The bottom line is, nothing’s really changing.

That’s how Marc Brooks, executive director and acting chief engineer of the New Jersey Water Supply Authority, described the multi-year rehabilitation project currently taking place at the Round Valley Reservoir in Clinton Township.

The project, overseen by the New Jersey Water Supply Authority and expected to be completed by summer of 2022, will make improvements and renovations to an over half-a-century old reservoir in order to secure its long-term future as the state’s largest source of drinking water.

“We’re really just doing this rehabilitation to make sure (the reservoir) lasts another 50 or 100 years. And I’m sure in 50 years they’ll probably look at it again,” Brooks explained.

The Cushetunk Trail bordering the reservoir has been rerouted to accommodate construction but remains open, as do both the reservoir itself and its recreation area.

Cushetunk Trail signCourtesy - New Jersey Water Supply Authority

County Route 629, which parallels the north side of the reservoir between Old Mountain Road and the boat launch area, will likely be closed until March 2021, Brooks said.

The rehabilitation project entered its third and largest phase at the end of January, the main component of which is the installation of a chimney drain -- or layer of sand and gravel -- in the dike on Prescott Brook, as well as in the North and South Dams, which Brooks said will not aesthetically change the structures.

“As the sand and gravel layer is going back in, you’re placing the same material that you took off the dam right back on the slope, so it’s really going to look the same," Brooks explained. "It’s going to have this sand and gravel layer on the inside that I’m going to know about -- but it’s not going to be anything that anyone’s going to see.”

The first and second phases of renovation, which involve construction work entirely separate from the implementation of the chimney drain, will be “substantially completed” within the next week, Brooks confirmed.

Phase one of the project, headed by Keller Construction of Rockaway, began approximately one year ago. It involves the grouting of the abutment, or the point at which the constructed embankment meets the original valley, of the North and South Dam of the reservoir.

“They’re drilling down through the soil, and into the rock. And they’re pumping cementitious grout under pressure to fill existing cracks and voids in the rock," Brooks explained.

North Dam facing Lebanon BoroCourtesy - New Jersey Water Supply Authority

Brooks said the grouting project will help to reduce the seepage of water out of the reservoir through the bedrock and below the embankments.

“When the reservoir’s full, there’s a lot of pressure that’s being exerted on the embankments itself and on the bedrock below it. And there is seepage (through or around) the dams ... but we’re trying to limit that seepage as much as we can," Brooks explained.

Phase two of the project, which Brooks labeled the “smaller” of the two phases, is being facilitated by Mount Construction, Inc. of Berlin and involves dredging in front of the South Dam Tower, or the cleaning out of the bed of the reservoir in the area by scooping out silt and rock with a dredge.

The dredging, which has been underway for approximately two months, will clear out the sediment build-up created by the pumping of water from the South Branch of the Raritan River into the reservoir.

“When we pump, oftentimes the sediment in the water and the river ... tends to settle out there in front of the tower (of the South Dam)," Brooks explained. "We’ve also had some erosion take place there, and the amount of sediment was getting to the point where it was actually obstructing and not allowing us to fully use the tower. It’s piling up right in front of the tower, and we had to get rid of that.”

Phase three, or what Brooks referred to as the “main part” of the multi-phased project, was initiated in January by general contractor Thalle Construction Company, based out of Hillsborough, North Carolina.

This phase involves the installation of the chimney drain in both the North and South Dams as well as in the dike of the reservoir.

Dike and County Route 629Courtesy - New Jersey Water Supply Authority

Brooks explained the layer of sand and gravel being installed is designed to move water seepage that may come through the embankments away from the structures.

“We’re putting the sand and gravel layer downstream, on the dryer side of the clay. So any water that does seep through the clay, because it’s not perfectly impervious, and it never was expected to be, gets captured by the sand and gravel layer and gets transported away from the dam," Brooks said.

“There’s lots of dams in the country and the world that still don’t have these (chimney drains), but we’re thinking we’re trying to bring (the dams and dike) up to more current standards," he added.

Brooks said he expected the implementation of the drains in the dike, followed by the North Dam, to be “substantially completed" in 2020. He estimated near-full completion of its installation in the South Dam in 2021.

At present day, the contractor has started to mobilize their equipment, submit shop drawings, and began clearing trees located near the North Dam and South Dam, to be followed by the dike.

Brooks particularly emphasized the importance of the clearing of trees in the area, explaining that the action creates room to place the material of the top layers removed from the dams and dike.

“We’re excavating all of this earth off of the dams. Between all three dams, it’s 675,000 cubic yards. So, that’s a lot of space, so you need a place to put that,” Brooks said.

With the excavation, all of which is taking place on the downstream side of the embankments, de-watering devices will be installed to lower the pressure of the reservoir and increase the efficiency of the construction process.

Other ancillary work accompanying phase three of the construction process includes renovations to and roof replacements of the towers of the North and South Dams, the rehabilitation of sluice gates or valves that control the flow of water in and out of the reservoir, and the replacement and grouting of piping located near the South Dam.

North Dam TowerCourtesy - New Jersey Water Supply Authority

To further move forward the multi-faceted project, the capacity of the Round Valley Reservoir has been lowered by approximately 25 feet. The reservoir currently contains a total of 36.7 billion gallons, or two-thirds of its maximum of 55 billion gallons.

Despite the diminished capacity of the reservoir, Brooks confirmed the boat ramp of the park remains open.

“Obviously there’s less water, but 36.7 billion gallons is still a lot of water to use for the reservoir," Brooks said.

Brooks expressed his hope that individuals acknowledge the necessity of the rehabilitation project, as well as its overall purpose to preserve the 180 foot deep and 2,350-acre wide state icon that draws thousands of swimmers, boaters, fishermen, picnickers and campers to Clinton Township each year.

“It’s a great state resource, and it’s been 50 years since it was built in the 1960s," Brooks said. “This is a huge resource, for all these people that use it for drinking water, and we just want to maintain it as such.”

Caroline Fassett can be reached at cfassett@njadvancemedia.com.

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