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Show Decision Maker ( Government, Industry, Agencies, etc.) LA •\ Second Level > Social and Economic Goals LA First Level Second Layer J Physical System First Layer Figure 4. Basic decomposition of a system into a hierarchical structure. tween social uses was the construction of the railroad causeway across the lake to aid transportation, but which at the same time produced negative effects on the south arm salt producers. The first level of the second layer must provide the decision- maker with all necessary information about each social use of the system. All interactions between social uses, of course, occur through the physical system. In the case of the construction of the railroad causeway ( social use), the hydrologic and salinity characteristics of the lake ( physical system) were altered which produced an adverse impact on the south arm lake brine industries ( social use). Thus, the arrows between the social uses and the physical system represent the impacts that social uses produce on the physical system, and, in the other direction, the impacts the physical system has on the social uses. Alterations of the physical system will, of course, have the potential of altering the impacts. The " what if" type of uncertainty about the consequences of altering the physical system can only be addressed if the understanding of the physical system is advanced enough to provide the answers. The predictive ability necessary to answer this " what if" type of question is best handled by the development of computer models of each component of the system. The hierarchical structure given in Figure 5 is easily adapted to the computer modeling of the complete system. Each subsystem of the hierarchy can be modeled in its own terms and at the level of sophistication required by the decision- maker. A thorough discussion of development of a framework of management models of Great Salt Lake in a Hierarchical structure is given in Riley et al. ( 1975). Although the development of computer models would greatly aid the decision- making process, the basic requirement is a complete understanding of the physical and social elements of the system. In order to assess the impacts of any management scheme, a clear identification of the entire system is needed, including the physiographic, hydrologic, salinity, biologic, limnologic, and social aspects, and the complex and dynamic coupling which are inherent in a system of this nature. The basic understanding of the system can only be gained through data gathering and research efforts directed at each component of the system. |