When I first started riding the trails around Folsom Lake eight years ago it was rare that I would encounter another rider on my afternoon trail rides in either summer or winter. Today, it isn’t uncommon to pass four or five groups of several riders on the narrow single track trails. And if a mountain bike race is scheduled, I could see fifty plus riders ripping across the trails.
Mountain Bike Destruction Continues in 2021
When the Covid-19 Pandemic shut downs occurred in 2020, Folsom Lake saw a phenomenal spike in attendance. The crowds were so large that the entrance at Granite Bay Beach was closed for a month. That did not stop the mountain bikers who descended on Cavitt Junior High School and tore down the fence to gain access to the Folsom Lake trails.
Even after California loosened outdoor restriction, Folsom Lake was now a hot spot for mountain bikers. The multi-use trails are now highways of mountain bikes. It is not unusual to see a pack of 5 to 15 riders riding as if they are training for a race. Hikers are a nuisance to them. From the perspective of some of these mountain bikers, hikers, walkers, and joggers are encroaching their mountain bike trails.
These mountain bikers are not content with the established trails. They want bigger thrills for danger and speed. They have started cutting new trails on dangerously steep slopes prone to erosion. In the past, when I have complained about the mountain bikes destroying the trails at Folsom Lake, the mountain bikers argued that hikers and horses cause as much damage.
The new trails have been solely formed by mountain bikers. The slopes are too steep for hikers and horses. The mountain bikers completely own the new destruction to the Folsom Lake State Recreation Area. On one trail beginning on top of Mooney Ridge, the mountain bikers used shovels to create a banked curve so they could go faster. These people would ride their motorcycle dirt bikes out at Folsom Lake if they could. In lieu of a motorized dirt bikes, more battery propelled mountain bikes are showing up at Folsom.
In 2019 I did not see one battery assisted e-bike on the trails. In 2021, it is not uncommon to see half of a group of riders using e-bikes. The battery assisted e-bikes allows more riders to get to the top of steep hills and ride down them at high rates of speed, their knobby mountain bike tires tearing up loose soil as they descend.
Does the management of the Folsom Lake State Recreation Area care about the numerous unauthorized trails being created by mountain bikers? Apparently not. Many people have complained, including myself. We hear sincere comments from management about the unauthorized trails and how they are going to do something to stop it. They never do anything.
Folsom Lake management is intoxicated by the increased revenue provided by all the mountain bikers. They have put some of their budget into stabilizing over used and highly eroded mountain bike trails. Folsom Lake has even created some new authorized trails for multi-purpose use. When it comes to the destruction of the public resources out at Folsom Lake by the mountain bikers, management of the park just shrugs their shoulders.
Mountain Bikers Cut New Race Course at Folsom Lake SRA
2020 New Unauthorized Mountain Bike Trails
Letter to California Dept. of Parks and Recreation
Folsom Lake State Recreation Area, PO Box 942896, Sacramento, CA 94296
Re: Unauthorized Mountain Bike Trails February 1, 2020
I was very surprised to come across not one, but two, unauthorized mountain bike trails at the Folsom State Recreation Area between the trail access point from Lakeshore Drive and Granite Bay Beach entrance. These were not merely trails created by bikers rolling down the hill, individuals used hand tools to create berms to bank on for greater speeds.
These unauthorized trails are short-cuts across where the fire and emergency service road makes a sharp turn and goes up the slope.
I have been hiking, jogging, and riding my mountain bike out at Folsom Lake since 2003. I noticed these short-cut trails starting to develop in 2015. A tree had fallen and prevented access to one of the first unauthorized trails. The scar from the first mountain bike trail was healing until individuals opened up the trail and constructed a new trail next to it.
One of my biggest concerns is erosion on these trails eating into the fire and emergency service road. We have already seen this happening at other spots where trails have been created on inappropriately steep slopes.
I have seen other trail maintenance workers place brush and downed tree limbs across these unauthorized trails to prevent access and help with the healing process. From that example, I have also tried to place brush and branches across the trail to prevent further use. They are constantly being removed to open up access to the unauthorized trail, right next to the perfectly good fire and emergency service road.
In May of 2018 I saw that the Parks Department had cut some new bike trails north of Granite Bay Beach. This was terrific as the original trails, in many spots, had been developed on slopes that encouraged severe erosion. Some of the trails have erosion gullies two to three feet deep. I have been riding my mountain bike on the new trails that seem to be far better suited to prevent erosion of the natural resources.
