Reasonable Arena Spinoff...understanding soil surveys? Did you dig to clay?

[TrotTrotPumpkn]

So I pulled up the NRCS map (in case you want to try that here it is: http://websoilsurvey.nrcs.usda.gov/app/ )and was able to plot out my arena on it (how cool is that!?). Half is “silty clay loams” and half is “silty clay loams 0-2%”

The typical profile is 0-18" silty clay loam 18-36" silty clay and 36-60" silty clay loam. Or it could be all silty clay loam down 60" (the size of the arena is too small for what they have on file).

The other half is also silty clay loam, but is classified as better draining (goes down at least 60").

I have no idea what this means. It is just dirt to me. Not particularly clay like (I did find some I would call heavy clay in another field), or gravel like, although I found some gravel pockets digging fences. My reason for posting is everyone who writes about arena construction is always saying dig down to the clay–well I can go 5’ without hitting clay. Do you HAVE to compact clay? This stuff will compact. Lord knows with the drought it’s hard as a rock right now. The area does drain well naturally. Did you all get down to clay?

I don’t know a single person in my area who did anything other than grade, pack the dirt, and put down sand, but everyone is always harping on base construction… (I know one person who did a base an hour north of me I guess–I have asked everyone I know with an arena how they did it). I don’t know of any professional arena installers around here either, but you can hire a road/construction crew to do dirt work. However I’m relying on myself to know what to tell them. It’s kind of a DIY part of the world. So I really need to figure out how to do this right, and yes, I have Underfoot.

[goldenrow]

Your silt factor in your loam is not going to be a good enough base- too many pockets to hold water. I don’t know where you are in the Upper Midwest, but where I am, we are all loams.

We put in a tile line around where we wanted the outdoor, then built the base up from that using lime screenings - which will pack and make a sheer surface for water to run off, after it filters through the sand.

I am great with the WSS tool, soils, and have lots of outdoor arena experience in the area. Let me know if you have questions!

[TrotTrotPumpkn]

THANK YOU!!!

Basically where IA & SD meet (south of Sioux Falls–Lincoln County). I’m not sure about lime screenings. I know they use those in MN. Quartzite is the local stone you see everywhere just north of us-- the one gal I know who did a base used quartzite, but she is probably an hour north, and right next to a quartzite quarry, and I haven’t looked into it either except to glance at the local stuff that you can find easily online. For example, my driveway was done with some yellow gravel originally, like all the gravel roads here, and crushed concrete the second time, so there must be other stone available relatively cheaply.

Did you do PVC tile? I was also thinking about doing a french drain, definitely on three sides and possibly all four. I started researching PVC and the flexible farm tile and it looks like PVC is better…plus you can work out clogs if they happen vs. the black flexible stuff they use in fields.

Did you put down any fabric on top of the packed native soil before the screenings? I do seem to have grapefruit and baseball sized rocks pop up on the site each spring. Not a lot, maybe 5 or so…

Whenever I talk to the horse owners around me, and I ask everyone what they did, they think I’m crazy to want to do a base. “Just level and add sand”…

My thought, and if this is not great, let me know, was to get the base done late this summer when we dry out (assuming spring rain). That way the big equipment won’t destroy my pasture (I’m stealing this from the pasture).

I would trench drains then too. Pack it. But then I’m going to wait until next year to start doing anything else. Largely, because I’m going to board this winter I think. My friend did her indoor, which was originally an outdoor that way…basically let it settle for a year.

[wildlifer]

Important note: the soil survey maps should be taken with a grain of salt & a confidence interval. They are a good starting point of reference, but not so accurate that you could rely on them on a single property scale 100%. You need to go dig holes to ground truth it.

[TrotTrotPumpkn]

That’s assuming I know what I’m looking at!

It (to me), overall, it really looks like a mix of brown dirt, a little black clay and a little gravel. It’s pretty nice soil, imo. Maybe not for a ring base though! You are right though–I know 300-600 feet to the west it gets really gravel/sandy (there is a shallow ridge that runs behind my shelter belt and the farmer assures me that’s gravel/sand) but you go 250 feet south of my center line and hit some heavy clay, which we encountered digging corner braces.

[secretariat]

Soil survey data is awesome, and I’ve found it very accurate. But for specific installations you need to get very specific to your site.

Silty loams/sandy/gravel do not make good bases. Haul in good base material.

I don’t like to french drain, as the drains can fill up and/or degrade over time. Best to go with good base material and surface drain/grade, IMO.

[Jim_in_PA]

It’s very good to get the soil analysis done for a variety of reasons, but it’s also a “best practice” in most cases to still prepare a good base with geo-textile (to prevent soil migration up into the arena) and then an appropriate compacted base before final footing. In many cases, good drainage can be assured at the point that the compacted base is being installed so that water will flow through and out properly so it doesn’t pool under the footing. Installing an arena functionally isn’t much different than installing a well designed driveway with the expectation of a little more consistency due to intended use.

[goldenrow]

If you have an iPhone, or access to one, download the SoilWeb app. It will give you the soil profile for the spot where you stand (I think I was told within 20 meters?). Pretty fun to walk around the farm with it!

We did field tile, as we hook up with a tile line about 50 feet out from the arena. I can’t say we have much tile clogging around here, unless it is under an alfalfa field and the roots get into it.

I think if you have yellow gravel, you might have some limestone around. It really is a super base. I did not do a material down, but we hauled in quite a bit, and it was well sifted.

I think waiting until late summer/fall is a good idea, but make sure that you have everything in order when you start, so the process is quick.

When there is little to no rain in the forecast:
Level and tile the outside, let it settle. Sprinkle with water or light rain, then let it bake in the July sun for several days.

Put down base - light sprinkles everyday, with afternoon baking, until firm.

Cover with sand before first big rain - or you’ll be starting over. If it nearly impossible to patch base areas.

[winter]

We removed most of the topsoil then built the base with packed gravel. The same as a road base. Started with pit run then with slightly smaller, then filled and packed then footing. We had to do the soil work to make it level, but I think you could easily build on top of the soil as you describe if you already have a level space.