How do you capture surface water when your catch basin sits deep in the ground? You give it a boost with the catch basin riser. Extend your 24 in. Square Catch Basin Drain by adding up to 8 in. of height to reach the surface with the 8 in. Riser. Easily customize to the right height by cutting to size, and fits right on top of the basin. Accommodates a 24 in. catch basin drain grate on top, no adjustments necessary. Made of polyethylene treated with UV inhibitors.