Reinventing land development with advanced sensor technologies

Land development projects are often a complex and expensive undertaking. In recent years, the scarcity of available land has made redevelopment an increasingly feasible option. Many former factory and office sites are now being targeted for higher-end use, including residential developments.

Drawbacks of the traditional sampling approach

Given the high stakes involved, developers need a high degree of certainty about their proposed site at an early stage, including contamination, lithology, hydraulics and local authority requirements. Because only then can they estimate the extent and cost of any remediation work required before construction can begin.

However, the standard site investigation approach recommended by many local authorities is often inadequate, irrelevant and far more costly in the longer term, because it is based on:

• A predefined investigation raster – with samples taken every five metres, there is a high risk of missing lithological, hydraulic or contamination ‘hotspots’;

• Physical sampling – this traditional approach is labour-intensive, noisy, invasive and very expensive, requiring additional laboratory analysis;

• Ineffective procedures resulting in huge remanent uncertainties.

The result is the true size and extend of underground anomalies is not accurately revealed.

Advantages of using modern sensing technology

The introduction of sensing technology to ground investigations is a game-changer. Delivering high-level site characterisation with an astonishing degree of accuracy, brings important benefits to site developers:

• The acquisition process is quick, straightforward, quiet and non-invasive, to depths of around 50 m to 60 m.

• Continuous data profiling allows contamination, lithology and hydraulic data to be acquired every centimetre on the vertical, eliminating the risk of missing anomalies;

• Results are delivered online in real time and displayed in 3D – this makes it easy for users to interpret and understand the data being collected.

Optimising the remediation strategy

Sensor technologies provide true indicator parameters for contamination, lithology and hydraulics.

For example, in the case of a contamination, the 3D view allows the developer to observe:

• The different layers below ground, such as sand and clay;

• The type and degree of contamination;

• Hydraulics controlling the spread of the contaminants;

• The overall spatial development of the contaminant body and its volume.

The live on-screen view allows you to quickly see the architecture of a hotspot – this approach facilitates an adaptive, flexible, iterative, cost-effective strategy.

It allows you to focus budgets on remediating areas of heavy contamination first, rather than starting with the outskirts, which may well continue to ‘bleed’.

Lithology is another important factor in determining the most effective remediation strategy – different approaches would be needed to remediate contamination in sand and clay, for example.

Using sensor technologies, any areas requiring further investigation are identified and precisely delineated, including underground structures and potentially weak zones.

Having identified uncertainties, recommendations are made on how to best mitigate risks and prevent catastrophic losses– material, financial and human. For example:

• In Italy we provided 3D assessments of the contaminant bodies affecting gas stations and helped the client to develop their future strategy;

• In the Netherlands we used our sensing technology on dams to highlight hydraulically weak areas that require stability remediation ;

• In Chile we used high-resolution investigation methods to assess the value of not exploited elements still present in mine tailings.

Conclusion

High-resolution 3D site characterisation provides developers with the certainty they need to derive a reliable proceeding strategy with measurable and scalable indicators.

Did you know?

• Data acquired in high resolution (every single cm)

• Daily performances up to 100m

• Live on screen view of preliminary results

About the author

Dr Eugeniu Martac is a Service Line Manager Site Investigation and Stefan Klostermeier is a Land Senior Consultant in Germany