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Product(s): |
PondPack |
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Version(s): |
Varies |
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Environment: |
N\A |
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Area: |
Calculations |
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When a pond's infiltration method is set to "Infiltration Head / Depth", two fields need to be entered. The Infiltration per unit of Head and the K Exponent.
For the example discussed in this article, the following values will be used:
Infiltration per unit of Head = 2 (in/hr)/(ft^K)
K Exponent = 0.5
The infiltration rate and K exponent are typically derived from physical infiltration tests performed for a pond site.
To view a table of pond infiltration calculations:
- Compute the scenario(s).
- Open the Report menu and select Report Builder.
- Select the scenario(s) that you would like included in the report and click OK.
- Click on the subsection Pond Infiltration Calculations to highlight the row.
- Click the Generate Preview icon.
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Elevation
(Water Surface)
(ft)
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Elevation (Low)
(ft)
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Head
(ft)
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Area (Total)
(ft²)
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Area (Edge)
(ft²)
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Infiltration
(ft³/s)
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Flow (Total)
(ft³/s)
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0.0
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0.0
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0.0
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100.0
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100.0
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0.000000
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0.000000
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0.5
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0.0
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0.5
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100.0
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100.0
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0.003274
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0.003274
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0.5
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0.0
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0.5
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108.5
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8.5
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0.000277
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0.003550
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1.0
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0.0
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1.0
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100.0
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100.0
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0.004630
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0.008180
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1.0
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0.0
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1.0
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108.5
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8.5
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0.000391
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0.008572
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1.0
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0.5
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0.5
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117.3
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8.8
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0.000288
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0.008860
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1.5
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0.0
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1.5
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100.0
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100.0
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0.005670
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0.014530
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1.5
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0.0
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1.5
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108.5
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8.5
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0.000479
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0.015009
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1.5
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0.5
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1.0
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117.3
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8.8
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0.000407
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0.015417
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1.5
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1.0
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0.5
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126.4
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9.1
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0.000299
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0.015716
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2.0
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0.0
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2.0
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100.0
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100.0
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0.006547
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0.022263
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2.0
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0.0
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2.0
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108.5
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8.5
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0.000554
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0.022817
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2.0
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0.5
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1.5
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117.3
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8.8
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0.000499
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0.023316
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2.0
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1.0
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1.0
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126.4
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9.1
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0.000423
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0.023739
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2.0
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1.5
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0.5
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135.9
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9.5
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0.000311
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0.024049
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The infiltration values are calculated using the equation:
Infiltration = (I/(H^K))*(H^K) *(A)*((1/12)*(1/60)*(1/60))
(I/(H^K)) is Infiltration per unit of Head and is entered in units (in/hr)/(ft^K)
H is the Head of over "Area (Edge)"
K is the head exponent.
A is the area of the segment and is labeled "Area (Edge)" in the table.
((1ft/12in)*(1hr/60min)*(1min/60sec)) is used to convert units (in/hr)/ft to (ft/s)/ft
The infiltration is calculated at each incremental segment and then summed to account for different head values.
When the water surface elevation is 0.5ft the total flow is:
0.003274cfs+0.000277cfs = 0.003550cfs
See Also
How to vary pond infiltration rate with water surface elevation
Reporting total cumulative infiltration volume
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Original Author: |
Craig Calvin |
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