New York State Department of Environmental Conservation Hudson River Estuary Program Title slide: Telling Hudson River Stories With Graphs – Storms & Water Levels Radar images of Tropical Storm Lee remnants (National Weather Service/Binghamton NY) Telling Hudson River Stories with Graphs 2. STORMS & WATER LEVELS

How might major storms impact water levels in the Hudson estuary? Hurricane Irene Hurricane Irene satellite image from the NASA/NOAA Geostationary Operational Environmental Satellite [GOES] Project; website at http://goes.gsfc.nasa.gov/

What is the story that each graph tells? Interpreting graphs: What is the story that each graph tells? Answer these questions when looking at each graph: 1. What time period is shown in this graph? 2. What is being measured in this graph? 3. Where was the information gathered? 4. What happens to it over the time period shown? 5. What is your hypothesis about what caused this to happen? 6. Measurements of what other parameters would help you test and verify your hypothesis? Questions to ask when looking at graphs of remotely sensed data from the Hudson River estuary. If you have Internet access, you can go to the Hudson Environmental Conditions Observing System website to check other parameters and test your hypothesis.

What caused this pattern of water levels in spring, 2011? Source: Hudson River Environmental Conditions Observing System Note that all three graphs cover the same time span and show the regular rise and fall of the tides. The interesting phenomenon shown is in the Albany plot, where water levels were higher for four days 4/28/11 – 5/1/11. After students have suggested hypotheses to account for these levels, Click to go to next slide for answers and relevant notes. The graphs from the Port of Albany and Norrie Point were generated on the Current Conditions page of the Hudson River Environmental Conditions Observing System website at http://www.hrecos.org/joomla/. The George Washington Bridge graph was generated on the New York Harbor Observing and Prediction System (NYHOPS) website of the Stevens Institute of Technology’s Center for Maritime Systems at http://hudson.dl.stevens-tech.edu/maritimeforecast/PRESENT/data.shtml. Both sites are hyperlinked on the slide. Source: New York Harbor Observing and Prediction System

Hudson River at North Creek hydrograph North Creek Gaging Station Runoff from heavy rains in the Hudson River watershed caused flooding in the estuary near Albany. The lower estuary remained at sea level. Image from National Weather Serivce/Binghamton Image from National Weather Serivce/Albany Hudson River at North Creek hydrograph River stage (water level) in feet River discharge in thousands o f cubic feet per second USGS North Creek Gaging Station Runoff from heavy rains in the part of the Hudson’s watershed that drains to the upper Hudson and the Mohawk River caused flooding in the northern part of the estuary from Troy roughly to Catskill. [the arrow shows the location of the gage at North Creek.] Flooding was not observed further south on the estuary. Discharge into the estuary from runoff fairly quickly equilibrates to sea level, so flooding due to heavy rain is uncommon south of Catskill. Notice that the peak in runoff shown in the Albany graph lasts for several days. It takes some time for runoff from distant parts of the watershed to travel all the way to Albany. National Weather Service [NWS] offices prepare analyses of past major weather events; several years’ worth are posted on line. These reports have interesting commentary and are a great source of graphs, diagrams, and images. The NWS offices in Albany, Binghamton, and New York City/Upton cover the Hudson and its watershed (use Google or another search engine to find these); look for links to past storms or past weather events.

What caused this pattern of water levels in October, 2012? Source: Hudson River Environmental Conditions Observing System Note that all three graphs cover the same time span and show the same perturbation, a spike in water level occurring late on 10/29/12 at the Battery, a few hours later at Marist College in Poughkeepsie, and just before dawn 10/30/12 upriver at Albany. After students have suggested hypotheses to account for these levels, Click to go to next slide for answers and relevant notes. The graphs from the Port of Albany and Marist College were generated on the Current Conditions page of the Hudson River Environmental Conditions Observing System website at http://www.hrecos.org/joomla/. The graph from the Battery was generated on the New York Harbor Observing and Prediction System (NYHOPS) website of the Stevens Institute of Technology’s Center for Maritime Systems at http://hudson.dl.stevens-tech.edu/maritimeforecast/PRESENT/data.shtml. Both sites are hyperlinked on the slide. Source: New York Harbor Observing and Prediction System

Wind speeds (average) & gusts at Piermont on the Hudson River Flooding due to storm surge from Hurricane Sandy extended all the way to Albany. Wind speeds (average) & gusts at Piermont on the Hudson River South Ferry subway station 10/30/12 Image credit: MTA Marina in Rockland County Image credit NYSDEC Unlike flooding due to runoff from the watershed, storm surge flooding is usually a sharp peak of short duration, associated with the passage of a strong coastal storm – hurricanes, tropical storms, and nor’easters are the usual culprits. Their strong winds (shown in the graph from Piermont), momentum, and low atmospheric pressure raise sea level in coastal waters as these storms track past or into New York. This elevated sea level in coastal waters is felt up the Hudson, which is close to sea level all the way to Troy. These storms may or may not cause flooding due to runoff from the watershed; whether heavy rain extends inland to the main part of the Hudson’s watershed in the Catskills and Adirondacks depends on a storm’s size and track. Sandy did not bring heavy rains to the northern reaches of the Hudson’s watershed. Thus the graph from Albany does not show a peak due to runoff. The wind graph from Piermont was prepared by the Lamont-Doherty Earth Observatory of Columbia University using data from the Hudson River Environmental Conditions Observing System. A similar graph can be created using the Current Conditions page of the Hudson River Environmental Conditions Observing System website, selecting Piermont meteorology as the station, wind gusts and speeds as the parameters, choosing the appropriate dates, and then clicking on Plot 1-2. Photo by Hudson River Park Naturalist Keith Michael

What stories do these graphs tell? Note that both graphs cover the same time span and show an event or events that started on 8/28/11. However, the event(s) played out differently in Albany than in Poughkeepsie. After students have suggested hypotheses to account for these levels, Click to go to next slide for answers and relevant notes. These graphs from Albany and Poughkeepsie were generated by visiting stations listed on the U.S. Geological Survey’s Hudson River Salt Front Data webpage at http://ny.water.usgs.gov/projects/dialer_plots/saltfront.html (hyperlinked on the slide). Source: U.S. Geological Survey’s Hudson River Salt Front Data website

Tropical Storm Irene’s one-two punch: Flooding in Poughkeepsie 8/28/11 Image credit NYSDEC Winds along the coast led to storm surge flooding, showing as a water level peak in Poughkeepsie and at the start of the flooding in Albany. Flooding in Schoharie County Image credit Natural Resources Conservation Service Runoff from heavy rain caused flooding in the watershed and at Albany. Runoff even affected water levels at Poughkeepsie in the days following the storm. Tropical Storm Irene’s impacts on the Hudson in August 2011 combined flooding from runoff and storm surge. The sharp peak at Poughkeepsie is the result of storm surge flooding on the day Irene hit (top photo). The impacts in Albany start with that storm surge peak; it reaches Albany a few hours after it hits Poughkeepsie. But instead of quickly falling, as occurs in Poughkeepsie, the water level continues to rise as runoff from the watershed reaches Albany. Unlike Sandy, Irene dropped huge amounts of rain and caused major flooding in the Catskills and Adirondacks (bottom photo) . Its runoff continued for several days, in such volume that the estuary flooded much further south than usual. Water levels were elevated at Poughkeepsie for several days after Irene passed, though not as high as in Albany.

For more information, contact: Steve Stanne, Education Coordinator NYSDEC – Hudson River Estuary Program/New York Water Resources Institute – Cornell University 21 South Putt Corners Road New Paltz, NY 12561 845 256-3077 spstanne@gw.dec.state.ny.us