نشریه مهندسی آب
سال هشتم شماره 4 (زمستان 1399)

In order to scheduling the irrigation time and estimation the crop yield with CWSI index, a research was done on maize (S.C. 704). The experiment was performed as factorial in a randomized complete block design. Treatments were included the water stress in growth stages of 6-leaf, 12-leaf, flowering, seeds doughing and a control treatment with full irrigation. At the threshold of water stress, CWSI index values for the above growth stages were estimated to be 0.37, 0.54, 0.63 and 0.47, respectively. Therefore, irrigation time was recommended when the CWSI index reached to the above values. Maize biomass yield in control and stress treatments at growth stages of 6-leaf, 12-leaf, flowering and seeds doughing, was measured equal to 60.1, 55.5, 48.2, 45.1 and 50 (t.ha-1), respectively. The results showed there was a relationship of Y(ton.ha-1)=-25.603CWSI+62.049 between the CWSI index and maize yield. Therefore, crop yield was estimated by the amount of CWSI index.

The dust crisis in Khuzestan province is an environmental crisis that is currently one of the main centers of dust production in the desert areas of southern Ahvaz and the destroyed parts of Shadegan wetland. Destruction of vegetation in arid areas is the cause of desertification, which is the biggest cause of dust production. In this study to evaluate the criteria and indicators effective in desertification of the region, with the help of the model (IMDPA) which includes 9 criteria that Two criteria, climate and vegetation, each of which contains 3 specific indicators, have been selected. The numerical value of each criterion is obtained from the geometric multiplication of its indicators and finally the total desertification of the region is obtained from the geometric multiplication of two criteria. Finally, the intensity of desertification in the region was calculated to be 1.99 based on the selected criteria, which was in the medium desertification class according to the model scoring table.

Labyrinth weir are a kind of multi-dimensional weirs that cause passing flow increment with two dimensions. This kind has more effective length than usual sharp tip weirs. In this regard, they can pass more flow than usual weirs for channel with similar width and height. In this study, effective geometrical parameters on single cycle labyrinth weir flow coefficient are measured by means of FLUENT software in three-dimensional way. To model turmoil, k-Ɛ model RNG method and to position free surface profile, VOF method are used. The results of numerical models are compared with those of rectangular weirs with same width. The results for specific H/P show that vertex angle increases with flow coefficient increase and rectangular weir performance of same width is less than single cycle labyrinth weirs, since in same width channel the interference of abscission blades is more severe than single cycle labyrinth weir and such an interference in vertex causes the flow coefficient decrease comparing with single cycle labyrinth weir. Moreover, single cycle labyrinth weir in less hydraulic loads has appropriate performance and ascending trend of flow coefficient.

Findings the efficient method for removing of terephthalate compounds from industrial wastewaters is considered a big challenge in the world. In this study, an efficient Iranian and worldwide methods to remove terephthalate compounds from petrochemical industrial wastewaters were investigated. In this regard, no studies with Persian languages were found. To review the studies conducted in the rest of the world, articles were searched with Google engine in databases including springer; science direct; online library Wiley; iwap online and.... 40 articles were included in this study. These articles were categorized and ranked based on the type of contaminant and the selected removal methods. The studies were ranked as fallow; 1: COD removal efficiency industrial wastewater including PTA (41%), 2: removal of soluble materials (14%), 3: removal of suspended solids (11%), 4: removal of heavy metal (9%) and investigation the type of bacterial colonies in the treatment plants (7%). These study showed that the anaerobic process has a good efficiency to treat this type of wastewater, so, has been mostly studied to remove organic matter and a satisfactory result has been obtained in this field. For industrial wastewaters containing terephthalate compounds, the neutralization, initial sedimentation, anaerobic and aerobic processes can be used as a reliable process to treat this type of wastewater.

The purpose of this study was to investigate the pollution of sari wells caused by heavy metals and determine its origin. In this research, after conducting related and basic studies, field surveys, interviews with experts and residents of the area under consideration, and sampling and testing, to identify heavy metal, copper, zinc, lead, cadmium, chromium, and mercury contamination in Selected Stations Effective in the Environment. Then to collect basic information from organizations, agencies, and various departments and GIS maps were prepared. To analyze and determine the source of heavy metals pollution using the provided maps, information obtained from the databases of the organizations, and the organs and departments, drinking water standards, the results of the experiments, and the map GIS was used.Considering heavy metal sampling in different seasons and different stations to confirm the presence of heavy metals in minerals and compare these metals with drinking water standards and to investigate and locate the natural factors and human factors making the input of these metals to the water of Sari wells It was found the origin of the arrival of the metals in the river as well as man-made factors, especially the use of pesticides in rainy seasons and natural factors in particular geological structure of the study area.

The aim of this study was to determine the nature of the foam produced in the process of water purification operations after the pre- ozonation which on a real scale on the pre-ozonation unit of Kuh Sabz water treatment plant in Fars province with has been done by changing the dose of ozone injection and sampling of the foams. The results showed that the foam formed in the ponds they are mainly composed of two parts, hydrophobic and hydrophilic which contains compounds such as turbidity, suspended solids, dissolved organics, surfactants, fats, nitrates, phosphates, cyanobacteria and chlorophyll a. Analysis of foam forming factors in process units showed that aromatic and aliphatic structures of compounds unstable due to reaction with other chemicals added to water and due to the lack of suitable conditions for coagulation and flocculation causes the formation of foam in water treatment process units.

the sediment accumulation in the reservoirs places upstream and downstream of the dam under the influence of ecosystem changes. In order to increase the volume of regulated water in the river basin and prevent the introduction of river sediments into the dam reservoir and as a result of increasing the useful life of the dam and the optimal management of water resources in the given time, the required data from the relevant companies from the Tangab Dam was obtained and Using Karun's analysis software, based on the calculations performed by the software, the modified volume (after sedimentation) after one year and after 50 years from the beginning of operation, using the method of increasing the level to The order of 1021.646 million cubic meters and 605.664 million cubic meters, and also for the method of reducing the level of these numbers is equal to 1021.6 million million Rmkb and 064/580million cubic meters is estimated. Given the reservoir type and sediment volume, the curves of hp and h'p are plotted. According to the power plant's level, the reservoir level of the dam increases with the calculation of sediment distribution by increasing the level after 110 years from the plant's level of utilization, and this also occurs in the method of reducing the level after 100 years.