2016 City of Imperial Beach Sea Level Rise Assessment
The City of Imperial Beach is a mostly residential community located in San Diego County, California. With 1.5 miles of coastline and waterbodies adjacent to three sides of the city, Imperial Beach is vulnerable to climate change-induced sea-level rise and flooding. This assessment projects sea-level rise along the coastline, assesses the associated risks to coastal resources and development, and evaluates adaptation strategies. Proposed near-term policy approaches include updating the zoning code with hazard zone overlays, developing a beach management plan, and working with state and federal partners to address vulnerabilities.
According to the report, 800 feet of wastewater pipes, 5 pump stations, 1.7 miles of roadway, and oceanfront properties are vulnerable to tidal inundation and erosion from extreme storms and sea-level rise. With a burgeoning coastal tourism and recreation industry, sea-level rise also threatens the local economy. In conjunction with the vulnerability assessment, physical and economic analysis on 5 adaptation strategies were conducted, including:
- Armoring of the entire Imperial Beach coastline
- Phased relocation (managed retreat)
- “Business-as-usual” sand nourishment
- Hybrid dune and cobble approach
- 5 groins w/associated sand nourishment
These proposed adaptation strategies - such as building a seawall, enhancing dunes, and retreating from the shoreline - were evaluated based upon economic cost-benefit (including impact on tourism and tax revenue), long-term viability, and ecosystem considerations. The report finds that seawalls may lead to a loss of beach recreation and ecological value, while managed retreat, coastal groins, and sand nourishment may be viable long-term solutions. Strategies to implement these options range from creating a transfer of development rights program, to increasing ocean development setbacks, and enabling conservation easements.
The report concludes with an analysis of next steps, which include integrating their findings into their Local Coastal Program, as required by the State of California and pursuing implementation of the proposed strategies. Additionally, the report discusses the need to work regionally with neighboring cities. In this section, the report outlines the legal and financing mechanisms Imperial Beach could use to support the adaptation strategies. For example, Imperial Beach could use a Coastal Hazard Abatement District financed through supplemental tax assessments that creates a funding reserve for future maintenance and rehabilitation.
Appendix A - Sector Profile Results - summarizes the findings and recommendations by sector, for use by decision-makers. Each sector has its own profile that includes a vulnerability map and 2- page description of findings for ease of communication. The vulnerability maps contain a combination of the existing and the projected future coastal hazards. Sector Profiles are included for:
- Land Use
- Public Transportation
- Hazardous Materials
Publication Date: September 2016
- City of Imperial Beach, California
- Policy analysis/recommendations