نتایج جستجو برای: clear water flow

تعداد نتایج: 1169381  

2016
Margaret Cook Michael Webber

Hydraulic fracturing—the injection of pressurized fluid, often water, to increase recovery of oil or gas—has become increasingly popular in combination with horizontal drilling. Hydraulic fracturing improves production from a well, but requires a significant amount of water to do so and could put pressure on existing water resources, especially in water-stressed areas. To supply water needs, so...

Journal: :مرتع و آبخیزداری 0
اصغر زارع چاهوکی دانشجوی دکتری آبخیزداری دانشگاه یزد علی سلاجقه دانشیار دانشکدة منابع طبیعی دانشگاه تهران محمد مهدوی استاد دانشکدة منابع طبیعی دانشگاه تهران شهرام خلیقی سیگارودی استادیار دانشکدة منابع طبیعی دانشگاه تهران سعید اسدی کارشناس مرکز تحقیقات هواشناسی کاربردی استان یزد

a flow-duration curve (fdc) illustrates the relationship between the frequency and magnitude of streamflow. applications of fdc are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation and habitat suitability. this study was carried out in 11 selected watersheds with commo...

ژورنال: آبخیزداری ایران 2019

Environmental flow is explained as the period of time, quantity and the amount of required water for maintaining the water, fresh, the river’s ecosystem, human beings’ welfare and the life depending on the water. The main goal of this paper is to investigate and compare the hydrological methods including Tennant, aquatic flow, Tessman, analysis of the flow duration curve and the flow duration c...

Journal: :مرتع و آبخیزداری 0
مهرنوش قدیمی دکتری ژئومورفولوژی دانشگاه تهران حسن احمدی استاد گروه آبخیزداری دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران ابراهیم مقیمی استاد دانشکده جغرافیا، دانشگاه تهران منصور جعفربیگلو استادیار دانشکده جغرافیا، دانشگاه تهران

to evaluate the hydrogeochemical characteristics of karst water resources of oshtorankooh, chemistry details of springs has been considered as the most important evacuator of karst resources. this research has been performed to study hydrogeochemical nature of karst springs and their origin with an emphasis on the type of formation.  accordingly, five samples of the water of permanent springs o...

Nowadays, water supply is more limited and providing water is more difficult due to increasing population and demand for water. Thus, due to rainfall shortage and impacts of drought, the need for forecasting monthly and annual rainfall and flow discharge through time series analysis is acutely felt. One of the key assumption in time series is their static condition. However, hydrological time s...

Journal: :journal of rehabilitation in civil engineering 2014
mohammad mehdi razmi mojtaba sanei cyrus ershadi

scour around hydraulic structures is an inevitable phenomenon . recognition of this phenomenon and dealing with it is an issue considering which will ensure the project success . local scour at piers has been reported as the most important factor in the destruction of the bridges . the use of submerged and non-submerged piles is one of the scour control methods . submerged piles have been rarel...

Journal: :آب و خاک 0
سینا رازی علی حسین زاده دلیر فرزین سلماسی داود فرسادی زاده

in this paper the effectiveness combination of bed sill and collar in reduction of local scour depth at cylindrical piers under clear water flow condition was investigated (v/vc=0.9). in the first of experiments, the bed sill was located in downstream and different distances from the piers. results indicated that minimum distance of the bed sill from the piers in downstream has maximum reductio...

Journal: :ماشین های کشاورزی 0
هانیه روشن سید جلیل رضوی مهدی قیصری

water scarcity is today’s world biggest challenge which requires different countries to manage their water resources in the most efficient way. sprinkler irrigation increases water consumption efficiency due to more uniform distribution of water across the field. precision farming is based on the site-specific use of inputs according to soil characteristics and plant needs. one of the main inpu...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده مهندسی علوم آب 1393

drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...

Base-flow can be considered as a part of stream-flow which is connected to discharged flow from aquifers. Due to high variations in rainfall values and other hydrological components in arid and semi-arid areas, watershed scale simulation of the flow is very important. Hydrological models are generally employed as an appropriate tool in this field of study. This work makes uses of use a distribu...

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