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Show Thus, it is clear that the problems considered at this first layer are of three dimensions as follows: 1. Geographic- Hydrological Considerations a. The lake itself b. Near shore c. The watershed 2. Temporal Considerations a. Short term time horizon ( 1- 5 years) b. Intermediate term time horizon ( 5- 15 years) c. Long term time horizon ( 15- 50 years or over) 3. Functional Considerations a. Hydrological b. Limnological c. Ecological A variety of considerations may be adopted for decomposition of the system, depending on the solution desired. For example, if the desired solution depends on examining the system from a functional point of view, a functional decomposition of the system logically is suggested. In this situation, all time horizons and all parts of the Great Salt Lake system ( hydrological, limnological, and ecological) will be included in each functional submodel. In other words, for the functional decomposition the temporal and geographical- hydrological dimensions may be viewed as parameters for the first layer decomposition, and an overlapping coordination is then applied ( Haimes and Macko, 1973). In other words, a functional decomposition at the first layer in one hierarchical structure and a geographical- hydrological decomposition at the first layer in another hierarchical structure might be integrated through an overlapping coordination between the two structures. This procedure frequently provides considerable insight into the system. Hydrological considerations are apparent from the need to concentrate on specific considerations within these groups. The temporal considerations are included because decisions may have entirely different and possibly converse impacts on the short term versus the long term planning horizons. The first level of the second layer in the hierarchy takes into consideration the societal and economic goals. These societal and economic goals have been identified and decomposed into several major components. Each of the six earlier named activities and goals must be quantitatively analyzed with respect to its benefits and utilities, cost to the public and environment, its impact on tlie hydrological, limnological, and ecological aspects of the lake and its basin over the short, intermediate, and long- term planning time horizons. In particular, all the information needed for analyzing and evaluating the trade- offs among all these activities will be provided at this level of the hierarchy. The trade- off analysis is conducted at the second level of the second layer by means of the multi- objective function analysis. The major efforts associated with the first level relate to the identification of measures ( decisions) that are aimed at enhancing the achievement of the economic and societal goals; the constructions of the corresponding objective functions which represent the earlier six stated activities and goals; the identification and construction of all the constraints - technical, physical, ecological, hydrological, economical, isocietal, political, legal, and others as related to the time domain; identification of all the needed data to ; be designed, collected, transferred, processed, and janalyzed along with their associated cost and worth; and finally, provision of a basis for coupling all these economic and societal ac- tivities at the second level of the second layer in the hierarchy, ' hierarchy. ! The development of utility functions, objective ifunctions, and the systems input- output relationships, fas well as the construction of the system constraints constitute the heart of the modeling efforts. This task is particularly difficult for large- scale and complex problems, such as a comprehensive planning effort involving Great Salt Lake and its basin. Here ( there are many competing, conflicting, and non- com- jmensurable objectives and goals which may be difficult to quantify. These objectives and goals are functions of many variables including a dependency on the time and space dimensions. The classical methodologies in cost- benefit analysis or, as often referred to, cost- effectiveness analyses, identify different classes of costs and benefits ( primary, secondary, and tertiary). Tangible and intangible costs and benefits are generally quantified in terms of the same units so they can be analyzed and compared with each other. Weighting coefficients which transfer one unit of activity one to a commensurable unit of activity two have traditionally been introduced to facilitate the comparative analysis. This is the case, for example, in multiobjectives analyses when the parametric approach is being utilized. In this study, a more realistic approach is advocated for the construction and evaluation of the various competing objectives and goals associated with the 36 |