Frequently Asked Questions

Q: What is the project?

The Round Valley Reservoir Structures Refurbishment and Resource Preservation Project is making improvements to extend the operating life of the Round Valley reservoir.

Q: Who is in charge of the project?

The project is controlled and led by The New Jersey Water Supply Authority.

Q: What is the project going to do?

The project will refurbish the reservoir structures with state-of-the-art design standards and construction techniques. The project will extend the operating life of the Round Valley reservoir, which is the largest drinking water supply by volume in New Jersey.

The success of the project will be vital to the State’s ability to sustain prolonged droughts by increasing this vital reservoir’s structural durability. This improved resilience will help ensure supplies of drinking water for future generations.

The Round Valley Project entails a number of components including installation of improved drainage systems on the embankments, abutment grouting, dredging the channel where the reservoir is filled, security upgrades, instrumentation upgrades, and a number of other structural and mechanical improvements. For additional information about the project components, please view our video here and/or our public presentation here. The project timeline is located here.

Q: When will the project start and end?

There are a number of project components that will be undertaken on different timelines. Additional project timeline details will be announced here as soon as the information is available.

Q: Will the project affect people who use the reservoir for recreational activities?

Construction efforts are scheduled to minimize disruption to the public’s use and enjoyment of all that the Round Valley reservoir has to offer; however, certain disruptions may be unavoidable. The details of these activities will be announced on this website and our email list as soon as the information is available. The reservoir was lowered to the target maximum construction elevation during the late summer/fall 2019. The reservoir will remain at or below elevation 360’ (25 feet below full pool) for the duration of the project.

The Cushetunk trail crosses through a restricted area of Round Valley which will be under construction during this project. Due to the nature of construction activities in that area (many trucks crossing, active earthmoving equipment, etc.), we have to plan for the safety of the public and workers as well as for the safety of the dam. A section of the trail has been re-routed . Signage has been posted in the vicinity of the trail and in the Park office at Round Valley. You can join our mailing list to receive periodic updates via email by clicking here.

Q: Will the project affect local drinking water usage?

The Round Valley reservoir is connected to natural river systems, which enables water to be stored and moved around within the reservoir’s service area of central New Jersey. Balancing the needs of everyone that relies on this water is a critical part of the New Jersey Water Supply Authority’s work.

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. No disruption to public water usage is expected from this project.

Q: Will you be cutting down trees as part of the project?

The largest construction component of the project is the rehabilitation of the three embankments, or dams: the North Dam, the South Dam, and the Dike. While under construction, a large volume of earthen material will be temporarily removed from each embankment and must be kept nearby. Additionally, gravel and sand will be brought onsite to be placed on the embankments as part of the rehabilitation. Staging and stockpiling areas are necessary at all three embankments to store these materials and tree clearing will be necessary to create these areas.

Approximately 40 acres of trees will be removed, more than half of which are located in heavily ash-dominant forest stands that are dead or dying as a result of the Emerald Ash Borer, an invasive insect. The ash stands were targeted for staging and stockpiling in part because the dying trees were already slated for removal to protect the public. Permits from the NJ Department of Environmental Protection will ensure that native wildlife and other natural resources are protected during the tree removal process. “No Net Loss” rules require reforestation, which will occur primarily in the same areas where trees will be removed. Native tree species will be replanted under the guidance of and approval by the State Forest Service.

More information about the tree removal, including maps of the staging and stockpiling areas and details about replanting plans, can be found in a presentation given at a Public Forum on February 8, 2019, which is posted at

Q: Will there be any public meetings?

Yes. The New Jersey Water Supply Authority hosted a Public Information session on November 14, 2017 and a Public Forum on February 8, 2019. The information
presented at the meetings is available here. If additional meetings will be held, announcements will be posted on the public meetings page and via our mailing list.

Q: What are the expected noise levels from the project?

There are three major projects that will occur at the reservoir on different timelines:
abutment grouting, dredging of the South Tower channel, and embankment rehabilitation (which includes a few other smaller projects). Noise levels and working hours will vary between the projects.

