Questions About Swales Pt1

I live in Hunt County, Texas (about 1 hour East of Dallas). I'm still in the planning process and want to get the water situation under control before I plant anything. We get great rainfall but the dry season can be very brutal. After watching several permaculture videos I'm thinking that swales is going to be a good solution.

My questions:

1. In our area, we have a lot of clay in our soil, so much so that the septic contractor said I'd need a leach field probably about 4000 sq ft. Are swales feasible in such heavy clay soil?

2. We have a big West Nile problem here in the Dallas area. We've had quite a few deaths here and so I was wondering if filling in the swales with rocks or mulch or something would eliminate the risk of mosquitoes?

3. What is a safe minimum distance from a house to have a swale to prevent the water from making it way under the house and causing foundation or other issues?

I have some more questions, but I'll wait until the next post. Any help is much appreciated!

If your clay dries out, and growing on top of it is like growing on concrete, then yes, maybe a swale will help. But if you are in flat country (and it seems to me East Texas is pretty flat), then it's not so much catching runoff and holding it that is the problem, but the amount of organic matter in the soil. I've been fighting compacted clay soil for four years now, and I am slowly getting the upper hand. I'm not doing it with swales, but by incorporating lots of organic matter. In the wet winter months, the clay is saturated and you can dig down a foot and it takes quite a while for water to drain out. In the summer, if we get a long dry spell, the clay turns to adobe and it's very difficult for roots to penetrate.

How long do low spots by the side of the road hold water after a heavy rainstorm? If it's only a couple of days, then the mosquitoes are breeding someplace else, like a real wetland. If you dig a swale that is a couple of feet deep, I would be surprised if it held water for more than a couple of days. If it does stay saturated, then your house was built on a wetland, and you need to think of how to get some better drainage, like putting in a French drain. If you are worried about your house and the drainage around it, put in a French drain. I did, and I'm glad I did after this very, very wet summer we have had.

But back to the clay. The best thing you can do with your clay is to work in more organic matter. Usually permaculture is more in keeping with no-till, but an exception can be made for compacted clay. I would suggest spreading 4"-6" of wood chips and then disking or roto-tilling it in. Tree trimming services in your area are probably looking for places to empty their dump trucks, so let them know they are welcome at your place.

Another thing that can help is to work in some gypsum. This can be done for free (well, just the cost of your own labor) if you collect up all the drywall scraps at a building site and leave them out over the area you are working on. After a few months out in the elements, the paper rots off and the drywall starts to crumble. At that stage, it works in pretty well when you go over it with the rototiller.

How much overburden do you have to work with on top of your clay? I have between 6"-10" here.

If you have slope, swales work well. Keyline in-between the swales. If you don't have enough slope for swales, try just keyline ripping.

Seed a cover crop mix with lots of rootcrop and legume (oats, peas, tillage radish, and clover for example). They will put carbon down into the soil and loosen the clay. Keyline mechanically decompacts and causes root die-back that injects carbon and stimulates more root development.

The key to mosquito control is larger bodies of consistent water. Frogs and fish will take care of the mosquitoes. My swales are LOUD with frogs.

John Elliott wrote:If your clay dries out, and growing on top of it is like growing on concrete, then yes, maybe a swale will help. But if you are in flat country (and it seems to me East Texas is pretty flat), then it's not so much catching runoff and holding it that is the problem, but the amount of organic matter in the soil. I've been fighting compacted clay soil for four years now, and I am slowly getting the upper hand. I'm not doing it with swales, but by incorporating lots of organic matter. In the wet winter months, the clay is saturated and you can dig down a foot and it takes quite a while for water to drain out. In the summer, if we get a long dry spell, the clay turns to adobe and it's very difficult for roots to penetrate.

