I-5 to Coastal Wildlands

 

traffic-semaphore-red-light-mdStatus

Currently not functional due to the undercrossings at I-5 and Lake Forest Drive that are designed solely for water movement, without accommodations for wildlife.

 

 

Description

Southern-Reach

The wildlife corridor in this reach is intended to follow existing creek channels through the Spectrum 5 research park, where three creeks converge. The channels for the San Diego and Serrano creeks are wide, vegetated, and screened/fenced from the surrounding development. The corridor reaches these channels by passing alongside Needlegrass Creek under the Lake Forest Drive extension to meet San Diego Creek. It follows this creek for a short distance, passes under Irvine Center Drive and Research Drive, then heads north along a vegetated swale that was built alongside the CarMax property. At the end of the swale, the corridor passes under the I-5.

Importance

Creeks in the Spectrum 5 research park area provide a natural—and crucial—connection between coastal preserve lands and the Central Reach of the wildlife corridor. The creek channels are suited for wildlife corridor use, and most surrounding land uses are good neighbors for wildlife.

Progress

  • bobcat

    Bobcats avoid crossing water and need a dry wildlife corridor.

    Channels for the San Diego and Serrano creeks are wide and vegetated, providing for wildlife movement. Adjacent properties have fences and screening vegetation where they abut the channels.

  • Wildlife movement is technically possible under Irvine Center Drive and the I-5 freeway, but uncertain (see Challenges below).

Challenges

  • The Serrano Creek I-5 culvert needs to function as part of the wildlife corridor but is too long, dark, and flood-prone. This culvert passes beneath Bake Parkway, the Bake Parkway southbound onramp, and the I-5 before finally emerging again. It is too long for animals to see daylight on the other side, so they do not perceive it as a passageway. Water in the culvert can make it impassible. Concrete benches 1-2’ tall on one or both sides would enable bobcats and coyotes to cross during low water. Other engineering solutions are needed to allow daylight to penetrate into the passageway.
I-5 culvert

For wildlife and people, passing through the I-5 culvert is currently only possible when there is no water. Concrete benches would enable bobcats and coyotes to cross during low water. The long culvert also needs to be illuminated with enough natural light for animals to perceive it as a passageway.

  • The Lake Forest Drive overpass for Needlegrass Creek was not designed with wildlife passage in mind. However, when water levels are low, animals may be able to pass through.
  • This segment of the wildlife corridor is not reflected on the City of Irvine zoning map. North of the I-5, the corridor is designated for Preservation, but south of the I-5 the zoning is industrial and residential. Zoning would help ensure that the corridor is properly buffered from light, noise, and intrusion from adjacent properties.
Lake Forest Drive overpass

The Lake Forest Drive extension made this section along Needlegrass Creek difficult for animal passage, especially when water levels are higher. Note the standing water even in a dry period.