The movement of sediment is a naturally occurring process in a watershed like Morro Bay. Erosion of stream banks and nearby lands can benefit habitat diversity by creating gravel bars that support steelhead or by forming sandbars that plants can colonize. However, excess erosion from events like intense rainfall after wildfire can have negative impacts on habitat by degrading water quality, clogging stream beds, and smothering eelgrass in the Excess sedimentation in the watershed can have negative impacts on downstream habitats. Erosion of stream banks and nearby lands can degrade water quality and clog stream beds, which can harm wildlife. Sediment that makes its way to the estuary can smother eelgrass and other important habitat types.

The Estuary Program works with partners to manage erosion and other causes of sedimentation that threaten the health of the creeks and estuary. Another factor to consider with sediment is its relationship to shifts in sea level. Rising waters across the globe present an emerging challenge to tidal marsh habitats like those in the Morro Bay estuary that are vulnerable to inundation. Although these areas increase in elevation as sediment from the watershed washes down Chorro and Los Osos Creeks and settles there, rising seas will eventually outpace this natural process. If marsh areas are continually inundated with water, analysis indicates that the plant and animal communities present in the marsh today will be replaced by plants and animals that can survive in mudflats by the end of the century. While both habitats have value, this would represent a loss of the estuary’s unique and fragile tidal marsh ecosystem.