watershed
Razieh Izanloo; Ebrahim Omidvar
Abstract
The damming can cause changes in the hydrological regime of the river. There is a crucial need to understand the potential impacts of water structures on river hydrologic regimes in order to set managed environmental flows. In this study, the statistics of Tang Esferjan hydrometric station at the outlet ...
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The damming can cause changes in the hydrological regime of the river. There is a crucial need to understand the potential impacts of water structures on river hydrologic regimes in order to set managed environmental flows. In this study, the statistics of Tang Esferjan hydrometric station at the outlet of Hoonejan watershed (Isfahan province) were used to investigate the monthly average discharge and flow duration curve alteration using IHA software (version 7.1). The amount of monthly flow has decreased in the post impact compared to the pre impact period. The flow duration curve is higher in all seasons before the construction of check-dams than after construction. The interpretation of flow duration curves shows the reducing effect of correction clauses in all types of flow. The hydrological indicators of the stream (normal discharge index in the high flow condition, normal discharge index in the low flow condition and normal discharge index) have decreased in the post-impact period compared to the pre-impact period. In all months of the year, except for February, March and April, the rate of decrease of the normal discharge index in the low flow condition (Q75) was higher than the normal discharge index in the high flow condition (Q25). The normal discharge index in the high flow condition has decreased more in the spring season than in other seasons after damming. The normal discharge index in the low flow condition in winter, autumn (91%) and summer (90%) has decreased more than in spring.
Hydrogeomorphology
Vahideh Moradzadeh; Zeinab Hazbavi; Abazar Esmali Ouri; Raoof Mostafazadeh; Shirin Zarei; Nazila Alaei
Abstract
Ecological indicators have become important tools for evaluating and monitoring natural resources. Understanding the relationship between biological activities and ecological interactions is essential to their structure. On the other hand, human activities have significant effects on landscape evolution ...
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Ecological indicators have become important tools for evaluating and monitoring natural resources. Understanding the relationship between biological activities and ecological interactions is essential to their structure. On the other hand, human activities have significant effects on landscape evolution through changes in sediment production, transport, and storage. Therefore, this issue should be considered in the comprehensive management of different watersheds and ecosystems. Accordingly, the present study was conducted to evaluate the spatial heterogeneity of the hydro-sedimentologic disturbance index (HSDI) in the watershed located in the central part of Ardabil province. For this purpose, sediment transport (ST), hydrological stress (HS), recharge potential of groundwater (Rec), and soil erosion potential (SEP) were first calculated for 27 different sub-watersheds. Then, these factors were weighted using the Shannon entropy method. The hydro-sedimentologic disturbance index (HSDI) was calculated and zoned using the weighted average. The results showed that the mean, maximum and minimum values of the HSDI index in the Samian watershed were 10.17, 45.67, and 0.20, respectively. In addition, 87.67, 5.33, 5.32, and 1.68% of the watershed area were classified into very low, low, medium, and high levels of disturbances, respectively. Sub-watershed 19 located in the northern part, and sub-watersheds 20 and 21 located in the central part of the Samian watershed have the most disturbances, so they are prioritized for management actions. The present research framework can be used as a potential tool to support decisions that should focus on improving natural resource management.
