Restored Critical Dune Habitat To Protect Threatened & Endangered Species
Hanford was awarded the Critical Dune Habitat Restoration project at Point Reyes National Seashore through the RFP process in the winter of 2010/2011. The project was designed to restore approximately 76 acres of native dune habitat, primarily through removal of the invasive European beachgrass and iceplant. The project will benefit the federally endangered snowy plover and several species of federally protected dune plants. The work area is immediately west and south of Abbott’s lagoon, north of the Point Reyes lighthouse.
ACREs restored: 76
Cubic YARDS MOVED: 1,000,000
Wildlife Protection Fence Installed: 20,000’
Contract amount: $2.5m
Project completed: 2011
LAND TYPE: Coastal Dunes
The project goal was to restore critical dune habitat to benefit special status species. To achieve this, Hanford employed mechanical and hand methods to remove the invasive European beachgrass. The mechanical method involved excavating the beachgrass to the rhizome depth (3’-6’) to reach ‘clean sand’. The excavated beachgrass material was buried in the same or adjacent pit or trench, then clean sand was removed and used to create a 3’ cap.
The hand removal method, was used in more sensitive areas of the project. This method consisted of hand excavation of beachgrass and iceplant biomass, transporting and burying the biomass, then transporting and burying the biomass in the mechanically excavated pits.
Although the project was designed to benefit special status species, those same species presented substantial challenges to construction logistics. The schedule and work areas were primarily dictated by nest or breeding season, and the proximity of sensitive habitat. Work areas were strictly limited by a mosaic of native dune habitat patches amongst the invasive species dominated areas.
Though the project scope was essentially invasive species removal. The approach resulted in a project that was primarily large-scale excavation. To remove and bury the European beachgrass, Hanford excavated approximately 1,000,000 CY of sand. Six, 22-30-ton excavators, three D6-D8 size bulldozers and two track trucks (one dedicated to fuel delivery) were required to operate full time to maintain an average production rate of approximately 8,000 CY/day of excavation over the 6-month project.
The massive task of flipping the large coastal dunes resulted in a significant reduction of European beachgrass thatch and seedbank which allowed the native plant diversity to establish.