Salt Creek Wetland Mitigation Project

Project Background

The Salt Creek Wetland Mitigation Project (Project) includes 11.36 acres of wetland habitat restoration targeting the removal of non-native plant species, native plant seeding, and replacement of select cattail areas with native willows in the City of Laguna Niguel (City). The Project serves as a mitigation model for the ongoing management of other wetland areas within the City and also helps to addresses potential environmental impacts caused by runoff from the surrounding neighborhoods, as the wetland acts as a filter for the watershed. Cooperation with State and Federal regulatory agencies, the habitat restoration contractor, and multiple environmental consultants were necessary to successfully deliver this Project and ensure the protection and restoration of the wetland.

Salt Creek Corridor Habitat Restoration AreaSalt Creek Trail

The Salt Creek Wetland

The Salt Creek Wetland is a highly-visible section of the Salt Creek Trail near the City’s Chapparosa Park, which required additional sensitivity to the habitat, flora, and fauna during Project construction. The Salt Creek trail is a regional connection that is popular with runners, walkers, and cyclists. Restoration efforts enhanced available habitat for the threatened and endangered birds, and other species that reside along this creek segment and provided improved wildlife viewing opportunities for trail users. Most Project construction activity was completed by hand to ensure noise levels did not disrupt nesting birds. There were additional Project restrictions and monitoring requirements due to the potential presence of threatened and endangered bird species and paleontological artifacts.

This Project enriches onsite habitat and improves downstream water quality in the creek that flows to the ocean. The Project also assists with achieving established watershed water quality improvement plan goals for habitat restoration and reducing pollutants.

Environmental Obstacles

The Salt Creek Wetland Project site presented a number of environmental challenges and offered limited access due to steep slopes. There was evidence of threatened and endangered bird species, which required careful maneuvering in and around the site. Instead of utilizing heavy machinery, the City opted for performing work in the wetlands by hand to minimize disruption to trail users and neighboring communities, and to ensure that Project sound levels did not disrupt nesting birds. 

The Project required the City to utilize Black Willow cuttings from other City wetland areas to increase the presence of native Black Willows in the Salt Creek Wetland. There was also uncertainty in planting survivorship due to drought conditions. Planting the Black Willow and Mulefat cuttings and seed mix in the Project site was completed without supplemental irrigation. This approach presented a significant cost savings to the City and preserved limited water resources during statewide drought conditions.  As an additional cost-savings measure, the removed non-native plant species were converted into mulch. 

Removal of invasive, non-native trees
Installation of native plant (Mulefat) cuttings

Before and After Photos

Area 3- Removing Cattails

Before - Removing Cattails from Salt Creek Trail

Area 3 - Planting Hydroseed

Planting Hydroseed

Area 3 - Willow growing (after 7 months)

Area 3 - Willow stakes growing (after 7 months)

Area 3 - Small fish (after 8 months)

Area 3 - Small fish (after 7 months)

Area 6 - Removal of non-native plants

Area 6 - removing non-native plants

Area 6 - Willow growing (after 4 months)

Area 6  - Willow establishing (4 months later)

Public Outreach

As an innovative public outreach component, the City created the interactive wetlands map (screenshot shown below), allowing viewers the ability to click on the City's 13 wetlands, including Salt Creek, to see information on each wetland's location, acreage, function, and predominate flora.

Interactive Wetlands Website

This project exemplifies how a diverse project team comprised of several consultant companies can work together to identify and implement creative solutions to project challenges.