Tim Ronan collects seismic and infrasound data in the Boise River.
A Boise State alumnus is using his degree to attempt to create better waves for surfers and kayakers at Boise River Park (colloquially known as Whitewater Park). Tim Ronan, who graduated from Boise State in 2014 with a bachelor’s degree in geophysics, is attempting to mathematically quantify how whitewater rapids move, in order to orchestrate better, more reliable waves for water sports.
“All waves produce acoustic noise,” explained Ronan, who is now earning his master’s in geophysics from the University of North Carolina. “We’re monitoring how they generate sound waves into the atmosphere and how they push on the ground to try and quantify them.”
To mathematically quantify waves, Ronan has teamed up with the City of Boise and Department of Recreation to conduct baseline experiments on the wave shaper at Harry W. Morrison Dam. The wave, which was built as part of Phase I of the Whitewater Park project, consists of an air bladder below the water’s surface that is manipulated by a hydraulic pump controlled by a city employee.
“The tricky thing with controlling the shape of the wave is that things change with the changing river level. Settings constantly need to be adjusted,” explained assistant professor of geosciences Dylan Mikesell, who is working with Ronan on the project. “Right now, someone has to actually look at the wave, decide if the shape should change, and then go play with the settings.”
Which means if the city’s sole wave shaper is not onsite, the wave can get stuck in a formation that is useless to surfers, kayakers or both. In addition, the wave is supposed to be changed on a daily basis to accommodate either surfers or kayakers. As lifelong kayaker Ronan explained, the two groups need very different types of waves in order to practice their sport.
“People love the wave but it’s not ‘in’ all the time,” Ronan said. “Surfers want a wave that’s ‘green,’ in other words, it’s got a bump and it’s a bit faster with no white foam at the top. Kayakers want a hole with a huge foam pile on top. It’s not as fast, because kayaks aren’t as fast, and the pile helps you stay in the wave. So by trying to measure the wave and standardize it, we can try and ensure the wave is constantly working and giving people what they want.”
On May 17, city officials closed the wave to kayakers and surfers so that Ronan’s team could conduct their preliminary experiments. For three hours, the researchers had the city’s sole wave-master change the angle, shape and size of the wave and then recorded its acoustic and seismographic readings.
“[He was] moving the wave every 30 minutes into a new position,” Mikesell explained.
The team recorded data for 30 minutes and then moved on the to the next wave shape. Ronan’s plan is to master the results like a DJ and quantify the seismic and acoustic signature of what constitutes the perfect wave for both surfing and kayaking.
“The goal is to automatically control the whitewater park wave offsite, without having to mess with 900 different parameters,” Ronan said. “For example, it would be great if we could say, ‘The wave is oscillating at this frequency, we want it oscillating at this other frequency, so we need to shift it this much.’”
BY: CIENNA MADRID PUBLISHED 1:28 PM / MAY 18, 2016