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...

Across Africa, perennial drainage density as a function of mean annual rainfall defines three regimes separated by threshold values of precipitation. This nonlinear response of drainage to rainfall will most seriously affect regions in the intermediate, unstable regime. A 10% decrease in precipitation in regions on the upper regime boundary (1000 millimeters per year) would reduce drainage by 1...

The evolution and structure of the steady state of an idealized nocturnal drainage flow over a large uniformly-sloping surface are studied using a nonstationary model with a height-dependent eddy diffusivity profile and a specified surface cooling rate. The predicted mean velocity and temperature profiles are compared with Prandtl’s stationary analytical solutions based on the assumption of a c...

The catchment, or catchment area, is the area associated with a segment of a drainage network. Surface runoff in a catchment flows into the associated network segment. Catchment area is commonly used for estimating watershed parameters, such as upstream drainage area, flood frequency, or surface-water flow. Hydrologic analyses require relatively accurate catchment area estimates to furnish subs...

Nonpoint, or diffuse, sources of water pollution include urban sources such as runoff from residential, commercial, industrial, transportation, and recreational land uses; construction activities; and onsite sewage disposal systems and rural sources such as runoff from cropland, pasture, and woodland, atmospheric contributions, and livestock wastes. These sources of pollutants discharge to surf...

l and drainage has been central to the development of North America since colonial times, with the first organized drainage efforts occurring as early as the 1600s (Evans et al. 1996). Drainage has been encouraged to improve public highways, reduce public health risks, promote increased crop yield and reduced yield variability, reduce surface runoff and erosion, and increase land value. Agricul...

One of the most important factors for appropriate performance of subsurface drainage systems is having adequate discharge for drains. For this purpose, knowledge about effect of drainage parameters change on drain discharge is essential in subsurface drainage systems. In this article, using change all of the drainage parameters by EnDrain software, changes of drains discharge has been investiga...

soil drainage conditions significantly affect the chemical properties of soil, particularly type and the extent of iron oxides. soil magnetic susceptibility (?) has a close relationship with drainage conditions. eight soil profiles, in four regions of fars province, with aquic and non-aquic soil moisture regimes were studied to determine the effect of drainage conditions on ? and on chemical fo...