ENGINEERING AND ECOLOGICAL EVALUATION OF ARTIFICIAL- ISLAND DESIGN, 

 RINCON ISLAND, PUNTA GORDA, CALIFORNIA 



by 



James M. Keith and Roger E. Skjei 



I . INTRODUCTION 



1. Objective of the Study 



The basic objective of this study was to improve design capabilities 

 for construction of fill-type islands in exposed offshore locations, and 

 to document environmental changes related to one such island. Rincon 

 Island (Blume and Keith, 1959), is a unique example of this type of island, 

 and a detailed comparison of its behavior with the assumptions made in its 

 design will provide a sounder basis for the design of similar structures 

 in the future. 



The design of Rincon Island required extrapolation of much available 

 data, and the adaptation of many design procedures to conditions differing 

 by various degrees from conditions for which the design procedures were 

 originally developed. The degree of conservatism has been evaluated to 

 determine if any design parameters were unconservative and could pose a 

 future threat to the stability of the island, or if, on the other hand, 

 the design was overly conservative and not as economical as it could have 

 been. As of the date of this study (1973) , Rincon Island has been completed 

 for approximately 14 years. 



Adequate data are not and were not expected to be available to fully 

 evaluate all phases of the island's design and subsequent behavior. Gaps 

 in available data have been evaluated, and appropriate recommendations for 

 future programs to supply data for an improved evaluation of critical de- 

 sign parameters have been made. 



2. Design and Construction History 



a. Background - In 1954, the State of California Lands Commission 

 called for competitive bids for the exploration, development, and produc- 

 tion of oil and gas from a 1,175-acre offshore area called the Rincon 

 Lease. This submarine land lies offshore from existing production wells 

 on piers constructed many years ago. Proposed offshore facilities had to 

 be designed to accord with 1954 requirements and court rulings, which 

 specified "solid manmade islands of natural materials". 



Richfield Oil Corporation was awarded the lease. The engineering firm, 

 John A. Blume S, Associates, had already performed preliminary offshore 

 studies as consultants to Richfield, and was told to proceed with all engi- 

 neering phases of the project except those pertaining to oil exploration 

 and production, which were done by Richfield. 



