نتایج جستجو برای: 1 gypsum in reducing sediment concentration diminished 35 min after runoff initiation whereas

تعداد نتایج: 17723790  

2012

The study concerns an experimental investigation in the laboratory of the water erosion using a rainfall simulator. We have focused our attention on the influence of rainfall intensity on some hydraulic characteristics. The results obtained allow us to conclude that there is a significant correlation between rainfall intensity and hydraulic characteristics of runoff (Reynolds number, Froude num...

2001
Pierre Y. Julien

Transforms reduce the distributions of surface-runoff and sediment-transport variables to nearexponential distributions typical of rainfall duration and intensity. Two transform parameters are determined from field measurements using either a graphical method or the method of moments. The transforms were tested on both small experimental plots and very large watersheds for the distributions of ...

   Agricultural hillslopes with susceptible loess enters a large amount of runoff and sediment into the Gorgan city annually, due to the inappropriate drainage system which cause a lot of financial losses city. The purpose of this study was to investigate the effect of different vegetation scenarios on the runoff and sediment discharge from three hillslopes of catchment of ​​5.9 hectares. The r...

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The growing population led to greater human need to use natural resources such as sand and gravel mines. Direct removal of sands from the bed river leads to increase suspended sediment concentrations in downstream of harvested area and creates other problems viz. filling reservoirs, change in hydraulic characteristics of the channel and environmental damages. However, the range of temporal and ...

2000
K. W. Farrish

Sediment loss and nutrient cpncentrations in runoff were evaluated to determine the effects of site preparation burning on a recently harvested loblolly pine (Pinur taeda L.) site in east Texas. Sediment and nutrient losses prior to treatment were approximately the same from control plots and pretreatment burn plots. Nutrient analysis of runoff samples indicated that the prescribed burn caused ...

Journal: :Journal of environmental quality 2007
Harold M Keener Britt Faucette Michael H Klingman

Soil loss rates from construction sites can be 1000 times the average of natural soil erosion rates and 20 times that from agricultural lands. Silt fence (SF) is the current industry standard used to control sediment originating from construction activities. Silt fences are designed to act as miniature detention ponds. Research has indicated that SF sediment filtering efficiency is related to i...

2009
Rodrick D. Lentz Robert E. Sojka Charles W. Robbins Dennis C. Kincaid Dale T. Westermann

Furrow irrigation systems have a greater application capacity, are less costly, and use less energy than sprinkler systems but furrow irrigation produces greater runoff, erosion, and deep percolation losses. Phosphorus (P) and nitrogen (N) losses are associated with runoff sediment, and can be minimized by eliminating irrigationinduced erosion. Excessive leaching of inorganic and organic solute...

Journal: :Journal of environmental management 2017
S Beganskas A T Fisher

Groundwater is increasingly important for satisfying California's growing fresh water demand. Strategies like managed aquifer recharge (MAR) can improve groundwater supplies, mitigating the negative consequences of persistent groundwater overdraft. Distributed stormwater collection (DSC)-MAR projects collect and infiltrate excess hillslope runoff before it reaches a stream, focusing on 40-400 h...

2008
A. N. Sharpley

The current emphasis on sustainable agricultural systems has led to a renewed interest in the use of cover crops to reduce soil erosion losses and retain soluble nutrients during the dormant season. Cover crop choices include a broad range of plant material, such as ryegrass (Secufe cereale L.), winter wheat (Triticum aestivum L.), forage grasses, and legumes. Historically, cover crops were use...

Journal: :مرتع و آبخیزداری 0
اکرم عارفی اصل کارشناس ارشد آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان علی نجفی نژاد استادیار گروه مرتع و آبخیزداری دانشگاه علوم کشاورزی و منابع طبیعی گرگان فرشاد کیانی استادیار گروه خاک شناسی دانشگاه علوم کشاورزی و منابع طبیعی گرگان عبدالرسول سلمان ماهینی دانشیار گروه محیط زیست دانشگاه علوم کشاورزی و منابع طبیعی گرگان

runoff and sediment measurement is difficult in mountain watershed because of many different problems such as time and financial limitations. so using simulation model is necessary in this regard. accuracy and precision evaluation of models for different watershed of iran is necessary. the aim of this study was the evaluation of swat model efficiency in simulation of runoff and sediment yield i...

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