Some Flooding Scenario Maps for Greenpoint and Long Island City

  In the maps below, I show some flooding scenarios based on  New York City RIM files.  These maps are produced on a "what if" basis if the polar ice caps should melt at a steady pace going to the year 2080.  These flood maps seem to be based on elevation.  In the recent local news, in the real estate sections are reporting  increased building activity in the Greenpoint and Long Island City areas of Queens.  Many of these zones of increased building activity are taking place a few hundred feet or less near the waterfront.  I am sure that the developers of these projects are taking into effect future water levels.  I would like to tell my readers that they should not make any decisions based on these maps.  I cannot tell if these maps are accurate or if the water level will rise due to melting ice caps.  I thought that the readers should be aware of this, if they are not so already.  Last weekend, the "G" train that was closed down for underwater tube reconstruction reopened.  It goes through the target area.  These Greenpoint tubes suffered much water damage due to superstorm Sandy.  I also wanted to show  mapping techniques as well.  It is possible to get a typographic map of New York City from the Rutgers' University Map Lab and bring it into a ARCGIS map. What is nice is that this file does not need to be geo referenced.

In the above map, I bring in the street pattern for Greenpoint Brooklyn and Long Island City Queens.  The black thick lines are the subway routes in the area.  You will see three flood scenarios for the area for years 2020, 2050 and 2080.  The location of the "G" line is indicated.  The "G" train crosses the Newtown Canal as indicated by the arrow.

In the map above, I brought in one flood stage scenario (2020), subway routes and a typographic map from around 1975 of the area.  This can be obtained from the Rutgers" University Map Lab.  It can be added to an ARCGIS map very easily.  At the Rutgers University Map Site, select New York City Typographic Maps.  Choose the "tile" that you need and download it as zip file to your desktop.  Open your already existing map in ARCGIS and add the *.tiff file after the file that was downloaded was unzipped.  It does not need to be geo referenced which can be a pain.

 

 



The map above is produced by GRASS and shows the direction and strength of water flow for the area based on rain and elevation.  The direction and thickness of the bars shows flow and direction.

I am not an expert in reading this but it seems that surface waterflow is not an issue for the area.  Notice the big waterflow vector for the Lower East Side of Manhattan to the left of the map.

Please ignore the legend.

Sea Surge Data from FEMA in Relation to Rapid Transit in New York

  As part of the shape file that is available from FEMA, is a sea surge variable that is interesting.  Not a geology student, I can see now that flooding can be caused by wave height and the shape of the waves as well.  Simple street elevation is not enough to show which areas are at risk of flooding.  The shape, height and angle of a barrier can determine the extent of damage that may occur.  I hope that this map is helpful even though according to FEMA, the data is not complete.  I brought in the shape files of New York Subways and Railroad because this is the subject of our blog.  Although not shown on the map below, Manhattan is not effected by this FEMA map, except for a very small area near Marble Hill.