Geology 135 Term Paper
The Flood of 1955 was one of the worst floods in the history of Southwest Connecticut. The amount of rain that fell in August 1955 so substantial that no event has come anywhere close to it in the last 100 years (Shea, Fury Unleashed). Two back-to-back hurricanes, Hurricane Diane and Hurricane Connie hit the Northeast region in August 1955. These hurricanes caused floods that resulted in many damages, including saturating the land and overflowing rivers.
Connecticut Flooding History
Flood data from the 1700 and 1800s was largely based on newspaper articles and eyewitnesses. Official government records of flooding did not begin until 1904.
In 1957, largely in part due to the recent flood, the U.S. Department of the Interior launched a project to gather information on flooding before government records. Seven years later, a detailed report called "Historical Floods in New England" was produced.
Following its exhaustive study, the government hydrologists concluded the four greatest floods in New England and Connecticut history had occurred in 1927, 1936, 1938 and 1955.
The Flood Of 1927
In early November 1927, Connecticut was visited by a tropical storm that produced seven inches of rainfall. The storm came without much warning. Raw sewage became a concern in Hartford due to the quick flooding. Only three deaths occurred in Connecticut (Shea). The Perfect Flood
During a snowy March in 1936, rainfall occurred for 13 days, resulting in raging rivers and streams. The already cold water and ice destroyed bridges, highways, and roads.
2,000 people were left homeless. The events that occurred during the flood caused more dikes In the aftermath, leaders decided to build more structures to contain rivers. Unfortunately, construction wasn’t completed in 1938, when a storm surged through Connecticut, where 10 inches of rain and heavy winds destroyed nearly all progress made on these structures.
August 1955
The flooding in 1955 was caused by two nearby Hurricanes: Hurricane Connie and Hurricane Diane. Hurricane Connie formed on August 3rd and dissipated on August 15th, whereas Hurricane Diane formed on August 7th and dissipated on August 23rd. These two hurricanes heavily affected the Northeast.
Hurricane Connie touched land on August 12, 1955. The storm moved slowly up the Chesapeake Bay and dumped roughly ten inches of rain in portions of northwest Connecticut. Connie did not produce much wind, but rainfall was so substantial to saturate the soil and raise river levels above flood stage.
Hurricane Diane first appeared in North Carolina, very close to where Connie struck. Rain over northwest Connecticut and western Massachusetts occurred as the storm passed over Long Island. Ten to twenty inches of rain was common in many areas, adding to the already heavy rainfall from Hurricane Diane. This record 24-hour rainfall was enough to push rivers to levels that hadn’t been seen in hundreds of years. For nearly 24 hours, strong convergence setup across Connecticut with deep tropical moisture northward from Diane.
Winsted, CT was said to be the most vulnerable area in the state prior to the floods, due to its lack of protection and dams. The Mad River in Winsted flooded many times during the 1800’s, damaging streets and buildings. Highland Lake, which is roughly 100 feet above the Mad River in terms of elevation frequently overflowed into the already vulnerable Mad River. The flood of 1955 caused the Mad River to flood from the hills of Norfolk while Highland Lake sent water from the lake into Winsted. The combination of both rivers destroyed most of Main Street. Main Street was never rebuilt and was paved over. The Sucker Brook dam was created alongside Highland Lake to help control the lakes levels and prevent flooding of the Mad River in downtown.
Farmington River
The Farmington River reached levels never thought attainable before the 1955 floods. Before the flooding occurred, the district created the Hogback Dam and Wester Branch Reservoir to maintain safe water levels. There were tentative plans for the Colebrook River Dam when the flood occurred. This dam was built following the floods by The United States Army Corps of Engineers. The Army Corps maintains the flow leaving the Colebrook Dam for both flood control and low flow augmentation, according to the MDC. The Colebrook River Dam is now a crucial part of the flood control system on the Farmington River.
The combination of the flood control on the Mad River and the Colebrook River provides sufficient flood control on the Farmington River.
Naugatuck River
The Naugatuck River flooded towns stretching from Torrington to Derby.
Seven dams were constructed by The United States Army Corps of Engineers which has substantially reduced the flow of the Naugatuck River. The Thomaston Dam on the Naugatuck River provides additional protection. The Naugatuck River never had significant flooding following the construction of the protection.
Quinebaug River
The Quinebaug River was began to flood on August 19th. Downtown Putnam was substantially damaged by the flood, sparking a spectacular fire at a magnesium factory in the city.
The Quinebaug connects a number of small lakes in Massachusetts that help alleviate the river, some of these lakes are natural, and others were built by the Army Corps for flood control purposes.
The Buffumville Dam on the Little River (a tributary of the French) and the Hodges Village Dam in Massachusetts provide flood control on those rivers.
Additionally, flood controls in the Thames River include the Mansfield Hollow Lake Dam. The Natchaug River flows into the Shetucket River and eventually into the Thames. The dam was built before the 1955 flood which likely saved Willimantic from more devastation.
