Water Quality
Monterey Bay

photo of a sediment plume in the ocean
A sediment plume is visible in the ocean following a landslide at Alder Creek in 2011. Excessive sedimentation can reduce water quality and negatively impact marine organisms. Credit: Steve Lonhart, MBNMS, NOAA

Why is it a concern?

Water quality can be impacted by the presence of contaminants (e.g., pesticides, hydrocarbons, and heavy metals), excessive sedimentation, and elevated nutrient loads. The runoff from rainfall and irrigation water can pick up a variety of contaminants and carry them into storm drains, streams, and rivers, eventually traveling to wetlands, harbors, bays, and shorelines, which can impair the quality of these water bodies. Urban runoff is a leading cause of water pollution and is difficult to prevent because it is nonpoint pollution with sources such as yards, sidewalks, streets, construction sites, and parking lots. Deposits of contaminants (e.g., oil, grease, pesticides, herbicides, soil, pet droppings) in these areas are flushed by rainwater and other means down the storm drains and directly into a river or bay. Runoff and spills along the sanctuary’s coastline have periodically resulted in high levels of coliform bacteria in coastal waters, resulting in hundreds of beach closures or warnings annually.

Water pollution from activities associated with marinas and boating within the sanctuary is also a pressure on sanctuary resources. Boater-generated impacts on water quality generally fall into four categories: toxic metals primarily from anti-fouling paints, hydrocarbons from motor operations and maintenance procedures, solid waste and marine debris from overboard disposal, and bacteria and nutrients from boat sewage. Cruise ships in the area can generate sewage gray water, oily bilge water, hazardous wastes, and solid wastes. Additionally, oil and chemical spills are another way that contaminants can be introduced to the environment and could have a major impact on foraging birds, marine mammals and fishes, as well as important habitat like kelp beds, wetlands and rocky shores.


Overview of Research

Project Name PI and contacts Links

Snapshot Day

 Lisa Emanuelson


Santa Cruz Ocean Observing Platform (SCOOP)

 Raphael Kudela, Kendra Hayashi, Mike Jacox


First Flush Event Monitoring by the Sanctuary Citizen Watershed Monitoring Network

Bridget Hoover (MBNMS), Lisa Emanuelson (MBNMS)


Science Needs and Questions

  • How have coastal wetlands and riparian environments changed over historic time in central California?
  • Where are present day coastal wetlands and riparian environments in central California, how healthy are they, and what are the potential impacts that could affect them?
  • What types of restoration methods are appropriate to central California?
  • What types of monitoring designs can be incorporated into wetland restoration projects to track long-term changes in water quality?
  • What are the potential sources and risks of emerging pollutants to surface waters and near shore environments?
  • Where and what types of improvements in land management have been made in coastal watersheds with the goal of improving water quality in watersheds and the near shore environment?
  • Determine and implement the necessary monitoring to assess the condition of water quality in the Sanctuary.

Education and Outreach Material

Monterey Bay National Marine Sanctuary Teachers Curriculum – “The Land Sea Connection”

photo of erosion of a cliff
The water flowing through storm drains is untreated and can carry pollutants into local waterways or directly into the sanctuary. Credit: MBNMS, NOAA


Office of National Marine Sanctuaries. 2015. Monterey Bay National Marine Sanctuary Condition Report Partial Update: A New Assessment of the State of Sanctuary Resources 2015. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 133pp.