Grate assembly

A drainage system grate assembly for covering a watercourse of a drainage system, the drainage system assembly comprising:

• a frame set within the watercourse;
• a grate set within the frame and including—
• at least one crossbar having a length, a width, and opposing ends, wherein the crossbar spans the watercourse alone the crossbar's length, and further wherein the crossbar is operable to be secured to the frame at each general end of the crossbar,
• a plurality of channels cut into each crossbar, thereby defining a plurality upstanding members located along the length of each crossbar, and
• a plurality of tread bars positioned between each upstanding member, such that the tread bars are supported by and positioned on top of the at least one crossbar;
• and
• at least one locking element, each of which is structurally separate from the frame and grate and of a rigid construction, such that each locking element is operable to interface with the frame so as to secure each crossbar to the frame.