With nearly 50 miles of city-owned retaining walls and some of the most dynamic hillsides anywhere, Cincinnati's undulating terrain presents an ongoing challenge to the technical staff of the Structures Section. The local geology and past development practices have left many miles of roadway affected by hillside movement. The goals of the retaining wall and landslide stabilization program are to bring all existing walls into good condition and stabilize landslides that impact the City's roadways. By inspecting each city wall on a five-year cycle, the wall group can effectively prioritize the needs for retaining wall replacement or rehabilitation. Input from the city's engineering geologist and geotechnical consultants give wall designers critical information needed to arrest landslides before city streets and utilities suffer serious damage. The wall and landslide program's annual infusion of capital funds is carefully allocated to meet the most urgent needs for wall construction and landslide correction.

Wall and Landslide Program - Historical Perspective

The city's engineering staff has been well acquainted with landslides for some time, as the following excerpt from the Chief Engineer's annual report to the Board of Public Works illustrates:

LAND SLIDES

These constitute the most difficult feature of engineering practice in this locality. They are due entirely to the action of seepage water upon the blue clay that abounds in this formation.

Three different remedies are employed for this evil: The first (which naturally suggests itself), is to remove the cause of the evil, viz., the water. Second, To sustain the mass of sliding earth by a wall. Third, To entirely remove the sliding mass.

Sometimes a combination of two or all of these measures is found advisable, i.e., a portion of the earth is removed, the remainder under-drained and further secured by a retaining wall.

Whenever drainage is necessary, it should be done at the very beginning of the improvement, otherwise the total cost will be greatly increased. The expenditure of a few hundreds of dollars in properly draining ground at the outset may save thousands in the end. It may even happen that the patching up and securing a sliding embankment will involve an outlay greater than the first cost of the fill. The numerous land slides and ruined retaining walls about Cincinnati, furnish us many illustrations of the old adage that "an ounce of preventive is worth a pound of cure."

-Excerpt of annual report submitted by Colonel A.L. Anderson, Chief Engineer, Engineering Department, to the Board of Public Works, January 1, 1877.

Thirty years later, Chief Engineer C.N. Danenhower felt compelled by the magnitude of the landslide problem in the city to include a list of landslide sites in his annual report to the Board of Public Service. Cincinnati landslide mavens will recognize several of the street names:

LAND SLIDES

Attention is called to the great number of landslides that has occurred in the various parts of the city, notably in the First Ward, Columbia Avenue [now Columbia Parkway] and Golden Avenue; Second Ward, Columbia Avenue [Columbia Parkway]; Third Ward, Alpine Place; Fourth Ward, Russell Street [Elsinore Place], East Sixth Street [Van Meter Street], and Gilbert Avenue; Tenth Ward, Rice Street, Mulberry Street, and Baltimore Street [Goethe Street]; Eleventh Ward, McMicken Avenue and Straight Street; Thirteenth Ward, Middleton Street [Middleton Avenue] and Dixmyth Avenue; Nineteenth Ward, West Sixth Street [River Road], Elberon Avenue, Kineon Avenue [Bowman Avenue], and Glenway Avenue; Twentieth Ward, Warsaw Avenue; Twenty-third Ward, Clifton Avenue, Fairview Avenue [Chickering Avenue] and Edgewood Avenue [North Edgewood Avenue]; Twenty-fourth Ward, Baltimore Avenue and Western Avenue [Beekman Street]. The same are the result of hillsides sliding into the streets, which can be readily removed by excavation and teams; others, which are more serious, are the slipping away of streets on fills. To restore the same will require the construction of retaining-walls and the reconstruction of streets. There is needed at this time, roughly estimated, about $150,000 to properly take care of the various slides.

-Excerpt of annual report submitted by C.N. Danenhower, Chief Engineer, to the Board of Public Service, December 31, 1906.

Wall and Landslide Program - The First Ten Years (1989 - 1998)

Growing concern over the steady deterioration of the city's infrastructure led to the creation of a blue-panel committee in the mid-1980s to study the problem and recommend corrective measures. The Infrastructure Commission, headed by Procter and Gamble's Chairman of the Board John Smale, issued several recommendations, some of which evolved into the present-day wall and landslide program. Infrastructure Commission Recommendation No. 12 led to creation of an inventory of all city-owned retaining walls. In 1989, the City maintained 1,046 retaining walls with a total length of 34.3 miles. After the initial inspection in 1990, 86.6% of those walls were found in good condition. Between 1990 and 1998, the city devoted more than $14,000,000 of capital funds and over $3,000,000 of maintenance funds to retaining wall construction and landslide correction work, stabilizing over seven miles of the city right-of-way in the process. Meanwhile, inspection of walls in a percentage of the city's neighborhoods by city forces each year added previously unknown retaining walls to the inventory. The result: At the end of 1998, the percentage of the 1,399 known city-owned retaining walls reported in good condition leapt to 94%.

Wall and Landslide Program - The Past Year (1999)

• The Highway Maintenance Division completed work on the Straight Street wall in September. The work consisted of setting five precast concrete retaining wall sections, constructing a reinforced concrete foundation at the base of the precast concrete sections, and constructing a stone veneer in front of the precast concrete.

• The Highway Maintenance Division also constructed three low Keystone walls on Overcliff Road, Monitor Avenue and Gracely Drive.

• Wise Construction completed work on the Columbia Parkway Wall "D" tiedback drilled shaft wall.

• Trend Construction began work on a drilled shaft wall for a landslide correction on Lafayette Avenue in November.

• Baker Concrete Construction started construction of a geogrid-reinforced segmental retaining wall over one-half mile in length as part of the widening of River Road between Maryland Avenue and Mt. Echo Road.

Wall and Landslide Program - The Present Year (2000)

In addition to completion of the drilled shaft wall on Lafayette Avenue and the segmental retaining wall on River Road, the following capital projects are either underway or are planned for 2000:

Wall and Landslide Program - The Five-Year Plan (2001-2005)

The Department of Transportation and Engineering proposes to construct retaining walls, correct landslides or otherwise stabilize the city right-of-way at the following locations over the next five years: