Terrace or Swale?

Hello everyone,

I have not made time to visit many permaculture sites (physical) in my travels but am changing that.  I travel past this property on a regular basis and, in an effort to better understand swales, terraces, and keyline design, would like to know if the structures in the photos are considered swales or terraces.  They do not seem wide enough to "farm" with the conventional equipment around here, but seem too large to be considered swales from what I've researched on the internet.  While listening to Jack's Podcast The Survival Podcast I often hear him define swales as "a ditch on contour" which I could imagine these being.  Any help will be greatly appreciated. Thanks.

On closer look, I would say they are swales.

Thank you.  These formations cover a large amount of land here in central Nebraska.  We have water conservation districts and I just wonder if they may have been built as part of that program.

Swale
1) ditch mostly on contour to spread the flow of water horizontally,
2) overflow protection should be built so it is slightly off contour and overflow to the next one ,
3) can be on relatively flat land or on very hilly land
4) it can be a lone "ditch" or a series of ditch
5) A swale can be build on a tiny city lot or 1000s acre property, it can be found anywhere

Terrace
1) ditch mostly on contour to spread the flow of water horizontally,
2) overflow protection should be built so it is slightly off contour and overflow to the next one ,
3) Unlike the catch all "swale"  a terrace cannot be on flat land it has to be ditch/swale on hilly land
4) Unlike the catch all "swale"  a terrace is more specific in that it has to be quite a few ditches vs just a lone one
5) It is less likely that you will find a terrace on a city lot, on average the size of the land tends to be bigger

Keyline
1) ditch mostly on contour to spread the flow of water horizontally,
2) overflow protection should be built so it is slightly off contour and overflow to the next one ,
3) Like a Terrace, this "ditch that is mostly on contour"  has to be on hilly land, and it is even more specific in that it has to be at a inflection point of hilly land
4) Keyline can be singular or more than one ditch similar to swales, in practice there is usally quite a few keyline
5) These seem to be found on plot of land that is truly huge, where you are working at the scale of a huge hill/mountain so that an inflection point is very obvious

In my brain a terrace is a subset of Swales that can only exist on hilly land, and a keyline is a subset of terrace than can only happen at the inflection point on hilly land

I'd agree with Todd Parr. This looks swales for me. I also think that it was naturally form like that by nature. If it was used by the local water conservation district there then they have spent alot of time for that. Well it looks beautiful.

Those are man made swale and berm structures, very nicely built ones at that.
I'd love to see those right after a big rain event.

They look more like swales to me, but it's not clear cut.
Swales can be any scale, from tiny footpath (or smaller) swales, for instance in an urban garden, up to "the amazon" of swales which can have a berm of several meters in height and are fantastic in desert (arid) landscapes.
Given the apparent steepness in the photographs, I would also be tempted to say they are like terraces.
Swales are only really effective up to an 18degree slope - steeper would better suit terraces.
It should also be noted that trees are more or less an essential part of swales - they are tree/forest growing systems. Otherwise waterlogging can occur, and rainfall can be adversely effected in arid areas particularly.
...food for thought more than definitives I'm afraid.

We see many farms that have similar form to this in Missouri.  We would typically call it a Terrace.  As noted by S Bengi, there are a lot of similarities.  

You may also not see it on all farms but many have drain systems built into the ditches.  They bury drain pipe that then moves water away from the property during heavy rain events.  So rather than catching and holding the rain, they are used to move water away.

Typically the biggest reason why farmers want the water to go away a symptom of their poor soil management.  The soil in most row crop fields does not absorb water very quickly, or at all, thus causing large puddles that kill the crop.  

They look like terraces. Terraces are flatter and sloped toward the hillside to catch rainfall. Swales are dug into the ground and have berms and are deep in order to catch and harvest rain water. Terraces are usually farmed on and swales are used to capture rain water.