How Watersheds Connect to the Ocean

Watersheds link to the ocean through three primary pathways:

1. Surface Water (Direct)

Rainfall runs overland into streams → rivers → estuaries → ocean. Carries sediment, nutrients, pollutants.

2. Groundwater (Subsurface)

Aquifers discharge via springs, seeps, or directly into the sea through submarine springs. Can convey nutrients and contaminants.

3. Atmospheric Deposition

Water vapor condenses as precipitation, falling directly on the ocean or on land (then entering surface/groundwater). Also deposits airborne pollutants (nitrogen, mercury).

Why It Matters

Polluted watersheds cause coastal eutrophication, hypoxia, harmful algal blooms. Altered hydrology (dams, diversions) reduces freshwater inflow, disrupting estuarine ecosystems. Protecting watersheds is essential for marine health.