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Archive for Thursday, November 5, 2009

Soil samples to help save Potter Lake

Jerry deNoyelles, deputy director of the Kansas Biological Survey and a professor in the ecology and evolutionary biology department at Kansas University, disassembles a coring unit after taking a core sample from Potter Lake Wednesday, Nov. 4, 2009 at Potter Lake. Both Kansas Biological Survey officials and Kansas University faculty from both the ecology and evolutionary biology department and the environmental studies department worked to extract core samples from the lake to measure sedimentation. In back are KU environmental studies professor Bob Hagen and Lenexa senior Ryan Callihan.

Jerry deNoyelles, deputy director of the Kansas Biological Survey and a professor in the ecology and evolutionary biology department at Kansas University, disassembles a coring unit after taking a core sample from Potter Lake Wednesday, Nov. 4, 2009 at Potter Lake. Both Kansas Biological Survey officials and Kansas University faculty from both the ecology and evolutionary biology department and the environmental studies department worked to extract core samples from the lake to measure sedimentation. In back are KU environmental studies professor Bob Hagen and Lenexa senior Ryan Callihan.

November 5, 2009

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Scientists analyze KU's Potter Lake

The Kansas Biological Survey's sediment coring rig visited Potter Lake Wednesday to quantify the amount of sediment and to take material for chemical analysis. The work could help restore the health of the landmark situated in the middle of KU's campus. Enlarge video

Kansas University scientists who travel all over the state gathering data on lakes stayed home on Wednesday conducting research in their backyard.

What they found was enough silt in Potter Lake to fill roughly 600 dump trucks with mud.

A group from the Kansas Biological Survey took soil samples at Potter Lake to determine how much it would cost to dredge the aging pond.

“That’s an awful lot of silt, considering we have a fairly small watershed here,” said Mark Jakubauskas, a research associate professor at the Kansas Biological Survey.

A campus treasure, Potter Lake once hosted canoe races and had diving platforms. In the 1950s, it was drained and dredged. Over the past half century, runoff has washed into the lake, filling it with sediment, nutrients and plant life.

This summer, the lake’s health was at a crisis point. Heavy rainfalls led to a burst in plant growth, which sucked oxygen from the water. As a result, hundreds of fish died.

This fall, student groups joined together to make improvements — scooping out 8 tons of coontail one pitchfork at a time. They also added aerators to increase the lake’s oxygen levels.

It’s time to dredge the lake again, said Jerry deNoyelles, deputy director of the Kansas Biological Survey.

“It is probably the only long-term solution that there is,” he said.

It was a solution that had the scientists building a wooden ramp Wednesday to launch a 24-foot pontoon boat into the one-and-a-half-acre lake.

“We’re in. We are not coming out,” deNoyelles joked as the boat glided into the water.

By using a 15-foot drilling rig called a vibracore — a kind of giant metal straw with a motor on top — the scientists were able to push through the silt to reach the original bottom of the lake and then pull the sediment up in a tube.

More than a half-dozen of these core sediment samples were taken. By noon, the group had enough data to estimate the lake had an average of two feet of sediment on the bottom — a total of 5,000 cubic yards of silt.

Previous student groups have estimated it would cost between $50,000 and $100,000 to dredge the lake.

Along with helping establish the cost of dredging, Wednesday’s sediment collection will be sent to labs to be analyzed. That information will help determine what dredging methods will work best.

And, just in case any former KU students were wondering, the group hadn’t come across any lost car keys, term papers or textbooks. So far, the scientists have pulled up only mud.

Comments

tyson travis 5 years, 1 month ago

Had a humorous flashback while reading this, it took me back to my mid-'60s days as a KU student, when conventional campus wisdom held that Potter Lake was the only rubber-lined lake in Kansas. Seeing as how students will be students, perhaps a 50-year thick layer of discarded latex rubber on the botom has inhibited natural biodegradation. Seriously, that's a LOT of sediment, what happens when old Snow Hall and Carruth-O'Leary fall into the lake due to the soil around their foundations washing away? Perhaps the creation of some kind of small catch basin where the sediment could be periodically scooped out before winding up in the lake would help, but I'm not a hydrological engineer.

Steve Miller 5 years, 1 month ago

Be green, put some asian carp in it , they'll not only eat all of the plant life, but also repopulate.

puddleglum 5 years, 1 month ago

dudedog, are you saying asians can't drive? or that they are all vegetarians? or that they are taking over the population of the world? this is so racialististic.

lounger 5 years, 1 month ago

consumer 1 is correct-like it or not. K.U. puts waaaay to much chemical fertilizer on the grounds near the lake. This is major issue that would improve things right away if they were more sensitive to potters lake. Actually K.U. puts waaay to much chemical fertilizer on EVERYTHING! Go green K.U. its about time!!!!

notjustastudent 5 years, 1 month ago

KU has been fertilizing for years and years, but the plant boom did not happen for years and years, it happened this year, when we had ridiculous amounts of rain. Logic tells us that it isn't the fertilizers, it's the rain. Extra silt is not a result of fertilizers. Science also tells us this, but I'm not a scientist so I'll go with what I know (logic) and point out that fertilizers help things grow, they have root systems, root systems hold soil in place, so silt would be less likely a result from over fertilizing, and more likely a result from (get this) the runoff that results from too much rain. Still, it wouldn't hurt for KU to be greener...

Dudedog- some of the fish that died were the carp they put in last spring to eat the grass.

Puddle- I hope you're being sarcastic, and if you are, thanks for making me laugh today. Well done!

Leslie Swearingen 5 years, 1 month ago

I enjoyed seeing the pictures of Potter Lake as it has been in the past. I remember when they had ducks swimming out there and families would throw bread into the water for them and the fish.

jimmyjms 5 years, 1 month ago

Nah, deNoyelles could pass for 50 any day.

Steve Miller 5 years, 1 month ago

PG, if you knew anything about fish, you would know that there is such a thing as grass eatting carp for the purpose of cleaning up water bodies. I have them in my pond on the farm.

3up3down 5 years, 1 month ago

I like all the old pictures as well. One problem though. They are missing the one picture that was the best. It was the cadaver taken from Snow Hall, propped up under a tree with sunglasses and a newpaper. Got to love those students and their sense of humor.

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