United States Army Corps of Engineers performs periodic maintenance of the Marsh including dredging of accumulated sediments near the area’s inlets, habitat management in the form of debris (trash) removal, removal of invasive species, and planting to reduce erosive processes along the channel banks and adjacent Santa Ana River levee.

Orange County Public Works is responsible for operation and maintenance of the adjacent Santa Ana River levee, tidal gates and outlet pipes and drains along the levee. Orange County Sanitation District maintains a wastewater pipeline under the access road that separates the upper and lower portions of the Marsh.

The City of Newport Beach operates an oil production facility within the marsh and is also responsible for maintenance of Semeniuk Slough which connects to the Marsh on the east side.

All USACE maintenance and monitoring activities are performed between Sept. 16 to Feb. 14 to avoid nesting season except for eelgrass monitoring, breeding bird monitoring, tidal range monitoring, and fence maintenance. Eelgrass monitoring will occur during the peak growth season in spring and summer months. Tidal range monitoring occurs in July to capture larger tides and limited rainfall. To avoid habitat damage due to trespassing, fence maintenance may occur during nesting season in the presence of a trained ornithologist.

Routine maintenance activities and frequencies are listed in the table below:

 *Frequency of tidal channel dredging tasks are dependent on the results of the topographic, bathymetric, and tidal monitoring surveys.  Current trends show dredging will be required every 10-15 years.

Upcoming Activities