Meltwater Storage Delay Glacier

Route piecewise-constant meltwater inflow through an exact linear storage reservoir and close interval volumes; no peak-lag inference or distributed drainage network.

Description

A linear reservoir delays meltwater release while conserving water volume.

A linear reservoir delays meltwater release while conserving water volume. Residence time controls the exponential relaxation toward steady storage.^[1]

Route piecewise-constant meltwater inflow through an exact linear storage reservoir and close interval volumes; no peak-lag inference or distributed drainage network.

When to use Meltwater Storage Delay Glacier

Use this for the following task: Route piecewise-constant meltwater inflow through an exact linear storage reservoir and close interval volumes; no peak-lag inference or distributed drainage network.

Prepare the measurements and calibration parameters in the declared units. Keep vector entries aligned and choose a consistent spatial frame and time basis.

How to use Meltwater Storage Delay Glacier and understand its results

Prepare the measurements and calibration parameters in the declared units. Keep vector entries aligned and choose a consistent spatial frame and time basis.
Enter intervalDurationsDays, inflowVolumesM3PerDay, initialStorageM3, reservoirResidenceDays using the field table, then run the tool.
Read endStoragesM3, releasedVolumesM3. Interpret flags, units, ordering and placeholder values using the rules below.
Review any reported issue or failed check, correct the supplied values when appropriate, and verify the result in its intended context.

Input field	Meaning	Value type and bounds	Requirement
intervalDurationsDays	Interval durations days	list of number; each entry: number	Required
inflowVolumesM3PerDay	Inflow volumes m3 per day	list of number; each entry: number	Required
initialStorageM3	Initial storage m3	number	Required
reservoirResidenceDays	Reservoir residence days	number	Required

Process aligned positive-duration intervals sequentially with nonnegative inflow rates and initial storage. Use an exact constant-inflow update and a small-step series to avoid cancellation in release.^[2]

Snext = S e^(−Δt/k) + inflowRate k(1−e^(−Δt/k)); release = S + inflowRate Δt − Snext

This summarizes the declared operation. Units, indexing, inclusivity and exceptional cases are explained in the surrounding text.

Output field	Meaning	Value type
endStoragesM3	End storages m3	list of number
releasedVolumesM3	Released volumes m3	list of number

json

{
  "input": {
    "intervalDurationsDays": [
      1,
      1
    ],
    "inflowVolumesM3PerDay": [
      10,
      0
    ],
    "initialStorageM3": 0,
    "reservoirResidenceDays": 1
  },
  "output": {
    "endStoragesM3": [
      6.321205588285577,
      2.3254415793482965
    ],
    "releasedVolumesM3": [
      3.6787944117144233,
      3.99576400893728
    ]
  }
}

Limitations and assumptions

Despite its name, inflowVolumesM3PerDay is a rate. This is one lumped reservoir, not a distributed drainage network or a peak-lag forecast.

Constants and empirical coefficients are supplied rather than calibrated. Check units and observational applicability before interpreting the model. Malformed requests produce input errors. A successfully evaluated request can still contain false flags, empty result lists or a result outside the supplied threshold; those outcomes have the meanings stated above.

Alternative or Complementary methods

Choose Subglacial Flow Direction Gradient for this operation: Compute isotropic downhill hydraulic-potential direction from bed/thickness gradients and pressure ratio; flat gradients have no defined direction and anisotropic transmissivity is excluded. For a complementary task, use GLOF Peak Discharge Envelope for this operation: Evaluate a caller empirical GLOF discharge coefficient envelope against normalized released volume; envelope is not a probability interval, dam-break hydrograph or safety assessment.

Further background: Subglacial hydrology.

References

Subglacial hydrology — PISM
Meltwater Storage Delay Glacier — tool.io

Similar or alternative tools

Subglacial Flow Direction Gradient
Compute isotropic downhill hydraulic-potential direction from bed/thickness gradients and pressure ratio; flat gradients have no defined direction and anisotropic transmissivity is excluded.
GLOF Peak Discharge Envelope
Evaluate a caller empirical GLOF discharge coefficient envelope against normalized released volume; envelope is not a probability interval, dam-break hydrograph or safety assessment.