Currently, I am at a loss of what to do with the new unauthorized trails. They are too steep for the soil and terrain conditions encouraging severe erosion. They encourage mountain bikers to go as fast as they can down the trail and rejoin the fire road, where there may be other park visitors. This stretch of the trail is not patrolled very often because of the difficulty to get to it. However, it is a very popular spot with runners, bikers, families, and hikers.
I am open to adopting part of this trail to pick up trash and do trail maintenance. Someone just needs to guide me through the process with an inventory of approved trails to maintain. I have seen the number of visitors to the Folsom Lake State Recreation Area increase every year and I think this is great. There is nothing better than seeing family’s picnic, enjoy the lake, fish, and explore the trails. At the same time, I understand it is part of your mission to protect and preserve the park amenities for everyone, today and into the future.
As someone who enjoys the park, and uses it extensively, I am willing to do what I can to work with you to help protect and preserve the Folsom State Recreation Park resources.
Thank you for your time and attention to my questions. – Kevin Knauss
The mountain bikers responsible for these sorts of unauthorized trails are always quick to blame horses for most of the trail destruction. These BMX style trails having nothing to do with horses. They were cut and are used by mountain bikers who think Folsom Lake is their own personal play ground to destroy for their enjoyment.
Aggressive mountain bike riders
All of this increased mountain bike activity is destroying the trails around Folsom Lake in Granite Bay. Some parts of the trail have become half exposed rock, eroded trails with gullies that are getting deeper and multiple corner tracks are being developed. In short, the trails are turning into scars that can’t be healed with good stewardship. Most of the damage being done can be attributed to the aggressive riding tactic of racers and those wanting a thrill ride down the hill.
Erosion beyond repair
Not only are the current trails being turned into gullies of erosion, some really lame mountain bikers are creating new trails on slopes to steep. Once they have killed the grasses and created a path of bare dirt, there is nothing to stop the winter rains from racing down the trail and creating an ever deepening rut.
There are many parts of the trails that are on relatively flat ground and are stable. Because they are wide and flat, with a stable base of decomposed granite, they support multitudes of hikers, bikers, horses and runners with no visible erosion taking place. This is the type of trail that needs to be supported and increased around Folsom Lake.
Horses outnumbered by growing mountain bikers
Some people believe horses are to blame for the rapidly decreasing state of the tails. There is no doubt that horses, because of their weight, can really destroy native grasses and cause erosion. However, for every horse I have seen on the trails there are 50 to 100 mountain bikers. Horses walk at a steady pace, almost blindly following the path and only venture off trail to allow a bike to pass.
This isn’t a BMX track
Mountain bikers, especially the racers, bike as fast and as hard as they can. They are jumping over rocks and landing hard on the moist dirt. Mountain bikers have no issues with going off trail either to avoid an obstacle, make a short cut or create a new trail just for fun. For the racers, it’s all about winning and not necessarily preserving the trails for others to enjoy.
New steep trails for fast thrills
Mountain bikers have become more irresponsible and more aggressive over the years. It is not uncommon to see a group of mountain bikes flying down the hill like it was their own personal course. They seem to have no clue that these are multi-use trails and right around the corner could be a family out for hike. I have also seen new trails, non-existent just 2 years ago, that are already showing signs for severe erosion because they are on slopes too steep.
In addition, many riders are aggressively riding like they are in a race. They make hard turns, jump over rocks and lock up the back tire cutting into the soil. The worst of the destruction happens in the winter and spring when the ground is wet and easily cut by the knobby tires.
Would you destroy your own backyard?
I like to bike hard through the mud puddle just as much as anyone. Mountain biking is fun. There are just parts of the trail around Folsom Lake that combine highly erodible sandy soil with slopes that is just perfect for long term scaring from erosion. Some of these ruts will never heal and will only get worse over time. No property owner would allow this sort of destruction and erosion on their own land, so why is it “OK” on public property?
As the trails become nothing more than eroded ruts; hikers, runners and even horse riders stop using the trails to avoid twisted ankles from the miserable condition of the trail. I run on the trails and I see and have experienced the danger of the deep ruts caused by mountain biking.
It is my hope that all interested parties will work together to improve and stabilize the trails. Here are a few suggestions, but I am certainly open to adding more if others have ideas.
While we may not be able to completely repair the damage done to existing tails, trail users and California State Parks must stop bikers from creating new trails on highly erodible steep slopes.
Where possible, CSP should look at rerouting mountain bike trails to paths with smaller slopes. Virtually all of the severely eroded trails our on steep slopes where rain easily washes the sandy soil away.
Institute a damage repair fee to organized race events. By far the greatest damage is done by aggressive mountain bike racers who slice through the moist soil deepening ruts and expanding the track. The collected fees could be used to repair damage to the trails and create obstacles to keep the racers on the designated path.
