Widgetized Section

Go to Admin » Appearance » Widgets » and move Gabfire Widget: Social into that MastheadOverlay zone

Recent Bioswell System Reduces Lagoon Pollution



While the Lagoon behind the UCen has no Loch Ness creature to its name, it has been known to have a monster smell.

However, some recent environmental engineering and other efforts over the past 30 years have significantly eased the area’s infamous odor, reducing it to a nearly undetectable level. Since August 2002, employees and interns from the UCSB’s Museum of Systematics and Ecology (MSE), which oversees management of the lagoon, have designed and constructed an organic system of “bioswells” to naturally filter surface water runoff before it deposits odor-causing chemicals in the lagoon.

Bioswells are man-made basins that look like small ponds, said Melanie Powers, MSE restoration project manager. The ponds collect runoff water that flows from higher elevation areas, such as Manzanita Village, to lower elevation areas like the lagoon.

Much of the pollution the bioswells capture comes from the ammonia and fertilizer used on campus lawns, Powers said. Contaminants such as oil and brake pad dust can also find their way into the lagoon from nearby roads, such as Ocean Road, and parking lots such as the lot adjacent to San Rafael Residence Hall.

The bioswells also prevent stench from “fishkill,” said Jennifer Thorsch, MSE interim director. Fishkill occurs when large numbers of fish die because of unusually high bacteria contamination caused by pollutants.

In the lagoon, Thorsch said excess bacteria leads to a process called eutrophication, which occurs when oxygen in the water is used up by the decomposition of algae. The decreased concentration of oxygen in the water is what kills the fish.

The Manzanita Village rooftops are another source of contaminants that play a role in leading the lagoon to stink, said George Thomson, MSE restoration ecology coordinator.

“The downspouts from the roofs run through the landscaped lawns, eventually collecting into the bioswells,” said Thomson, a Donald Bren School of Environmental Science & Management graduate student. “Off the roofs we’ve got bird feces and other things that accumulate over the dry season, and, in high concentrations, contaminate water quality … It’s most likely nitrogen compounds that are coming off of the roofs of Manzanita and other landscaped areas as well as nutrients that are normally found in the soil.”

Thomson said if the bioswells had not been constructed, runoff pollution could spread to other parts of the environment.

“A lot of the runoff water on-campus goes either directly into the ocean or into the campus lagoon. So it is critical to control the quality of the water before it hits those areas,” Thomson said.

The western part of the Lagoon, adjacent to Manzanita Village, has approximately 1,400 linear feet of bioswells, said Melanie Howard, a Donald Bren School of Environmental Science & Management graduate. Within this range are the 45 wetland basins that make up the bioswells. This system replaces the traditional approach of using pipes and open culverts to direct water flow into and out of the lagoon.

“With this type of bioswell we’ve created a number of basins that fill up and flow into each other much like our local creeks,” Thomson said. “So once you have basins that retain water, then you have an opportunity for plants to uptake nutrients, an opportunity for the water to slow down and decrease erosion and trap sediments.”

Using bioswells instead of pipes and culverts creates a beautiful addition to the Lagoon, Thomson said. Compared to a ditch or concrete pipe, bioswells can have wildlife, vegetation and flowers in them.

“We have something that is exclusively beneficial to humans such as aesthetics,” he said. “From a human sense, we’ve got a certain structure that is visually pleasing.”

The plants are all native species grown locally at the MSE greenhouse adjacent to Harder Stadium. The plants break down organic compounds, take up plant nutrients, and decrease the amount of eroded soil that can find its way into the Lagoon and create an offensive smell.

In the battle between man and the Lagoon’s stench, the university in years past has relied on outsourcing its water supply. Thorsch, who was a UCSB student in the 1970s, said the university has integrated various amounts of saltwater to deter unpleasant stenches. Before the university applied certain tactics, the Lagoon’s water conditions varied dramatically.

“During the winter months when there would be rain, [the Lagoon] would get flushed, but then when we wouldn’t have rain between March and October the water level would go way down and then the oxygen levels would go down and the algae would bloom and then you’d get fishkill and it would really be a stinking mess,” Thorsch said. “But that is a natural process.”

In 1965, the university constructed a pipe system, beginning near the Marine Science Institute, which reached a quarter of a mile out into the ocean to pump seawater back into the lagoon for circulation purposes, Thorsch said. The campus more actively used this resource beginning in 1976 to maintain water levels.

The increase in water circulation coupled with a steady water level – which today varies between six to eight inches – decreases the water temperature, which decreases algae blooms that lead to an odor, Thorsch said. As a somewhat recent addition to the original pipe, two overflow pipes on the southeastern side of the Lagoon drain excess water during rain events.

Due to the actions taken thirty and forty years ago, as well as the increase in the water level and the construction of bioswells, the smell of the Lagoon has dramatically dropped, Thorsch said.

“I was a student here in the seventies, and the lagoon really did smell then because the water levels were not monitored and controlled as they are now,” she said. “So the smell that’s out there now is somewhat of a natural process and it’s not bad. We used to not be able to get close to it.”

While MSE has succeeded in reducing the Lagoon’s smell so far, the department plans to continue its efforts to provide effective Lagoon management, Thorsch said.

“The museum is the entity that is the steward for this area,” he said. “There are plans to increase bio-diversity and enhance the area both scientifically and aesthetically. A lot of people do not even realize that there is an organization that helps oversee the management of the lagoon.”

The MSE hires student-interns for course credit, she said. Over one hundred of these interns play a role in the creation, maintenance and management of the bioswells and habitat restoration at Manzanita Village.

“It’s been very fulfilling to see a definite change,” Thomson said.

Print Friendly

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>