What is the test for establishing "coast rights" under the California Coastal Act?

The issue of whether vested rights have arisen has been a subject of frequent dispute since the adoption of the 1972 Coastal Act. In Patterson v. Central Coast Regional Com. (1976) 58 Cal.App.3d 833, 844, 130 Cal.Rptr. 169, the court succinctly summarized the doctrine: "Where an [191 Cal.App.3d 177] owner of property, in good faith reliance upon a governmental representation that construction is fully approved, has suffered substantial detriment by proceeding with development, the government is estopped from prohibiting the project by a subsequent change in law."