MPSF Open Water Championships

Marine Stadium is a saltwater channel, sheltered from the open swells of the Pacific Ocean by the Peninsula. It is here, in the coastal waters at Long Beach, California, that the MPSF Open Water Championships take place. Organized by the Mountain Pacific Sports Federation, the competition takes the name of the collegiate conference that brought competitive open water racing into this historic aquatic arena. The gathering holds a distinct place in American collegiate swimming history, as the federation established the nation's first open water intercollegiate conference championship here in 2023. The event centers around two primary race distances, featuring a fast 1,000-meter sprint alongside a demanding 5,000-meter endurance test set inside the protected marine basin.

Swimming within the stadium's enclosed straightaways gives the competition an arena-like atmosphere rarely found in open sea racing, allowing competitors to track competitors with exceptional clarity down each stretch. In past editions of the championship, competitors have encountered exceptionally calm, flat conditions with comfortable, mild water temperatures under overcast skies. That glass-like surface encourages aggressive racing strategies from the outset. In the men's 5K, winners have broken away from the pack right from the starting horn, controlling the race at the front over the entire course. The enclosed circuit also tightens pack dynamics, and past editions of the women's 5K have seen decisive, physical clashes as swimmers jostled and collided around the critical final turn buoys before the finishing chute.

Alamitos Bay and the Olympic rowing course

Marine Stadium itself is an integral part of Alamitos Bay, a natural inlet of the Pacific Ocean resting between Long Beach and Seal Beach right at the mouth of the San Gabriel River. The primary shield protecting this water is the Alamitos Peninsula, a geological sandspit that formed over ancient layers of sedimentary rock and Catalina Schist. Working in tandem with the offshore Long Beach Breakwater, this natural spit serves as an impenetrable physical barrier between the open Pacific and the bay, absorbing the ocean's heavy energy before it can penetrate inland. Inside the basin, swimmers experience genuine seawater buoyancy without the rolling swells, breaking surf, or heavy drift that typically define ocean courses. Much of this aquatic landscape took shape through significant human intervention. Over decades, extensive dredging and landfill operations fundamentally modified the natural contours of Alamitos Bay.

Puvunga and the ancient Tongva shoreline

About two kilometres from the race course lies Puvunga, an ancient settlement perched on a prominent hill that once looked out across the original San Gabriel River marshes. The Tongva people who inhabited Puvunga were accomplished ocean navigators. The enduring relationship between the ancient inhabitants and these rich waters remains etched into the surrounding soil. Extensive shell middens were formally documented across the Rancho Los Alamitos landscape during field surveys in 1933, confirming generations of coastal foraging.

Los Cerritos Wetlands along the San Gabriel River

Just about two kilometres from the stadium basin, the remaining segments of the Los Cerritos Wetlands flank the course of the San Gabriel River. Historically, this sweeping estuarine complex encompassed roughly 2,400 acres of thriving coastal marshland, absorbing seasonal river runoff and tidal surges. Today, the fragmented ecosystem centers around two functioning tidal wetlands known as Steamshovel Slough and Zedler Marsh. The rhythm of the Pacific Ocean remains vital to these surviving marshlands. These protected wetlands provide critical sanctuary for specialized coastal bird species that feed and nest in the estuary.

The canals of Naples and Alamitos Peninsula

Naples is a distinctive residential neighborhood constructed across three islands within Alamitos Bay. These islands were built atop what had previously been low-lying delta marshland at the outlet of the San Gabriel River. Transforming this marsh into a navigable network of sea canals was a remarkable engineering feat that began in 1905, requiring 300,000 cubic yards of dredged earth and 13,000 linear feet of concrete bulkheads to stabilize the new waterways. When the powerful Long Beach earthquake struck in 1933, the original seawalls suffered damage, leading to an extensive reconstruction program that rebuilt the bulkheads in 1938 to protect the island banks from the tides. Today, the edges of Alamitos Bay offer a relaxed coastal life centered entirely on sheltered water.

Within the bay, Mother's Beach provides a protected haven celebrated for its gentle ripples and shallow waters. Strolling along the Alamitos Peninsula reveals a historic boardwalk built in 1926 that lines the sandspit between the bay and the ocean. Through winter evenings, the canals and open waters of Alamitos Bay become illuminated by an annual Christmas boat parade, a local maritime tradition sustained continuously since 1946.