The St. Lawrence River is one of the largest rivers in North America. Its flow impacts both the US and Canada, including the five Great Lakes. It’s also the site of large hydroelectric power plants owned by the US and Canada and functions as a deep water seaway connecting the Atlantic Ocean with the Great Lakes. The energy production and seaway have provided many benefits but have also created some ecological concerns including impediment to migration for young American eels.

American eels are extremely beneficial to the ecosystem of the area as they devour dead fish, invertebrates, carrion and insects. For the ecological balance to continue forward, young eels need to move from the ocean to the upper St. Lawrence River and Lake Ontario to live out their adult lives.

The challenges to migration have been overcome by the construction of highly effective eel ladders installed by Ontario Hydro, owner of the Canadian half of the power project, and the New York Power Authority (NYPA) owner of the US hydroelectric plant.

On the US portion of the project, an 182ft eel ladder provides safe passage for the American eel to navigate around power plants located on the St Lawrence River Power Dam during the eels’ summer migration upstream to the Great Lakes.

Engineering challenges

While the eel ladders have proven effective, their construction was an engineering challenge – from the positioning and angle of the ladder to the water flow necessary to encourage the eels to swim upstream and finally how to safely release the eels so they would not fall back through the plant’s turbines.

A team of biologists, civil engineers, electricians and software engineers were called upon by the NYPA to assess the challenges and create a solution. Gaining best practices information from other eel ladder projects, particularly the Ontario Hydro ladder built in the 1990’s, engineers determined, for example, that the ladder could be built at a greater angle giving the eels a shorter distance to migrate.

Deadline Solutions – an engineering services company headquartered in Syracuse, NY, which has extensive experience with control systems and software development for unique applications – was one of the firms contracted by the NYPA. In turn, Deadline Solutions used Kepware Technologies, Inc., of Portland, Maine, for its communications software for automation.

Deadline Solutions customized a .NET Windows application that monitors the eel ladder water flows and provides access for pump control logic using a PLC (Programmable Logic Controller) and a PC. The customized application uses a Kepware Technologies solution for communications between the PLC and the PC. Via the KEPServerEX, its .NET Windows Application allows for communicating and distributing the data among designated recipients.

As the water flows are so critical to the success of the project, alarms were built into the system via the custom Windows application, which sends alerts to the designated recipients if there is an alarm condition that requires immediate attention.

Communication controls

This eel ladder water flow application was mission-critical as flows had to be kept at a certain rate to allow the eels to successful migrate. KEPServerEX was proven as Deadline Solutions had used it in previous applications. According to Mike Silliman, Software Engineer at Deadline Solutions: “Kepware was the most robust communications technology we could find. It enabled us to track some of the internal events such as system level monitoring, for example, which could set an alarm if PLC communication was lost.” Now running successfully for four years, the communications is handled through fiber optics to remote I/O blocks.

“The KEPServerEX is straightforward and easy to set up and does not require a lot of leverage to make it work,” Silliman adds. “You install the software, address the device and right away you’re collecting data, proving out the base system for retrieving information.”

Tracking results

Biologists located at the power dam track flow data to ensure enough water is being fed into the eel ladder system. Having the capability of monitoring and trending the flow data, NYPA can maintain its licensing requirements as mandated by the US Fish and Wildlife Service. The eels’ migratory period begins in July and ends in October. Migration begins upstream just after dark when personnel are not always present. Throughout the evening, the eels are moving up the ladder system with the aid of water flows. The American eel requires a steady stream of water to encourage them to continue up the eel ladder. The water flow must be maintained within a range of a few gallons per minute. If the flow is too aggressive the eels will tire or not attempt to continue up the ladder. If flows are too low the eels will abandon the ladder or become stranded. It is the system level monitoring capability of the KEPServerEX that enables NYPA to record the data accurately and reliably throughout the evening hours.

Eel counts and water flows are analyzed the following day and recorded for future reference as dictated by federal regulatory requirements.

The construction company had specifications for pumps and controls systems and software. It relied on Deadline Solutions to come up with the control strategy and develop the software to run the system. Kepware’s ‘out of the box’ approach saved time configuring the I/O. And Kepware’s licensing scheme allowed Deadline Solutions to fully develop and test out the system prior to implementation, thereby streamlining the business aspect of the project and ensuring success upon delivery.

“I can download, build tags and know what I’m getting right out of the gate,” comments Silliman. “When I arrive at the customer site, it’s just a matter of turning on the licensing switch. This guarantees our success at the customer site, maintaining a high level of efficiency across the breadth of the project.”

This system also enables the NYPA to report to regulatory agencies that the water flows are constant and “eel migration friendly”.

“This was a truly collaborative effort between the New York Power Authority and the US Fish and Wildlife Service to design a ladder that would enhance the conservation of American eels without reducing any power to NYPA’s customers,” says Michael Thabault, assistant regional director of Ecological Services, U.S. Fish and Wildlife Service. “This eel ladder utilizes state-of-the-art techniques to pass American eel upstream at the project.  This structure will help our efforts to conserve the American eel by passing more juveniles upstream where they may live to be 30 years old before returning to the ocean to spawn. The monitoring data resulting from daily eel counts at the ladder will provide the Service with very valuable information about the numbers and timing of the migrations of this catadromous species.”

For further details please visit Deadline Solutions at and Kepware at