Watershed Health Characterization Using Reliability–Resilience–Vulnerability Conceptual Framework Based on Hydrological Responses

An attempt was made to employ the reliability (R_el)–resilience (R_es)–vulnerability (V_ul) conceptual framework to develop a typical indicator system for quantitative assessment of watershed health. The study aimed to conceptualize and customize the R_elR_esV_ul framework to watershed health assessment for the Shazand Watershed in Markazi Province, Iran, for the period of 1977–2014. To this end, four easily, reliable, available and accessible criteria viz. standardized precipitation index (SPI), low and high flow discharges (LFD and HFD), and suspended sediment concentration (SSC) were selected, and corresponding indices for reliability–resilience–vulnerability (R_elR_esV_ul) framework were accordingly conceptualized and calculated. The thresholds of 0.1, 0.16 m³ s^?1, 12.63 m³ s^?1 and 25 mg l^?1 day^?1 were thus selected for SPI, LFD, HFD and SSC, respectively. The results showed a decreasing trend in R_el and R_es, and an increasing trend in V_ul for SPI and LFD in the Shazand Watershed. The results further showed an increasing trend in R_el, and a decreasing trend in V_ul for HFD and SSC. A decreasing trend was ultimately recognized in watershed health index for all criteria except SSC. Additionally, the integrated hydrological watershed health index of 0.16 ± 0.11 obtained from the geometric mean of the R_elR_esV_ul framework indices also showed a decreasing trend for the Shazand Watershed health during the study period. The results of the present initiative study can be considered as a baseline by decision makers and managers to effectively adjust watershed management strategies to handle land degradation issues in the area. Copyright © 2016 John Wiley & Sons, Ltd.