A new study from San Diego State University shows that bigger storms transport greater amounts of pollutants through the San Diego River watershed. Researchers analyzed storm data from 2016 to 2024 and found a clear link between peak flow and total pollutant loads, including dissolved organic carbon and nitrogen. The heavily urbanized Alvarado Creek, a small tributary, exported about five times more pollutants per area than the main river, pointing to continuous sources like leaking sewer pipes rather than simple storm flush effects. These findings matter for urban water quality management and climate adaptation. As storms become more intense with climate change, the pollution load into coastal waters is likely to grow unless infrastructure is upgraded. The study also underscores the value of long-term monitoring and public flow data from USGS for estimating pollutant transport. For cities and agencies, this is evidence that fixing aging sewer systems is not just a maintenance issue but a climate resilience priority.
