That's crazy rainfall for Nederland. When the forecasts were calling for over 50" of rain in Houston before Harvey even made first landfall I thought they were just hyping things for ratings. Boy was I wrong!
Here's the rain gauge data from work which is a few miles from my house. Notice the over 15" rainfall in 3 hours Saturday night. This was during the fight so you had many people out at parties watching the fight and not at home to protect their pets, cars, etc from raising water.