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## ANSQUICK > Groundwater mound >## Local infiltration |

The dialog window "Groundwater mound" combines several analytical solutions for groundwater mounding caused by local recharge. Local recharge is applied to rectangular, circular or strip areas that can be bounded by a river or an impermeable boundary.

The window opens after selecting menu "File > Hydrogeologist workbench > Groundwater mound > Local infiltration".

Samples of "Groundwater mound" dialog box for rectangular area of recharge: infinite aquifer (top) and near the river (bottom).

The dialog window changes for different types of aquifers and boundaries. The profile and required parameter fields appear on the left side of the dialog window. The right side of the window shows plan view and required parameter fields. Some of the parameters are the same on the plan and the profile views and they can be entered on the either view.

Explanatory table

"ε, m/day" text box |
Recharge rate |

"t, day" text box |
Time from start of recharge |

"s(max), m" or "sс, m" text box |
Information field displaying the maximum height of a groundwater mound (smax) or a groundwater mound in the center of the recharge area (sc). Maximum mounding occurs in the center of the recharge area in aquifers without boundaries. In bounded aquifers smax shifted right (Constant head boundary) or left (No-Flow boundary) |

"s, m" text box |
Information field displaying the height of groundwater mounding at a specific distance from the center of the recharge area or from the boundary (for bounded aquifers) |

"k, m/day" text box |
Hydraulic conductivity of aquifer |

"Sy, –" text box |
Specific yield of aquifer |

"m, m" text box |
Initial saturated thickness of an aquifer |

"Lc, m" text box |
Distance from the center of recharge area to a hydrodynamic boundary. This field is enabled for bounded aquifers (see options "Нет", "I", "II"). The specified value has to be higher than half the width of the recharge area (Lc > A/2 or Lc > D/2). In other cases, the entry is considered as error and highlighted in red |

"No", "I" and "II" option |
Sets up hydrodynamic boundaries: "Нет" – delete boundary, "I" – Constant Head Boundary, "II" – No-Flow boundary. These options are available for rectangular and circular aquifers |

"T, m^2/day" text box |
Information field displaying aquifer transmissivity for initial saturated thickness |

"a, m^2/day" text box |
Information field to display hydraulic diffusivity |

"Recharging area" frame |
Selection of type of recharge area: "Rectangle" – rectangular area "Circle" – circle area "Strip" – strip area of unlimited length "Boundary (No-Flow)" – one side hydrodynamic (no-flow) boundary for bounded aquifers "Boundary (River)" – one side hydrodynamic (Constant Head) boundary for bounded aquifers |

"Find x(max)" button |
This button appears for bounded aquifers for rectangular or circular recharge areas. After pressing this button, the programm iteratively determines point location for maximum mounding and puts its distance in the text box "х, m", and mounding height in the text box "s, m" |

"Plot (max)" button |
Plots mounding hydrograph for the location with maximum mounding |

"R" button |
Plots hydrograph of drawdown after cease of recharge for the location with maximum mounding |

"Plot" button |
Plots mounding hydrograph for selected location |

1. Rectangular recharge area

"Groundwater mound" dialog box for rectangular recharge area.

Additional Explanatory table for rectangular recharge area

"A, m" and "B, m" text box |
Side lengths of recharge ara. Inputs to text box "A" can be done on plan or profile views |

"х, m" text box |
X-coordinate of the location to determine mounding "s". Distance from the center of the rectangular area along X axis. The coordinate value can be entered on the plan or the profile views. Enter a negative value to calculate mounding at the location between the center of the area and a hydrodynamic boundary |

"y, m" text box |
Y-coordinate of the location to determine mounding "s". Distance from the center of the rectangular area along Y axis |

Analytical solutions that are used to calculate mounding (rectangular recharge area):

m – initial saturated thickness, m;

mt – saturated thickness in the centre of recharge area at specified time, days.

To calculate mounding for bounded aquifers, the principle of superposition is applied. In that case the maximum mounding may be different from the value smax in the centre of recharge area.

2. Circular recharge area

"Groundwater mound" dialog box for circular recharge area.

Additional Explanatory table for circular recharge area

"D, m" text box |
Diameter of the circular recharge ara. Inputs to text box "D" can be done on plan or profile views |

"х, m" text box |
X-coordinate of the location to determine mounding "s". Distance from the center of the rectangular area along X axis. The coordinate value can be entered on plan or profile views. Enter a negative value to calculate mounding at the location between the center of the area and a hydrodynamic boundary |

"y, m" text box |
Y-coordinate of the location to determine mounding "s". Distance from the center of the rectangular area along Y axis |

Analytical solutions that are used to calculate mounding (circular recharge area):

R – radius of circular recharge area, m.

To calculate mounding for bounded aquifers, the pronciple of superposition is applied. In that case the maximum mounding may be different from the value smax in the centre of recharge area.

3. Strip recharge area

"Groundwater mound" dialog box for strip recharge area.

Additional Explanatory table for strip recharge area

"A, m" text box |
Width of the recharge area. Inputs to text box "A" can be done on plan or profile views. |

"х, m" text box |
Distance from the center of the area to the location, where mounding "s" is calculated. The value can be entered on plan or profile views. |

Analytical solutions that are used to calculate mounding (strip recharge area):

For x < A / 2

For x > A / 2

4. Strip recharge area with No-Flow boundary

"Groundwater mound" dialog box strip recharge area: aquifer with No-Flow boundary.

Additional explanatory table for strip recharge area with No-Flow boundary

"A, m" text box |
Width of the recharge area. Inputs to text box "A" can be done on plan or profile views. |

"х, m" text box |
Distance from the center of the area to the location, where mounding "s" is calculated. The value can be entered on plan or profile views. |

Analytical solutions that are used to calculate mounding for strip recharge area near no-flow boundary:

For x < A

For x > A

5. Strip recharge area with Constant Head boundary

"Groundwater mound" dialog box for strip recharge area: aquifer with Constant Head boundary.

Additional explanatory table for strip recharge area with Constant Head boundary

"A, m" text box |
Width of the recharge area. Inputs to text box "A" can be done on plan or profile views. |

"х, m" text box |
Distance from the center of the area to the location, where mounding "s" is calculated. The value can be entered on plan or profile views. |

"х(max), m" text box |
Information field displaying the distance from the boundary, where the maximum mounding is determined |

Analytical solutions that are used to calculate mounding for strip recharge area near constant flow boundary:

For x < A

For x > A

To determine maximum maounding, calculate distance distance from boundary, where the maximum mounding occurs. This distance should be calculated iteratively and entered in the solution above for x < A. smax is then calculated for a specified time.

References

Hantush M.S. Growth and decay of groundwater-mounds in response to uniform percolation // Water Resources Research. 1967. Vol. 3, N 1. P. 227–234.

Hantush M.S. Growth of a ground water ridge in response to deep percolation. Proc. Symp. Trans. Ground Water Hydraul., Ft. Collins, Colorado. 1963.

Marino M.A. Growth and decay of groundwater mounds induced by percolation // Journal of Hydrology. 1974. Vol. 22. P. 295–301.