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Predicting suspended sediment loads in areas without detailed measurements, or with only short-term records, is crucial for the sustainable management of water resources. This study aimed to establish the relationships between specific suspended sediment loads and the characteristics of 23 sub-basins within the Haraz-Neka River basin, in Iran, to create regional models to estimate the sediment loads. To achieve this, several analytical methods were used, including cluster analysis, principal component analysis, principal component and classification analysis, and general linear modelling. Among these, the principal component analysis regression model was the most effective for estimating suspended sediment loads in the clusters. The principal component and classification analysis revealed that the best predictor was the first principal component, which strongly correlated with the minimum and mean elevation of the sub-basins. The general linear model regression showed the best overall performance for estimating regional suspended sediment loads in the study area. [ABSTRACT FROM AUTHOR]

The objectives of this study were to apply base flow index (BFI) for assessing stream flow regime and basin water storage and to validate this index in drought studies in Lorestan Province. To view of this, daily BFI and mean of annual BFI were calculated based on the minimum 5-day periods in 24 gauging stations with period 35 years. The results showed that the regional mean of BFI with 0.77 value (SD=0.08) is stable. BFI ranged between 0.61 and 0.95 and also based on the 25, 50 and 75 percentiles river flow regime in the study area divided to four categories that most of catchments in the study area have stable regime. So the catchments will be able to provide river flow during dry weather. Therefore, the results of this study can be used in classification of stream flow regime of river and hydrological drought monitoring. [ABSTRACT FROM AUTHOR]

Rice seed deterioration rate due to aging is correlated with ambient temperature, relative humidity, and moisture. Eight cultivars were analyzed for differences in seed deterioration via accelerated ageing at 45°C and 100% relative humidity (RH) for 24, 48, 72, 96, 120 hr. Khazar and Neda had highest germination percentages when exposed to 120 hr seed ageing. For Lenjan, with increased seed ageing, moisture content increased from 9.8% in the control to 21.7% after the 120 hr treatment. Khazar and Shiroudi had the lowest decrease in shoot length. Root length decreased from 0 hr control to 120 hr treatment, and was lowest in Fajr and Khazar. Minimum electrical conductivity was observed in Neda and Fajr after 120 hr. Lowest increases in lipid peroxidation from control to 120 hr treatment was in Fajr, Khazar, and Neda. Neda and Khazar are the most suitable cultivars to store in the humid, sub-tropics of northern Iran. [ABSTRACT FROM AUTHOR]

• Seismic activity is known to elevate sediment production. • The relationships between sediment sources and earthquake attributes were investigated. • Geochemical composite signatures were used to trace tributary sub-basin sediment sources. • Sediment source contributions correlated with recorded seismic events. Elevated soil erosion and suspended sediment loss are some of the most severe environmental problems in the river catchments of Iran. Seismic activity is known to elevate sediment loss and this study investigated sediment sources and loads in the Talar Drainage Basin in Iran, in the context of earthquake frequency and magnitude. A catalogue of earthquakes in the study region was assembled to estimate the expected high-frequency ground motions (i.e., Peak Ground Acceleration (PGA)). The horizontal ground acceleration was estimated using five global and reginal attenuation relationships. To fingerprint sub-basin spatial sediment sources in the study area, two size fractions (<63 μm and 63–125 μm) and 49 geochemical elements were analysed on 30 sediment samples collected from three potential tributary sub-basin spatial sediment sources and 10 target sediment samples collected at the overall basin outlet. Source contributions were estimated using a Bayesian un-mixing model. The estimated relative contributions of the individual spatial sediment sources for both the <63 μm fraction (51.9% (48.6–55.3), 48 % (44.6–51.3), and 0. 1% (0–0.2)) and 63–125-μm fraction (68.2% (66.4–69.8), 31.7% (30.1–33.6), and 0.1 % (0–0.2)) correlated with recorded seismic events. The correlations between sub-basin specific sediment loads and PGA were r = 0.68 for the <63 μm fraction and r = 0.99 for the 63–125 μm fraction. The results demonstrate that seismic activity and ground acceleration can elevate erosivity and erodibility factors. This study supports environmental planners for targeting management to reduce elevated suspended sediment loads and preserve fluvial habitats. [ABSTRACT FROM AUTHOR]