DULUTH — One fact seems certain: Hartley Pond needs some attention.
The man-made lake is filling with silt and continues to grow shallower by the year. With its diminishing depth, oxygen levels in the water have declined, as well. Once, the pond sustained a healthy population of bass but no longer, due to the drop in water quality, said Kate Kubiak, natural resources coordinator for the city of Duluth.
In recent years, the pond also has become home to a dense growth of submerged aquatic vascular plants, observed John Lindgren, principal planner of fisheries for the Minnesota Department of Natural Resources.
He noted that the proliferating weeds fuel the depletion of oxygen in the water at this time of year, as bacteria breaks down the vegetation, consuming oxygen in the process and producing winter kill.
“So, because Hartley Pond is shallow and has dense vegetation, the fishery would be expected to remain in a condition of low quality. If the pond were to be deepened, a higher quality fishery could be established,” Lindgren said.
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The pond in the heart of Hartley Park also impedes the flow of Tischer Creek, a designated trout stream. Water impounded in the reservoir heats up in warm weather, providing a ripe environment for E.coli bacteria to multiply and increasing the temperature of Tischer Creek at its outflow.
Those conditions are not conducive to the health and reproduction of native trout species.
Kubiak said the negative effects of the pond have been documented up to a mile downstream.
As natural sediments in Tischer Creek drop out in the relatively stagnant water of the reservoir, the downstream waterway is deprived of a valuable resource, Lindgren said.
“If there is not sediment in the water, there is no sediment to be deposited in the downstream substrate. Natural and balanced sediment transport and deposition secures the substrate and causes the stream channel to be stable. If there is not sediment in the water, the water tends to remove sediment from the stream channel, causing erosion and incision (downcutting) of the channel,” he explained.
Inaction does not appear to be a good option to Jim Filby Williams, Duluth’s director of parks, properties and libraries.
“If we do nothing whatsoever, the pond; the recreational, cultural and aesthetic values of the pond, which are already deteriorating, will deteriorate at an accelerated rate, because as the pond silts in, temperatures rise and the water becomes less hospitable for swimming, paddling and aquatic life,” he said.
On Thursday evening, the city hosted the first of three planned public meetings to inform residents of a feasibility study now underway to explore different options for Hartley Pond and Tischer Creek.
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Kubiak said the city already has begun to discuss a number of possibilities, including:
- Rerouting Tischer Creek around the north or south side of the pond
- Installing an intake to feed cool water from the bottom of the pond into the Tischer Creek outflow
- Removing the dam altogether
- Building rock arch rapids that would cause water to back up but also would allow for the free passage of fish
Filby Williams stressed that the process is just beginning.
“We are not pre-committed to any particular course. What we do want to help the community do, is make an intentional, informed choice, and not, by virtue of our potential inability to make a decision, simply lock us into a trajectory that right now is pretty negative,”
The Minnesota Department of Natural Resources is managing the $200,000 study with support from the Great Lakes Restoration Initiative. The research should be completed by the end of this year.
While Hartley Pond presents certain challenges, Kubiak said she knows how much it means to park users.
“Enhancing the biological and recreational value of that pond is very important to the city and will be part of any alternative that’s selected,” Kubiak said.
She expressed hope that the study will bring greater clarity to the picture, including whether the pond is fed not just by Tischer but by natural spring water.
“This whole feasibility study has been a wish of many people for more than 10 years,” Kubiak said
Recalling a mini-master plan developed to guide the future development of Hartley Park, Filby Williams said: “It directs us to conduct a feasibility study of the possibility of restoring Tischer Creek in a manner that, to the maximum degree possible, preserves and enhances the aesthetic, recreational and cultural values of the pond. So that is our expressed aim and aspiration. And it is definitely aspirational, because all the options that one can conceive will involve unique trade-offs for those different values. So, we are looking forward to working with the community to find the option that minimizes those trade-offs and provides a balance of community values that the community can be comfortable with.”
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Filby Williams acknowledged difficult decisions likely await, as the community discusses the future of Hartley Pond.
“I think that contemplating and effecting change in beloved natural places is really hard. People have strong attachments to these places and strong feelings as a result. And we have those strong feelings, too. So, we respect and understand that these are significant decisions for the community,” he said.
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