The six dams throughout the Thames River Basin have virtually eliminated the threat of a 1955 flood repeat. Some rivers in the Thames River basin are still vulnerable to flooding though. The Yantic River is not flood controlled. The Mt. Hope River in Ashford reached a major flood stage in October 2005. The Willimantic River is also very vulnerable, reaching major flood levels in October 2005.
Erosion
In 1958, researchers M. Gordon Wolman and Jack Eiler studied the effect the 1955 flood had on erosion and deposition. Eiler and Wolman state, “Large areas in the valley bottoms were overwhelmed by the flood of August 1955. Erosion of the channel and valley bottom appears to have been most severe in narrow, steep valleys. Environments of deposition were diverse. They appeared to be related to rate and direction of flow, quantity and size of sediments locally available, and in some cases to the presence of vegetation. Most of the coarse sediment deposited in the valley appears to have been derived from local sources such as valley walls and terraces composed of glacial outwash and till and flood plains containing considerable gravel. Fine sand predominated in most of the sediment deposited. Considering the magnitude of the runoff, the quantity of fine sediment transported or deposited by the flood was small. The paucity of deposition in such ideal depositional environments also indicates that the flow did not have a high concentration of fine sediments. Severe erosion in the uplands was minor. In this reconnaissance we saw little evidence of newly formed gullies and no areas of severe sheet erosion. This was the case in both woodland and pasture land. Large amounts of subsurface flow and relatively unerodible ground are presumed to be responsible for the absence of erosion.”
Timeline
Thursday, Aug. 18, 1955
3 a.m. Rain from Hurricane Diane begins in western Connecticut.
9:30 a.m. Torrential downpours cause flash flooding in Torrington — state of emergency is declared.
10 p.m. The Shepaug River begins flooding Washington Depot.
11 p.m. Steele Brook and Turkey Brook in Watertown flood their banks.
Friday, Aug. 19, 1955
12 a.m. Main Street in Winsted is flooded.
12:15 a.m. Thomaston is flooded.
1 a.m. Torrington & Naugatuck begin evacuation. Governor Ribicoff mobilizes the National Guard.
1:15 a.m. Thomaston Avenue in Waterbury is partially submerged.
1:57 a.m. The Naugatuck River overflows its banks near the Chase factory.
2 a.m. Waterbury and Thomaston fire departments receive phone calls about flooded basements
2:45 a.m. Police began evacuation of North Riverside Street in Waterbury.
3: a.m. Bank St. in Waterbury completely submerged. Mayor Snyder declares state of extreme emergency
3:15 a.m. Winsted streets under 2 feet of water. 4 a.m. Three of Waterbury's seven bridges are gone.
5:30 a.m. Rising water threatens businesses on North Main Street in Naugatuck.
5:41 a.m. Air raid sirens used to mobilize Civil Defense volunteers in Waterbury.
6 a.m. In Naugatuck, the Howard Whittemore bridge is under a few inches of water.
6:30 a.m. Residents on West Main Street and Waterville Avenue in Waterbury are advised to evacuate.
6:45 a.m. The Whittemore bridge in Naugatuck is under two feet of water.
6:55 a.m.Thomaston loses power.
8:10 a.m. Waterbury's Freight Street bridge collapses.
10:20 a.m. Ansonia loses power.
11:30 a.m. The Naugatuck River returns to its banks in Torrington.
10 p.m. The Naugatuck River returns to its banks in Waterbury.
Aftermath
The 1955 floods destroyed entire neighborhoods, entire downtowns, and entire families. The death toll throughout Connecticut was 87 people (LeBlanc, The Lost). Three months after the flood, The Connecticut Flood Recovery Committee reported 668 houses and residential buildings were completely destroyed, and over 7,000 suffered considerable damage (Connecticut Flood Recovery Committee). Damage to the land in Seymour, CT was so severe that coffins and bodies from a cemetery were found floating in the streets. Damage estimated at $36.8 million, which is approximately $336 million today. Following the floods, The United States Army Corps of Engineers spent two decades and $70 million to build walls and dams to prevent future floods from having such a devastating result. There will never be another flood like the Great Flood of 1955.
References
Connecticut Flood Recovery Committee. "Report of the Connecticut Flood Recovery Committee." (1955)
Hanrahan, Ryan. “Flood of August 1955.” RyanHanrahan.com, www.ryanhanrahan.com/flood-of-august-1955/.
LeBlanc, Jeanne A. "The Lost." Hartford Courant, August 2005.
Shea, Jim. "Fury Unleashed." Hartford Courant. Aug. 15, 2005.
Shea, Jim. “Floods: Connecticut Knows The Power Of Water.” Courant.com, 15 Jan. 2014,
Wolman, M. G., and J. P. Eiler (1958), Reconnaissance study of erosion and deposition produced by the flood of August 1955 in Connecticut, Eos Trans. AGU, 39(1), 1–14,
Waterbury Time Machine. "Flood of 1955."