San Luis Rey Mitigation Bank Construction Update

This year brings another exciting and long anticipated project to realization: the San Luis Rey Mitigation Bank in Oceanside, California (San Diego County). A meandering channel with an accessible floodplain has been created at the 53 acre wetland mitigation bank. Agricultural activities during the past century had caused the river to be channelized, disconnected from its floodplain and denuded of riparian vegetation.


The construction has been a significant and exciting effort requiring the excavation of over 650,000 cubic yards of soil. During mass grading, 14 scrapers were operating simultaneously. Fine grading was completed by bulldozers equipped with GPS machine-control systems.


As this goes to press, the channel has been realigned and final touches are being made on subtle topographic details. But once the earthmoving equipment leaves, there is still much to do. Temporary irrigation will be installed in the autumn. In order to reduce transplant shock, planting will occur in the winter. 10,000 cuttings will be planted along with 4,000 container plants. The site will be seeded with a mix of native shrubs, forbs, and grasses.


When complete, the restored riparian corridor will likely provide habitat for state and federally listed species including least Bell’s vireo and southwestern willow flycatcher.