Historical Events

New Jersey has experienced a number of dam failures since the State Water Policy Commission began keeping records in the early 1900’s.

Dam failures can occur suddenly, without warning, and may occur during normal operating conditions. This is referred to as a “sunny-day” failure.

One such failure is the November 1927 failure of the Sarubbi Dam in Morris County. The sudden loss of concrete sections caused this dam to fail in November 1927.

Dam failures may also occur during a large storm event. Significant rainfall can quickly inundate an area and cause flood waters to overwhelm reservoir. If the spillway of the dam cannot safely pass the resulting flows, water will begin flowing in areas not designed for such flows and a failure may occur.

The September 1940 Storm

On September 1st, 1940, Southern New Jersey experienced an unusually large storm event associated with a tropical system. The system inundated portions of Camden, Gloucester, Salem Cumberland and Atlantic Counties.

Damage throughout South-Jersey was widespread, from Millville to Clementon.

Dozens of roads, bridges and dams were damaged or destroyed as a result of the ensuing floods.

Portions of the area experienced over 24-inches of rain in less than 12-hours. This extraordinary rainfall intensity was experienced over a localized area near Parvin State Park, located north and west of the City of Vineland.

Hurricane Floyd

On September 16, 1999, Hurricane Floyd, a tropical storm by the time it hit New Jersey, combined with a weather system from the west to drop significant rainfall in portions of the state. View Here.

Hardest hit was the Raritan River Basin. Click here for Hurricane Floyd data center. Although the state’s dams were spared the worst and no loss of life or significant property damage was attributed to the failure of a dam in the state, the storm did not go away without leaving behind a trail of damage to the state’s dams.

In the weeks following the storm, the NJDEP Dam Safety Section inspected over 50 dams to assess the impact of the storm. To date, the Section documented complete failure of three dams and notable damage to an additional 21 dams. The following table identifies the dams that were damaged by the storm:

August 2000 Storm

More than 14-inches of rain fell in a small area of southeastern Sussex and northwestern Morris County in northwestern New Jersey during August 11-14, 2000.

Flood peaks at some U.S. Geological Survey gauging stations on Lake Hopatcong, Musconetcong River, Green Pond Brook, Rockaway River, and Russia Brook tributary were the highest ever recorded.

About 2,700 homes and businesses in Sussex, Morris, Warren and Hunterdon Counties were flooded, and about 2,600 people were evacuated.

Many bridges, dams, and roads were damaged or destroyed. Damage was estimated at $179 million, and Sussex and Morris Counties were declared Federal Disaster Areas. (Courtesy U.S.G.S. Fact Sheet FS-104-01, Dec. 2001)

The areas hit most severely were in Sussex and Morris Counties, with the storm centered over the townships of Sparta, Hopatcong and Jefferson. A total of four dams completely failed as a result of the ensuing floods.

Automated rain gauges from the New Jersey Automated Flood Warning System (AFWS), under the National Weather Service (NWS) reported rainfall data of 5.67 inches and 8.49 inches for West Wharton and Berkshire Valley respectively. These readings were taken over a 24-hour duration from 8:00 AM, Saturday, August 12, 2000 to 8:00 AM, Sunday, August 13, 2000. Preliminary rainfall data from the Passaic Flood Warning System reported rainfall gauge recordings of 18.65 inches* and 14.11 inches* for Jefferson Township and Sparta Mt. respectively. See graphical display of rainfall.

As a result of the flooding, the Dam Safety Section dispatched emergency inspection teams, consisting of section engineers, to assess damages and hazards associated with the area dams. Engineers conducted preliminary inspections of the entire impacted area on Sunday, August 13, 2000. Beginning on Monday, August 14, 2000 and ending on Thursday, August 17, 2000, teams were sent to specific areas to conduct more detailed investigations of all affected dams.

