Bulldozer Digging Swales

Bulldozer Digging Swales from Midwest Permaculture.

The Design

We had been invited by a family in Southern Missouri to assist with the design of a 320-acre farm. They want to transition the land into a Permaculture landscape capable of producing a wide range of perennial foods (nuts, vegetables, herbs, fruit, etc.) as well as livestock (beef and goats).

Over generations, rain has slowly degraded this sloping landscape with a loss of nutrients and topsoil. It is not uncommon for a million gallons of water to wash off this landscape with 1-inch of rain.

The owner has a priority of rebuilding the degraded topsoil so in the first phase of this design we will be putting in a series of swales and ponds across the entire landscape. This will allow the rains to soak deep into the earth while keeping the soluble nutrients right where they belong. Here is a cross section of the preliminary design strategy.

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The grassy areas between the linear food forests (hugging the swales) are for the grazing of livestock.

The Dozer

The owners had immediate access to a small bulldozer and since it was already October we all wanted to get a few swales cut into the landscape so we could observe how they function over the winter months. All of our experience has been with excavators, front-end loaders and shovels but it certainly made sense that a bulldozer could do this work as well.

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The Case 850E Bulldozer – 90 hp and 20,000 lbs.

This particular bulldozer is made by Case. It weights about 20,000 lbs. and has almost 90 hp (horse power). In comparison, the big units we see along the side of the road (when they are being built) or on building project sites are often the Catapillar D-9 dozers. The D-9 weighs in at 100,000 lbs. and has about 460 hp. That makes the D-9 about 5 times bigger than this little 850E. But by gosh… this little guy did the job.

The Cut

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This is what the swale looks like after the first pass.

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This is following the third pass. Throw in some clover seed and by spring it will be a green & lush swale.
What we Learned

This soil has a fair amount of rock in it and the ground was pretty dry. Consequently, the bulldozer could not take too big or too deep of a cut otherwise it stopped dead in its tracks and the blade needed to be pulled up to lessen the back-pressure to keep moving.

My sense is that for this landscape, a bulldozer about twice this size would be the better choice. This spring when the project resumes we’ll be looking for a 200 hp bulldozer.

We just wanted to share this information for those considering cutting-in swales with a bulldozer. We hope this will help you with your planning. Let us know how what kinds of success or challenges you have, should you try this as well.

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This Swale is Almost 300-Feet Long.

Toward leaving the planet in better condition… Bill Wilson – Midwest Permaculture

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6 thoughts on “Bulldozer Digging Swales

  1. Hi Bill. Nice project and great sharing of info. Thanks.

    Do you think the angle of the blade could have been slightly shallower such that the cut would have been wider, thereby getting a deeper cut overall after multiple passes? Hard to convey that in words, so I’ll try it another way just in case. With a bucket it’s more feasible to cut a more U-shaped swale. With the dozer it’s not, so might we need to change our thinking a bit to envision more of an angled-L shape instead? It looks like maybe by aiming for an approximation of a U shape, the best you could do with the blade was to cut a V shape, but that put a limit on the depth you could reach, it seems. A more angled-L-shaped cut (with the long leg pointing upslope and the short one forming the upslope face of the berm) might move more soil from the wider cut to the berm. I hope that’s understandable. Maybe others with experience have thoughts on that too.

  2. You are not going to see a lot of D9 dozers on construction projects where they are only needed for a few days or months – those are mostly used for mining or multi-year earth moving projects because they are too heavy to easily haul so they typically stay on a site for years. Anything bigger than a D5 needs a hauling permit for width and/or weight and D7s are the largest dozers that can easily be hauled. D6K blades exceed the 8.5′ maximum width but are under the 38,000 maximum weight limit for hauling without a permit (costs $500 for 1 year in Virginia). Pretty much anything bigger than a D7 needs special permits and dis-assembly to haul. You tend to see the big dozers on large mountain road projects — D11’s from the coal industry are being used to build a multi-year freeway project in Dickenson and Buchanan counties in Virginia.

    Note that CAT 312 or bigger excavators also need hauling permits due to their width and ~CAT 325’s are the largest that can be hauled easily without some dis-assembly or special permits.

  3. Great article Bill. As I think swales are a technique over used in the permaculture construction world. I have learned that good site analysis is very necessary. And context is everything. I have worked with all kinds and sizes of equipment doing earthworks. The dozer, no matter the size, moves a lot of earth. When using the Dozer for swales I have found me it best to use the blade to make an angled back cut on the first pass. The blade of small dozers are nice because you can construct a bench swale. Or ‘twale’ a trail and swale.
    When using equipment and gas to carve landscape it is especially important to stack as many functions as possible. More later….. Gotta go Keyline a farmers field.

  4. You can also use a grader blade mounted on the back of a tractor, its slower but can sometimes be cheaper then hiring a digger or dozer.

  5. Hi Bill,
    My farm is located in North-Central Missouri. Currently we are in the process of restoring a combination of hillside pasture and tilled acreage similar to your project but on soil with fewer rocks and a steeper overall grade portrayed in your photo. We are using a plow to cut and build the majority of the swale/berm structures per the recommendations of Mark Shepard.

    Because I only had a small garden tractor we began the project with a neighbor’s borrowed single bottom plow and achieved after two passes only slightly lesser depths than your dozer did in your photo. after two passes. I have access to a larger tractor now and will be reworking the swale we began in November with a 2-bottom plow to both widen and deepen the swale. Our sills are located at the edge of the of the hilltops where the water will gently sheet across what was previously the driest points of the field/pastures after pulling the water from what are now the highly eroded valleys.

    A dozer will be required to complete the valley drive through ponds and the locations where a small dam/pond structure will be required. The tractor/plow work would appear to be at least, if nor more effective at creating the swale cut and less compacting on the heavy clay soils of Missouri while also saving the landowner money in hired dozer hours. Our first swale is pitched 0.025% downhill off level of the contour after choosing the keypoint. I would approximate at over 2000 feet in length extending through two pastures and one previous tilled field. The plan is to parallel another swale/berm, structure approx. 24 feet below the original, again using the plow as the main earth sculpting tool and limited dozer work for the valley drive through ponds and dams. This width will allow for the planting and maturing of a food forest while utilizing the row areas for a combination of pasture grazing, hay harvesting, and/or or row crop.

    The initial goal is to capture the water eroding the valleys and redistribute it while cross the landscape while also driving it into the soil as a “bank”. For the heavy Missouri soil I see this as not requiring mammoth swale/berm construction in regard to depth, width and height in order to hold water as much as the usefulness and highly effective installation of a smaller, more economical build using both the plow and the smaller dozer given our state’s historical average of at least 40″ rain/yr.. In my opinion, I do not believe given Missouri’s clay and the rock in Southern Missouri that by up-scaling the size of the bulldozer that you are going to find that one machine is going to fit all your needs for this client’s project.

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