Waterway level change benchmark (Water Module): Difference between revisions

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The ground is setup with:
The ground is setup with:
[[Water storage fraction (Water Overlay)|Water storage fraction]] set to <math>f_s</math>
[[Terrain_water_storage_percentage_(Water_Overlay)|Water storage fraction]] set to <math>f_s</math>
An aquifer is added for the region as well, initialized with the [[Aquifer_KD_(Water Overlay)|Aquifer KD]] set to kD.
An aquifer is added for the region as well, initialized with the [[Aquifer_KD_(Water Overlay)|Aquifer KD]] set to kD.

Revision as of 10:01, 11 December 2020

Initially, the ground water table is the same as the water level in the waterway. Suddenly the level in the waterway rises with h0 meters. This causes water to infiltrate into the ground, raising the ground water table.

Situation of the waterway level change benchmark for groundwater

Formulas

When the water level in the water way changes, the water table level will also change over time. The relation between water level in the waterway and the ground water table at distance x from the water way is described by the following formulas: In case teh water level is raised, the following formula should hold:

In case the water level is lowered, the following formula should hold:

The formula erf is the complementary error function.

where:

: change in freatic groundwater table (m)
: change in water level in the waterway(m)
: distance to the water way (m)
: time since the water level change
: transmissivity of the aquifer (m2 / day)
: freatic water storage fraction.

The expected values are visualized in this graph

Setup

5 Inlets, each on one cell, each with:

UPPER_THRESHOLD set to X.
LOWER_THRESHOLD set to X.
Inlet Q set to 0, such that is unlimited.

This ensures that the water level is instantly raised to level X and that it remains at X at all times.

The ground is setup with: Water storage fraction set to An aquifer is added for the region as well, initialized with the Aquifer KD set to kD.