A backyard that has a steep slope can be a difficult place to relax or to grow a garden, and it can be dangerous to mow with a power mower. With the help of a contractor, some heavy machinery or some substantial muscle and time, you can remove the slope in your backyard and replace it with a more useful and attractive flat area. Whether you choose to do this yourself or hire someone else generally depends on whether you prefer to invest time or money in the project.
Fill in the Slope
Find a source of clean fill to dump in your backyard if you want to remove the slope by filling it in and creating a yard with an area that is all at the same height as the top of the slope.
Build a retaining wall around the lower perimeter of the yard. The top of the wall should be even with the high point of the sloped yard. The retaining wall can be built out of stone, logs, railroad ties or any other durable and rot-resistant material.
Lay a perforated pipe along the base of the wall on the side of the wall that will be filled in. Direct the end of the pipe to an area where water can drain without causing erosion. The potential of standing water exists where there is inadequate drainage.
Fill in the area behind the retaining wall to the level of the top of the slope.
Plant grass, ground cover or other plants that will help to hold the soil in place with their root systems.
Remove the Slope
Hire a backhoe or digger to remove the slope from your backyard by digging it out -- if you prefer to have a flat yard that is at the height of the lowest point of your slope.
Locate a person or company who will take your fill before you begin removing it. If it is clean topsoil, somebody may even pay you for it.
Build a retaining wall to an appropriate height after the slope has been removed, to keep the remaining soil in place. Install a drainage pipe beneath ground level just behind the retaining wall. Be sure the drainage pipe runs at a slight slope to facilitate the removal of water.
Import topsoil if the topsoil has all been removed during the excavation. If your sloped yard has quality topsoil on it, you may be able to scrape it off, then remove the slope, then put the topsoil back onto the newly flat yard.
Plant grass to keep the soil in place.
Split the Difference
Build a retaining wall across the center of the slope to create a two-tiered yard area that can be beautiful and offer opportunities for creative gardening. Put in a drainage pipe behind the wall and run it away from the yard to a location where it can drain away water harmlessly.
Dig out the lower area of the slope and use it as fill for the upper area.
Put in flower beds at the top of and in front of the central retaining wall.
Add an attractive and useful accent by including a small stairway at the center of the retaining wall to provide access between the upper and lower parts of the yard.