Watershed Health (Part one): Reliability, Resilience and Vulnerability Conceptual Model

Nowadays, numerous risks seriously threat the health of watershed ecosystems. Human driven modifications of the Earth's natural environment largely affect ecosystem structure and functions. Therefore, assessment of the relative condition of watersheds is essential to plan appropriate management practices. In this regards, various approaches such as reliability-resilience-vulnerability (RRV) indicator based and conceptual model have been proposed. Assessment and monitoring ecosystem health using a promising approach of the RRV model to ascertaining watershed health provides early warnings of environmental degradation causes. So, watershed ecosystems health assessment is a fundamental and an essential step to ecological services conservation. To apply the RRV model, several criteria have been used within a riskbased standpoint. Although, the application of the RRV model has been commonplace for years in various ecosystems, but, the use of the RRV indicators in watershed health assessment has been rarely reported. Towards this, the present research was conducted to introduce, to explain the application and to review the literatures of the RRV model. The results of the literature review indicated that more studies have been limited mostly to reservoir operations management. While, the recent studies have focused on health assessment of the different ecosystems such as stream, urban and even watershed ecosystems. Based on these researches, the application of the RRV model has been suggested as a prerequisite for appropriate and integrated watershed health assessment.