Los Peñasquitos Marsh, located near San Diego on California’s South Coast, is a 0.6-square-mile estuarine wetland at the confluence of Los Peñasquitos Creek and the Pacific Ocean. Draining a 60-square-mile watershed, the marsh receives an average annual rainfall of 10 to 15 inches, with significant seasonal flows influenced by winter storms. The estuary features tidal marshes, mudflats, and riparian zones, which provide essential habitat for endangered species like the Ridgway’s rail and the California least tern.

Human activity has heavily influenced the marsh, with urban development, infrastructure, and runoff altering sedimentation patterns and water quality. Excessive sediment delivery from the watershed has led to marsh infilling, while urban stormwater inputs affect salinity and nutrient levels, impacting ecosystem health. Sandbar closures at the estuary’s mouth can create dynamic water levels, increasing the risk of flooding during high flow events and storms.

Real-time water level monitoring at Los Peñasquitos Marsh tracks tidal dynamics, sandbar behavior, and flooding patterns. This data supports efforts to restore wetland habitats, manage sedimentation, and mitigate flood risks, balancing the preservation of this critical coastal ecosystem with the challenges posed by surrounding urban development.