NY STORM SURGE HAZARD EXERCISE

General Instructions: When completed, the table shown below will provide a basis for comparison of conclusions about storm surge hazard for NYC reached by two major organizations. In the left column of the table are conclusions reached by the NASA-Goddard Institute (taken from the article you read entitled "Rising Seas: A View From New York City"). In the right column, when you fill in the spaces, will be found conclusions based upon information provided by the Army Corps of Engineers for Lower Manhattan Site 3.

What you need to do:

Print out these instructions.
Print out the Storm Surge Comparison Table Worksheet D-3B.
Click on the grey button and go to the 'Storm Surge Flooding in NYC' web page.
On the NYC map, click on red-bordered box labeled Lower Manhattan.
On the map of Lower Manhattan, click on Data Point 3.
Examine the 'Lower Manhattan Site 3' graph and the contour map of Lower Manhattan.
Use the information you find to fill in the seven blank spaces in the Storm Surge Comparison Table Worksheet D-3B marked with an asterisk (*).
For help, click on the four button links provided in the Storm Surge Comparison Table shown below.
Check your answers using the Answer Check:

STORM SURGE COMPARISON TABLE

According to the NASA-Goddard study:

According to the Army Corps of Engineers (ACE) study for Manhattan Site 3:

Right now, a '100-year flood' could inundate areas of NYC whose elevation is less than 10 feet.

For Site 3, right now areas less than what elevation would be inundated by a 100-year flood?
Less than *______ feet (to the nearest tenth of a foot).

On the basis of the above information, indicate which organization (NASA-Goddard or ACE) predicts more damaging consequences if a 100-year flood took place tomorrow:

*_______________

By the 2080s, in a worst case scenario (in which sea level rises by nearly 3.6 feet for some NYC coasts), those areas that now would be inundated by a 100-year flood (that is, a flood with a recurrence interval = 100 years) instead could be flooded (on average) every four years. That is, by the 2080s, a line that marks the floodwater limits for what is now a 100-year flood, would mark the limits of a four-year flood.

Remember that when a storm surge occurs, the rise in water level is always added to whatever is the sea level at that time. Thus, in the future, for example, if sea level rises by 2 feet, then a 10 foot storm surge would inundate areas that today have elevations up to 12 feet.

Assume that by the 2080s, sea level rises by nearly 3.6 feet. By how many feet would a storm surge have to raise the level of the water to flood areas that today are less than 10 feet in elevation?
By *_______ feet (to the nearest tenth of a foot).

At Site 3 in Manhattan, what is the percent chance annually for such a storm surge?
The percent chance annually is *______%.

What is the recurrence interval for such a storm surge? The recurrence interval is *_______ years.

*On the basis of the above information, for the frequency of flooding for areas that today are less than 10 feet above sea level, how do estimates of hazard in the 2080s made by the Army Corps of Engineers compare with estimates of hazard in the 2080s made by NASA-Goddard? (About the same? Much greater? Lesser?)('About the same' means from about one-third to three times the value.)*_____________

Having made this comparison, how important do you feel it is to check more than one source of information? (Very Important; Somewhat Important; Not Important)
*___________________