The Mechanism of Natural Ground-Water Recharge and Discharge: 1. One-dimensional, Vertical, Unsteady, Unsaturated Flow above a Recharging or Discharging Ground-Water Flow System

The unsaturated flow processes of infiltration and evaporation are in physical and mathematical continuity with the parallel saturated processes of recharge and discharge. Water table fluctuations result when the rate of ground-water recharge or discharge is not matched by the unsaturated flow rate created by infiltration or evaporation. A water-table rise provides the source of replenishment to the ground-water zone that allows the prevailing rate of recharge to continue. This dynamic water-table behavior can be simulated by a one-dimensional, numerical mathematical model involving transient flow through an integrated saturated-unsaturated system. The solutions are applicable to homogeneous, isotropic soils in which the functional relationships show hysteresis properties. The model allows upper boundary conditions of constant rate rainfall, ponded water, evaporation, and redistribution. It can be used to determine the water-table fluctuation that will arise from a given set of initial conditions, boundary conditions, and soil type. The effects of variations in the parameters that control the flow are examined to arrive at a better understanding of the mechanism of natural ground-water recharge and discharge.

[1]  A. Liakopoulos RETENTION AND DISTRIBUTION OF MOISTURE IN SOILS AFTER INFILTRATION HAS CEASED , 1965 .

[2]  J. Philip THE THEORY OF INFILTRATION: 1. THE INFILTRATION EQUATION AND ITS SOLUTION , 1957 .

[3]  F. D. Whisler,et al.  The Numerical Analysis of Infiltration, Considering Hysteresis, Into a Vertical Soil Column at Equilibrium Under Gravity , 1965 .

[4]  P. Wilh Werner,et al.  Some problems in non‐artesian ground‐water flow , 1957 .

[5]  E. C. Childs The nonsteady state of the water table in drained land , 1960 .

[6]  J. Rubin,et al.  Numerical Method for Analyzing Hysteresis-Affected, Post-Infiltration Redistribution of Soil Moisture1 , 1967 .

[7]  W. O. Smith Infiltration in sands and its relation to groundwater recharge , 1967 .

[8]  J. Rubin,et al.  Soil Water Relations During Rain Infiltration: I. Theory1, 2 , 1963 .

[9]  Eng. Aristides C. Liakopoulos THEORETICAL SOLUTION OF THE UNSTEADY UNSATURATED FLOW PROBLEMS IN SOILS , 1965 .

[10]  E. G. Youngs,et al.  MOISTURE PROFILES DURING VERTICAL INFILTRATION , 1957 .

[11]  R. J. Hanks,et al.  Numerical Solution of the Moisture Flow Equation for Infiltration into Layered Soils 1 , 1962 .

[12]  P. R. Day,et al.  A Numerical Solution of the Differential Equation of Flow for a Vertical Drainage Problem 1 , 1956 .

[13]  W. Staple Infiltration and Redistribution of Water in Vertical Columns of Loam Soil1 , 1966 .

[14]  A. Klute,et al.  A NUMERICAL METHOD FOR SOLVING THE FLOW EQUATION FOR WATER IN UNSATURATED MATERIALS , 1952 .

[15]  M. S. Hantush,et al.  Growth and Decay of Groundwater-Mounds in Response to Uniform Percolation , 1967 .

[16]  P. R. Day,et al.  Lateral Flow Above a Sloping Water Table 1 , 1955 .

[17]  E. C. Childs,et al.  THE MOISTURE PROFILE ABOVE A MOVING WATER TABLE , 1962 .

[18]  Irwin,et al.  Vertical Drainage of an Unsaturated Soil , 1965 .

[19]  P. Witherspoon,et al.  Theoretical Analysis of Regional Ground Water Flow: 3. Quantitative Interpretations , 1968 .

[20]  G. Dagan Linearized solutions of free‐surface groundwater flow with uniform recharge , 1967 .

[21]  C. E. Jacob Correlation of ground‐water levels and precipitation on Long Island, New York , 1943 .

[22]  Wilfried Brutsaert,et al.  Intermittent Infiltration into Soils with Hysteresis , 1968 .

[23]  D. V. D. Leur Some effects of the unsaturated zone on nonsteady free‐surface groundwater flow as studied in a scaled granular model , 1962 .

[24]  Marinus Maasland,et al.  Water table fluctuations induced by intermittent recharge , 1959 .

[25]  George M. Hornberger,et al.  NUMERICAL ANALYSIS OF SOIL-MOISTURE SYSTEMS , 1967 .