Questions & Answers on the Lake Surprise Dam Project

The dam must be replaced to meet modern safety standards. While there have been upgrades over the years, the earthen core dates back to 1845. Currently, over 1,500 gallons of water leak through or under the dam each day.

Why now?
By starting in the spring, the contractors are optimistic the lake will be drained for only one summer. If the project were to commence in the fall, the inability to construct various sections of the dam during the winter months could result in the lake being drained for two summers.

Why is the lake being drained?
The primary reason for draining the lake is for the safety of the workers who are rebuilding the dam. If the water were to remain in the lake, there would be pressure against the structure. As one engineer put it, “Leaving water in the lake would be a loaded gun.”
Dam projects often present unique challenges. In neighboring Morris County, the MC Parks Commission has had to replace five dams over the past several years, with each project requiring a different approach.  With the Lake Surprise project, the professional opinion was that draining the lake provided the safest work environment with minimal effect on the environment.

Why are the fish being removed?
To save them. The fish are being relocated to other nearby lakes, including Seeley’s Pond, at the western edge of the Watchung Reservation.

When are the fish being removed?
The first phase was undertaken in early June, with the final phase to take place once the Lake is lowered.  That is expected to happen between June 19 and June 23.

Are there other places to fish in the area?
Absolutely. To learn more about fishing in Union County, go to: To view a listing of all locations where the State st+ocks trout, go to

Will the Lake environment be damaged as a result of this project?
The State of New Jersey’s environmental rules and regulations were enacted to  protect the environment and are administered by the NJDEP. The Contractor is required to abide by the conditions of the various permits which were issued by the NJDEP. With regard to the ecology of the lakes and the Watchung Reservation, the proposed construction is not expected to degrade the existing environment.

Are there other places to go canoeing or kayaking?
Yes. For a listing of other Union County parks where private boating is permitted, go to the UC Parks activities chart. But don’t forget, the County requires all boats to be registered. For that form, click here.

How will the project affect hiking in the Reservation?
Parks staff is currently evaluating the area and hopes to post a map soon detailing any restrictions required for the project.  That said, most of the 40 miles of trails in the preserve will not be affected.

How will the project affect horseback riding in the Reservation?
Horseback riders are being advised to avoid the area during the duration of the project.

How long will the lake be drained?
There is no firm answer at this point in the project. The contractors are hopeful the lake can be raised once all the upstream side of the dam work is completed.

Should homeowners or businesses downstream from the lake be concerned?
The Lake Surprise dam is classified as a Class II dam, which means that because of its location, even if there were a dam failure, it would not present a life-threatening hazard. That said, the waters from the Reservation ultimately flow to the Green Brook and the County wants to do everything possible not to exacerbate downstream flooding problems or place downstream towns at any risk because the County failed to live up to its responsibility to maintain the Lake Surprise dam.

Does emptying the lake present any threat to downstream communities?
Draining the lake will not present any problems for downstream communities. Once drained, there will be almost no difference in the amount of water flowing down the Blue Brook, either with or without the dam in place.

Why were trees removed from the existing fire trail and the route widened from the Lower Loop parking area to the Lake?
The project requires some large equipment that would not be able to get down to the lake at the fire trail’s present width.

Will the work be noisy?
Sometimes. Workers will be on site from 7 am to 3:30 pm, Monday through Friday. But there may be times when it will run longer, or on weekends.

Who is building the new dam?
Ritacco Construction Company Inc. of Belleville, New Jersey was awarded a $3,608,000 contract for the Lake Surprise Dam rehabilitation.

Is there anything else involved in this project?
Yes. The project will also include improvements to the dam at Seeley’s Pond, which is downstream from Lake Surprise. However, that work will not require lowering the water level there.

How will the lake be drained?
The contractor has elected to lower the lake in accordance with the terms and conditions of the Dam Safety Permit Application Permit No. 1381 issued by the NJDEP Bureau of Dam Safety and Flood Control. The contract documents allow the contractor to lower the lake to complete the work; however they do not require lowering the lake. The option is completely up to the Contractor, who is the entity that applied for the Water Lowering Permit, since granted by the New Jersey Division of Fish and Wildlife (“NJDFW”).

Were environmental concerns taken into account in that lowering the lake will affect flora and  fauna? And was there consideration given to not lowering the lake?
The NJDFW issues water lowering permits for the sole purpose of protecting the state’s aquatic biota. The nature of the work requires cofferdams, the cost of which increases significantly with the height of the water retained by the cofferdam system.  There were also significant safety concerns if the workers were in an area where the water pressure created by a full lake was brought to bear.
It is generally accepted practice to provide for lowering the lake to facilitate more efficient construction, a lower price to the public, while providing safeguards to the fish. The contractor has submitted a lake lowering plan which is being reviewed by the County’s engineering consultant which is pending approval. The plan includes the use of pumps intended to safely lower the water surface elevation of the lake, which discharge into sediment control devices.

Was any consideration given to just eliminating the dam?
While there is a growing movement in the United States to remove dams, much of that effort is related to returning rivers to their natural state to enable fish to spawn again.
Lake Surprise is a man-made lake, created as a reserve power source to run mills downstream. (One can visit the Deserted Village to see the remnants of one of these dams)
In addition to the decommissioning of a dam being a lengthy and costly process, the County believes that Lake Surprise is an oasis that visitors have come to enjoy and should be there for generations to come.

Will the dam still look the same?
The contractor is to recreate a façade similar to the one that now exists. The dam will be reconstructed with concrete, with a stone masonry facing on the downstream (visible) face of the dam. It is the intent of the project to select stone masonry that matches the appearance of the existing stone masonry wall.  Photographs were taken of the existing dam to facilitate coming up with a similar looking façade.

How will the area around the dam look after the work is completed?
All dams in the State of New Jersey are required to comply with the New Jersey Dam Safety Standards, N.J.A.C. 7:20 (“The Standards”).  The Standards set forth procedures for application to construct, repair or modify a dam, as defined in N.J.A.C. 7:20-1.2 and set standards for design and maintenance of dams.
Removal of trees from the dam, and the vicinity of the dam,  required by The Standards. (N.J.A.C. 7:20-1.4n).  The root system of trees on a dam creates seepage paths, which threaten the stability of the structure. In addition, large trees have the potential to fall during high winds, and remove large portions of the dam embankment, leaving the embankment vulnerable to overtopping.

Were drawings or renderings prepared showing what the dam will look like once it is completed?
No renderings were prepared for the project. However, plans and specifications for the dam rehabilitation were prepared.  And as mentioned before, photographs of the existing dam will help guide the recreation of the downstream side of the dam.

W. R. Tracy Drive, which leads to Glenside Avenue, was closed for several days recently. Why were residents not notified that the project would require road closures?
The closure of W. R. Tracy Drive was unrelated to the rehabilitation of Lake Surprise Dam.  The Dept. of Public Works was repairing and repaving sections of the road. That work is now complete.  The DPW routinely posts road projects on the County website,

Will any signs be posted regarding the dam project?
Signs have been posted at the boat launch off Tracy Drive and at the Lower Loop parking lot, two of the main locations from which visitors access the lake.  Additional signage is planned for the area to be fenced off for the project and additional information will be posted on the County website,

What paths will be used by the construction company and what plans are there for restoration?
The contractor will be using the existing access road from the Lower Loop parking lot to the dam. While the roadway had to be widened to enable the heavy equipment to access the site, when the dam is completed, the contractor will restore the site to the satisfaction of the Department of Parks and Recreation.

What was the source of the funding for this project?
This project is funded in full by the County of Union.

What selection criteria and process was used to award the contract?
The Contractor was awarded the project through a fair and open bidding process. The County received 12 responsive bids for the project. Ritacco Construction, Inc.’s bid was the lowest responsive bid for the project. Subsequently, recommendations to award were made by the T&M Associates – the County’s engineering design consultant, County Counsel, and the County Engineer.  Construction Administration shall be provided by French & Parrello Associates, PA.

What are the governing agencies that are involved in this project?
The NJ Department of Environmental Protection is deeply involved in all aspects of this project.

What is the nature of the work planned for the dam at Seeley’s Pond?
As a result of the biennial inspection of the Seeley’s Pond Dam, a dam safety deficiency was identified.  To satisfy the standards, overtopping protection was selected as the preferred alternative to protect the downstream retaining wall from erosion and potential dam failure, due to overtopping flows during the Spillway Design Storm. Gabion mattresses and gabion baskets will be installed to serve as overtopping protection.  The newly protected area will be restored to the pre-existing grade with topsoil and seed.

What is the ecological impact of the two dam projects and what will be done to address this both during the work, and when it is completed?
The proposed construction is not expected to degrade any of the natural aspects that currently exist.  With regard to the ecology of the lakes and the Watchung Reservation, the Contractor is required to abide by the conditions of the various permits which were issued by the NJDEP:

a)   Dam Safety Permit,
b)   Freshwater Wetlands General Permit No. 18 and Water Quality Certification,
c)   The Scientific Collection Permit,
d)   Freshwater Fish Stocking Permits,
e)   Water Lowering Permit, and
f)    The Somerset-Union Conservation District Soil Erosion and Sediment Control Plan Certification

Conditions of these permits allow for the fish within Lake Surprise to be collected and relocated to other bodies of water so they are not adversely affected by the water lowering. Other permit conditions are intended to protect wildlife in, and around the lake.

Who is responsible for monitoring the project and seeing to it that there is no damage to the environment and that DEP rules are being followed?
These concerns are covered within the various NJDEP permits listed above regarding potential adverse impacts to species of plants and animals.
French & Parrello Associates was retained by the County to observe the rehabilitation of the dam to ensure conformance with the plans and specifications. In addition, DEP officials may visit the site at any time, at their discretion.

What were the engineering concerns for this undertaking?
The rehabilitation of the two dams was driven primarily by compliance with the NJDEP Bureau of Dam Safety and Flood Control’s Dam Safety Standards. The intent is for the dams to be rehabilitated to provide structures which comply with the Standards that safely pass the Spillway Design Storm. Historically, the majority of dam failures are caused by overtopping, the chances of which will now be greatly reduced by the Rehabilitation of Seeley’s Pond Dam and Lake Surprise Dam. The cost of the dam repairs is minimal when compared with the economic consequences of a dam failure.
There are various Dam Safety deficiencies that needed to be addressed based on Inspection Reports and Engineering Analyses. To address the major deficiencies, the County’s consulting engineer recommended that:

a)   The spillway and dam be rehabilitated to safety pass the Spillway Design Storm, which is considered the 100 year storm. Flows from this storm event overtop the dam and threaten the stability of the structure. (N.J.A.C. 7:20-1.9)
b)   Installation of a low level outlet structure, which is required for all dams, based on The Standards. (N.J.A.C. 7:20-1.9i). Currently there is no low level outlet structure to safely lower the water surface elevation of the lake in a controlled manner.

Was there a formal environmental assessment of the project performed by the DEP?
Since the dam is being rehabilitated, not permanently removed, and as the normal pool elevation, and hydrology and hydraulics associated with the proposed dam will match that of the existing dam, a formal Environmental Assessment was not required.

Is there an Emergency Action Plan or Safety Plan?
There is no Emergency Action Plan required for the Lake Surprise Dam as it was recently downgraded from a Class II, Significant Hazard Dam, to a Class III, Low Hazard Dam. The New Jersey Dam Safety Standards do not require Emergency Action Plans for Class III, Low Hazard Structures. The contractor did submit a Health and Safety Plan at the pre-construction meeting.

If I have more questions?
Send your questions using the Parks feedback page,