Kinnick Stadium Field Replacement
Heavy showers before a football game would completely overwhelm the drainage system at Kinnick Stadium. The field drainage system was badly in need of upgrading or repair due to subbase pipe collapsing so the university analyzed options to solve this problem and also upgrade the field turf.
The University decided to upgrade the field drainage system and replace the existing sand-based natural grass field with new synthetic turf provided by FieldTurf. But the University wished to keep future options open. The field base was designed to accommodate constructing a sand-based natural turf at some point in the future while still providing adequate drainage and a solid base for the synthetic turf. The drainage design consists of 1"x12" flat drainage panels laid out in a herringbone pattern at 15' centers. A wedge of a minimum of 2" USGA graded gravel was placed over the drainage panels with another 5" of USGA graded sand bridging over the gravel. Finally an additional 5" of specially graded free draining rock was placed over the sand directly beneath the synthetic turf.
One of the advantages of using the FieldTurf artificial turf system is that it is very porous and can drain and dry very quickly after a rain event (up to 20 inches of rain in an hour). This is very important for Kinnick Stadium as the field is well below the street elevation and is served by a storm sewer system that was installed when the stadium was built in the 1930s and is undersized for large storm events. Once the major storm flows have escaped Kinnick Stadium, the FieldTurf system will dry out quickly and be ready for action – a significant difference and improvement when compared to natural turf systems. The flexible and careful planning for the project allows for future adaptations to the field as necessary.