نتایج جستجو برای: drainage depth control
تعداد نتایج: 1511160 فیلتر نتایج به سال:
In the irrigated western U.S. disposal of drainage water has become a significant economic and environmental liability. Development of irrigation water management practices that reduce drainage water volumes is essential. One strategy combines restricted drainage outflow (by plugging the drains) with deficit irrigation to maximize shallow groundwater consumption by crops, thus reducing drainage...
Tropical peatland fires play a significant role in the context of global warming through emissions of substantial amounts of greenhouse gases. However, the state of knowledge on carbon loss from these fires is still poorly developed with few studies reporting the associated mass of peat consumed. Furthermore, spatial and temporal variations in burn depth have not been previously quantified. Thi...
This study was conducted to evaluate the performance of DRAINMOD /DRAINMOD-N on an experimental drainage field at Southeast Purdue Agricultural Center (SEPAC), based on the comparison between observed and predicted subsurface drain flows and nitrate-nitrogen losses via drainage. The site was under conventional drainage management, consisting of two replications of three tile drain spacings—5m, ...
abstract one of the ways to increase economic and environmental efficiency of drainage systems is water table management. water table management consists of, controlled drainage and subirrigation. this study examines the effect of controlled drainage on yield, root distribution pattern and water use efficiency of maize (sc 704) in karaj. the experiment was performed as a randomized complete des...
In view of the high gas pressure and low permeability deep coal seam, it is difficult to control gas, which affects safety production mine. The technical scheme hydraulic fracturing improve seam put forward, drainage technology used emission seam. effect under different water pressure, gradient times, in situ stress analyzed by using 3DEC (3-Dimensional Distinct Element Code) discrete element s...
Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observ...
measuring sensitivity of hydraulic structures is considered as an approach for evaluation of water projects performance, due to lower distribution efficiency in irrigation and drainage project schemes. sensitivity analysis approach for irrigation structures is one of flow analysis methods which are developed in recent years in order to measure the behavior of flow in hydraulic structures in an ...
designing effective strategies for sediment management and control is closely related to identification of sediment sources in a drainage basin. one of the methods for investigating sediment sources is using magnetic tracers for erosion and sediment yield studies. sediment source identification using magnetic characteristics is a simple, inexpensive, quick and non-destructive method having appl...
The momentum equation in the kinematic wave model is a power-law equation with two parameters. These parameters, which relate the discharge to the flow area, are commonly derived using Manning’s equation. In general, the values of these parameters depend on the flow depth except for some special cross sections. In this paper, improved estimates of the kinematic wave parameters for circular chan...
in this study, scour of mashkid bridge pier located in mashkid river of saravan county has been studied and to measure the scour rate, the numerical model hec-ras 4.0 has been used. upon selection of mashkid river as the case study and whereas the studied zone is important with respect to the climatic conditions and showery monsoon raining and flowing the great and destructive floodwaters, ther...
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