http://localhost/xmlui/handle/123456789/2199 2026-04-07T00:37:52Z 2026-04-07T00:37:52Z Amiri-Tokaldany, E. Darby, S. E. http://localhost/xmlui/handle/123456789/4147 2018-02-15T09:43:18Z 2018-02-15T00:00:00Z

A Model for Stability Analysis of a Multi-Layered River Bank (SAMLR) Amiri-Tokaldany, E.; Darby, S. E. River bank erosion can result in considerable riparian land loss and the delivery of large volumes of sediment to reaches downstream. Consequently, the ability to predict the stability and failure geometry of eroding river banks is an important prerequisite for estimating the rate of bank erosion and sediment yield associated with bank erosion. In this paper a new model capable of analyzing the stability of layered river banks is introduced. The new model takes into consideration the effects of positive pore water pressure in the saturated portion, and negative pore water pressure in the unsaturated portion, of the bank. Also, the role of hydrostatic confining pressure due to the water level in the river and the effects of the water in tension crack on stability analysis is accounted for. Unlike many previous analyses, the failure plane is not constrained to pass through the toe of the bank. However, it considers only planar-type failure mechanism. Finally the bank profile geometry is not restricted to a special case. The new model has been tested using field data sets from a site on the Sieve River in Italy and a site on Goodwin Creek in Mississippi. The results show some agreement between the predicted and observed values of bank stability. paper

2018-02-15T00:00:00Z Jalali1, B. Barzegar, M. http://localhost/xmlui/handle/123456789/4145 2018-02-15T09:36:33Z 2018-02-15T00:00:00Z

Fish Parasites in Zarivar Lake Jalali1, B.; Barzegar, M. Twenty four ecto- and endo- parasite species were found in different organs of eight native and exotic fish species in Zarivar Lake situated in the far west of Iran. Overall, 1000 fish specimens belonging to the Dactylogyridae, Gyrodactylidae families the Cyprinidae, Poeciliidae and Mastacembelidae families were examined during 2001 and 2002. Of them, five Protozoans, including Trichodina pediculus, Trichodina sp and Myxobolus molnari, a pansporogenic stage of the Myxosporean plasmodia and Ichthyophthirius multifiliis were recorded. Of the Metazoan parasites, 12 monogenean species, mostly belonging to the Dactylogyridae, Gyrodactylidae families and the Ancyrocephalinae subfamily, were found and identified at species and genus level. The number of helminthes reached 15 by adding one Digenea metacercaria (Diplostomum spathaceum) and 2 coelozoic Cestoda species. Crustacean species found on both of native and exotic fishes, belonging to Copepoda and Branchiora orders comprised of Argulus foliaceus and Lernaea cyprinacea, in addition an unknown Argulus was also found on skin and gills of spiny eel which identified to genus level. The only nematode found in the intestine of common carp was identified as Pseudocapillaria tomentosa. Besides the first record of parasites of spiny eel, the seasonal prevalence of ligulosis is presented. Additionally, zoogeographical analysis and species composition of parasitic fauna of Zarivar Lake are discussed. paper

2018-02-15T00:00:00Z Khorsandi, F. Yazdi, F. Alaei http://localhost/xmlui/handle/123456789/4120 2018-02-14T13:38:44Z 2018-02-14T00:00:00Z

Prediction of Irrigation Water Salinity by Means of Hydrometry Khorsandi, F.; Yazdi, F. Alaei Salinity is the primary water quality concern in irrigated agriculture. An Electrical Conductivity (EC) meter and a hydrometer are two possible methods for measurement of irrigation water salinity. The conductivity meter method is based on measuring the amount of electrical current that a fluid will support. Although it is the most widely used method, the instrumentation is rather expensive and in some instances may require sample dilution. The hydrometer method is based on measuring the density of the fluid. The main objectives of this study were to compare these two methods and, based on hydrometer method, develop empirical models for prediction of EC, sodium adsorption ratio (SAR), and the principle ion concentrations in the irrigation waters of Yazd Province, Iran. The electrical conductivity, temperature, and density of 206 water samples from wells across Yazd Province were measured. Temperature correction factors for adjusting the hydrometer reading to 25 oC were determined. The correlation between EC and hydrometer readings was high (R2 = 0.97). Although the empirical model developed for prediction of EC slightly underpredicted the measured values, it is still accurate enough for practical purposes. Hydrometer readings were also highly correlated with the principle ions and SAR. The salt type also affected the hydrometer readings. Magnesium sulfate solution had the highest density among the major salt types present in irrigation waters. Finally, a chart was developed for rough estimations of EC, sodium and chlorine concentrations in irrigation waters of Yazd Province, Iran. paper

2018-02-14T00:00:00Z Yazdian, A. R. Kowsar, S. A. http://localhost/xmlui/handle/123456789/4116 2018-02-14T12:48:19Z 2018-02-14T00:00:00Z

The Agha Jari Formation: A Potential Source of Ammonium and Nitrate Nitrogen Fertilizers Yazdian, A. R.; Kowsar, S. A. Nitrogen deficiency ranks right behind water shortage as the second-most constraint to crop production in the coarse-loamy sand of the Gareh Bygone Plain (GBP) in southern Iran. Since better resource utilization is essential for wise energy management, contrary to reported cases, surface water pollution by N maybe a boon in the GBP. The Agha Jari Formation (AJF), in which the Bisheh Zard Basin (BZB) has been formed, contains anomalously high concentrations of NO3 − and NH4 + in its calcareous sandstone, siltstone and marl components. As about 60% of our irrigation water is supplied through underground resources and are heavily over-exploited, the artificial recharge of groundwater (ARG) is actively pursued in Iran. Therefore, a major proportion of the ephemeral discharge of the BZB is spread over 1365 hectares of sedimentation basins and recharge ponds of the ARG system in the GBP. These basins and ponds are covered with improved rangeland, and eucalyptus (Eucalyptus spp.) and acacia (Acacia spp.) plantations. Therefore, it is expected that some of the geological-N dissolved in floodwater, and also carried by the suspended load, will reach the groundwater and supply the plants coming in contact with the water and/or sediment. Moreover, as both NO3 − and NH4 + are considered pollutants of groundwater, the relative abundance of each should be determined, so that possible remedial measures can be designed and implemented. To study the origin of N in the BZB, and to investigate the fate of the dissolved and adsorbed N as it travels from the watershed to the root zone, 13 rock samples, 5 floodwater samples and 81 soil samples were collected and analyzed for NO3 −and NH4 +. The NO3 −-N concentration was lower than that of NH4 +-N in most of the samples: 5.1 vs. 9.6 mg kg-1 in rocks, 13.4 vs.17.4 mg L-1 dissolved in floodwater, 1.3 vs.4.3 mg kg-1 carried by the suspended load, and 10.6 vs.15.5 mg kg-1 in the 0-125 cm soil profile. Assuming that the mean annual inflow of the GBP-ARG system is 7 million m3 ,we receive 89.4±52.4 kg ha-1 yr-1 of NH4 +-N and 68.7± 24.6 kg ha- 1 yr-1 of NO3 −-N, of which some furnishes the vegetative cover with N. A part of what remains may reach the watertable after passing through the vadose zone.

2018-02-14T00:00:00Z