Category: Clinton

Round Valley Reservoir Project Seeks Permanent Closure Of CR-629 Due To “Security Concerns”

July 19, 2022

CLINTON TOWNSHIP, NJ (HUNTERDON)–According to the Clinton Township website discussions are underway to close County Road 629 permanently in the area of the Round Valley Reservoir by the request of the New Jersey Water Supply Authority due to security concerns of “bad actors”

From the Clinton Township website:

As you probably already know, County Road 629 in Clinton Township, Hunterdon County has been closed since April 8, 2020, from the corner of Cherry Street and Old Mountain Road to just east of the driveway to the NJDEP “fishlabs”. The fish labs are located just east of the parking lot access to the Round Valley Fish and Wildlife Boat Ramp. This was originally proposed as a temporary closure during the construction project on the Round Valley embankments. This temporary closing was allowed by Hunterdon County Engineering at the request of the New Jersey Water Supply Authority.

Recently, the Authority has had informal conversations with the Hunterdon County Engineering Department, the Borough of Lebanon, and Clinton Township about making the existing temporary closure of County Road 629 permanent. Following our informal discussions, a specific request to close the road permanently has been asked of the mayors of Lebanon Borough and Clinton Township in advance of a formal similar request to Hunterdon County. If the closing is allowed, it is our intent, after all construction is complete, to continue to allow public access on the road for pedestrians and bicycles only. Keys to the vehicular access gates would be provided to Lebanon Borough, Clinton Township, and Hunterdon County emergency staff for vehicular access. This is not out of the ordinary as keys have already been provided to the same emergency services groups for to access other Authority-owned secure areas.

The purpose of this change is to improve dam safety. We cannot share specifics, but I can tell you that a very serious threat to earthen dams by bad actors would be facilitated by vehicular access to the structure. County Road 629 is the crest of the Round Valley Dike. Be aware that failure of any of the three Round Valley dams would have catastrophic impacts on downstream residents and water supply to over one million people in central New Jersey.

It is also noted that the Authority has received verbal support of this proposal from New Jersey Department of Environmental Protection’s Bureau of Dam Safety. The Round Valley Dike is the only one of the three embankments (at Round Valley) with unrestricted vehicular access to the crest. To my knowledge, there are no earthen embankments of this size in the state of New Jersey that allows public vehicular access.

I hope this helps you understand the situation. We do plan to add this information along with updates to our website in the future. The link to our project-specific webpage follows.


According to the website:

The Round Valley reservoir was formed in the 1960s in the Township of Clinton, New Jersey after the State constructed three large earthen embankments and flooded a large valley. The reservoir was named after the ring shaped Cushetunk Mountain that surrounds the area.

While the large valley was caused by the erosion of soft sedimentary rock, the surrounding mountain ridges endured due to the dense and durable underlay of volcanic rock.

Reaching depths of 180 feet, this 2,350-acre reservoir is known for its clear blue waters. At full capacity, the reservoir contains 55 billion gallons of water for use in central New Jersey, making it the largest water supply reservoir by volume in the state. Its water is primarily released to the nearby South Branch of the Rockaway Creek, which feeds the North Branch of the Raritan River.

The Round Valley reservoir is an “off-stream pump storage” reservoir, which means that it is filled primarily by pumping water into it. The New Jersey Water Supply Authority operates a pumping station in the Hamden section of Clinton Township to move water from the South Branch of the Raritan River into the reservoir via a large underground pipeline. Round Valley reservoir is part of a larger water supply system supply called the Raritan Basin system, which also includes the Spruce Run Reservoir. Additional information about the Raritan Basin system can be found on the Authority’s website.

Round Valley reservoir was designed for water supply purposes, but is also managed for recreational activities such as fishing, boating, hiking, swimming and camping. The New Jersey Department of Environmental Protection’s (NJDEP) Division of Fish and Wildlife manages the fishery and game resources at Round Valley Reservoir and the NJDEP State Park Service manages the other recreational aspects of the reservoir.