Improving Water Quality

By monitoring water quality, analyzing results and implementing data driven solutions, the Coastal Watershed Council is working to improve water quality in the San Lorenzo River.

The San Lorenzo River is cleaner than you might think. Still, there are a number of challenges to a healthy San Lorenzo River, including pollution from bacteria, sediment and nutrients. A unique partnership, consisting of water quality experts and stormwater specialists from the City of Santa Cruz Water Department and Public Works Department, Santa Cruz County Public Works and Environmental Health Services, Surfrider Foundation, Central Coast Regional Water Quality Control Board and the Coastal Watershed Council have been collaborating to address water quality concerns in the San Lorenzo River, focusing on bacteria. Here’s how we do it:

Collecting Water Quality Data

CWC and partners start by collecting the most useful data to determine the location and sources of pollution. With a focus on bacteria, this team of experts uses multiple lines of evidence to measure human and non-human sources of contamination in the San Lorenzo River.


Analyzing Water Quality Data

Next, CWC and partners analyze the data collected. In 2014 and 2016, most water quality samples collected and analyzed indicated that bacteria affecting the lower San Lorenzo River is predominantly from avian (bird) contributions. Monitoring in 2016 revealed a slight increase in bacteria from humans coming from lower San Lorenzo River tributaries particularly near the confluence of Branciforte and Carbonera Creeks in the City of Santa Cruz. Public health experts focus on controlling human sources of bacteria, which in the San Lorenzo River are usually well below the level likely to pose a risk to human health.

Data-Driven Solutions

Once the location and source of bacteria had been determined and analyzed, CWC and partners determine best management practices that can be implemented by businesses, households and residents in daily activities to reduce bacteria and improve water quality. These best management practices include inspecting sewer lines for cracks and breaks, picking up pet waste in public and private spaces and preventing incidental flows of illicit substances down storm drains.

Implementing Solutions

Everyone has a role to play. CWC implements best management practices by inspiring community and civic participation by individuals who work, live, and play along the San Lorenzo River. In partnership with the City of Santa Cruz, CWC launched a public information campaign to engage Santa Cruz residents and business owners in reducing common bacterial pollutants entering the San Lorenzo River. Learn what you can do!

Measuring Effectiveness of Solutions

When data-driven solutions are implemented through behavior change, management decisions and municipal policies, people are addressing pollution at its source. To measure the effectiveness of these measures on actual water quality, the cycle begins again and CWC and partners collect data, analyze results and continue to hone management practices.

Take Action for Clean Water

CWC needs your help in keeping the San Lorenzo River clean. Learn what you can do to make a difference for cleaner water:

Community Science Programs

Connect to your inner scientist and help collect critical water quality and habitat data for the San Lorenzo River and other watersheds.