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Paul Block
May 24, 2019

Getting ahead of algae with long-range cyanobacteria forecasts

Written By: Tom Ziemer


Summers in Madison, Wisconsin, mean paddleboarding, kayaking, boating and, of course, lounging at the Memorial Union Terrace along Lake Mendota.

Madison’s lakes—Mendota and Monona flanking the isthmus, Wingra on the near south side, and Waubesa and Kegonsa southeast of the city—are an elemental part of life in the region.

“If you see more than two pictures of Madison, I guarantee there will be a lake featured in at least one of them,” says Paul Block, an assistant professor of civil and environmental engineering at the University of Wisconsin-Madison.

Unfortunately, those summertime images also sometimes include unsightly blooms of toxic blue-green algae, the result of heavy rains carrying phosphorus from surrounding farm fields into the Yahara Watershed. Those smelly cyanobacteria formations can—and regularly do—force beach closures and deter all activities on the lakes.

Block hopes to enable agencies and stakeholders to plan further ahead for cyanobacteria blooms through a National Science Foundation CAREER Award. He’ll use the five-year grant of more than $450,000 to develop modeling tools to predict seasonal cyanobacteria levels, allowing natural resource and public health decision-makers to shape budgets and allocate resources before the start of each summer.

“If we expect the water quality conditions to be worse this summer, that means there’s just going to have to be that much more water quality testing, maybe additional lifeguard training, definitely lifeguard awareness, maybe more signage,” says Block, who solicited input from the Wisconsin Department of Natural Resources, Public Health Madison & Dane County, and other entities while writing his grant application. “These are very practical, pragmatic things, but they take time, they take budget.”

The project is a shift for Block, who has previously created long-range forecasts for managing water resources, largely in international settings. He’s keen to work with water quality experts across the UW-Madison campus, such as his environmental engineering colleagues and researchers from the Center for Limnology and the Nelson Institute for Environmental Studies.

“We’re not trying to re-create or even really improve what so many others are working on at UW. It’s really complementary,” he says. “A lot of what’s being done now is thinking about these lake dynamics, which are on the order of hours or days. We’re looking at a longer lead timescale here; for example, it’s the end of the spring. What do we expect for summertime conditions?”

To answer that question, Block will examine the number of intense rainstorms and streamflow levels, along with global climate conditions that can influence seasonal temperatures and precipitation. With the help of citizen scientists who are part of the Madison nonprofit Clean Lakes Alliance, he and his student researchers will also collect water samples to explore how that data might enhance predictive models.

Block will focus on Lake Mendota to start, but plans to expand the project to Green Lake in central Wisconsin and Little Arbor Vitae Lake in the northern part of the state near UW-Madison’s Trout Lake Station. By studying lakes with starkly different surroundings—rural versus urban, and, in the case of Little Arbor Vitae Lake, in the Northwoods and away from farmland—Block hopes to gauge the pliability of his predictive tools.

True to the collaborative spirit of his project, Block plans to tap expertise in the UW-Madison School of Education and the Discovery Building to create curricular programming for K-12 education and Saturday Science at Discovery community outreach events. He’s also interested in developing game-like simulations that ask players to make resource decisions based on evolving forecast information.

For a researcher whose work often pulls his interest further afield, Block is eager to turn his attention to a problem right here in Madison.

“A lot of our work is international, and I hope that will always be a big part of the portfolio,” he says, “but I’m very excited to have something that’s going to give us an opportunity to work locally.”