This highway repair on Kauaʻi addressed decades of shoreline erosion, which degraded portions of Aliomanu Road.
01
Decades of coastal erosion
Aliomanu Road runs along the Anahola Bay shoreline on the northeast side of Kauaʻi. The road sustained damage from decades of increasingly severe wave action, which was worsened by a barrage of surf from Hurricane Iniki in 1992. After the hurricane, portions of Aliomanu Road collapsed, rendering it unsafe for vehicles and recreational use. For public safety, a section of the two-lane road was narrowed to a single lane. Eventually, a segment of the road and a critical bridge were permanently closed, splitting the road into two dead end streets.
02
Providing temporary emergency repairs
Shoreline erosion continued to degrade the southern road segment, which was declared a safety hazard by the state as waves eroded the soil beneath the remaining single-lane roadway, causing the pavement to collapse into the sea. Oceanit’s RiSE team implemented temporary emergency repairs by designing and placing coir sandbags to stabilize the road closest to the water.
Oceanit monitored water quality in Anahola Bay to assess potential changes caused by the placement of emergency sandbags, which were filled with sand from a nearby beach berm at the mouth of Anahola Stream.
After emergency repairs were completed and traffic barriers were installed, the southern road was designated for use only by emergency vehicles and residents living along that portion of the coast.
03
Taking community input
Community members voted to repair Aliomanu Road rather than reroute it away from the shoreline. Following the community’s decision and supported by the state, Oceanit collaborated with the Hawaii Department of Hawaiian Homelands (DHHL).
Oceanit’s RiSE coastal engineers designed and oversaw the restoration of the damaged section of Aliomanu Road to its original two-lane width. Additionally, Oceanit oversaw the construction of a new protective rock revetment on the makai side, which stabilized the embankment, protects the road from wave damage and erosion, and prevents soil erosion runoff into the ocean. The design retains the rocky nature of the existing shoreline.
Rehabilitation work was completed in December 2024, ensuring that the road is now safe, reliable and accessible for local residents and emergency services access.
At a glance
Two phases of repair and restoration
Phase I tasks included:
Conducting site inspections, evaluations, and providing emergency repair recommendations; and Preparing emergency plans and securing permits for temporary measures. While emergency repairs were being pursued, Oceanit also began ideating alternatives and developing concept plans for long-term, permanent road restoration, including a new protective rock revetment and two-lane road repairs. Phase II tasks included:
Designing a shore revetment and two-lane road repair, and developing construction documents; Preparing a draft Environmental Assessment (EA) and completion of a full final EA, including an analysis of the potential impacts of projected sea level rise; Preparing permit applications and securing construction permits; Providing support services during bidding; and Providing construction management and project administration.
