global warming, as a consequence of greenhouse gases accumulation, has exerted significant impacts on biosphere. methane, a product of reduction processes of organic carbon in anaerobic conditions, is mainly emitted from paddy fields. the aim followed in this research is to evaluate the impact of midseason drainage on methane emission from paddy fields. the research was conducted with three tre...

the dominant traditional view to designing drainage systems explains drainage goals only in terms of crop yield increase and rhizosphere improvement while ignoring the environmental impacts of drainage projects. nowadays, this view has been changed into a new one in which both environmental and agricultural purposes are taken into consideration. depth and spacing of subsoil drains are important...

A FORTRAN code for liquid water flow in unsaturated soil under the isothermal condition was developed to simulate water infiltration into Yolo light clay. The governing equation, that is, Richards' equation, was approximated by the finite-difference method. A normalized sensitivity coefficient was used in the sensitivity analysis of Richards' equation. Normalized sensitivity coefficient was cal...

The populations, infrastructure and ecology of cities are at risk from the impacts of climate change which affect urban ventilation and cooling, urban drainage and flood risk and water resources. Built areas exert considerable influence over their local climate and environment, and urban populations are already facing a range of weather-related risks such as heat waves, water pollution and floo...

Abstract The possibility of estimating groundwater inflow to irrigation drains in Minia, Egypt, using stable isotopes has been explored. The evaporation pan technique described here makes use of small variations in the concentration of naturally occurring stable isotopes (oxygen-18 and deuterium) in irrigation-fed groundwater and surface water as well as agricultural drainage water. The agreeme...

Installing subsurface tile drain systems in poorly drained claypan soils to improve corn ( L.) yields could potentially increase environmental phosphorus (P) loss through the tile drainage system. The objectives of the study were to quantify the average concentration and loss of ortho-P in tile drain water from a claypan soil and to determine whether managed subsurface drainage (MD) could reduc...

Abstract Steam-water capillary pressure is often either ignored or determined artificially in geothermal reservoir engineering. However steam-water capillary pressure plays an important role in geothermal reservoir performance and may not be substituted by air-water capillary pressure. To this end, preliminary mathematical models have been developed to calculate drainage and imbibition steam-wa...

A 2-year field and incubation experiment was conducted to investigate δ(13)C during the processes of CH4 emission from the fields subjected to two water managements (flooding and drainage) in the winter fallow season, and further to estimate relative contribution of acetate to total methanogenesis (Fac ) and fraction of CH4 oxidized (Fox ) based on the isotopic data. Compared with flooding, dra...

Mine drainage is increasingly becoming a problem in the UK as water tables rise and acid drainage waters rich in heavy metals impact river systems. The impacts of mine drainage at two sites, the River Pelenna in Wales and the Wheal Jane Mine in Cornwall is assessed. Mathematical models have been developed and applied to investigate heavy metal pollution in the Pelenna case study and the models ...