How long do low spots by the side of the road hold water after a heavy rainstorm? If it's only a couple of days, then the mosquitoes are breeding someplace else, like a real wetland. If you dig a swale that is a couple of feet deep, I would be surprised if it held water for more than a couple of days. If it does stay saturated, then your house was built on a wetland, and you need to think of how to get some better drainage, like putting in a French drain. If you are worried about your house and the drainage around it, put in a French drain. I did, and I'm glad I did after this very, very wet summer we have had.

But back to the clay. The best thing you can do with your clay is to work in more organic matter. Usually permaculture is more in keeping with no-till, but an exception can be made for compacted clay. I would suggest spreading 4"-6" of wood chips and then disking or roto-tilling it in. Tree trimming services in your area are probably looking for places to empty their dump trucks, so let them know they are welcome at your place.

Another thing that can help is to work in some gypsum. This can be done for free (well, just the cost of your own labor) if you collect up all the drywall scraps at a building site and leave them out over the area you are working on. After a few months out in the elements, the paper rots off and the drywall starts to crumble. At that stage, it works in pretty well when you go over it with the rototiller.

How much overburden do you have to work with on top of your clay? I have between 6"-10" here.

My land is indeed flat. From the high point on my land it drops about 8 ft over about 600 ft.

As far as how long the low points by the side of the road hold water, that's something I haven't really paid attention to. I'm only on my land a few days per month. I'll definitely pay closer attention now that you mention it. French drains around my house are definitely in my plan (i own a seamless gutters and french drain business).

As for organic matter, that's in my plans too. I've been watching Geoff Lawton's videos and hope to model my farm around his ideas and he includes a lot of organic mater into his soil. When you say to till the ground, is that something that should be done indefinitely? I was under the impression that the soil would build itself and turning the soil would not be needed after its been built up.

R Scott wrote:If you have slope, swales work well. Keyline in-between the swales. If you don't have enough slope for swales, try just keyline ripping.

Seed a cover crop mix with lots of rootcrop and legume (oats, peas, tillage radish, and clover for example). They will put carbon down into the soil and loosen the clay. Keyline mechanically decompacts and causes root die-back that injects carbon and stimulates more root development.

The key to mosquito control is larger bodies of consistent water. Frogs and fish will take care of the mosquitoes. My swales are LOUD with frogs.

My land is definitely flat. I've heard the term keyline a few times, but hadn't explored it in depth, but certainly will now. Thanks for the advice. It's much needed at this point

R Scott wrote:If you have slope, swales work well. Keyline in-between the swales. If you don't have enough slope for swales, try just keyline ripping.

Seed a cover crop mix with lots of rootcrop and legume (oats, peas, tillage radish, and clover for example). They will put carbon down into the soil and loosen the clay. Keyline mechanically decompacts and causes root die-back that injects carbon and stimulates more root development.

The key to mosquito control is larger bodies of consistent water. Frogs and fish will take care of the mosquitoes. My swales are LOUD with frogs.

I tried searching for information on keyline ripping but couldn't find anything. Can you direct me to a site that explains it or perhaps explain to me what the concept is?

Brandon Griffin wrote:

As for organic matter, that's in my plans too. I've been watching Geoff Lawton's videos and hope to model my farm around his ideas and he includes a lot of organic mater into his soil. When you say to till the ground, is that something that should be done indefinitely? I was under the impression that the soil would build itself and turning the soil would not be needed after its been built up.

Tilling is disturbing the soil and should only be done for good reason. Back in the days when tilling meant plowing with a team of oxen once a year, that was little enough disturbance that it could be justified. These days it means ripping up the soil a foot or more deep and exposing it to the sun to dry out, and it is greatly overdone. If your land is compacted dirt on top of clay, tilling in a few inches of wood chips will help build the soil a lot faster than waiting for Nature to build it. Here in the sub-tropical South, organic matter decomposes quickly, and if you just pile decaying vegetation on top of compacted dirt, it is often the case that the vegetation decays away faster than the soil life can incorporate the organic matter into the soil.

