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Mitigation Projects > Wetland > Construction

[Wetland] Construction

clearing ruderal vegetation early excavation
Clearing ruderal vegetation in preparation for grading. Early excavation of the basin that comprises most of module W1 located west of the San Diego Freeway (I5) in the background.
opening basin
Opening of the large constructed basin (W1) to tidal exchange.

Construction of the wetland restoration project at SDL began in August 2006 (see for details of construction). Construction included the initial building of haul roads to transport dredge materials to disposal sites, the importation, screening, and stockpiling of rock and sandy clay to create berms and permanent access roads, and the clearing and grubbing of vegetation and debris from project areas to the south of the San Dieguito River and west and east of Interstate 5. Construction of subtidal and intertidal habitat included the large basin (44 acres) in Area 2A (Module W1) west of Interstate 5, that was opened to tidal exchange on January 23, 2008.

  excavation of modules   aerial view of tidal creek networks
Excavation of modules W4 and W16 located east of the San Diego Freeway. Aerial view of the tidal creek networks in modules W4 and W16.
  tidal creek   San Dieguito river channel
Recently excavated tidal creek in W4. Berm 8 and the San Dieguito River channel.

Excavation and grading to create middle and high marsh occurred in Areas 2A (Modules W2, W2A, W3) and 2B (Modules W5, W10) adjacent to the San Dieguito River. Excavation and grading to create intertidal vegetated marsh, mudflats, and tidal creek networks, was conducted in Area 3 (Modules W4, W16), which was open to tidal exchange on December 3, 2008. Material excavated from the construction site was deposited in disposal sites within the project area. These disposal sites were covered with topsoil and hydroseeded to control erosion. Berms that will constrain storm runoff were completed along the boundary of the effective flow area of the San Dieguito River.

  flats of native plants crew planting native plants
Flats of native plants (primarily pickleweed) ready for planting. Work crew planting native plants along the west side of W16.

Following excavation and grading, portions of the restoration project will be planted with salt marsh vegetation. This is anticipated to be accomplished in two phases. The first phase, involved planting selected species in high marsh habitat in December 2008 and early 2009. The second phase, involves planting cordgrass (Spartina foliosa) in the low marsh habitat of Area 2B after the inlet is dredged. Inlet dredging for full tidal exchange is anticipated for Spring 2010.