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  2. Drainage equation - Wikipedia

    en.wikipedia.org/wiki/Drainage_equation

    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

  3. Water retention curve - Wikipedia

    en.wikipedia.org/wiki/Water_retention_curve

    Due to the non-linearity of the equation, numerical techniques such as the non-linear least-squares method can be used to solve the van Genuchten parameters. [4] [5] The accuracy of the estimated parameters will depend on the quality of the acquired dataset (and ). Structural overestimation or underestimation can occur when water retention ...

  4. Drainage density - Wikipedia

    en.wikipedia.org/wiki/Drainage_density

    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 ...

  5. Hydrological transport model - Wikipedia

    en.wikipedia.org/wiki/Hydrological_transport_model

    An example of these efforts was developed at the Southeast Water Laboratory, [19] one of the first attempts to calibrate a surface runoff model with field data for a variety of chemical contaminants. The attention given to surface runoff contaminant models has not matched the emphasis on pure hydrology models, in spite of their role in the ...

  6. Darcy's law - Wikipedia

    en.wikipedia.org/wiki/Darcy's_law

    Darcy's law is an equation that describes the flow of a fluid through a porous medium and through a Hele-Shaw cell.The law was formulated by Henry Darcy based on results of experiments [1] on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth sciences.

  7. Agricultural hydrology - Wikipedia

    en.wikipedia.org/wiki/Agricultural_hydrology

    According to the figure, the drainage period is from November to March (120 days) and the discharge of the drainage system is D = 180 / 120 = 1.5 mm/day corresponding to 15 m 3 /day per ha. During winters with more precipitation than normal, the drainage requirement increase accordingly.

  8. Matrix (chemical analysis) - Wikipedia

    en.wikipedia.org/wiki/Matrix_(chemical_analysis)

    In chemical analysis, matrix refers to the components of a sample other than the analyte [1] of interest. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results are obtained; such effects are called matrix effects. [2]

  9. Groundwater energy balance - Wikipedia

    en.wikipedia.org/wiki/Groundwater_energy_balance

    The energy balance of groundwater flow can be applied to flow of groundwater to subsurface drains. [2] The computer program EnDrain [3] compares the outcome of the traditional drain spacing equation, based on Darcy's law together with the continuity equation (i.e. conservation of mass), with the solution obtained by the energy balance and it can be seen that drain spacings are wider in the ...