The California Coastal Commission issued to the California Department of Transportation (Caltrans) a Coastal Development Permit (CDP) 1-18-1078 on September 12, 2019. The permit covers the Eureka-Arcata U.S. Highway 101 Corridor Improvement Project (aka the Corridor), which consists of five component projects within a six-mile segment of U.S. Highway 101 along the east side of Humboldt Bay. In accordance with CDP 1-18-1078, Special Condition 1, the California Department of Transportation (Caltrans) is submitting the Sea Level Rise and Flooding Impact Monitoring Report. This 2023 Annual Report references the Baseline Report, which was submitted to California Coastal Commission staff on May 1, 2020, the 2021 Annual Report submitted on May 1, 2021, and the 2022 Annual Report submitted on May 10, 2022.