The sinkhole on number 6 at The National Golf Club of Kansas City. Photos courtesy of Brayden Schweizer
Most superintendents and assistants know that when you get a call from your golf shop during your time off, it’s typically not good news. On August 13, 2023, I received a call from the clubhouse claiming the number six green was “caving in.” Luckily, I was playing on the course that day. Not knowing exactly what they meant, I rushed over to the hole in question.
When I got to the green, it was in fact caving in. There was a 15-foot-wide hole with heavy flowing waters going through the bottom, and a busted irrigation line at the top. We isolated the irrigation line and began to assess what had happened.
The hole was directly over a drain culvert that received overflow from the pond. One can only speculate exactly what caused it to collapse on itself, but just two hours prior it had rained over four inches. We concluded a possible crack or hole in the pipe was amplified from the amount of rain before collapsing. Whatever the cause, we still had a big issue on our hands and a lot to figure out.
The repair of number 6 in progress.
The next day we began to figure out next steps. We contacted a company and asked for help to restructure the 6 ft. diameter drainpipe that collapsed, as well as the entire green. They started by digging out the crushed pipe. After the new pipe was shipped, they installed it and began packing the soil back around it. Due to the size of the hole, we decided it was best to rebuild the entire green instead of just the specific area that had fallen in.
Once the pipe was fixed, it was time to start rebuilding the green. Viridity, the landscape construction company we worked with, did a great job handling most of the work of putting down the soil mixture and shaping it with our assistance. Once the new soil was down, we put down our soil amendment at 150lbs/1,000sq ft., with a total of 1,100 lbs of soil amendment before laying the sod.
the repaired number 6 hole.
On October 24, 2023, we were finally able to lay the sod for our new green. After laying the sod, we put 100 lbs. of fertilizer on top and let the rain that night, water it in. Luckily, even though we sodded late in the year, the next two to three weeks were warm enough to leave the sod uncovered. Once the temperature dropped, we used a turf blanket to cover the green to allow the green to continue to grow during the winter months, leaving it uncovering on the few days it was warm enough.
By the end of March, hole number six was back open for our membership to play, looking like the best green on the course. The green is not back to the desired firmness level, but hopefully that will come with time. We saw the project as a big success.
Brayden Schweizer is an assistant superintendent at the National Golf Club of Kansas City and a 1-year GCSAA member.