Ballona Creek is an approximate nine-mile-long waterway that is located within the coastal plain of the Los Angeles Basin and empties into the Santa Monica Bay between Playa del Rey and Marina del Rey. The Ballona Creek Watershed encompasses approximately 130 square miles; approximately 82.2 percent of the watershed is in the City of Los Angeles, 4.8 percent in Unincorporated Los Angeles County, 4.6 percent in the City of Beverly Hills, 4.1 percent in the City of Culver City, 2.5 percent in the City of Inglewood, 1.5 percent in the City of West Hollywood, and 0.3 percent in the City of Santa Monica. Most of the Ballona Creek drainage network has been modified into storm drains, underground culverts, and open concrete channels.