Abstract: The present invention is directed to a retaining panel of one-piece construction for a body of water. A preferred embodiment of the retaining panel comprises a central portion, two side portions, and two flanges. The central portion has a first end and a second end. One side portion is integrally connected to and extends at a first angle from the first end of the central portion. Similarly, the other side portion is integrally connected to and extends at a second angle from the second end of the central portion. It is preferred that the first angle and the second angle are approximately equal. It is further preferred that the lengths of the first and second side portions are approximately equal. One flange is integrally connected to and extends at a third angle from a rear end of one side portion, and the other flange is integrally connected to and extends at a fourth angle from a rear end of the other side portion. It is preferred that the third and fourth angles are approximately equal.