Saying it's no longer a good use of taxpayer money, the Thirty Lakes Watershed District will cease paying for studies of the black hole on North Long Lake.
The hole, which first appeared in 2002 and which re-opened again after the ice initially froze in November, continues to baffle observers. A team headed by A.W. Research Laboratories in Brainerd studied the hole twice in recent weeks but cannot explain what is causing it. The studies, which involved divers from the Minnesota School of Diving, cost the Thirty Lakes Watershed District just under $6,000. Chairman Dick Beeson said it's time to call it quits.
"We accomplished what we set out to do," Beeson said Tuesday after meeting with A.W. Research to discuss the latest findings about the hole. "We got the word out that this is a dangerous area and we know from their tests that the lake is in good shape."
The district disputes a claim made by St. Paul Pioneer Press columnist Joe Soucheray that the cause of the hole has been explained, Beeson said. Soucheray supports a theory put forth by Steve McComas, who runs Blue Water Science in St. Paul. He says the hole on North Long and similar holes on other Minnesota lakes are being caused by strong groundwater upsurges resulting from heavy rains in recent summers.
"That theory doesn't hold water. It doesn't fit anything we've found," Beeson said. "For one thing, North Long is the only lake around here that's doing this. The other thing is that we didn't get any appreciable rain around here since July."
Indeed, tests made by the study team support Beeson's belief that groundwater upsurges are not causing the hole. Using dye and underwater cameras, the hole was monitored through time-lapse photography that didn't show any movement of water or unusual currents in the lake. The most recent theory, Beeson said, is that the hole is being kept open by a greenhouse effect on North Long.
"Out there on the ice there's no snow cover at all," Beeson said. "Last year we didn't have any snow cover either. There's plant life (on the bottom of North Long) that's still green. Without snow on the ice the sun might be interacting with the plant life in some manner that's keeping the water warm. The temperature in the hole is 38 to 40 degrees top to bottom. But we know it isn't being kept warmer by the groundwater."
Geologists and other members of the scientific community in Wisconsin, New Hampshire and New York "have the same problem" with the groundwater theory, Beeson said, adding that independentally-funded study teams might continue to investigate the hole.
Meanwhile, the hole continues to draw the interest of the international media. In past weeks Al Cibuzar, head of A.W. Research, has been interviewed by the Canadian Broadcasting Corp. and a network-affiliated radio station in South America. The Wall Street Journal and ABC World News Tonight also did stories about the hole.
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