Eight feet over 600' is hardly worth considering putting in a swale. A couple of built up berms here and there, or a series of parallel hugel beds is going to give you all the catchment you will need or use. The only reason you would need to dig would be to have some dirt to put on top of the hugel beds. When I build one, I dig down to the bed clay about a foot down and then I mix in some sand and biochar before I cover all the organic matter.

How much of your property is woods as opposed to open fields? The open fields, especially if they have had a lot of equipment traffic over the years, may be quite compacted. If it is oaks and pines, then there is more soil-loosening activity going on, plus mulching from the leaf fall, and it shouldn't be as bad. I have an on-going project to move biomass from my wooded areas over to the open areas and work it in so that it can build the soil. I'm fortunate to have neighbors that have wooded areas with lots of fallen branches, and they are glad to have me come by and clean it out on occasion.

The soil does build itself, but the soil in my garden has needed and still needs a lot of help. I think I have turned in enough wood chips that I can give up the tillage and rely on surface mulching from here on out. One sign that you have arrived is when the area supports a healthy crop of mushrooms after a heavy rain. I still have a lot more mushrooms that pop up in the woods than in the garden, so I know it's still a work in progress.

check out the earthworks forum here for lots of keyline discussion. Here are a couple threads to get you started, make sure to watch the linked videos.

https://permies.com/t/22381/earthworks/Darren-Doherty-keyline-expert-instructor#185023

https://permies.com/t/21884/earthworks/Darren-Doherty-Youtube-Keyline-beach#179898

https://permies.com/t/22469/earthworks/Agriplow-keyline#184355

R Scott wrote:check out the earthworks forum here for lots of keyline discussion. Here are a couple threads to get you started, make sure to watch the linked videos.

https://permies.com/t/22381/earthworks/Darren-Doherty-keyline-expert-instructor#185023

https://permies.com/t/21884/earthworks/Darren-Doherty-Youtube-Keyline-beach#179898

https://permies.com/t/22469/earthworks/Agriplow-keyline#184355

Thanks for the links. I've only watched the first 3 videos but so far it very much looks like it's for sloped land.

Just make sure both the swale and the swale mound are uncompacted.

Also, I think Jack Spirko is doing an earthworks workshop in Texas (or maybe Louisiana) but not sure how close that is to you:
http://www.thesurvivalpodcast.com/earthworks-nick-and-nick

Jack actually did a workshop in May. This thread from his forums has some good pics:
http://thesurvivalpodcast.com/forum/index.php?topic=43428.0

Brandon - how much land are we talking here?

Also - if you haven't read Brad Lancaster's books "Water Harvesting for Drylands and Beyond, Vol 1 and 2" you're probably going to want to get them.

In volume 2 p. 42 he has a convenient chart of types of water harvesting earthworks and under which situations they are used.

My questions:

1. In our area, we have a lot of clay in our soil, so much so that the septic contractor said I'd need a leach field probably about 4000 sq ft. Are swales feasible in such heavy clay soil?

2. We have a big West Nile problem here in the Dallas area. We've had quite a few deaths here and so I was wondering if filling in the swales with rocks or mulch or something would eliminate the risk of mosquitoes?

3. What is a safe minimum distance from a house to have a swale to prevent the water from making it way under the house and causing foundation or other issues?

1 and 2. Yes - we have heavy clay in Phoenix and Tucson (and West Nile issues too!) and use swales on sloped land and infiltration basins on flat land. Test your perk rate. Also, as was mentioned by John, fill with mulch from area tree trimmers.

Not sure about the safe minimum distance but I know both Brad Lancaster and Geoff Lawton advise diversion swales to keep water from around the house. However, if you are on flat land, simply make sure you grade AWAY from the house (house at highest point). I would also check with Ag Ext. in your area about the stability of your soils. I know where I'm at, in the historic alluvial flood plain of the Salt River, our clay soils can get a little unstable under certain situations. Because dryland soils are complex, your local Ag Ext would best be able to help you with that.