By Amy Batista, Special Writer
CRANBURY — A leak in the dam prompted officials to drain Brainerd Lake on Aug. 22.
”That looks like that is the culprit there,” said Mayor David Cook as he pointed to a large hole in the ground that caused the lake’s level to drop last week. “(It) looks like there is one particular spot that may be the cause of the leaking we are having on the west side.”
Township Engineer Bill Tanner said Mayor Cook noticed a drop in the level of the lake and began investigating the cause, even checking with work being done in the area on the N.J. Turnpike.
”(The drop in the lake’s level) doesn’t happen unless there is some sort of obstruction so we actually called the New Jersey Turnpike Authority to see if that project might be constricting it,” Mayor Cook said. “(We also checked) if the Monroe Sewer and Water Department (was doing anything), and they both said ‘no.’”
Mayor Cook also said that the floodgate, which could have caused the drop in the lake’s level, was not open.
”On Monday after a conversation with Jerry Thorne, public works superintendent, I made an inspection of the dam and confirmed that the dam was leaking,” Mr. Tanner said.
On Aug. 22, the dam was then inspected by the Middlesex County Engineering Department, the county’s consultant and representatives of the Dam Safety Section who were present during the inspection. The decision was made to empty the lake.
Mr. Tanner said that the lake has a valve that allows the township to drain the lake if it is needed.
”At this meeting the decision was made with the concurrence of the Dam Safety Section, to empty the lake as a precaution and to investigate further,” Mr. Tanner said.
”There was significant seepage observed from the downstream side of the dam adjacent to the culvert flowing under and through the masonry wall itself,” said Larry Hajna, a state Department of Environmental Protection spokesman, on Monday. “The lake had dropped rather quickly as a result of this.”
The lake’s level had dropped about a foot according to Mr. Hajna’s report, which triggered the original reason to investigate what was causing the level of the water to drop.
”The municipality had emptied the lake to protect against any potential or further damage to the dam and to Main Street, that goes over it,” Mr. Hajna said, “The township was monitoring the road surface for any potential settling issues (caused by the leak).”
Mr. Tanner said that once the lake was drained, Mr. Thorne discovered a hole near the base of the spillway.
Mr. Thorne estimated the hole to be “about 3 feet deep” in an interview Aug. 24.
Public Works crews worked on the dam on that day, trying to find a way to temporarily fix the problem. The first attempt was to see if they could fill the hole with clay, but it was unsuccessful.
”After discussing the finding with Dam Safety Section, and the consultant, we proceeded with a plan to fill the hole with clay. Jerry (Thorne) did this on Aug. 24 but the hole turned out to be larger than anticipated,” Bill Tanner said.
”They put about four cubic yards of clay material in there,” Mayor Cook said.
”On Monday, we filled (the hole) with concrete. This appears to have resolved our current problem,” Mr. Tanner said. “The plans for (temporary) repair are almost completed and we are now awaiting the approval of the permits necessary to do the permanent repairs.”
”Currently we believe the problem is resolved in the short term but are pushing to get the permanent repairs underway as soon as possible,” Mr. Tanner said. “There is no evidence that it occurred as a result of Hurricane Irene but it certainly did not help.”
Mayor Cook said that for the time being, the lake will remain drained until the rehabilitation project gets under way, which is anticipated in December, and said that it all has to do with the “speed of the permits” getting issued by the state.
”The lake, as you see it, is probably going to stay the way you see it,” Mayor Cook said. “Originally, the thought was (that) we were going to drop the level in November, because of starting the bridge (and) dam project in December.”
”(The) state felt we should just drop it now as a precaution,” Mayor Cook said. “The breach has accelerated the process. If there is any silver lining, this should accelerate the permitting process.”
Mayor Cook said that the county agencies have been “supportive,” and the project is estimated to take six to nine months.
”The original dam dates back to 1840,” Mr. Hajna said. “The town is currently working on a design to rehabilitate the dam and we will be closely looped into the process. The masonry wall has been compromised so additional exploratory work is going to be needed to find exact location of the seepage.”
Mr. Tanner said that the project is an inter-local agreement with the county to make certain repairs to extend the life of the dam structure.
He said the upcoming project will include the installation of sheet piles in the upstream side of the dam to prevent seepage of water, construction of a new larger, spillway, the armoring of areas downstream to prevent future erosion, and the removal and replacement of sidewalks and curbs.
There will also be a slight decrease in roadway width on Main Street to increase “green” space on the bridge, the repair or replacement of some of the storm sewer piping, and re-grouting of the culvert under the road.
”The total estimated cost for this option will be $3 million of which the township is responsible for 50 percent or $1.5 million,” Denise Marabello, township administrator and director of finance said in an email on Monday.
”I already have a capital ordinance in place for $948,000 which is funded by bond anticipation notes,” Ms. Marabello said. “I will do a capital ordinance for the remainder of the money by the end of this year or early next year.”
According to Ms. Marabello, the township is waiting on permits from the NJDEP for the project to begin.
”DEP’s role under the NJ Safe Dam Act is to make sure that the dam is safe and the township and county will be ordered to undertake the necessary prepares to bring the dam into compliance,” Mr. Hajna said.