All of the construction will occur within Clinton Township, which has a noise ordinance.
Work at the North Dam will occur very close to Lebanon Borough, which also has a noise ordinance. The Authority has met with officials of both municipalities to review the anticipated noise and proposed working hours to ensure compliance with local

- The abutment grouting project will involve drilling into the bedrock foundation under
the North and South Dams and injecting cementitious grout into the bedrock using a drill rig and a generator. Sound levels are measured in decibels (dB): a drill rig in operation creates approximately 94 dB and a grout generator creates approximately 80 dB, measured at the source. Decibel levels decrease inversely with distance, and the minimum distance between the North Dam crest and the closest residential property is approximately 800 linear feet. A decibel level of 94 would be reduced to approximately 38 dB at a distance of 800 linear feet.

For comparison, the use of an outboard motor or farm tractor has a decibel level of
approximately 100 dB, a vacuum cleaner has a decibel level of 70 dB, and bird calls have a decibel level of 40 dB. Utilizing these comparisons, noise disturbances to neighbors of Round Valley during the abutment grouting project should be minimal. It should be noted that in 2014 and 2017, drilling operations were conducted at all three embankments with similar decibel levels.

- The dredging of the South Tower channel will involve the use of excavators, floating barges, and push boats. This work will all be done in the reservoir and will not generate noise that will travel beyond the Authority’s property lines.

- The embankment rehabilitation will occur at all three embankments: the North Dam,
the South Dam, and the Dike. Staging and stockpile areas will be located near the embankments. The Authority is making efforts to condense the construction periods on the embankment rehabilitation to as short a period as possible. Shorter construction duration reduces the risks associated with the project, reduces road closure periods, and lessens the impacts to neighbors.

Embankment rehabilitation will involve the use of equipment including excavators, backhoes, dump trucks and generators. Sound levels are measured in decibels (dB), and the levels generated by this equipment range from 73-81 dB, measured at 50’ distance from the source. Decibel levels decrease inversely with distance, and the minimum distance to the closest residential property is approximately 500 linear feet. Decibel levels at the nearest residential property should not exceed 61 dB, which compares to the noise levels generated by a normal conversation or an average air conditioner.

Additional work will occur at the North Tower and South Tower, both of which are located in the reservoir and will not generate noise that will travel beyond the Authority’s property lines.

Q: How long will the public road be closed by the North Dam? Will it also be closed to pedestrians and bicycles?

The segment of Route 629 that crosses the dike is expected to be closed for 3-4 weeks for the grouting project. The road will be closed again for at least 1 and a half years for the embankment project. It will be closed to the public entirely. The segment planned for closure is shown here. The current project timeline is shown here.

Q: What will the truck routes be? Will trucks be traveling Molasses Hill Road?

The trucking routes are shown here. There will be no heavy truck traffic related to the project on Molasses Hill Road.

Q: As part of the project will there be any new pipes put in under Old Mountain Road?


Q: In the embankment rehabilitation part of the project, why wouldn’t all embankments be worked on at the same time to limit impacts on roads and users of the park?

Through a careful and detailed planning process, the Authority determined that sequential construction, meaning excavation work on one dam at a time, would be the safest approach. Construction will start at the Dike (the embankment that carries Route 629 along the reservoir), then move to the North Dam (which faces Old Mountain Road) and then to the South Dam (which faces Molasses Hill Rd).The current project timeline is shown here.

Q: How much are you dredging? How long, deep, and wide will the channel be by the south tower?

The length of the dredging project will cover approximately 800 feet. The depth of sediment to be removed ranges from 3’ – 15’ and we expect to remove several thousand cubic yards of sediment and rock. The dredging is being done simply to restore the channel to its original design capacity. The bottom of the channel is approximately 10 feet wide. The proposed final elevation of the channel bottom ranges from EL 338.5 (closest to the tower) to EL 336.9 at the point farthest from the tower. Full pool elevation is EL 385.

Q: How and where will the dredged material be disposed? Does it contain heavy metals?

