Khadije Haji; Raoof Mostafazadeh; Abazar Esmali-Ouri; Shahnaz Mirzaei
Abstract
Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in ...
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Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in the West-Azarbaijan Province in a 20-years recorded data using double-mass curve and annual variation analysis (coefficient of variations, annual distribution of regulating coefficient, and concentration rate). The logarithmic rating curve equation was used to sediment estimation according to the nature of discharge and sediment load variations. According to the results, the maximum discharge and sediment amount were observed in the May of spring season that can be related to the high amounts of snow melt and spring precipitation and associated high river flow discharge in the study area. The cumulative double mass curve of the runoff and sediment had a constant slope in the Pole-Bahramlou, Choplojeh, Sarighamish, Peighale, Naghadeh, Dorood, and Chapasabad stations, in which the sediment load is consistent with the runoff amounts. While, the decreasing pattern of sediment load was observed in the Dizaj, Urmia, Dashband, Ghasemlou, and Bayazidabad, which can be related to rainfall decrease and conservation measures (dam construction) and lower sediment amount in the study period. The highest coefficient of variation of runoff and sediment was observed in Pole-Bahramlou (16 and 173 percent), respectively. The highest monthly runoff-sediment uniformity was identified in Chaparabad station, where the lowest concentration rate of runoff and sediment were observed by 0.25 and 0.35 percent respectively; while, the Urmia station identified as a high rate of runoff and sediment concentration rate with 0.58 and 0.84 percent in the study area. It can be concluded that the seasonal variations of runoff and sediment had a consistent manner and some different spatial variations due to climatic, hydrologic and anthropogenic conditions.
Shirko Ebrahimi Mohammadi; Seyed Hamidreza Sadeghi; Kamran Chapi
Abstract
In this study, the seasonal variations of discharge and concentrations of soluble nitrite, nitrate, ammonium, orthophosphate and potassium and also the concentrations of these substances during baseflow and rainfall runoff in the seasonal and perennial rivers entering the Zarivar Lake were investigated. ...
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In this study, the seasonal variations of discharge and concentrations of soluble nitrite, nitrate, ammonium, orthophosphate and potassium and also the concentrations of these substances during baseflow and rainfall runoff in the seasonal and perennial rivers entering the Zarivar Lake were investigated. The results showed a great variation of discharge in the spring than the other months because of frequent rainfalls and the maximum discharge in this season. Despite the differences of the stream lake behavior and also the different nature of nutrients, generally, nutrients concentrations have different seasonally significant so that the maximum concentrations and the maximum concentration variations of soluble nitrite, nitrate, orthophosphate and ammonium were seen in summer. The results of the inter and intra storm variability analysis of nutrient concentrations indicated a significant differences between nitrite and nitrate during and between storm events with sig=0 and sig
