نتایج جستجو برای: soil infiltration
تعداد نتایج: 231295 فیلتر نتایج به سال:
A Cellular Automata model for soil erosion by water, SCAVATU, was developed. It involves a larger number of states in comparison to the previous models: alti-sidering some of the most significant processes of the phenomenon: water flow, infiltration, soil erosion by water flow, sediment transport and deposition. Simulations gave encouraging results, in agreement with the findings of other studi...
flood spreading has an effective role in the soil improvement and fertility, ground water storage, revival of vegetation and prevention of fluent sands movement. one of the main problem of flood spreading projects is the entrance of sediment to the spreading systems and sedimentation in it. sediment reduces the efficiency of the flood spreading system and after awhile lose its efficiency.the ma...
soil conservation service (scs) adjusted the kostiakovs infiltration model by adding a constant coefficient, for improvement of estimation. the improved model has three constant parameters, which are difficult to calculate. so scs has taken the third constant parameter as equal to 0.65-0.7 cm to simplify the estimation. this parameter varies in different soil and often outranges the scs estimat...
to design subsurface drainage systems, it is necessary to determine the saturated hydraulic conductivity of the soil. one of the most common methods for field measurement of this parameter is the shallow well pump-in test method. another method which has recently been introduced for the above measurement is the guelph permeameter method. both methods are used to measure the soil saturated hydra...
Simulating infiltration in soils containing macropores still provides unsatisfactory results, as existing models seem not to capture all relevant processes. Recent studies of macropore flow initiation in natural soils containing earthworm channels revealed a distinct flow rate variability in the macropores depending on the initiation process. When macropore flow was initiated at the soil surfac...
During a rainfall water infiltration into an unsaturated soil, zones of saturation may be developed anywhere within the flow domain. Consequently, a natural question arises: under which conditions depending on the rate at which rain water is supplied, the initial moisture distribution in the soil, the presence of underground sources and the boundary permeability, the flow domain may be separate...
Tillage practices significantly influences soil physical characteristics and crop productivity. The infiltration characteristics, bulk density, porosity, penetration resistance, grain yield of rice and wheat were measured under no-till without residue (NT), roto-tillage (RT), and no-till with residue i.e. happy seeder (HS) in rice-wheat cropping system in sandy loam (SL) and loamy sand (LS) soi...
Infiltration is the most crucial process affecting surface irrigation uniformity and efficiency as it is the mechanism that transfers and distributes water from the surface to the soil profile. As a direct method of infiltration measurement, the volume balance method requires time, accuracy and high costs. Moreover, before the land preparation and at the research phase the use of this method is...
Polyacrylamide (PAM) in furrow irrigation water eliminates 94% of runoff sediment. Higher infiltration (15-50%) can result in upperfield uverirrigation. We hypothesized that PAM would lengthen advance time, but that interactions with flow rate and wheel-track (WT) Ihrrows would occur, influencing erosion and infiltration with potential for improved water management. A 2-yr study conducted on 1....
Highway runoff from IP 4, a mountain road in the north-east of Portugal, has been monitored using a system integrating a raingauge, a flowmeter and an automatic water sampler. Average daily traffic (ADT) is 6000 and the study catchment has 5970 m2 of total area and 2500 m2 of road pavement. A single stormwater outlet discharges into an infiltration pond with overflow to a creek. Sampling was ca...
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