The USGA has prepared three holes on Merion's West Course to deputise if storms disrupt the US Open.
The 11th, 12th and 4th are all prone to flooding and the report, published by Golf Digest, has revealed the governing body has long discussed potential US Open weather issues.
Torrential weather hit Ardmore on Friday, with the remnants of Tropical Storm Andrea leaving more that three inches of rain in its wake.
Merion itself had an estimated six inches in certain parts of the course, particularly the 11th green.
The 12th is also susceptible to major leaks, with both holes sitting in the lowest-lying area of the property. There have been overflows of water before and Arron McCurdy, the golf course superintendent, was in disarray following the downpour.
"It was six inches from flooding over the top of the green," McCurdy told Golf Course Superintendent Association of America's website. "We ordered six emergency loads of bunker sand and will get after it in the morning."
Rain is only expected on Thursday afternoon according to the current 5-day forecasts and the USGA will be desperate for a smooth US Open without any disruption.
