The Zumbro Parkway Bridge is historically significant as an excellent example of a stone-faced, Multi-Plate, arch highway bridge. Multi-Plate is a type of decorative modular construction often employed on New Deal, work-relief, bridge projects.
Multi-Plate is a galvanized, corrugated-iron product that is fabricated in curved segments so that individual pieces can be bolted together in the field to form a load-bearing arch. Multi-Plate was introduced by the Armco Culvert Manufacturer's Association in 1931, as a replacement for prefabricated corrugated-iron pipe, which had been used in culverts since the 1890s. Although corrugated-iron pipe was durable, its prefabricated lengths were difficult to handle in the field. Multi-Plate alleviated this problem with its built-up modular design, permitting the construction of larger spans with thicker gauge. Although Multi-Plate's chief application was backfilled culverts, Armco also aggressively marketed a low-cost bridge design using Multi-Plate arches for spans up to 30 feet. To prevent undermining and shifting of the structure, the arch generally was anchored to concrete abutments and headwalls. When decorative stone facing was used on the headwalls, the bridge took on the appearance of a stone-arch bridge, which strongly appealed to the New Deal agenda of encouraging roadside beautification, local craft skills and labor-intensive public works projects.
In Minnesota, approximately 35 Multi-Plate stone-arch bridges survive from the New Deal era. Designed for the WPA by J.M. Evans, who apparently was an engineer with the Wabasha County Highway Department, the Zumbro Parkway Bridge is one of the finest examples of its type. The quality of its stonework and the visual interest of its Gothic Revival design were recognized by its New Deal sponsors. When the Works Progress Administration (WPA) of Minnesota showcased its achievements with WPA Accomplishments in 1939, the book's "highway section" included photographs of only two stone-faced Multi-Plate bridges, a triple-arch structure in Whitewater State Park, which has been demolished, and the double-arch Zumbro Parkway Bridge. The bridge has not been significantly altered since its completion in 1937. The structure's historic name is based on the caption in the WPA book.