Before you begin the exercise, it is important to review some concepts and terms that are used to describe flooding as well as data about both flooding and hurricanes.  First, let's review the hydrologic cycle.  You can find one illustration of the hydrologic cycle below. 

Source:  http://www.ec.gc.ca/water/en/nature/prop/e_cycle.htm

Precipitation falls to the earth's surface and may then take one of a number of pathways back into the atmosphere. On a natural landscape, such as a forest, much of the rainfall is caught on the tree leaves and evaporated into the atmosphere.  The water that reaches the ground is absorbed into the soil and can then become ground water. Ground water feeds rivers between storms.  Whatever does not evaporate and go to the soil or groundwater is called runoff and flows directly into streams and lakes.  A good illustration of each of these pathways can be found at: http://observe.arc.nasa.gov/nasa/earth/hydrocycle/hydro1.html.

During a storm, runoff accumulates and moves downstream.  If the amount of runoff is modest, it will remain contained within the river banks.  If there is too much runoff in a short period of time, the river leaves its banks and floods the surrounding area.  The amount of runoff in streams is measured by a special stream gage.  Many of these are maintained by the U.S. Geological Survey (USGS).  USGS also maintains a glossary of water science terms.  If there are any terms here you need a definition for, go to http://ga.water.usgs.gov/edu/dictionary.html.  There is also a nice picture of a gaging station at http://nd.water.usgs.gov/gage/how.html and a web cam on an Arizona gage at http://az.water.usgs.gov/webcam/cam_09511300.html.  A gaging station is a small building that takes a feed from the stream and measures both flow's the velocity and height.  The data are digitally recorded and can be used to help record and predict flows.