Naugatuck River Flow & Flood Information

NaugatuckRiver_VolunteerParkFlooding-March302010_CourtesyMichaelAKrenesky.JPG
The Naugatuck River flooded in late March 2010 when heavy spring rains fell on a still frozen ground. 
Above: The Naugatuck River floodwaters began climbing the stairway at Volunteer Park in Beacon Falls. 
Photo Courtesy of Michael A Krenesky
(Photo taken March 30, 2010) 


Available Online Data Sources


Several sources of streamflow and flood data exist for the Naugatuck River.  The U.S. Geological Survey (USGS) maintains two gauges that measure streamflow and flood information -  one in Thomaston and one in Beacon Falls.  The USGS gauges record two streamflow measurements: 'gauge height' and 'discharge.' To access current ('real-time') or historical streamflow data at either location click the links below:
The National Oceanic and Atmospheric Administration (NOAA) also maintains a very useful website summarizing available streamflow and flood data for the Naugatuck River at Beacon Falls.


Understanding Streamflow and Flood Data:
Exploring Historic Floods


Gauge height measures the height of water surface compared to a horizontal reference point on the gauge.  As the river floods and the surface of the water grows higher and higher above the river's normal level, the gauge height increases.  When the Naugatuck River gauge height reaches 12-feet it is considered to be at 'Flood Stage.'  'Moderate Flood Stage' is reached when the river exceeds 13-feet, and 'Major Flood Stage', the most severe flood rating is reached when the river exceeds 14-feet.
 
To put gauge height in perspective, consider the following references offered by NOAA NWS:
  • At 12-feet flooding begins in the upstream towns of Waterbury and Naugatuck
  • At 20-feet the river level just touches the underside of the bridge on Bridge Street
  • At 21-feeet flooding begins along Route 8 from the Naugatuck town line downstream to the Seymour town line.
2008-2012FloodEvents-BeaconFallsUSGSGauge.gifAt right is a graph of all of the recorded gauge height measurements at Beacon Falls between October 2007 and March 2012.  The red line indicates the 12-foot flood stage, while the blue line shows the data points recorded.  When the blue line extends above the red line it means that the river was considered to be at flood stage.  Notice that gauge height varies, ranging from about 1 foot to over 14-feet.  In 2011, the river exceeded Flood Stage twice at the USGS gauge in Beacon Falls.  During Hurricane Irene in August of 2011, the river exceeded the 14-foot Major Flood Stage rating.  

Discharge, on the other hand, is a measure of streamflow or the volume of water flowing past the gauge in a given amount of time.  The USGS gauges measure discharge in cubic feet per second (CFS) - that is how many cubic feet of water (approximately the size of a basketball) pass the gauge in a given second.  The greater the number, the more water there is flowing past that gauge.   The graphs below shows the annual peak streamflow recordings for all years on record, beginning in the early 1900s, at the Beacon Falls gauge - the blue dots indicate the highest streamflow or discharge recorded for each year. 
  
PeakStreamflowatBeaconFallsGauge.gifNotice that while most annual peaks were below 20,000 CFS, the 1955 recording was an impressive 106,000 CFS!  Based on this discharge data, the 1955 Flood was five times greater than the biggest flood recorded in any other year on record!  Similarly, at the Thomaston gauge (data not shown), most of the records fall well below the 10,000 CFS.  The highest recording in 1955, however, was well over 50,000 CFS!  In contrast the flooding produced by Hurricane Irene in 2011 is barely distinguishable from previous years.

When we look at the USGS gauge data we can begin to understand how large - and how devastating - the Flood of 1955 really was.

NaugatuckFlood1.jpg   
The Great Flood of 1955.  Photo Courtesy of the Naugatuck Historical Society.

Special thanks to our sponsors:
Naugatuck Savings Bank, Connecticut Community Foundation
Union Savings Bank, Wesson Energy, Inc., The United Illumination Company, Friends of Naugatuck River
The Platt Brothers & Company, Thomaston Savings Bank, Valley Community Foundation