Abstract: A cover for a storm drain collection box is formed usig falsework that includes a portion that is prefabricated and another portion that is constructed in-situ. The prefabricated portion of the falsework is used to form the throat section of the collection box inlet and can be mass produced under quality- and research-controlled conditions. The in-situ constructed portions of the falsework permit it to be modified according to the needs of the particular collection box. Alternatively, both the cover and the collection box can be precast for in-situ assembly.