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GREEN-AMPT INFILTRATION
Adapted from GreenAmpt.xlsx
Complete the spreadsheet with the hydraulic conductivity set to 5 cm/hr. See
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Section 8.4.3; Exercise 8.5
S.L. Dingmanhomework assignment for other soil characteristics.
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Physical Hydrology, 3rd Ed.
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Input Data
Calculated Values
Then you can copy this spreadsheet to new tabs for the 3 and 1 cm/hr scenarios.
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(Don't forget to rerun the solver)
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Soil Name:Bob
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Finally, you can add the 3 and 1 cm/hr scenarios to the graphs for comparison.
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Soil Properties:
f =|yae| =cm b =
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Kh =cm/s =0 cm/hr
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Event:w =cm/hrTw =hr
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Initial Conditions:
q0 =
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|yf| =0.0 cmw*Tw =0.00 cm
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Tp =#DIV/0!hrF(Tp) =#DIV/0!cm
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yf*(f - q0) =
0.00 cm
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Infiltration
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Enter values of F(t) beginning in the third row of the table below.
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Each F(t) value must be greater than that in the previous row. Values
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of F(t), f(t), zf(t), and t are calculated. t cannot exceed Tw; use
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solver to find final value of F(t) such that t = Tw as nearly as possible.
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Interval0.2 Objective#DIV/0!To complete the calculation, change the "Interval" in cumulative infiltration
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F(t)f(t)zf(t)tTime since tpuntil the objective value is as close to zero as possible.
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(cm)(cm/hr)(cm)(hr)<--------Remarks-------->(hr)
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=======The solver can be used to perform this optimization, as well.
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0 0 0 0
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#DIV/0!#DIV/0!#DIV/0!
time of ponding
#DIV/0!The idea is that you (or the solver) are guessing at total cumulative infiltration
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Start =>#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
until the time at which total infiltration occurs matches the duration of the event.
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
This strategy works because the time at which a given total infiltration occurs can
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!be calcluated explicitly (see Dingman text).
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!This type of trial and error calculation is a common approach to solving implicit
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!equations, like this one where f(t) and F(t) are calculated from each other.
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!#DIV/0!
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