Sand across the trail: it sucks, literally. It causes wipeouts in corners and strains pedaling on flats. What I have observed is that people are sometimes reluctant to move it. They may think a certain area of the trail is just naturally sandy and there's nothing you can do. By what I've observed, this isn't true.
It looks to me that heavy rains cause erosion and bring sand drifts (along with sediment that does not get caught) to lower levels of the trail. In my hometown trail this shows up as drifts across the flat sections of trail that line a creek, coming down from the bluffs above. In another trail upstate, they are most prevalent in curves on hills that may not get the best drainage.
In your experience is this true? Is it a good idea to remove sand? I've been using a broken shovel that I ride in with, scoop it off, and throw it as far downhill as I can.
If the sand is not native to the trail section, then I don't see how it could be bad for the trail to remove it. I will admit that just leaving the sand there does provide some degree of protection for the tread, but it is only there in sections of about 30 feet or less.
Can you post pics?
It sounds like you're treating a symptom rather than the cause.
Originally Posted by Trail Ninja's Son
The sand buildup sounds like a symptom of trails in which rain water is running down the length of the trail and depositing the sediment in low spots all while causing substantial erosion. Soil form one part of the trail should not be migrating to other parts of the trail. Lighter weight particles of soil (organics, silt, and clay) are usually carried off of the trail by rain water and the heavier parts (sand and rock) remain behind or don't travel as far. The sand deposits are probably a clue that there is a large amount of soil moving when the trails experience heavy rainfall.
If this is the case, removing the sand isn't going to fix the problem in the long run. It will come right back unless the trail design is modified to keep water from running down the length of and collecting on the trail.
If you are so inclined, I would recommend putting your efforts into figuring out how to stop the sand from getting there in the first place instead of removing it.
One way to deal with natively sandy areas is to use Turfstone pavers buried in the sand to reinforce the trail. This might be an option if the trails run through or cross a stream bed and sand buildup cannot be prevented.
Ok here is a photo. To the right (Northeast) is a tributary creek that ends up in the Mississippi river, to the left (Southwest) are bluffs that rise up about 100 feet and contain the best parts of the trail, where sand and overgrowth are not a problem. In between it is a flat pasture. The trail pictured gets you to the good stuff in a shaded area. I noticed last year after a tropical storm that the sand had appeared on these flat sections of trail where it wasn't before. The grass was all swept towards the creek so it looks like there was a massive flow of water off the steep loessial bluffs. We get good drainage around here but the downside is the potential for heavy erosion runoff in low areas.
On the other trail upstate, it does look like there's some runoff down the trail with sand pooling in the low areas, and more troublingly, the corners. It's deep enough to see that it has happened over time and shoveling it out is worth the trouble, just like cutting slappers it is something that may have to happen seasonally. I suspect that one shoveling work day will probably make the trail more ridable for a couple of years. This trail has very gradually-sloping hills and it is decently graded and benched throughout for the most part, but residing on a lake it probably has a high sand content in the soil all over the trail's area.
Last edited by chomxxo; 10-27-2012 at 09:38 PM.
So if I understand correctly, the water is flowing (from left to right in the photo) across a pasture area at the base of the bluffs, across the trail, and then into the stream? Do you think the sand is coming from the bluffs or the pasture area? Is the trail tread in that photo normally lower than the rest of the surrounding ground? If it is lower, this may explain why the sand is accumulating in that spot. I don't think removing the sand is going to make it any worse as long as you then build up the tread height to that of the surrounding ground and slightly slope the tread towards the drainage. Maybe try replacing the sandy soil you remove with soil which has more clay in it and construct a swale and/or some type of sediment barrier on the uphill side to trap the sand before it reaches the trail.