Bulldozer Digging Swales
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.
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.
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.
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.
Toward leaving the planet in better condition… Bill Wilson – Midwest Permaculture