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A drainage equation is an equation describing the relation between depth and spacing of parallel subsurface drains, depth of the watertable, depth and hydraulic conductivity of the soils. It is used in drainage design. Parameters in Hooghoudt's drainage equation. A well known steady-state drainage
Drainage research is the study of agricultural drainage systems and ... is mainly physical and can be described by drainage equations, ... chemical /biological, and ...
Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and is often expressed as a flux to the water table surface.
Point drainage, which intercepts water at gullies (points). Gullies connect to drainage pipes beneath the ground surface, so deep excavation is required to facilitate this system. Support for deep trenches is required in the shape of planking, strutting or shoring. Channel drainage, which intercepts water along the entire run of the channel.
Spacing equations of subsurface drains and the groundwater energy balance applied to drainage equations [5] are examples of two-dimensional groundwater models. Three-dimensional models like Modflow [6] require discretization of the entire flow domain. To that end the flow region must be subdivided into smaller elements (or cells), in both ...
According to Montgomery and Dietrich’s equation, drainage density is a function of vertical hydraulic conductivity. Coarse-grained sediment like sand would have a higher hydraulic conductivity and are predicted by the equation to form a relatively higher drainage density system than a system formed by finer silt with a lower hydraulic ...
Both above equations are used in aquifer tests (pump tests). The Hooghoudt equation is a groundwater flow equation applied to subsurface drainage by pipes, tile drains or ditches. [14] An alternative subsurface drainage method is drainage by wells for which groundwater flow equations are also available. [15]
A newer method that allows 1-D groundwater and surface water coupling in homogeneous soil layers and that is related to the Richards equation is the Finite water-content vadose zone flow method solution of the Soil Moisture Velocity Equation. In the case of uniform initial soil water content and deep, well-drained soil, some excellent ...