A soil quality map is a geographic reference document that displays the chemical composition and contamination levels of soil across a defined area. It helps determine whether soil is suitable for construction, excavation, or reuse without further investigation.
Purpose of a Soil Quality Map
Municipalities and regional authorities create soil quality maps based on extensive sampling data. These maps classify zones by soil type and contamination level, providing a standardised reference for:
- Assessing whether excavated soil can be reused on-site or elsewhere
- Determining if a full soil investigation is required before construction
- Streamlining the permit process for earthworks and land development
How Soil Quality Maps Are Created
- Data collection — existing soil investigation reports, historical land use records, and geological surveys are gathered
- Sampling — additional soil samples are taken to fill data gaps
- Classification — zones are assigned quality classes (e.g. clean, lightly contaminated, heavily contaminated)
- Mapping — results are plotted onto geographic information system (GIS) maps
Reading a Soil Quality Map
Each zone on the map indicates:
- The background concentration of heavy metals, PAHs, and other contaminants
- The soil type (clay, sand, peat, or mixed)
- The applicable quality standard for that zone
Application
Soil quality maps are used by developers, contractors, and municipalities during the planning and execution of construction projects. Common uses include:
- Evaluating building sites before purchase or development
- Planning soil removal and disposal during excavation
- Matching excavated soil with receiving sites for reuse
- Meeting environmental regulations for land development permits
A soil quality map does not replace a site-specific soil investigation where one is legally required, but it can reduce costs by eliminating unnecessary testing.
Related Terms
- Soil investigation
- Contaminated land assessment
- Environmental site assessment
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