Water rushes through a downspout and into the yard under tremendous pressure that can wash away any soil in front of the spout. You can create a simple, homemade splash guard out of concrete that will protect your yard. Total labor time for the project is under 60 minutes, but the concrete will have to dry for at least a week before you can use it.
Pour 2 to 3 tablespoons of motor oil in the bottom of the pan and wipe it with a paper towel to coat the inside. Set the pan on a steady surface with a 1-inch-thick book under one end, tilting the pan up on that end.
Mix 3 pounds of the concrete with water in a 5-gallon plastic bucket until it has the consistency of peanut butter with no lumps. Pour enough concrete into the pan so that there is a 2-inch-thick layer at the end that is tilted up.
Work the concrete around in the pan with the trowel, similar to what you'd do with cake batter, to remove any air bubbles. Smooth out the surface with the trowel.
Decorate the concrete however you choose. Family handprints pressed into the wet concrete will always be a reminder of the day you made the splash guard. Glass beads, bits of a broken mirror with the sharp edges sanded off, smooth river rocks and other items pressed into the wet concrete allow you to make it a unique yard piece.
Cut away the aluminum pan after 24 hours. Let the splash guard season for a week and then set under the downspout, tilted so that the water drains into the yard after it has spent its energy against the concrete.