Noorangiz Gholami; Karim Solaimani; Ataollah Kavian; Vahid Gholami
Abstract
Destruction of the riverbed and activities in the river area, including mining activities, road construction, non-standard bridges, etc., often increase the risk of floods. Due to importance of this issue in the present study, the effect of mining activities on determination of channel boundary of Haraz ...
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Destruction of the riverbed and activities in the river area, including mining activities, road construction, non-standard bridges, etc., often increase the risk of floods. Due to importance of this issue in the present study, the effect of mining activities on determination of channel boundary of Haraz River, (Noorrud junction to Kelerd forest area as a given reach) has been investigated with a length of 40 km. In this regard, to study changes in river mineral activity levels during the years 1985 to 2021 from satellite images, to simulate the hydraulic behavior of the river from the HEC-RAS hydraulic model and to compare changes in river area during the study period the DLSRS model were used. Thus, satellite data with visual interpretation techniques were used to determine the level of mining activities. Then, a 1: 2000 scale topographic map of the riverbed in the HEC-GeoRAS (GIS) extension and the HEC-RAS model was used to simulate the hydraulic behavior of the river. Finally, by estimating the five parameters of the DLSRS model, the quantitative values of the river at 10-year intervals were determined in the period 1300-1399. The results of changes in the levels of mining activities indicate geometric changes of the bed of the given reach such as displacement and narrowing process. The results of the study of the factors of channel boundary changes also showed that increasing human activities and changing the river flow regime increase the quantitative boundary of the channel. The results also showed that during the last century, the level of mines in the study area has increased from 3.35 to 13.57 ha in 2021, the maximum development of which has been since 2011. As a result, the quantitative area of the river has increased from 9 m in 1922 to 17 m in 2021.
Iman Saleh; Ataollah Kavian; Mahmoud Habibnejad Roshan; Zeynab Jafari
Abstract
Iran has an arid and semi-arid climate as well as a more unstable ecosystem than humid regions; so the importance of water and soil resources conservation becomes higher in this country. The use of vegetative buffer strips is an effective strategy to reduce pollutions in surface waters as well as soil ...
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Iran has an arid and semi-arid climate as well as a more unstable ecosystem than humid regions; so the importance of water and soil resources conservation becomes higher in this country. The use of vegetative buffer strips is an effective strategy to reduce pollutions in surface waters as well as soil erosion. The present research has been conducted with the aim of study the effect of runoff rate, plant age and plant species on the efficiency of vegetative buffer strips to control runoff quality and quantity in Sari, Mazandaran, Iran. 1×10 m experimental plots were used and artificial runoff with two rates equal to the runoff generated by a precipitation with 25 and 100 years return period. The results indicated that the efficiency of vegetative buffer strips containing vetiver grass and turf grass affected by the runoff with a rate equal to the runoff generated by a precipitation with 25 years return period was higher than the buffer strips affected by the runoff with a rate equal to the runoff generated by a precipitation with 100 years return period, during the study period. Also, it was found that the efficiency of vegetative buffer strips to control runoff quality and quantity is affected more by the flow properties than characteristics of buffer strips, their plant age and species, when runoff rate is high. Two studied plant species including vetiver grass and native turf grass also showed a different performance to reduce runoff volume and its pollutants. On the other hand, variation of the plants’ age caused different efficiency for the studied vegetative buffer strips.
Leila Gholami; Ataollah Kavian; Abdulvahed Khaledi Darvishan; Azame Alipour; Zahra Besarand
Abstract
Determination of time to runoff and runoff volume in watershed response management against rainfall are the key parameters in watershed system management. Among different factors of effect on time to runoff and runoff volume, the rainfall intensity is one of the most important factors. In this study, ...
