In the first chapter, I point out that rarely are information (e.g., knowledge about nutrient cycling, sediment!. transport)and analysis techniques (e.g., ecologic modeling, ecosystem analysis) used in land use planning decisionmaking. These products of science can significantly improve the technical quality of resource use allocations developed by land use planners and recommended to decisionmakers—particularly the planning areas, the complexity and infrequent use. Some planners have scientific backgrounds but none are broadly enough trained to use the plethora of diverse, scientific information commonly available on their planning areas and problems. Planners' training and function is to organize and to direct the process producing for decisionmakers a set of well evaluated, alternative plans and/or to recommend a best plan. Their role is not to be or become scientific experts. However planners need to·be able to work with scientific experts when such information is needed to analyze important problems.
Conceptual ecologic models (CEM) and ecologic simulation models (ES) natural science information for analyzing the problems of planners which have important scientific components. I note that the frequently encountered task of developing a land capability classificaton (LCC) for a regional planning area can be greatly improved by using CEMs to establish which variables and values define capability classes. I examine the use of CEMs as an analysis approach for developing technically improved and scientifically supported LCC by application to a case study.
In Chapter 2, I outline the general advantages of using scientific information and scientific analysis approaches, such as ESMs, for decisionmaking, and how to decide when they are appropriate tools for specific types of planning problems. I then present a general procedure for determining which analysis technique to use. The best scientific techniques (1) availability of data, equipment, skills and other analytic needs; (2) dominance of the problem by scientific and/or quantitative information; (3) working behavior of the planners (e.g., the relative consideration they give to formal analysis, expert judgment, public preference); and (4) working environment constraints within which the plan must be developed (e.g., time and funds available for analysis, political considerations, type of decisions to be ntade, size of the area for which decisions are to be made). In Chapter 3, from these four considerations I develop and explain a set of guidelines for deciding whether ESM is the most appropriate analysis technique. In Chapter 4, I develop a planning problem of the Lake Tahoe Basin region as an example of using the guidelines to assess the feasibility of CEM and ESM for developing a LCC for protecting the water color and transparency of the lake. In Chapter 5, I develop an overall CEM of the system of variables controlling water color and transparency as affected by suspended sediments and nutrients from watershed lands. In accord with the assessment guidelines, I also discuss the availability of adequate levels of scientific principles and data to enable construction of an ESM. I then divide the overall system CEM into a series of subsystems, subsequently developing CEMs for each in Chapters 6 through 10 and 13 through 16. Chapter 6 presents a CEM of the factors controlling the water color portion of the system model.
In subsequent chapters I present CEMs of subsystem variables controlling: biotic production and distribution of subtances affecting water color and transparency (Chap. 7); transport of suspended sediment by overland flow and stream flow processes (Chap. 8); release, transport and delivery of nitrogen (Chap. 13) and phosphorus (Chap. 14); and suspension of particles in lake waters and retention once settled on the lake bottom (Chap.16). In Chapters 11 and 12, respectively, I develop estimates of the quantities of nutrients and potential suspended sediment particles on watershed sites. In Chapter 17, I develop a LCC scheme based upon the information in the preceding subsystem EM mapping and procedural decisions needed for its implementation. In the last chapter (18), I evaluate CEM use as an analysis technique likely to increase area planners' use of scientific information and analysis techniques. I also discuss why, in spite of their considerable promise, I think scientific information and analysis techniques will not be used more widely by land use planners.