County Helps Prevent Flooding in Millburn

The 277-foot dam at Diamond Hill Pond is getting an overhaul in an effort to control water flow and prevent flooding to downtown Millburn, both township and county officials said Wednesday.

"It's not a question at all that it's a big help," Millburn's mayor, Sandra Haimoff, said at the announcement of the renovations, Aug 1. 

The dam, creating Diamond Mill Pond, is located on Brookside Drive in Millburn, which overflowed last year during Hurricane Irene flooding downtown Millburn.

The county took out a loan with the state to pay for the improvements while waiting on a grant from the New Jersey Department of Environmental Protection. 

"I just didn't want to wait any longer," said Essex County Executive Joseph N. DiVincenzo Jr..

The dam stopping water from the West Branch of the Rahway River is part of the South Mountain Reservation, which contains 2,047 acres streching across West Orange, Maplewood and Millburn.  

The $756,134 project, which started in June, will improve water flow along West Branch of the Rahway River when completed in September. The improvements include a new spillway, a sluice gate to control water level, an abutment, concrete cap and headwall to control the levels of the 3.5-acre Diamond Mill Pond.

A new important addition to the dam is a 12,000-square foot articulate concrete block reinforcing the dam, said an official from HAKS, the engineering firm contracted for the project from Newark. The block will be installed on the east side of the dam to protect the dam in the event of extreme weather, such as Hurricane Irene.

Haimoff and DiVincenzo both explained though, the improvements will help with flooding but will not prevent it entirely. "It's not the answer to all," DiVincenzo said.

DiVincenzo also said he's been in contact with the mayor Orange to repair a dam at Cambell's pond, as well as a footbridge, which goes over the dam. The project would cost an estimated $3 million. DiVincenzo explained the walkway is not safe and many residents use it. 

"The only way to get this to work is to get that dam to work in connection with this dam, especially downstream," DiVincenzo said.

The project started in 2011, after Hurricane Irene, when NJDEP told the county to lower the water level three feet below the spillway. The last time the 19th century dam was renovated was 1935. 

Navka Construction received the $660,044 contract for the improvements on the dam. HAKS engineering firm, of Newark also, was contracted at $90,094 to draft the designs.