The NJDEP Dam Safety Section inspected over 50 dams to assess the impact of the storm. To date, the Section documented complete failure of four dams and notable damage to an additional 26 dams. The following table identifies the dams that were damaged by the storm:

Burlington County Storm – July 2004

On July 12, 2004, parts of Burlington County, New Jersey experienced an unusually heavy rainfall event. The areas hit most severely were Evesham Township, Medford Township, Medford Lakes Borough, Mt. Laurel Township, Pemberton Township, Southampton Township, and Tabernacle Township. Doppler radar estimates of total rainfall for the 24-hour period ending 0700 hours EDT on July 13, 2004 were between 8-12 inches. The rain gage at Tabernacle recorded 13.2 inches and the rain gage at the USGS gaging station on Greenwood Branch at New Lisbon, NJ in Pemberton Township recorded 11.3 inches. See graphical display of rainfall.

A total of 18 dams failed as a result of the ensuing floods, and another 28 were damaged.

Property damage from the flood was estimated at $50 million. The flooding led to the evacuation of about 760 residents, the complete destruction of seven homes, major flood damage to approximately 200 homes, flood damage to approximately 1,000 homes, the closing of 25 major roads, (including the New Jersey Turnpike and New Jersey State Routes 70 and 73), and serious damage or destruction to 14 bridges (NOAA, National Climatic Data Center, U.S. Storm Events Database).

Inspection teams, consisting of Division engineers, performed inspections to assess damages and hazards associated with the area dams. Engineers conducted preliminary inspections of the impacted area on Tuesday July 13, 2004 followed by more detailed investigations of all affected dams. A total of 90 dams were inspected over a six-day period. The following table identifies the dams that failed as a result of the storm:

August 13-14th, 2011 Storm

Between August 13 and 14, 2011, heavy rains resulted in flooding in southwest New Jersey. The areas hit most severely were eastern Salem, western Cumberland, eastern Gloucester, eastern Camden, and western Atlantic Counties. Rainfall totals in these counties included 10.82 inches in Upper Deerfield Township (Cumberland County), 8.53 inches in Franklin Township (Gloucester County), 8.04 inches in Winslow Township (Camden County) and 7.51 inches at Hammonton (Atlantic County). See graphical display of rainfall.

A total of 4 dams failed as a result of the ensuing floods, and another 26 were damaged.

In Cumberland, Gloucester, and Salem Counties, more than 181 homes were damaged including 33 homes that received major damage. Overall, this storm resulted in 1 death and over $25 million in property damages in New Jersey (NOAA, National Climatic Data Center, 2013).

Inspection teams, consisting of Bureau engineers, performed inspections to assess damages and hazards associated with the area dams. A total of 125 dams were inspected by Bureau engineers in the days following the event. The following table identifies the dams that failed as a result of the storm:

Tropical Storm Irene – August 27-28, 2011

Tropical Storm Irene struck the State of New Jersey between August 27 and 28, 2011. Irene was reclassified from a hurricane to a tropical storm just prior to making landfall in New Jersey. The storm caused the largest coastal evacuation in State history, record flooding on many rivers, power outages to over 700,000 residents, and at least 12 fatalities (New Jersey State Hazard Mitigation Plan, 2014).

The statewide rainfall average was approximately 7 inches, making Tropical Storm Irene New Jersey’s largest rainstorm in over a century. Portions of Monmouth, Union, Morris, and Passaic Counties received in excess of 10 inches of rainfall. See graphical display of rainfall.

A total of 6 dams failed as a result of the ensuing floods, and 51 dams were damaged.

The heavy rains flooded both major and local roadways, causing hundreds of road closures. Portions of State Route 3 in Bergan County; U.S. Route 46 in Essex County; and I-80, State Route 20, State Route 23, U.S. 202 and U.S. 64 in Passaic County, all remained flooded for days following the event. In Morris County, a portion of I-287 collapsed. An aerial survey of Bergen, Essex, Morris, Passaic, and Somerset Counties was performed on August 30, 2011 and found that at least 2,080 homes suffered major damage. (New Jersey State Hazard Mitigation Plan, 2014). Overall, Tropical Storm Irene resulted in over $760 million in property damages in New Jersey (NOAA, National Climatic Data Center, 2013).

Inspection teams, consisting of Bureau engineers, performed inspections to assess damages and hazards associated with the area dams. A total of 119 dams were inspected by Bureau engineers in the week following the event. The following table identifies the dams that failed as a result of the storm: