Restoring water quality in Mill Pond will be a long, expensive and arduous process, a lake ecology expert told members of the Southampton Town Trustees on Monday.
Years of expensive mineral treatments to the pond’s nutrient-rich bottom sediments, a major effort to remove carp and invasive plants, and efforts to reduce the flow of pollutants into the pond will likely be required to have a chance at restoring the pond to its once clear and healthy state, limnologist Lee Lyman told the Trustees. And, he added, even efforts that are successful might simply spawn more problems down the road.
The Trustees have hired Mr. Lyman to lead a study of the pond and devise a management plan that will resurrect it from the algae-choked conditions that have killed off most of its once ubiquitous game fish and left the pond a soupy green mess, neither inviting nor safe for human use in the later summer months.
“Basically, you have a pond that is getting old and dying,” Mr. Lyman said. “First, you’ve got to get together and talk about solving your algae blooms.” That will require a coordinated effort focusing on both the conditions in the pond itself and on factors in its watershed, he said, likely requiring extensive efforts to educate and enlist the public on assisting the effort.
The Trustees have already been weighing a number of options. Mr. Lyman and local consultant Jim Walker have said that ridding the pond of carp, which eat native plant species that can help oxygenate the pond, should be one of the first priorities. The Trustees have ruled out poisoning the fish and starting over with a new re-stocking of gamefish species, in favor of hiring commercial fishermen to net the carp.
Addressing the nutrient loads, particularly phosphorus, in the pond’s bottom, which are fed by polluted road runoff and groundwater laced with decades’ worth of fertilizers from nearby farm fields, will likely have to be dealt with. One way is to apply heavy minerals that will bind with nutrients and sink to the bottom of the pond, preventing them from stirring in the water column and feeding the algae blooms that plague the pond. Mr. Lyman said that depending on which minerals are chosen, as much 20,000 to 30,000 gallons of liquid solution might have to be released into the pond two or three times each year for several years to get the nutrient loads under control. And since the pond is receiving nearly half of its phosphorus inputs from outside inputs, those treatments will likely have to continue well into the future.
“Two or three years is not going to do it,” he said. “This is going to be a long process.”
on Feb 9, 2011