vahid chitsaz; Aliakbar Nazari Samani; Saeed Soltani; sadat feiznia
Abstract
Sediment and erosion are two natural phenomena in watersheds. Due to irregular recording and sampling difficulties, daily data are not available for sediment records. Therefore, decision makers and researchers have to apply interpolating methods to estimated sediment yields. In this study, 30 watershed ...
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Sediment and erosion are two natural phenomena in watersheds. Due to irregular recording and sampling difficulties, daily data are not available for sediment records. Therefore, decision makers and researchers have to apply interpolating methods to estimated sediment yields. In this study, 30 watershed characteristics including physiography, geomorphology, vegetation, climate conditions in 69 watersheds located in the Karoon and Karkheh basins were used to statistical analysis. Based on the principle component analysis, eight characteristics including area, perimeter, river length, relief, mean of elevation at 85% upstream and 15% point of longest flow path and the number of landslide events were selected. Then using Cluster Analysis, six homogenous regions were identified and multiple regression models were applied. Due to constriction of large dames on the studied watersheds, access to the reliable data is a challenges for sediment yield analysis. Based on the sediment-precipitation double-mass curves 29 out of 35 stations were influenced by upstream dam. Results indicated that the effects of large reservoir dams can influence the downstream sediment yield along 98 Km of river length. The results show that in each group a particular combination of variables influence the sediment yields of the watersheds. According to the validation indices (NS and R2) the obtained models have the high performance (R2 = 0.71 and NS=0.72). In general, the physiographic characteristics of the watershed such as length, area, main flow path and relief are more important than other climatic, vegetation and geological factors. The total explain variance by the mentioned variables is 87.3%.
Mohsen Farzin; Aliakbar Nazari Samani; saeideh menbari; sadat feiznia; gholamabbas kazemi
Abstract
This research tries to show the role and importance of karst formations in the infiltration of surface flows and recharge of groundwater resources in the region by determining the lineaments of geological formations in watersheds leading to the Persian Gulf and explaining the relative contribution of ...
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This research tries to show the role and importance of karst formations in the infiltration of surface flows and recharge of groundwater resources in the region by determining the lineaments of geological formations in watersheds leading to the Persian Gulf and explaining the relative contribution of each formation. For this purpose, The closest sub-basins to the Persian Gulf from the four basins of the rivers including Mond, Helleh, Kol-Mehran and Zohreh, to extract the lineaments, draw rose diagram and analyze them using ENVI® 5.3 software, PCI Geomatica, GIS10.3.1 and Rock works 2016 was selected. Initially, the frequency, density, intersection, direction, size and intensity of the lineaments in the formations of the region were determined. Then, by explaining and defining the lineament index, the importance and impact of each formation in the potential recharge of groundwater resources were determined. The results show that the highest percentage of frequency, intersection percentage and length of lineament are attributed to Asmari-Jahrom Formation and the highest percentage of Lineament intensity to Ilam-Sarvak Formation; the numerical value of the lineament intensity in the karst formations is three times as non-karstic formations. In general, the investigation of the condition of the lineament shows that the lineaments are basically created in the karst formations, so that the numerical value of the lineament index in the karst formations is 72.7, while the value in the non-karstic formations is 2.3. Furthermore, orientation of lineaments according to their frequency and length, in the whole range of study,
Sadat Feiznia; Asghar Kouhpeima; Hasan Ahmadi; Ali Asghar Hashemi
Abstract
Due to successes of fingerprinting method in producing rapid and low-cost information of sediment sources, in this research this method was used in three sub-cathments of Chasht-Khoran Basin in Semnan Province: Amrovan, Atari and Ali-Abad. Samples below 63 μm were separated and 15 fingerprinting propertis ...