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Determination of time to runoff and runoff volume in watershed response management against rainfall are the key parameters in watershed system management. Among different factors of effect on time to runoff and runoff volume, the rainfall intensity is one of the most important factors. In this study, the effect of rainfall pattern on variables of time to runoff, runoff volume and coefficient was studied under simulated rainfall in the southeastern Noshahr city, Mazandaran province. To achieve the study purposes, four rainfall patterns, each with three changes in rainfall intensity (I: Low-Medium-High, II: Low-High-Low, III: High-Medium-Low, IV; High-Low-High) were simulated. Then, the time to runoff, runoff volume and runoff coefficient were measured for each rainfall pattern. The measured data were analyzed in Excel and SPSS 23 softwares to determine the relationship between the rainfall pattern and variables of time to runoff, runoff volume and runoff coefficient. The results showed that there was a significant difference (P≤0.05) in variables time to runoff, runoff volume and runoff coefficient resulted rainfall patterns. Also the results showed that, in all of rainfall patterns between mean amounts were the significant differences on time to runoff, runoff volume and runoff coefficient in level of 99 percent. The results showed that the rainfall pattern I had the longest time to runoff and rainfall pattern III had the largest amounts of runoff volume and runoff coefficient. The average time to runoff in rainfall patterns of I, II, III was 5.90, 4.24, 0.71 and 1.25 min, respectively. Also, the average runoff coefficient in rainfall patterns of I, II, III and IV measured 30.03, 49.63, 88.82 and 75.16 percent, respectively.
Leila Gholami
Abstract
In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the ...
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In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the present study, woodchips as a soil organic amendment was applied to control runoff variables including time to runoff, runoff volume and coefficient. For this purpose, three levels of woodchips treatment of 0.5, 1.0 and 1.5 kgm-2 were used in three replications at in 1 m2- plot scale. The plots were located in 30% slope in accordance with field conditions under simulated rainfall of 60 mmh-1 and duration of 15 min. The results showed that application of woodchips in 0.5, 1.0 and 1.5 kgm-2, time to runoff increased 97.50, 192.38 and 203.31%, respectively. The runoff volume decreased 35.23, 55.11 and 60.43% and runoff coefficient also decreased 42.43, 67.40 and 72.14% in three levels of woodchips treatments, respectively. The results of GLM showed that woodchips treatment had a significant increasing effect on time to runoff (p≤0.01) as well as a significant decreasing effect on runoff volume and coefficient (p≤0.05). The application of woodchips as a conservation treatment on the soil surface showed that this amendment can be used for runoff control especially where large quantities of woodchips are simply available.
Freidoon Soleimani; Aaollah Kavian; Karim Solaimani; Forod Sharifi; Kaka Shahedi
Abstract
The major issues that must be addressed in watersheds is correct estimating threshold from the rainfall events. According to the agricultural leveling land and irrigation and drainage network of study area is exposed to sourounding runoff destruction, so watershed management activities such as design ...
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The major issues that must be addressed in watersheds is correct estimating threshold from the rainfall events. According to the agricultural leveling land and irrigation and drainage network of study area is exposed to sourounding runoff destruction, so watershed management activities such as design of small-scale water structures, sediment control structures, implementing the management actions in vegetation, soil and land utilization is required to understand and estimate surface runoff threshold. The aim of this study was to determine the effect of soil conservation practices on runoff initiation time and runoff coefficient using rainfall simulator in the Arayez plain. For this purpose, a rain simulator with a metal plot that has a square meter area was used. The treatments consisted of natural soil (observed), polyacrylamide at two levels 3 and 6 grams per square meter (P3 and P6, respectively) and Parsian mulch (Pc) that were conducted in sandy clay loam and sandy loam soil with three replications. The rainfall intensities set up to be of 32 and 50 mm per hour in slopes 7.5 and 12.5 percent. For statistical comparison split split plot design was used. Least Significant Difference (LSD) method was used for comparison of means. Results indicated that the mean of runoff initiation time in observed treatment is higher than mulch treatments, it means which runoff begins later in observed treatment. Mulches of P6 and Pc have not significantly differences in runoff initiation time. Runoff initiation time in P3 mulch much earlier began than the other treatments. Also, results revealed that the mean of runoff coefficient in different treatments (observed, P3, P6 and Pc) have a significant differences, and belonged to separate group.
