This activity is one of a series of 17 teacher-developed instructional activities for geography at the secondary-grade level described in SO 009 140. The activity investigates economic change in a developing region in the United States. "Rinnsal" is a geographical simulation game lasting three weeks that involves location analysis concepts. Specifically, students are involved in the process of deciding on plant location for industrial development. A steel company has decided to build a new integrated steel mill at one of five port cities on the Arkansas River. It contacts five industrial location-analyst companies. Each industrial location analyst prepares a written and oral report containing a discussion of reasons for locating the new steel plant in each of the five port cities. Additionally, the report specifies one of these cities as its locational choice and gives reasons for choosing the particular city. The report is submitted to the executive board of the steel company which studies the report and awards a contract to one of the five industrial location companies. Game roles consist of the executive board of the steel company, industrial location-analyst company, and planners. Students organize groups, do research, prepare and deliver reports, role-play awarding contracts, and discuss their decisions. A map of the Arkansas River Basin Project is provided. (DB)