Are we headed for a dam disaster?
185 N.J. dams could fail in catastrophic flood, but state won't say which ones
[Posted by Carla Astudillo | NJ Advance Media for NJ.com October 02, 2015, 9:48 AM]
It only takes one big rain storm for a dam disaster.
Dams are just one part of our deteriorating infrastructure, one that receives little attention, especially since New Jersey has never experienced a catastrophic dam failure with huge loss of life. However, with 500 year storms becoming more common, many New Jersey dams are still not up to standards and potentially endanger thousands of lives downstream. There are more than 1,500 total dams in New Jersey, and they are classified into three general hazard potential groups:
· Low Hazard and Small Dam Low Hazard – if these dams were to fail, it would not cause any damage of life or property. The majority of dams in New Jersey fall into this category.
According to DEP, 556 dams — more than one-third — fall into the following two groups:
· Significant Hazard– if these dams were to fail, it could lead to significant property damage
· High Hazard– if these dams were to fail, it could lead to both significant property damage and potential loss of life.
But due to "security concerns resulting from [9/11] attacks," DEP has not published a full list of high and significant hazard dams.
However, the U.S. Army Corp of Engineers keeps a National Inventory of Dams, which lists bothsignificant and high hazard potential dams, as well low hazard dams that are of certain height and storage size. It was last updated in 2013.
When NJ Advance Media requested dam inspection data, DEP would only release numbers by county. They would not release which dam received which rating or any other detailed information because of security concerns.
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The data shows that out of 556 high and significant hazard dams, 185 of them received a rating of "poor" in their last dam inspection.
However, a "poor" rating does not mean the dam is necessarily falling apart, according to John Moyle, manager of the NJ Bureau of Dam Safety. It means if an event such as a catastrophic flood were to occur, the dam has the potential to fail and cause significant damage.
In addition, Moyle said that there may be dams that have already been fixed and are awaiting inspections. Inspections on high and significant hazard dams are required every two years, according to DEP guidelines.
Morris and Sussex counties are home to the greatest total number of "poor" rated dams, with 29 and 24, respectively. However, those are the two counties with the most high and significant hazard dams in New Jersey. Both counties have about 35 percent of these dams rated as "poor".
Camden County has only 21 high and significant hazard dams, but 17 of them received a "poor" rating. Inspectors gave 14 out of the 23 high and significant hazard dams in Monmouth County a "poor" rating.
Overall, five counties, Camden, Monmouth, Cumberland, Salem and Atlantic, had half or more than half of their high and significant hazard dams rated as "poor".
In addition, two dams, one in Sussex and one in Warren, were given a rating of "unsatisfactory" which means that the dams are considered "unsafe" and require "immediate or emergency remedial action," according to DEP guidelines.
HOW DAMS CAN FAIL
There are a few ways that dams can fail, said Andrés Roda, senior research manager at the Center for Advanced Infrastructure and Transportation at Rutgers.
Seeping water can cause erosion inside the dam and can lead disastrous leaks.
"It's like the classic cartoons where you put your finger in one spot, and it starts to leak in another," Roda said. "Overtopping" of a dam is also pretty common when you have a storm that dumps rain for a long period of time. The resulting soil erosion can eat away at the dam until it collapses. "You can also have cascading failures," Roda said. "If you have two or more dams in the same corridor, once that first dam fails, you have a volume of water that packs a punch to other one." In fact, heavy rains and flooding have caused several dam failures in New Jersey over the years. Among them:
· In July 2004, flooding in Burlington County led to the failure of six significant hazard dams and caused damage to two high hazard dams.
· Rainbow Lake Dam, located in Pittsgrove Township in Salem County collapsed during an April 2007 Nor'easter draining the 91-acre lake and causing damage along Rte. 56.
· An early August 2011 storm in Cumberland County caused four dams to fail, including the high hazard Sunset Lake Raceway Dam, which caused more than $20 million in damage, according to initial reports.
· Two weeks later, Hurricane Irene struck and resulted in the failure of six dams, including one on Weldon Brook, a tributary to Lake Hopatcong and one in a tributary to Crosswicks Creek in Burlington County.
Deteriorating dams are not just a New Jersey phenomenon. According to the Association of State Dam Safety Officials, the percentage of dams with "poor" or "unsatisfactory" ratings increased from 7 percent to 15 percent nationwide, as more states ramp up inspection of high and significant hazard dams.
The American Society of Civil Engineers 2013 Report Card gave the nation's dams a D grade for the growing number of deteriorating high hazard dams in the last couple of years. In addition, a recent U.S. Government Accountability Office report found that the 707 dams built and maintained by the U.S. Army Corps of Engineers may be at risk from both extreme weather and the sea level rise.
DAM RISKS AND REGULATIONS
As the years go by, it is even more important for dams to be properly maintained by their owners, according to Roda, from the Center for Advanced Infrastructure and Transportation at Rutgers. This is because as the state's population increases, more people move to areas downstream of dams, causing the dam's hazard classification to go from low to high. "Private dam owners may be surprised to discover that a potential failure of their small dam, built years past, could potentially cause costly damages or be life threatening," Roda said.
In 2002, the number of high hazard dams nationwide stood at 10,118. Ten years later, it went up to 13,991, according to the American Society of Civil Engineers.
Also, dams are aging. According to the National Inventory of Dams, 457 out of the 826 dams in their New Jersey database are older than 50 years old, which is the standard expected lifetime for dams. Not all dams in the NID's inventory include the year they were constructed so there could be even more.
These dams were built using the engineering technology available at the time when they were first constructed, but may be outdated and in need of upgrade.
Even though the NJ Bureau of Dam Safety has vastly reduced the amount of high and significant hazard dams in poor conditions since 1980, maintaining New Jersey's dams in compliance is still easier said than done.
"Every dam has its own story," Moyle, of the dam bureau. "Whether there's a funding issue or a design issue or in the middle of an enforcement action or in litigation."
The NJ Bureau of Dam Safety's 14 dam inspectors are in charge of inspecting and keeping track of more than 1,500 total dams in New Jersey, and the process can hit a snag when questions of ownership and money come in:
· In 2011, upkeep for a significant hazard dam in Wyckoff reached a deadlock when the township and the homeowners could not come to a decision as to who would pay for it.
· In 2014, repair work at an Atlantic County high hazard dam near Lake Lenape was suspended because of a dispute between the contractors and the county.
· After years of litigation, courts ruled that Gloucester County and several landowners must pitch in for the repair costs of several dams.
But even when ownership issues are ironed out, one set of repairs is not enough.
"They're living structures," Moyle adds. "And they need to go back and fix them again and again."
Because money is a big issue, DEP has a grants and loans program that has given out a total of over $98 million to dam owners needing help in paying for dam repairs.
DEP also requires dam owners of high and significant hazard dams to keep an emergency action plan, which is a formal document outlining emergency pre-planned procedures, in case the dam should break.
According to a 2015 list of high and significant dams without emergency action plans given by DEP to NJ Advance Media, there are currently 17 high and significant risk potential dams without emergency plans.
Mark Ogden, project manager at the Association of State Dam Safety Officials, particularly singled out New Jersey "as one of the best states" in prompting the creation of emergency action plans.
However, many experts point out that one of the biggest obstacles for regulators is raising awareness on dam safety — both among dam owners and the surrounding community.
"There are a lot of stakeholders when it comes to dams, and sometimes it's not as high profile with the public because they're not a bridge or a road where people travel on every day," Ogden said. "But if they were to fail, there would be a huge impact."
Carla Astudillo may be reached at firstname.lastname@example.org. Follow her on Twitter@carla_astudi. Find NJ.com on Facebook.