It usually is in PA, USA - because local ordinances usually require it. But I have never been able to figure out why. Most dry ponds are 6 feet deep or less and drain within 24 hours of being filled. I don't know when or why piping is supposed to occur, but apparently someone thinks it will.
Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve
