Subsidence Overlay: Difference between revisions

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{{learned|what the Subsidence overlay is|what information is displayed by the subsidence overlay|how to configure the subsidence overlay}}
[[File:Subsidence-Overlay.jpg|thumb|200px|right|The subsidence overlay]]
[[File:Groundwater-Overlay.jpg|thumb|200px|right|The ground water overlay]]
The Subsidence Overlay is an [[Grid overlay|overlay]] that shows which places in the [[project area]] are subject to subsidence due to oxidation and/or compaction of peat. The [[subsidence calculation|calculation]] results can provide insight into the subsidence taking place, and the effects it has on groundwater levels.


==What is the subsidence overlay==
The Subsidence Overlay can be used to calculate the amount of subsidence which takes place on peat soil, specifically due to peat oxidation and compaction. The calculations are specific for peat soil. Separate formulas for other soil types have not yet been implemented. Although it's possible to use the overlay to give an impression of subsidence resulting from other factors, the results will be less accurate. This means that results have a greater margin of error for different use-cases.


==How the subsidence overlay calculates==
It is possible to add multiple subsidence overlays to a project. By varying their configuration slightly, it is possible to calculate multiple scenario's or time-frames simultaneously.
Subsidence is currently composed of 2 forms of reduction of peat: oxidation and subsidence. These forms of subsidence are both relevant for the complete picture of subsidence, but are, in principle, calculated via separate formulas. The results of these formulas are added together to get the total amount of subsidence.


===Oxidation===
A project can be enriched with other overlays that are interesting in combination with the Subsidence Overlay. Examples are:
Peat, when exposed to oxygen, can oxidize. In this process the peat combines with the air to form CO2, reducing the total mass and volume of the peat. The amount of oxidation depends on the clay thickness, because clay may insulate the peat, preventing it from oxidizing. It also depends on the (lowest) ground water level in relation to the surface of the land.


The amount of subsidence due to oxidation is calculated by the following empirical formula:
* The initial [[Ground_watertable_result_type_(Water_Overlay)|Groundwater level]] calculated by the [[Groundwater Overlay]]
<code style='clear:all'>Subsidence = GLG * a - clay thickness * b - c</code>
* The [[Waterwijzer_Overlay|Waterwijzer Overlay]] which calculates the yield loss of crops based on [[Waterwijzer_Overlay#Considerations|several parameters such as Subsidence]]
===Settlement===
Peat is a porous and relatively soft terrain type, meaning it can be compressed. Based on the amount of peat in the ground, the density of the top layer, and the net height increase.


The amount of subsidence due to settlement is calculated by the following formula:
{{article end
|howtos=
* [[How to add and remove an Overlay]]
* [[How to edit an overlay legend|Edit an overlay legend]]
}}


This formula is based on provided expert data in the form of a reference table, indicating the amount of subsidence based on the parameters used in the formula above. The formula's results conform to the reference table to within a fifth of the margin of error of the original table.
==Module==
 
A Subsidence Overlay can be configured by opening the Subsidence Overlay Wizard. More in-depth information can be found under each of the categories below.
===Multi-year calculations===
{{SubsidenceOverlay_nav}}
 
[[Category:Overlays with result types]]
Subsidence is calculated in 1-year steps. For each year, the amount of subsidence is calculated. That amount is then used to recalculate the input parameters for the overlay. The next 1-year step is then calculated.
{{Overlay nav}}
 
For more information on the way the multi-year calculation is performed, see [[Subsidence calculation]].
 
==How to configure the subsidence overlay==

Latest revision as of 14:19, 28 February 2024

The subsidence overlay
The ground water overlay

The Subsidence Overlay is an overlay that shows which places in the project area are subject to subsidence due to oxidation and/or compaction of peat. The calculation results can provide insight into the subsidence taking place, and the effects it has on groundwater levels.

The Subsidence Overlay can be used to calculate the amount of subsidence which takes place on peat soil, specifically due to peat oxidation and compaction. The calculations are specific for peat soil. Separate formulas for other soil types have not yet been implemented. Although it's possible to use the overlay to give an impression of subsidence resulting from other factors, the results will be less accurate. This means that results have a greater margin of error for different use-cases.

It is possible to add multiple subsidence overlays to a project. By varying their configuration slightly, it is possible to calculate multiple scenario's or time-frames simultaneously.

A project can be enriched with other overlays that are interesting in combination with the Subsidence Overlay. Examples are:

How-to's

Module

A Subsidence Overlay can be configured by opening the Subsidence Overlay Wizard. More in-depth information can be found under each of the categories below.

Subsidence Module
Benchmarks button.png
Subsidence wiki2.png
Subsidence Overlay
Benchmarks button.png
Getting started button.png
Tutorials
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Overview button.png
Overview
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Theory button.png
Theory
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Benchmarks
Group
Model
Overview • Calculation • Theory
Formulas
Parameter a recalculation • Ground water depth • Oxidation • Compaction • Subsidence • Indexation
Related
Features • Model attributes • Rasters • Result type
Overlays
Categorization
Grid • Parent • Result Child • Result Parent • Result type
Default
City
Administrative
Ownership • Ownership Grid • Zipcodes • Zoning • Neighborhoods • Municipalities • Vacancy
Environmental
Heat Stress • Traffic Density • Traffic Noise • Traffic NO2 • Livability • Aerius
Water
Rainfall • Flooding • Groundwater • Subsidence • Watershed • Waterwijzer
Raster Calculation
Average • Combo • Distance • Sight Distance • Travel Distance
Geo Data
Area • Attribute • GeoTIFF • WCS • WMS • Image
Topography
Digital Surface Model • Digital Terrain Model • Underground • Function • Source
Network
Network Distance • Network Overview • Network Ownership


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