SIGNIFICANT LANDSLIDES IN CINCINNATI, OHIO - THEIR INFLUENCE ON THE PASSAGE AND IMPLEMENTATION OF GRADING REGULATIONS AND STABILIZATION PROGRAMS

In their “National Landslide Hazard Mitigation Strategy”, the U.S. Geological Survey states that Cincinnati, Ohio is a leader in landslide loss reduction measures. The USGS cites the City's passage of its excavation and fill ordinance in 1974 and the creation of a geotechnical office in 1989 as reasons for their bestowment of this title. This status of “leader” only came after the occurrence of a numerous landslides several of which were instrumental in the development, passage and implementation of grading regulations and a stabilization program.

Landslides have been relatively common in Cincinnati, Ohio since at least the mid 1800's. Photographs as recent as 1930 and as far back as 1848 show barren hillsides, stripped of vegetation. Although written accounts of 19th Century landslides are sparse, landslide scars are clearly visible in historic photographs of the hillsides.

The first widely known published account of a landslide was Otto Von Schlichten's 1935 description of a massive landslide that occurred on the west side of Cincinnati in 1926. City transportation projects, such as Columbia Parkway and the Warsaw-Woldvogel Viaduct, initiated several large landslides throughout the 1930s, 40s and 50s. It was not until the mid 1960s, when private development began to surge uncontrollably onto the hillsides did City officials recognize the need for regulation to prevent unstable conditions.

The proposed regulations for hillside development were not without opposition and the initial enthusiasm soon waned during a period in which landsliding was relatively infrequent. Above normal precipitation in the spring of 1972 and 1973 initiated a dramatic increase in landslide activity and renewed interest in grading regulations. Significant landslide activity, including the Mt. Adams landslide triggered by excavation for I471 ramp construction, continued throughout 1973 and 1974. The occurrence of these landslides, spurred the passage of the Excavation and Fill Ordinance in October of 1974.

Continued landslide activity throughout the 1970s prompted the development of a Landslide Susceptibility Map in 1979. Emergency repairs of landslide, which disrupted the City's Infrastructure, was ongoing throughout the 1980s which resulted in the establishment of a geotechnical office and a landslide correction program in 1989.