The material will be relocated from the channel into a deeper part of the reservoir. A total of eight sediment samples were taken to represent the length and depth of the
dredging limits. USEPA and NJDEP environmental sampling, handling and shipping protocols were followed throughout the process. The samples were analyzed for petroleum hydrocarbons, heavy metals and the list of organic chemicals that is the standard for environmental investigation. Results for all eight samples were below or were typical of “background” levels as reported by NJDEP.

Q: Will the dredging of the inlet channel impact water quality?

In-water silt curtains will be used to contain the material, so the impact to water quality should be very temporary and very localized to the dredge site, and therefore very minimal.

Q: What will happen to the hole that is drilled to inject the grout? Will it be filled in when the project is complete?

Yes, the hole is filled with grout after the grout reaches the bottommost point (in bedrock). Pipes and/or sleeves used while drilling the grout holes will be removed as the hole is filled with grout.

Q: Will drilling have an impact on residents and will it affect local wells?

The drilling and grouting operations will be performed under applicable NJDEP requirements, including N.J.A.C. 7:9D, to comply with regulations related to potential impacts to groundwater quality and local wells.  These operations will also be reviewed by NJDEP, Bureau of Dam Safety, as part of the overall dam rehabilitation project. Noise levels associated with drilling are also regulated and should not be disruptive to neighbors.

Q: Will the reservoir be lowered for construction?

As of February 2020, the reservoir has been lowered to 25’ below full pool (full pool is EL 385). This level is comparable to the elevation during the summer of 2016 when the pool was down due to water usage. Water supply needs during construction may necessitate additional releases, and if so, the pool would naturally be reduced beyond the current level (EL 360). The reservoir will be refilled after construction is complete. The current project timeline is shown here.

Q: When do you anticipate lowering the water level and how long will it take to lower?

The targeted reservoir water level for the embankment rehabilitation project is elevation 360 and drawdown is likely to occur in 2019. More specifics of the schedule will be announced in the Project Updates section of this website and on our mailing list. The current project timeline is shown here.

Q: What are the conditions at the Round Valley boat launch?

The Round Valley boat launch is maintained by the NJ Department of Environmental Protection’s Division of Fish & Wildlife. The Authority has no additional information on the conditions at the boat launch. As reservoir water levels fluctuate, the Division of Fish & Wildlife makes efforts to accommodate boats. Real-time reservoir water level information is available at NJWSA Operations Report and here.

Q: Can the boat ramp(s) be extended with concrete?

That decision is not up to the Authority as we do not operate the boat ramp(s). We will continue to keep the Division of Fish and Wildlife aware of anticipated reservoir levels.

Q: Will there be any boating restrictions during construction?

The Authority does not anticipate any boating restrictions during construction, unless they are dictated by reservoir pool elevation. For security purposes, there is a chance that the restricted areas near the embankments may be extended.

Q: With the reservoir so low, boaters to the camp sites have a difficult time beaching their boats to walk to the camp sites because of silting around the exposed shore line. The silting is a safety issue. Will this be addressed during the project?

The wilderness campground area is operated by the State Park Service and questions or concerns about it should be directed to them.

Q: What is the pumping schedule for filling and releasing water from Round Valley?

There is no set schedule for pumping. When and how much water is pumped into Round Valley is based on a variety of factors, the most critical of which is the presence of sufficient flow in the South Branch of the Raritan River, which is dependent on precipitation and other upstream withdrawals of water. Pumping is less effective when there is freezing in the river and intake pond. Pumping in the summer months is rarely done because flows in the river are low at that time.

Q: How much will this cost and how will it be paid for?

The engineering/construction budget as of December 2019 is $80,000,000. It will be paid for by the water customers who purchase water from the reservoir, through their
water rates. No tax money is involved.

Q: How much does it cost to fill the reservoir?

It costs approximately $100,000 per billion gallons.

Q: How long until all the work is complete?

The project schedule as of January 2020 anticipates all work being substantially completed by the end of 2022. The current project timeline is shown here.

Q: How can I contact a representative for more information?

To contact a project representative via email or phone, please click here.