The exposure of the Earth’s surface to the energetic input of rainfall is one of the key factors controlling water erosion. While water erosion is identified as the most serious cause of soil degradation globally, global patterns of rainfall erosivity remain poorly quantified and estimates have large uncertainties. This hampers the implementation of effective soil degradation mitigation and restoration strategies. Quantifying rainfall erosivity is challenging as it requires high temporal resolution(<30 min) and high fidelity rainfall recordings. We present the results of an extensive global data collection effort whereby we estimated rainfall erosivity for 3,625 stations covering 63 countries. This first ever Global Rainfall Erosivity Database was used to develop a global erosivity map at 30 arc-seconds(~1 km) based on a Gaussian Process Regression(GPR). Globally, the mean rainfall erosivity was estimated to be 2,190 MJ mm ha−1 h−1 yr−1, with the highest values in South America and the Caribbean countries, Central east Africa and South east Asia. The lowest values are mainly found in Canada, the Russian Federation, Northern Europe, Northern Africa and the Middle East. The tropical climate zone has the highest mean rainfall erosivity followed by the temperate whereas the lowest mean was estimated in the cold climate zone.

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A pressure–state–response framework was customized to outline the watershed health (WH) concept. To achieve this, the watershed indicators of pressure, state (S), and response (R) were conceptualized according to 17 climatic, anthropogenic, and hydrologic criteria. Four node years of 1986, 1998, 2008, and 2014 were selected to provide a running picture of the Shazand Watershed condition. The WH index was then calculated using geometric mean of pressure, S, and R indicators and assigned a range of values varied from 0 (unhealthiest) to 1 (healthiest). (a) The main pressures on the Shazand Watershed come from climatic factors in 1998 and 2008 and human factors in all study years. (b) The climatic factor and then anthropogenic factors had the maximum effectiveness in explaining the S indicator. (c) In calculating R indicator, the anthropogenic factors in 1986 and the hydrologic factors in other study years played significant contributions. (d) The greatest percentage of the study area were assigned to moderate condition of S indicator in 1986, 1998, and 2008 with value of 42, 46, and 73%, respectively, whereas in 2014, 44 and 42% of the watershed were respectively recognized as relatively healthy and moderately healthy in terms of S indicator. (e) For the first to fourth study node years, some 53, 77, 78, and 60% of the Shazand Watershed had the relatively unhealthy condition, respectively. (f) The Shazand WH decreased about 12% during periods of 1986–1998 and 1986–2008. (g) An improving trend was also found in WH for some sub‐watersheds.

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An attempt was made to employ the reliability (Rel)–resilience (Res)–vulnerability (Vul) conceptual framework to develop a typical indicator system for quantitative assessment of watershed health. The study aimed to conceptualize and customize the RelResVul 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 (RelResVul) 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 Rel and Res, and an increasing trend in Vul for SPI and LFD in the Shazand Watershed. The results further showed an increasing trend in Rel, and a decreasing trend in Vul 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 RelResVul 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.