Another example of an inexpensive wall to support your waterfall is a pressure treated wood wall. The pressure treated wood will last longer than other lumber, and is a better alternative than the dwindling supply of redwood trees. When using pressure treated wood, it is important to wear gloves when handling, and proper ventilation masks and eye protection when cutting the material. Pressure treated wood is treated with chemicals to prevent decay, should not be inhaled, and hands should be washed.

A good support wall should have 4×4 posts set in a hole at least 18″ deep. Each post should be set no further than 4′ apart and each post should have 2 pieces of rebar driven down in the hole, and filled with concrete. Make sure the posts are level in all directions, and leave the posts to dry for at least one day. It is important to measure the posts properly to fit the desired length and width as well as the length of wood used. For instance, if you are using 8′ long pieces of lumber, make each post 4′ on center from each other. This will insure no wasted wood, and less labor and cuts.

After the posts are set its time to screw in the wood. Each piece of wood should be screwed into the post facing the front (waterfall side). The size of lumber that you use is really up to you, but I would recommend utilizing a 2x12x8′. This length is easy to use and makes for simple measuring.

After the wood is screwed into the posts it is important to attach landscape fabric to the wood that will be touching the soil, this will allow the wall to last even longer. Drainage is also an important factor in building these walls. Even though the support walls used for waterfalls will not be holding much weight, it is still important to have drainage.  Slowly fill the area next to the landscape fabric with 6″ wide of drain rock, all the way to the top. As you move in the drain rock tamp down the soil next to it all the way up to the desired height. After you have tamped down the soil for the waterfall, you are ready to build your water feature.