Client: City of Newport Beach / Coastal Conservancy International

Project Features:

  • Funded by State Costal Conservancy and City of Newport Beach, this project is located within the Upper Newport Bay State Ecological Reserve at the outlet of Big Canyon. WRC provided hydrology, hydraulics, water supply analysis, floodplain mapping, water quality management evaluation, drainage and grading design, soils analysis, utility study, and civil engineering plans and estimates.
  • Big Canyon's Serious Problems: Contaminated Urban Runoff, Erosion/Sedimentation, Dredge Spoils, Flood hazards, Inadequate Public Access, Non-native Invasive Plants, and Subdued Tidal Influence.
  • Dredged spoils, man-made freshwater ponds, and Back Bay Drive provided physical constraints to tidal flows. WRC recommended the team to consider relocation of this trail road and freshwater pond to the north. The realigned Back Bay Drive coincides with historical tidal boundary.
  • In contract to restoration of natural wetlands, another alternative is to provide a major opening under the road and dredge the upstream elevated water pond to below the mean sea level. The natural wetland alternative received positive comments in the public meeting and by regulatory agencies. This alternative provides ensured tidal influence without the restriction by culverts as well as lower flood damage potential and less construction and maintenance costs.
  • In addition to tidal restoration, a future water quality treatment system was proposed. This includes main channel flow pretreatment, first constructed wetland treatment, riparian wetland filtration, open water detention, and a lower constructed wetland treatment. The ultimate management system may extend to upstream source control when the agreements with the landowners are defined.

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