Morgana and I spent two lovely mornings on Maidu trail making motifs on boulders. This part of the trail is dirt studded with boulders that were previously covered in top soil, now exposed by trail erosion. Perfect for motifs to track vertical erosion that is turning this trail into a trough.
February 8, 2025
Another atmospheric river brought plenty of rain to the Park and sent Aidan and I back to making motifs on boulders. We were sobered to find that motifs made before this wave of storms showed inches of soil lost. Those that we made today will track future erosion.
Motifs made before the recent storms are tracking erosion in real time on Manzanita trail. This one made on flat bedrock shows 4″ of horizontal erosion from the latest round of storms.
While this one on a boulder shows 5″ of vertical soil loss.
January 29, 2015
Janie, Aidan, and I enjoyed a perfect spring (in January) day on the Erosion Line. Great for art making (Janie is a fellow artist) but perhaps not so much for rainfall totals. We continued making motifs on the flat bedrock, taking advantage of its workability while the sun shines.
January 26, 2025
Molly, Llewen, Tauschen and Elliot teamed up to make a set of Erosion Line motifs on Manzanita trail. We began with an interactive lesson, the boys noting the speed, direction, and distance traveled of water poured over various trail surfaces. Superstar Aidan demonstrated tool use and the boys got busy. Before we wrapped up, we noted that their spot was half way up the trail, next to a coffeeberry shrub. Now, they can track erosion each time they visit Monkey Face.
January 25, 2025
Chrysanthoni and I added motifs to exposed bedrock that will help track widening of the Maidu trail. This type of erosion is caused both by rain water carrying away soil as it rushes down hill and by people walking or riding on soil at the edges of the trail. With the help of Erosion Line, we’ll soon know how fast this erosion is occurring.
Today Jim, Aidan, and I were happily surprised to be working alongside new split-rail fencing on the Maidu Trail. The fencing, installed by Trailworks, a volunteer group run by Chico Velo, will protect sensitive ecological recovery areas by helping people to stay on the trail. This meshes perfectly with the intent of Erosion Line to raise community awareness of environmental issues in Bidwell Park!
January 19, 2025
Today, the lower park of Maidu trail was dry enough for Jose and Dakota, today’s volunteers, to tackle. Attempts a couple of weeks ago, following heavy rains in November and December, resulted in aborted motifs as the bedrock was too crumbly to continue.
We start each 3-hole motif by first making the ‘tip’ of the triangle – the hole that touches the existing edge of soil. This is the most important feature of each motif as it will provide the reference point from which to measure future erosion. If the bedrock isn’t stable enough for this hole, we move to a different location. But today, most every spot we tried worked. We ended up with many beautiful new motifs that connected two previously completed sections of trail.
January 15, 2025
Julia, Aidan, and I tried a section of the Maidu trail that was previously too fragile to work. The dry weather had worked its magic and we were able to make clean, round holes for the motifs. The motifs on this bedrock will help track horizontal expansion of erosion. Aidan also worked on boulder motifs further up the trail.
January 12, 2025
Another beautiful day in the Park, we got a lot done. Vanessa, Brandon, Jess, and Chris continued on patch of exposed bedrock that was dry and sturdy enough to work. There’s a gap in Erosion Line where we skipped sections that were unworkable after the rains. Two rainless weeks have made this part of the trail workable.
January 11, 2025
Aidan and I focused on portions of the Maidu Trail that are composed of soil, with no exposed bedrock. The soil is easily displaced by normal trail use. Signs of erosion are apparent: the trail level is below the surrounding intact landscape, and the lower portions of boulders sitting in the trail have no lichens forming on their surface, indicating that the soil line was previously higher. Adding motifs at the current soil line of the boulders will help track the progression of vertical erosion.
January 5, 2025
Lisa, Eliana, and Tom worked a layer of exposed bedrock that, though wetted by rain a day ago, was firmer than other bedrock on Maidu trail. Much of the bedrock in Upper Bidwell Park is composed of volcanic material deposited in layers over millions of years. Generally, these layers feel and look like ‘petrified’ mud. But there is a subtle variety of textures and materials that affect our work. Some layers are composed of fairly uniform fine particles, like sandstone. Others have large, chunky aggregates in mud-like matrix. Some are etched with hairline cracks, like clay that has dried too fast. Each trail section requires assessment of the characteristics of the bedrock and whether rain penetration has rendered it temporarily too unstable. We adapt carving techniques and what trail section we choose to work to reflect conditions.
January 4, 2015
Aidan and Humberto, having a grand time demonstrating creative ways to make motifs in boulders.
Some portions of the Monkey Face and Maidu trails feature bare soil with no exposed bedrock. But, like the bedrock, many of the boulders that sit in the middle of trails have been completeley or partially exposed by trail erosion. By making motifs at the soil line at base of these boulders, we can track future erosion.
