Image courtesy of NASA
April showers bring May flowers, but what do coastal storms bring? Extreme storms such as severe nor'easters and hurricanes can bring heavy property damage, habitat destruction, and loss of human and animal life. The devastation results not just from the immediate rainfall and tidal surge during the storm, but often to a greater extent from the resultant flooding of creeks, streams and rivers.
When the rains from a heavy storm continue over days, the water cannot drain fast enough through the groundwater, creeks and rivers. Water levels rise, eventually causing floods. As the volume of water traveling through a waterway increases, the water's rate of flow or speed increases. The flood waters move downstream picking up anything in their path including sediments, pollution and debris, eventually dumping this in our estuaries.
In order to protect developed areas from flooding, humans build dams and levees to help control the flow of water. These structures may protect developed areas, but when the water levels rise above capacity the damage can be significant. This is because the structures prevent the water from spreading out over its natural floodplain which would help to absorb the water and slow down the current.
Some of the U.S. east coast's worst flooding happened in 1999 when Hurricane Floyd hit the coast. Much of the coastal area was still soaked from Hurricane Dennis which hit on September 5th when Floyd hit on September 15th. Hurricane Floyd was nearly 600 miles across and brought up to 20 inches of rain in only 12 hours. Because the ground was already soaked and the waterways were swollen, there was nowhere for the water to go. Water levels rose almost immediately by as much as 8 inches per hour, rising as high as 24 feet above normal water levels. Devastation to humans in terms of death and property loss was obvious, but what about all the animals and plants impacted by the flooding?
Data Activity & Discussion
In this data activity, we will investigate the impacts of a hurricane on the New River in North Carolina. We will use streamflow data from the United States Geological Survey's (USGS) website to compare "normal" streamflow in the river with streamflow resulting from Hurricane Floyd in September 1999. Finally, we will develop hypothetical scenarios describing the impact of the increased streamflow on specific estuarine organisms.
- Access a map of Gum Branch, NC where the gaging station is located. Based on what you see on the map, would you classify this area as urban, suburban or rural? If time allows, develop a written report on the natural and human histories of the area, including past and present land use.
- Access streamflow data from the USGS Real-Time Water Data for North Carolina. Select/enter the following information for the categories, then click "Go":
- Predefined Displays: Daily Streamflow
- Group Table By: No Grouping
- Select Sites by Number or Name: 02093000
What was yesterday's mean steam flow in cubic feet per second? Click on the station number 02093000 next to the station name to see the past month's mean daily streamflow.
- Access streamflow data for the New River for January 1999 through December 1999. Go to the Daily Streamflow Data page, and enter the following values and click "Submit":
- Retrieve data from: 19990101 to: 19991231
- Select Graphs of Data: Log Scale
When was the lowest discharge recorded? How much water was discharged? When was the highest discharge recorded? How much water was discharged?
- Look at the data for September 1999 by returning to the Daily Streamflow Data page, and enter the following values and click "Submit":
- Retrieve data from: 19990901 to: 19990930
- Select Graphs of Data: Arithmetic Scale
When did the impact of Hurricane Floyd occur? What was the maximum streamflow during the storm?
- Describe some of the impacts on water quality that might have occurred due to the storm (e.g., dissolved oxygen, salinity, turbidity, nutrients, toxins, sediments, etc.).
- Divide students into groups and have them research the potential impacts of the storm on a specific wetland organism from the list below. Use reference material to learn about the organism's physical characteristics, habitat requirements, feeding and reproduction, etc. Develop a scenario about what might have happened to this organism during and after the storm. Write a report from the point of view of a research scientist. Then write a story based on the point of view of the organism. You may illustrate your report with drawing and pictures or other creative strategies.
sea nettle fiddler crab blue crab crayfish grass shrimp freshwater mussel oyster false razor clam lugworm inland silverside spot hogchoker American shad Marsh Wren Great Blue Heron Red-Winged Blackbird American eel southern leopard from muskrat cattail spartina sp.
For related information and activities, check out the Bridge's Storms resources.
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