Sediment build-up deteriorates Guilford’s lake

The Guilford College Lake used to be known as a recreational destination, attracting everyone from swimmers to sightseers. But in more recent years, the quality of the water has deteriorated to the point where its primary use is as a science lab. The lake was made in the early ’50s by damming a small creek that runs through campus. It was originally built with a pier, whose pylons can still be seen near the middle of the lake. After the dam was built, a drainage pipe was then placed with its lip at a certain height to regulate the overflow, effectively limiting how high the lake could get before it continued downstream by way of the pipe.

This set-up, though simple and efficient, also filters the clean water out of the lake: as it comes down the stream, water picks up dirt and other detritus and carries it down into the lake. Gravity then pulls the heavier particles to the lake bottom, leaving the cleaner water nearer to the surface of the lake and nearer to the drainage pipe.

“Our biggest problem with the lake is sediment erosion,” laments Angela Moore, Assistant Professor of Geology and Environmental Studies program co-coordinator.

This natural filtering process does have its benefits. The cleaner water eventually feeds into Lake Brandt, which is one of the three reservoirs used to provide Greensboro residents with drinking water. However, over the past decades feet and feet of this sediment muck has been deposited at the bottom of our lake, creating its current unsightliness.

“It’s not like it’s a natural pristine lake that’s been around for hundreds of years,” said Moore. “It will need to be dredged eventually.”

Initially built on a natural field, the lake has a base of compact dirt while the sediment has fallen into a loose layer of dirt. In some places closer to the middle of the lake, the layer of sediment has filled in almost a third of the initial depth of the lake. On the outside, however, there is significantly less sediment.

“There is a layer of sand at the bottom near the edges,” reported senior Andrew Gottlieb. “It’s more like gravel than anything else.”

The sediment that has not settled is just one of the causes for the general cloudiness of the water that makes it feel grimy to the touch. Another is the presence of algae that has a much more detrimental effect on the lake than its aesthetics.

Besides reducing the clarity of the water, when the algae die they mess with the already precarious chemical balance of the lake. This happens when bacteria use the dissolved oxygen in the surrounding water to decompose the dead algae.

The N.C. Division of Water Quality states, “North Carolina has adopted a water quality standard of 5.0 mg/l [of Oxygen] (daily average with minimum instantaneous measurements not permissible below 4.0 mg/l) in order to protect the majority of its waters.”

Oxygen levels in the lake have been tested as low as 4.5 mg/l.

At that level it is nearly impossible to promote aquatic health and diversity. It impedes animals’ ability to reproduce and negatively influences their immune systems.

“If they are stressed all the time they’ll be more susceptible to disease,” agrees Moore.

The recent renovation of the practice football field, located behind the gym, could be one of the main culprits. Dirt from the field undoubtedly erodes into the lake’s ecosystem, and any chemicals used to stimulate the growth of the grass on the field, fertilizers etc. that may have found their way into the lake have stimulated algae growth as well.

“The hill was just so steep, and the lake is right there,” said Moore.

That hill, located just above the creek, at the edge of the practice field, had visible runoff rivulets early in the fall semester before a light layer of grass grew in. In fact, any construction job up-creek of the lake significantly increases the rate at which sediment is deposited into our lake, filling it up even quicker.

The real tragedy of all this is that our lake has slowly become less and less popular on campus. Swimming and boating, once two of the most popular lake activities, have been banned.

“(Swimming) would be a major liability to the College,” said Keifer Bradshaw, Security Coordinator.

The fear of not being able to jump into the lake without hitting a golf cart is infinitely more effective at keeping kids out of the water than any blurb in the student handbook, especially when such myths have all the corroborative evidence they need in the murkiness of the water.

It’s a shame that at the time when the lake needs us the most, as it is slowly evaporating down a drainage pipe, it is also disappearing from our minds.