HydroGeo knowledge library

Technical insights for better-grounded decisions

Practical introductions to common investigation methods, evidence needs, outputs, quality checks, and professional limits. These articles support enquiry preparation; they do not replace a site-specific assessment or qualified review.

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12 governed explainers

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Each article separates measured evidence from interpretation and identifies what may still require confirmation.

Conceptual ERT field line above a layered subsurface response, separating surface measurements from the inferred resistivity model.

Geophysical Investigations

Electrical Resistivity Tomography (ERT): What It Measures—and What It Does Not

A practical explanation of how ERT estimates subsurface electrical contrasts, how inversion shapes the result, and why independent evidence is still needed.

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Conceptual ground-model workflow combining mapped terrain, boreholes, laboratory evidence, groundwater observations, and interpreted layers.

Geotechnical Ground Models

Building a Geotechnical Ground Model from Multiple Lines of Evidence

How boreholes, laboratory testing, mapping, geophysics, groundwater observations, and uncertainty are correlated into a traceable ground model.

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Conceptual groundwater investigation showing terrain, geology, possible aquifer pathways, a proposed well, and confirmation activities.

Groundwater and Hydrogeology

Before Drilling a Water Well: What a Groundwater Investigation Can Clarify

What groundwater evidence can improve well-planning decisions—and why occurrence, yield, and water quality remain unconfirmed until field testing.

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Conceptual comparison between a broad regional hazard map and a detailed site assessment informed by local observations.

Engineering Geology and Geohazards

Hazard-Map Screening versus Site-Specific Assessment

The different roles of regional hazard screening and site-specific evidence, including scale, date, uncertainty, and field-confirmation limits.

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Conceptual catchment and drainage assessment linking rainfall, terrain, flow paths, channels, culverts, and downstream constraints.

Hydrology, Drainage and Flood Assessment

What Inputs Are Needed for a Drainage and Flood Assessment?

A decision-focused guide to terrain, rainfall, catchment, drainage, flood-history, and design inputs needed before hydrologic or hydraulic assessment.

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Conceptual comparison of LiDAR point measurements, a bare-earth terrain model, a surface model, and derived elevation products.

LiDAR, GIS and Remote Sensing

LiDAR, DEM, DTM and DSM: Choosing the Right Terrain Data

How common elevation products differ, what each represents, and what resolution, date, vegetation, and coordinate controls mean for use.

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Conceptual ERT section branching into groundwater and engineering decision paths while retaining the same measured physical property.

Geophysical Investigations

ERT for Groundwater and Engineering Investigations: Same Physics, Different Decisions

Why the same ERT physics can support different groundwater or engineering questions, with interpretation governed by the decision and confirmation evidence.

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Conceptual geophysical model checked against boreholes, samples, water levels, laboratory results, and monitoring observations.

Geophysical Investigations

Why Geophysical Interpretations Need Borehole, Sampling or Monitoring Confirmation

How non-uniqueness and resolution limits make geological, borehole, sampling, pumping-test, or monitoring evidence essential to interpretation.

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Conceptual side-by-side seismic acquisition showing surface-wave dispersion for MASW and refracted travel paths for seismic refraction.

Geophysical Investigations

MASW and Seismic Refraction: Different Waves, Different Outputs

A comparison of surface-wave and refracted-wave methods, the velocity information they provide, and the limits on geological or design interpretation.

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