Last night, as I walked from my parents house to the subway, getting thoroughly drenched, I marveled at the water flooding over the curbs. It had been raining almost that hard for close to an hour, and what was running through my head was, what intensity of a rainstorm is this? A 25-yr event? 50? Or a measly 5? This is on my mind these days because I'm currently designing stormwater management plan for a project in Idaho, and yesterday's crazy storm made me question whether it could really handle that kind of rain.
So for reference, I checked out the National Weather Service and discovered it rained approximately 1.41" fell in an hour. My textbook tells me that this is around a 2-yr 60-min storm (amazingly, a 100-yr 60 minute storm would dump 2.75" of rain in a hour!). So no big deal really, but stormwater systems are supposed to be designed for 2-yr events and all the curbs were overflowing. Compared to Idaho, though, it was huge! A 100-yr 60-min storm only tops out at around 1", so I guess we'll never see anything like I did yesterday. Which is a relief, because I had visions of our swale eroding away and the golf course flooding and Jack Nicklaus yelling at me for ruining his putting green.
Oh, and on the matter of flooding, you would think the MTA would learn how to deal with a 2-yr storm. I mean, seriously, this will happen EVERY OTHER YEAR! I should have had to wait for the 1 train for 20 minutes before giving up and walking to the C, which was running on the express tracks to that I had to take the B and transfer at 59th St and all in all take at least 1 1/2 hrs to get from the Upper West Side to Brooklyn. The C tracks don't even go above ground! Bah.
Posted by dahl at August 11, 2006 9:40 AM