background: rivers and streams are important sources of surface waters. water quality of these resources depends on many factors including hydrologic, physicochemical and biological factors. these resources are important in terms of social, economic and political development.. zayanderood river is the only river in central basin of iran that has permanent fresh water. this river has an importan...

treated sea water is the most significant source of water and surfactant floods. the various chemicals employed in treatment plants should be compatible with surfactant systems. based on surface tension experiments, the activity of these chemicals is examined over a wide range of concentrations in different solutions, including distillated water, sea water by using three types of surfactant mix...

surface-piercing propellers (spps) have been widely used in high speed craft due to some desirable features such as high efficiency, omission of resistance of equipment attached to the propeller and proper functioning of cavitation. unlike the submerged propellers, theoretical methods have no significant application on simulation of sppsbecause of problems related to modeling of these propeller...

the purpose of this study was to survey impacts of drought on socio-economic conditions of guilan paddy farmers. besides recognizing these impacts, it ranked them according to the viewpoint of the paddy farmers. it was of the descriptive- correlation type. questionnaire was the main tool of this study. to determine the validity of questionnaire used of comments of panel experts and reliability ...

abstract in refrence to un appropriate time and place dispersal of precipitation in iran and having low efficiency in agriculture, water as the most limitative factor in agriculture is discussing. in this study, the existing pattern of mashhad-chenaran plain is considering and with gathering data related to 1388, with target of decrease in water consuming, optimum and nearly optimum cropping pa...

There is an increasing awareness among regional natural resource managers of the value of data collected by community groups. This includes monitoring of surface rivers, streams, lakes, reservoirs, wetlands, estuaries, coastal waters and groundwater. Water quality and condition data collected by community groups supplements information collected by state, regional and local resource management ...

Jiangsu is a major province located in the east of China, consuming a large amount of water resources. It is considered that improving the comprehensive water use efficiency has an important significance to achieve sustainable development of the economy in Jiangsu. Through extensive literature research and investigation of Jiangsu Province, this paper establishes comprehensive water use efficie...

Invasive aquatic plants are an ever-growing nuisance to water resources in Mississippi and the rest of the United States. These plants are generally introduced from other parts of the world, some for beneficial or horticultural uses. Once introduced, they can interfere with navigation, impede water flow, increase flood risk, reduce hydropower generation, and increase evapotranspirational losses...