Three researchers use yellow tape to set up a grid covering bare and grassy vegetation for observing marine debris via uncrewed aerial systems near a railroad bridge overpass.

Missing Marine Debris? Understanding the Sources of Marine Debris in the San Diego River

San Diego State University is conducting a study to understand and compare the amount of debris entering the San Diego River from stormwater systems, unhoused communities, and illegal dumping. 

Type of Project: Research

Region: California

Project Dates: September 2021 - August 2024

Who is involved?
With support from the NOAA Marine Debris Program, researchers from San Diego State University are conducting a study to understand the amount of marine debris that ends up in the San Diego River watershed from unhoused communities (especially abandoned communities), illegal dumping, and storm drain outfalls. In collaboration with San Diego River Park Foundation, this project is also evaluating the use of an uncrewed aerial system (UAS) to detect debris in the river margin to target clean up efforts.

What is the project and why is it important?
To prevent and reduce marine debris from entering the ocean, we need to better understand where it comes from and the pathways through which debris may enter the environment. Much research to date has focused on how debris moves through wastewater, however, recent research has shed light on the importance of stormwater systems in transporting debris to waterways and the ocean. Though stormwater systems transport much debris to rivers, lakes, and the ocean, other sources of debris, such as illegal dumping and debris from unhoused communities, may also contribute to the problem.

In this study, researchers from San Diego State University are examining river margins, or areas bordering rivers, in the San Diego Watershed to measure and understand the movement of debris that comes from unhoused communities and illegal dumping. Researchers are observing which items remain in the river margin after storm events and which items are more likely to enter the river, potentially making their way to the coastal waters and ocean. They are also evaluating how this debris can break up and fragment after months in the environment. The researchers will use uncrewed aerial systems to evaluate their ability to identify debris hot spots along river margins with different amounts of vegetation. 

To measure debris from stormwater sources, researchers are using existing data to create a storm drain database from ~300 existing storm drains across Southern and Central California. Researchers and students will also meet with unhoused individuals to understand the causes and sources of marine debris, and discuss solutions for waste reduction that recognize these waste management challenges. 

For more information about this project, visit the Marine Debris Program Clearinghouse.

Last updated Wed, 03/02/2022 - 09:41 am EST