|I have a slope backyard and a drain way across in the middle of the yard.
|I think a curtain drain at strategic places will help redirect the excessive runoff so the bricks are not undermined. A curtain or French drain is simply a gravel-filled trench. The advantages of French drains are low cost and easy installation. In addition, they can be covered over with turf, groundcover or even rocks after installation, making them less conspicuous. A French drain starts with digging a trench. The depth and width of the trench can vary, but 5 to 6 inches wide and 8 to 12 inches deep are common sizes and usually satisfy most needs. Add gravel to the trench to within a few inches of the surface. Gravel for this use is typically 0.5 to 1 inch in size. On top of the gravel, lay at least 3 or 4 inches of coarse sand. Then set your bricks. This should work to stop erosion on the slope.|