Marina Lagoon, also known as Seal Slough, is a crucial water resource in San Mateo, California, managed by the local government. Built in 1953, this earth dam serves the primary purpose of flood risk reduction, while also offering recreational opportunities in the area. With a height of 17 feet and a hydraulic height of 14 feet, Marina Lagoon has a storage capacity of 1600 acre-feet and covers a surface area of 200 acres. Despite being labeled as low hazard potential, the dam is regularly inspected and deemed to be in satisfactory condition.

Located on the Belmont Slough in the San Francisco Bay area, Marina Lagoon plays a significant role in managing water flow and protecting the surrounding communities from flooding. The dam is regulated by the Department of Water Resources and the Safety of Dams agency in California, ensuring that it meets all state permitting, inspection, and enforcement requirements. While no spillway type or width is specified, the dam's construction and design reflect its effective flood risk reduction capabilities, contributing to the overall safety and resilience of the region.

With Congresswoman Jackie Speier representing the area, Marina Lagoon stands as a testament to effective water resource management and climate resilience efforts in California. As a key infrastructure for flood risk reduction, this earth dam not only safeguards communities but also provides a space for recreational activities, highlighting the harmonious coexistence of human development and environmental conservation. The continuous monitoring and maintenance of Marina Lagoon demonstrate a commitment to ensuring its long-term functionality and safety for generations to come.