QUANTIFYING TRENDS IN SYSTEM SUSTAINABILITY

This paper focuses on the measurement of the relative sustainability o f renewable water resource systems. Being able to quantify sustainabil ity makes it possible to compare alternative plans and policies, and t o include sustainability as one of the multiple objectives to be consi dered when making decisions regarding the design and operation of thes e systems. Commonly used measures of reliability, resilience and vulne rability, based on subjective judgements concerning what is acceptable or unacceptable with respect to multiple system performance indicator s, are combined into an index and used as a measure of changes in rela tive system sustainability over time.