You need to add some cross braces between the legs or skin it in plywood to prevent racking. Otherwise it is likely to fail over time, especially with the lateral loads produced by the moving water.
RedEDGE2k1;686423 wrote: You need to add some cross braces between the legs or skin it in plywood to prevent racking. Otherwise it is likely to fail over time, especially with the lateral loads produced by the moving water.