# Oxidation formula (Subsidence Overlay)

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

${\displaystyle S_{O}=a_{y}\cdot d_{gw,y,c}-b\cdot d_{ct,c}-c}$

where

${\displaystyle S_{O}}$ is the subsidence due to oxidation.
${\displaystyle d_{gw,y,c}}$ is the calculated ground water depth for year y in cell c.
${\displaystyle a_{y}}$ is the calculated a parameter value for the current year ${\displaystyle y}$.
${\displaystyle d_{ct,c}}$ is the clay thickness of the terrain in cell c, defined by CLAY_THICKNESS
${\displaystyle b}$ is the b parameter value, defined by the model attribute B
${\displaystyle c}$ is the c parameter value, defined by the model attribute C

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