Epilimnion Hypolimnion Volume Split

Integrate a supplied piecewise-linear area-depth curve across thermal-layer boundaries including split contour intervals; geometry is supplied, not reconstructed from map coordinates.

Description

Thermal layers partition a lake’s water volume rather than its surface area alone.

Thermal layers partition a lake’s water volume rather than its surface area alone. Integrating an area-depth curve across the chosen boundaries gives epilimnion, metalimnion and hypolimnion volumes.^[1]

The tool returns epilimnionVolumeM3, metalimnionVolumeM3, hypolimnionVolumeM3, totalModeledVolumeM3. The computation uses supplied observations and parameters rather than acquiring measurements.

When to use Epilimnion Hypolimnion Volume Split

Use this for the following task: Integrate a supplied piecewise-linear area-depth curve across thermal-layer boundaries including split contour intervals; geometry is supplied, not reconstructed from map coordinates. Prepare observations and calibration parameters on the same unit and reporting basis.

How to use Epilimnion Hypolimnion Volume Split and understand its results

Prepare the measured quantities and supplied model parameters. Match the units and align paired lists before calculating.
Enter depthsM, areasM2, epilimnionBottomM, hypolimnionTopM according to the field table, then run the tool.
Read epilimnionVolumeM3, metalimnionVolumeM3, hypolimnionVolumeM3, totalModeledVolumeM3. Use the calculation below to interpret the selected mean or the model’s signs, units and comparison flags.
Review the supplied assumptions and calibration before comparing or reporting the result.

Input field	Meaning	Value type and bounds	Requirement
depthsM	Depths m	list of number	Required
areasM2	Areas m2	list of number	Required
epilimnionBottomM	Epilimnion bottom m	number	Required
hypolimnionTopM	Hypolimnion top m	number	Required

Supply aligned increasing depths starting at zero, nonnegative areas and ordered nonnegative thermal boundaries within the measured range. Split intervals at each boundary and integrate trapezoids for all three layers.

layerVolume=integral of piecewise-linear area over the layer’s depth interval

The symbols and boundary conditions refer to the supplied fields and the implementation described above.

Output field	Meaning	Value type
epilimnionVolumeM3	Epilimnion volume m3	number
metalimnionVolumeM3	Metalimnion volume m3	number
hypolimnionVolumeM3	Hypolimnion volume m3	number
totalModeledVolumeM3	Total modeled volume m3	number

json

{
  "input": {
    "depthsM": [
      0,
      10,
      20
    ],
    "areasM2": [
      100,
      50,
      0
    ],
    "epilimnionBottomM": 5,
    "hypolimnionTopM": 15
  },
  "output": {
    "epilimnionVolumeM3": 437.5,
    "metalimnionVolumeM3": 500,
    "hypolimnionVolumeM3": 62.5,
    "totalModeledVolumeM3": 1000
  }
}

Limitations and assumptions

No contour geometry or thermocline location is inferred. Coincident boundaries may give zero layer volume, and interpolation is limited to the supplied curve.

Numerical inputs must be finite. Input-shape and calculation checks do not establish measurement quality or the validity of a supplied calibration.

Alternative or Complementary methods

Choose Hypsographic Curve Integration when you need its operation: Integrate observed hypsographic area-depth contours into a cumulative volume curve with trapezoids; contour geometry is supplied and only the measured depth range is represented. Choose Metalimnion Thickness for the complementary operation: Locate one contiguous sampled metalimnion using a caller absolute-gradient threshold; disjoint layers are ambiguous and are not merged into a false single thickness.

Background reference: Digital Library of Mathematical Functions: Quadrature.

References

Digital Library of Mathematical Functions: Quadrature — National Institute of Standards and Technology

Similar or alternative tools

Hypsographic Curve Integration
Integrate observed hypsographic area-depth contours into a cumulative volume curve with trapezoids; contour geometry is supplied and only the measured depth range is represented.
Metalimnion Thickness
Locate one contiguous sampled metalimnion using a caller absolute-gradient threshold; disjoint layers are ambiguous and are not merged into a false single thickness.