December 21, 2024
Aidan: I went on a hike when we had a break in the weather this past Tuesday. Took the liberty of measuring the erosion from the past three weeks-
Eve: Wow, thank you for doing that and sending these great images! I went up the Maidu trail and noticed erosion at several of the motifs. Also several were completely covered with deposits from erosion uphill. Its shocking how quickly it happens!
Aidan: Right? Did not expect to see results that fast.
December 19, 2024
Spent a lovely, foggy, drippy morning leading North State Public Radio’s Ava Norgrove on a tour of Erosion Line. She had previously interviewed me in the NSPR studio but wanted to come out in person. She helped make a motif and produced a wonderful segment that aired on the radio and is posted on the NSPR website. Thank you for lending your talents for in-depth reporting and helping to get the word out, Ava! We are fortunate to have high quality local journalism in our region!
December 11, 2024
So moving to learn that today’s volunteer, Adia, chose to work on Erosion Line today in memory of her father, who passed away two years ago. Thank you for honoring this project with your respectful presence, Adia.
December 8, 2024
Today’s volunteer, Kyle, worked with me on exposed bedrock on Manzanita trail (aka Monkey Face trail). He developed a more streamlined chiseling technique by rolling the chisel back and forth between thumb and index finger rather than continuously in one direction. Seems to require less dexterity and minimize tearing in soft bedrock. Thank you Kyle!
December 7, 2024
Back to working on Manzanita trail with Aidan. Motifs in November are showing that, following a recent big rain event, several inches of soil has been eroded away in some areas. The point of the triangular motif, next to my thumb, used to touch the edge of soil. The current edge of soil touches my pinky in this image.
November 30, 2024
Volunteers Paul and Katy continued work on Maidu trail as Monkey Face bedrock is still quite fragile. As we made motifs, we discussed Paul and Katy’s ideas to promote a community culture of stewardship for Bidwell Park by coordinating with the many service groups already involved in the park. They are working to organize a 120-year Park anniversary event to galvanize environmental education and volunteerism in Bidwell Park.
November 27, 2024
Today, the bedrock on Manzanita trail is rain soaked and too fragile to work. Volunteers Calvin and Aidan are working on Maidu trail. The bedrock is not too soft here, so workable. We work carefully to prevent blow outs, starting each hole with a narrow 1/4″ chisel then finishing with a 3/8″ chisel. Delicate tapping and turning – drilling, not pounding.
November 23, 2024
Aidan is back! He’s a recent biology major volunteering on environmental projects while seeking work in his field. Thrilled to have his continued help on Manzanita trail! The bedrock, softened by rain, was too fragile to work. We made motifs on the vertical faces of boulders that are imbedded in soil and on the faces of stone steps.
November 16, 2024
Inaugural Erosion Line event with community volunteers! Here we are: Aidan, Sally, me, Stephanie, and Fernanda on Manzanita trail, which leads from Parking lot E to the top of Monkey Face rock formation. We worked in teams of two, one making holes while the other made sure that the chisel is held perpendicular to the slope of the bedrock to prevent shearing. Got a lot done!
November 15, 2024
Action New reporter Diego Moctezuma came out to interview me and film the future site of Erosion Line on Maidu trail in Upper Bidwell Park, Chico CA. He attended the BPPC meeting where the project was approved and kindly followed up. Thank you for covering Erosion Line, Diego! I hope to see you out on the trail soon! You can read his informative story and watch the segment here!
September 29, 2024
Test run #3! Dear friends Laura, Mari, Carla, Mary, Suzanne, and Jeanette arrived for the final trial run. We refined our techniques on horizontal volcanic bedrock which is somewhat friable and workable. Also tried some holes on upright faces on boulders that protrude from portions of the trail still covered in soil. Much harder but doable.
September 23, 2024
Test run #2, with volunteer and dear friend Julia! We noticed that the layers of volcanic bedrock that trail erosion is exposing feature a variety of textures and levels of structural cohesion. We will use great care in making the motifs to respect these conditions.
September 16, 2024
Earthen Iron’s Dave Richer kindly sharpened the star chisels. Ready for action!
September 15, 2024
Now that Erosion Line has been approved by the Bidwell Park and Playground Commission, it’s time to see if the theory works: can small holes be carved into the erosion-exposed bedrock on Monkey Face? Using a two-pound mallet, I carefully tap-turn-tap a star chisel provided by Chico sculptor Matt Auvinen. This traditional sculpting tool is used to hand-drill holes in masonry and stone. The hole takes shape. Soon, I’ve made a 3-dot motif! It works!
September 6
Chico sculptor Matt Auvenin kindly advises me on the best way to make holes in stone. He pulls out some antique star chisels, traditional hand tools that look somewhat like phillips head screwdrivers but with sharpened edges. When slowly turned while being tapped by a mallet, they drill a neat hole into the surface that is to be perforated. I leave this informative meeting with four star chisels of varying size and a 3 pound mallet that Matt has donated. Thank you, Matt!
August 26, 2024
Following a slide presentation and a thoughtful question and answer period, the Bidwell Park and Playground Commission voted unanimously to approve the Erosion Line project!