I’ll do my part
As a community member who hikes, runs and bikes on the trails around Folsom Lake, I contribute to the overall destruction of the trails as well. I am willing to accept restrictions, new flatter trails and physically work to repair the trails within the framework of a solid plan. Folsom Lake is a great place and a resource that will only see more use as our population and the sport of mountain biking grows. If we don’t start preserving the trail system now, the hills around Folsom Lake will be a series of crisscrossed scars and an ugly reminder of how communities fail in their stewardship of public resources.
One year update on trail erosion (2014)
It’s been almost one year since I originally posted this blog on how I have seen mountain bikes irrevocably destroying the trails out at Folsom Lake. From the comments below and the numerous emails sent to me, most passionate mountain bikers don’t feel their activities on the mix use trails around Folsom Lake cause any long term harm. Below are a few pictures where I was able to compare the photos from 2013 to the photos of the same trail spot one year later.
New trail becomes permanent
This comparison shows the beginning of a new bike trail to avoid numerous rocks on section of the trail. By February 2014, the initial tire marks have become a well used trail widening the overall trail by several feet.
This comparison shows a multi-track bike trail has gotten too much worse in the last year. The drought of 2014 has prevented any native grasses from growing potentially stabilizing the soil in the future.
New Trail Cuts
In an effort to avoid a large granite rock and the deep rut, the trail has been widened as bikes maneuver around the outcrop. The next photo shows the beginning of a new trail as bikers avoid a deep eroded rut on the side of the hill up to the “Bench”.
2016 New Mountain Bike Trail Scars
In the three years since I first posted this blog, we continue to see new mountain bike trails and scars at Folsom Lake. Contrary to the view of many mountain bikers, these new trails have not been created by horseback riders. They are primarily short-cuts off the main road, notable between Cavitt Junior High School entry point and Granite Beach State Park. In an effort to spice up the ride, some bikers are creating steep trails to gain speed and then ramping off the opposite side of the road bank. There are a subset of mountain bike riders at Folsom Lake who have no respect for the park. For many bikers, if they aren’t ripping up the environment, they aren’t having fun. Folsom Lake State Recreation Area is a public resource for all who like to walk, hike, bike and horseback ride. It’s sad that the Park’s Department doesn’t attempt to stop the destruction of the area. I know many mountain biking organizations attempt to create brush barriers to prevent unauthorized mountain bike trail creation. Perhaps we need to start putting up more brush barriers to protect the Folsom Lake trails from mountain bikers who wish to destroy it in their zeal for a fun ride.
Click on the thumbnails to enlarge
Wet soil, high speed mountain bike racing
This is a recording of a mountain bike race on the mixed use trails around Folsom Lake. On this February 16th morning, the soil was wet from a previous rain storm. This is the first lap of a two lap race. Within 5 minutes, 29 riders had passed as they negotiated the slope, ruts, rocks and trees on this particular down hill curve. Five years ago this curve was single track trail. Today, the original trail is a rut 6″ deep and two other tracks have been established around it. Hikers and horses didn’t expanded the the trail and turn it into a scar.
Comparing hiking, mountain biking and horse riding impacts on vegetation and soils in Australia and the United States of America
Excepts from page 5 From
the Journal of Environmental Management, an article published in July of 2009: Comparing hiking, mountain biking and horse riding impacts on vegetation and soils in Australia and the United States of America. I have received so many comments that mountain bikes caused no damage that I decided to include this scientific review of different studies assessing the impacts of mountain bike riding on multi-use trails.
The extent and severity of mountain biking impacts appears to
be connected with different riding styles. Impacts are likely to be
greater when riding is faster, less controlled, occurs on steeper
slopes and in wetter conditions. In Western Australia impacts from
different styles of bike riding were compared on trails (Goeft and
In contrast to the findings of Goeft and Alder (2001) Newsome
and Davies (in press) identified mountain bike related impacts to be
a significant management problem both on and off trails. Impacts
included the deliberate modification of existing trail networks and
the creation of informal trails.
These impacts relate to particular riding styles and especially the thrill
seeking adventure components of downhill riding, free riding and
dirt jumping. Although this method was found to be useful for
assessing mountain bike specific impacts and especially the
impacts of informal trail development by mountain bikers it is not
suitable for comparing the relative impacts of different use types on
What is abundantly clear from the studies is that destruction to the trails is related to aggressive riding on multi-use trails not designed to tolerate such activity. I’m not advocating that all mountain biking or races be stopped at the Folsom State Park Recreation Area. We just need to invest in new or alternate trail systems more suitable for aggressive riding.