A Civil Action - The Woburn Toxic Trial > Learning Modules > Flooding

Module 6: Flooding of the Aberjona River Wetland

Module Goal:

  • Learn how hydrologist's monitor and categorize floods based on frequency
  • Evaluate what occurs in floodplains, particularly fine-grained sediments, during a flood
  • Understand why the defense implicated flooding as a cause of the overall spread of contamination in the Aberjona River valley

Student Assignment


To gain a general understanding of flooding and flood controls go to USGS Fact Sheet regarding floods. During the trial, W.R. Grace considered flooding to be an important part of its defense, especially considering the history of industrial development along the Aberjona River upstream of municipal wells G and H.

How do floods occur and how can we control them?

On smaller streams, floods are often unpredictable and changes in flow can occur quickly. On larger streams, floods can be predicted when weather conditions are monitored. Floods on larger streams and rivers have been called "slow disasters". When they occur on larger streams, those communities downstream of the flood wave often can only wait and see if their flood protection can withstand the test of the oncoming crest of the flood wave. In drainage basins where streams have developed floodplains, it is common for flood events to deposit a new layer of sediments and redistribute materials placed in the floodplains in the upper reaches of the drainage.

What's normal flow in the Aberjona River?

The National Oceanic and Atmospheric Administration NOAA maintains a hydraulic monitoring station, just a few miles downstream of Woburn in the town of Winchester. As part of the NOAA's "real time" monitoring network, it allows us to see stream stage data and understand how streamflow discharge fluctuates, both in the near term and in the past.

Go to Student Assignment