Sunday, September 5, 2021

Bound Brook, NJ: NJ Transit Train vs. Flood Gates and Definition of 100-Year Flood

(Satellite)

It appears as though should have put those signals a few feet further west so that the train stops outside of the gates!
Walter Borys posted
Amazing piece of engineering (misengineering?) In Bound Brook, NJ on Sept 2. Remnants of hurricane IDA caused 100 year flooding in this river-bound community. Since 100 yr flooding seems to occur every 20 years, flood gates were built in several low-lying areas, including a rail right of way.
Somehow no one anticipated that there may be trains stuck on the tracks. Neither town nor NJ Transit published any details or comments about this snafu so far...
Kelly Sandford Glover: The folks stranded in those rail cars were some of the last to be rescued, even though first responders knew their predicament. Though afraid and very uncomfortable, it was determined that the commuters were high, dry, and safe.
Walter Borys
[12 hours later]: Finally, 'official' word on what happened, from NJTransit. Around 9:30PM Wednesday, the in-service train got surrounded by surging flood water and debris. it had to stop, and couldn't back up, since it couldn't see the condition of the track behind it. Unfortunately, it stopped in the middle of the flood gate closure area. Local officials decided a little later to close the flood gates, but NJT could not move the train.
James McMillan: The legal definition of "100 year flood" is, in a given year, it has a 1% chance of occurring. Not that, in fact, it's only expected to occur only once in 100 years.
Steve Russo: James McMillan And in that definition, is the actual amount of rainfall and stream flow of so many thousands of cubic feet per second. "100 year flood" is just a term that is used by Meteorologist, climatologists, and Hydrology people, but not really what it sounds like. Just like Astronauts using the term "zero-Gravity", when there is no such thing as Zero gravity". (Along with being a professional in the meteorology field, I am also a professional Astronomer and Space Scientist).
Mark Wallace: James McMillan & Steve Russo: Respectfully disagree. Your definition is used by insurance risk managers and in some legal circles. That is not the USDA or USG definitions hard wired into so many zoning or land-development codes throughout my state (PA) and adjacent states. For the last 45 yrs, I have designed with civil engineers and landscape architects, successful storm-water management systems that held up in Ida's passage on Wednesday based on recorded statistical criteria. Rainfall criteria from a storm is not based on probability but rather is based on actual, comparative, published records sometimes going back 175 to now 200 yrs. These include river heights and amounts of rainfall in 24 hrs down to one (1) hour discharges as maintained by our local Soils Conservation Districts, State Environmental Depts, Highway dept., USG and others. What is happening due to climate changes; the 10 yr and 25 yrs storms are now occurring every 1 or 2 yrs! I've seen two 50 yr storms in 1972 & 2011. The Ida remnants rainfall amounts were impressive and in fact exceeded the 7.8 inch amount in 24 hrs, putting it squarely in the 100 yr territory for my community. Based on climate changes I would never, since hearing the "probability definition," ever gamble using those odds.


So why didn't they send a supervisor out to the back of the train and allow the engineer to use his cell phone to call him to get eyes at the back of the train? Sometimes managers need to use some common sense rather than just quote the rule book.

I had trouble finding the satellite image because I was looking for tracks going across a river. Then I realized that Middle Brook became a river during the flash flood. 

This route was used by Lehigh Valley and Reading Railroads. It is evidently now owned by NJ Transit.
1955 Bound Brook Quadrangle @ 1:24,000

Street View





No comments:

Post a Comment