There are several great backyard waterfall ideas. One example of great backyard waterfall ideas is sloping waterfall. Consider a gradually sloping waterfall at the head of a riverbed for backyards that have a natural slope. The winding riverbed can disappear into the woods or blend into your landscape. The height of the waterfall can be as low as 2 to 3 feet at the beginning of a gradual slope that stretches into river rocks lining the riverbed. The river rocks will partially cover the reservoir at the base of the waterfall. You can purchase a preformed foundation for your waterfall, or you can build it with large stones to match the river rock. The water from the falls will not feed down the riverbed; it will be recycled back up the waterfall by a pump and plastic tubing. Rainwater will collect and run down the riverbed, making it a beautiful solution to drainage problems in the backyard. The trench for the riverbed can be shallow but should have a noticeable dip when the rocks are in place. Line the trench with plastic pond liner before you cover it with rock to make the riverbed.