Water quality in Santa Cruz County is impacted most by runoff from urban, rural and agricultural areas. Known as nonpoint source pollution, runoff picks up pollutants that we as a community deposit across the landscape and delivers them to creeks and streams and ultimately the ocean. Primary pollutants of concern include sediment, nutrients and pathogens. Herbicides, pesticides and metals are also detected in streams draining developed watersheds and regular but scattered occurrences of pesticides have been found in south county streams and sloughs. These pollutants have a variety of impacts, including damaged riparian systems, toxicity to aquatic organisms, increased treatment costs for potable water supply, flooding, fisheries decline, and public health impacts from recreating in contaminated waters.
Pollutant sources are as varied as the different land uses occurring in the county. Sediment sources include road networks, land development, new construction, timber harvest activities, agriculture and landscapes scarred by wildfires. Bacteria and nitrate originate from septic and sewer systems, storm drains, homeless encampments, livestock, and agricultural operations. Hydromodification, or the alteration of natural runoff timing and volume, has occurred throughout much of the developed areas of the county. The effects of hydromodification include increased runoff, erosion, sedimentation and pollutant loads in receiving waters. Toxicity can be caused by a variety of contaminants including improperly disposed automotive fluids or other discarded materials that break down to toxic substances.
Whereas point sources of pollution can more easily be controlled at the end of a pipe with technology; nonpoint pollution requires a more comprehensive approach that includes source reduction and treatment. This means we must each do our part to keep pollutants out of water and protect healthy, functioning ecosystems that act to filter and remove any contaminants that do enter runoff. Reducing nonpoint source pollution will require the concerted effort of residents and resource agencies alike.