Serious about Sand
By Lynn Bolt Rosendale '85

Calvin geography professor Deanna van Dijk and student assistant Annelia Tinklenberg (Westminster, Colo.) collect data from sand traps at Hoffmaster State Park on Lake Michigan.

For Deanna van Dijk work is like a walk on the beach…really. In fact, the Calvin geography professor spends a lot of time at the lake and in the sand.

But being an aeolian/coastal geomorphologist requires more than just rolling up your pant legs and getting your toes wet. Van Dijk spends her time measuring the wind processes on coastal dunes—namely those near Lake Michigan.

Through the use of erosion pins and sand traps strategically placed on the dunes in Hoffmaster State Park in Muskegon, Mich., van Dijk is studying the sediment transport by wind and resulting dune change on the east coast of Lake Michigan.

Deanna van Dijk records measurements in her notebook.

"I have always been interested in physical geography," said van Dijk. "Then in graduate school my advisor was really enthusiastic about dunes. They're so interesting because they are so dynamic."

Van Dijk, who grew up in Iowa but hails from Hamilton, Ontario, was surprised to find upon coming to Calvin that very little research had been done on the Lake Michigan coastal dunes. "I started asking what was happening to the dunes in Michigan. What could happen to the dunes? Was sand shifting from one part of the dune system to another? People could not answer those questions."

So she began taking basic measurements in 2000 to get answers.

Data are collected weekly through measurements taken on metal pins or wooden dowels placed in the sand. Also vertical plastic tubing is used to trap blowing sand, which is then collected and measured. Most of the data collection occurs from fall through spring.

"There is not that much movement and change of shape during the summer because the winds aren't as strong," she said. "Also there are a lot fewer people around in the winter to interfere with the results."

Deanna van Dijk and Annelia Tinklenberg (Westminster, Colo.) collect data to study dune movement.

This summer though, with the support of an Alumni Association grant, van Dijk plans to broaden the study area to include larger parabolic (blowout) dunes. The project, which will utilize efforts by two student researchers and van Dijk, will produce a detailed map and geomorphic description of a specified area of Lake Michigan coastal dunes and will describe the spatial and historical context of the mapped area.

"The data will provide the basis for future comparisons of dune position and characteristics, thereby allowing rates of change to be calculated," she said.

Van Dijk's research is a natural response to her work at Calvin, she said. "As God's stewards we are responsible for taking care of his beautiful creation," she said, "and the first step of stewardship is understanding."

She hopes her data will enhance the ability of park managers to make decisions concerning the area and will assist local residents and regional managers to better manage the dunes which have been 'developed' through house construction, sand extraction and other human activities.