Oxidation formula (Subsidence Overlay)

The amount of subsidence due to oxidation is calculated by the following formula:

$S_{O}=d_{gw}*a_{y}-d_{ct}*b-c$

where

$S_{O}$ is the subsidence due to oxidation. $d_{gw}$ is the ground water depth, based on the lowest ground water level (glg). $a_{y}$ is the calculated a parameter value for the current year $y$. $d_{ct}$ is the clay thickness of the terrain, defined by CLAY_THICKNESS $b$ is the b parameter value, defined by PARAMETER B $c$ is the c parameter value, defined by PARAMETER C

• The ground water level (expressed in meters below surface), most commonly the lowest ground water level. This value is recalculated as part of the calculations over multiple years. (This value is capped as 1.2m. If the ground water level is further from the surface than 1.2m, 1.2m is used.)
• The clay thickness is an attribute in the project. The exact attribute which provide this value can be configured as Keys in the overlay.
• The a, b and c parameters are climate values which can be configured as Attributes in the overlay. the a value is also recalculated as part of the calculations over multiple years.

This formula was provided by experts, who have established this formula empirically.