Emergy Evaluation on Watershed Management of Taiwan

Watershed managements are optimized in consideration of the greatest benefits with a balanced development among resources utilization, disaster prevention, and ecology preservation. Too emphasize resources utilization and proper disaster prevention, might be harmful to the long term benefits of ecology preservation, and unfavorably influence the efforts of current economic development. Therefore, some methods by way of comprehensive and multi-scaled analysis are needed to provide for the decision maker to consider their policy. Emergy (spelled with an `m') is the available energy of one kind of previously used up directly and indirectly to make a service or product. Its unit is the emjoule (abbreviated sej). All product and service can consider the energy input of the historical production process, then with the common unit foundation `solar emjoule' to compare, it is a kind of objective method and can be really comparing the value and efficiency of its intension. The ideas and developments of analytical method of emergy are based on the theory of systems ecology. The purpose of this paper is using emergy evaluation to analysis watershed management variation between ecology and economic development of Taiwan from 1981 to 2005.