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Due to successes of fingerprinting method in producing rapid and low-cost information of sediment sources, in this research this method was used in three sub-cathments of Chasht-Khoran Basin in Semnan Province: Amrovan, Atari and Ali-Abad. Samples below 63 μm were separated and 15 fingerprinting propertis was measured. In the first stage comparison of means and differentiation analysis were used for determination of the characteristics that can differentiate sediment source as well as possible. In second stage, by minimizing composite multivariate model by optimization methods, the share of each source was determined. The results shown that, in Amrovan Catchment, For properties consisting of Co, Ph , Kaolinite and K were recognized as optimum composition of sediment tracers which could differentiate sediment source completely. In Atary Catchment, the optimum composition of tracers are Na, Co, XLF and kaolinite which differentiate source by %91.7. In Ali-Abad Catchment five parameters were recognized as optimum composite which are :Na, XLF, Ca, Co and smectit which completely differentiated sediment sources. The results of calculated composite multivariate model have shown that Upper Red formation in Amrovan, Atari and Ali-Abad Sub-Catchment has the highest share in sediment production. The sediment production in these three sub catchment are as follows:35.9, 23.53 and 86.64% respectively. Therefore sediment management and control strategies should be performed on these sources.
M. Padyab; S. Feiznia
Abstract
Importance of sediment storage has been expressed as being higher than that of water in floodwater spreading networks. To determine the contribution of each geological formation in sediment input of Gachsaran Floodwater Spreading Station after 12 years of flood spreading, sediment sampling was conducted ...
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Importance of sediment storage has been expressed as being higher than that of water in floodwater spreading networks. To determine the contribution of each geological formation in sediment input of Gachsaran Floodwater Spreading Station after 12 years of flood spreading, sediment sampling was conducted in 16 points and 0-15 cm depth of the field. Using dry sieve analysis, all samples were analyzed for granolumetry. To determine mineralogical composition of sediments, particles on 150 and lower than 62 micron sieves were used. The lithology of formations was identified using geologic maps. The mineralogical composition of samples was also compared with lithological units of upstream watershed. Then percentages of share of each lithological unit in sediment production were determined. By considering the area of each lithological unit, weighted percentage of share of each unit was calculated. The results showed that Pabdeh-Gurpi formations with 55.3 % of the sediment input, has had the most contribution in the production of the largest particle size of 150-300 micrometers, followed by Kazhdomi formation with 14.1% share, Ilam-Sarvak formations with 13.1 % share, Khami formation with 10.8 % and Asmari formation with 6.5% share in the sediment production, respectively. With regard to the particles size less than 62 micrometers, Pabdeh-Gurpi formations with 80% of input sediment, had the largest contribution in the production of these particles. By using erosion control measures and storing sediments of streams on Pabdeh-Gurpi formations, 80% of very fine sediments (less than 62 microns) and 50% of fine sediments (150-300 micrometers) will be decreased.
S. H. Hosseini; S. Feiznia; H. R. Peyrovan; Gh. R. Zehtabian
Volume 62, Issue 2 , October 2009, , Pages 215-228
Abstract
In Iran, fine grained formations (Neogene's units) are very susceptible to erosion. Also, they are the units producing runoff and causing soil loss in watersheds. The objectives of this study is to assess the effect of physical - chemical and mechanical properties of these formations on sediment and ...
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In Iran, fine grained formations (Neogene's units) are very susceptible to erosion. Also, they are the units producing runoff and causing soil loss in watersheds. The objectives of this study is to assess the effect of physical - chemical and mechanical properties of these formations on sediment and runoff rates at different rainfall intensities, based on using field simulator in Taleghan Basin. For this purpose, Neogene's units were separated into five sub-units including Halite siltstone (NgSiH), Siltstone (NgSi), Mudstone (gy1C), Gypsum mudstone (gy1CG) and Halite clay stone (gy2CH), based on physical and chemical properties. Then, runoff and sediment rates were determined in each sub-units at two different intensities (30 and 60 mm/h) using rainfall simulator. Analysis of variance and Duncan's tests showed that NgSiH sub-unit has produced the highest amount of runoff and sediment rates and then the runoff and sediment rates of other subunits in decreasing order are as follows: NgSi, gy2CH, gy1CG and gy1C are 5% significant level. The trend of induced runoff and sediment rates at different times showed that in NgSiH and NgSi sub-units, runoff amounts were fixed rapidly at second ten minutes. Also, on the other sub-units, runoff amounts were fixed at third ten minutes but sediment yield was increased rapidly at third ten minutes.
