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SDSU researching where river debris originates and how it moves to ocean

Posted at 4:48 PM, Oct 21, 2021
and last updated 2021-10-21 19:48:52-04

SAN DIEGO (KGTV) - A team of researchers at San Diego State University are working to determine the cause of debris in the San Diego River.

The San Diego River feeds into the ocean, so trash collected in the river has an impact on the coast. The California Trash Amendment Mandate was created to install filters in storm drains that prevent road debris from getting in the water, but SDSU researchers believe the issue is more complex.

“We think that a lot of the trash is going directly into the channel so that’s by illegal dumping or littering or abandoned homeless encampments,” said head researcher Hilary McMillan, an associate professor of Water Resources.

McMillan said in order to stop the problem, they have to know how it starts.

Through a three-year grant from NOAA, the team will document trash in the river, taking note of where the trash is before big storms, then what happens to it after it rains and waters rise.

“During a flood event, does this trash stay on the bank and get buried under layers of mud, or does it get washed into the channel?” asked McMillan.

She said they’ll use tools including drones, remote sensing, homeless outreach and more. This tracking will help them determine where the trash comes from and how quickly it moves to other areas then ultimately, the ocean.

“Final result will be that we can tell you what percentage of trash and what types of materials are coming from what source,” she said, adding that ”We really want to help prevent that source before the plastic gets into the ocean where it’s much more difficult to retrieve, and the first step in preventing it is knowing where it’s coming from.”