A recent assessment of three sinkholes that have appeared in Stadium Bowl has discovered failures in the underground drainage system, according to geotechnical engineers who investigated the sites this week.
As a result, Tacoma Public Schools has closed Stadium Bowl temporarily to all access and use for the safety of the public and student athletes. Additional engineering tests next week will determine whether a contractor can repair and fill the sinkhole areas in time for the first football game there Sept. 11 or whether the damage will require more extensive repairs and a longer closure.
Meanwhile, the district’s athletic director already has rescheduled football, girls soccer and other practices and community uses to other locations.
The district called in technical experts from GeoEngineers after a small depression appeared Aug. 21 on the football field on the 15-yard-line nearest Commencement Bay. The district closed the Stadium Bowl field that day as a precautionary measure, pending the more detailed technical investigation. Gates will remain locked. Signs announcing the field closure hang from the gates.
Earlier this week GeoEngineers reviewed Ground Penetrating Radar (GPR) images, drainage maps and the long history of past damage and failures at Stadium Bowl since it opened in 1910 with seating for 32,000. In addition, the district hired a contractor this week to clean out debris from the sink holes – including one on the track and one near a catch basin – so GeoEngineers could examine exposed drain pipes.
The assessment indicated that the drainage system – a combination of the original 1910-era drain pipes and more modern drain pipes tied together – failed in multiple areas. Gravel and sand washed away through the drain pipes.
Next week, a team including the district, field turf company, engineers and a contractor will cut back the turf and probe additional areas where the GPR indicated potential anomalies.
To prepare in case the bowl will require an extended closure, the district’s athletic department has begun work on a district-wide master event schedule as if Stadium Bowl didn’t exist. That would require rescheduling and reprioritizing many events across the district.
Last November, an intense rainstorm combined with clogged storm drains uphill from Stadium Bowl caused massive flooding that covered the bowl, washed away dirt from the bowl hillside and spread dirt and debris all across the field. The bowl was closed for an extensive cleanup.
In 2008, ESPN ranked Stadium Bowl the 11th best stadium for football in the country.