Table 7.2.

Data to be recorded on an Engineering Geology Map

Geological data
  • Map units (chrono- and/or lithostratigraphy)

  • Geological boundaries (with accuracy indicated)

  • Description of soils and rocks (using standard engineering codes of practice)

  • Description of exposures (cross-referenced to field notebooks)

  • Description of state of weathering and alteration (note depth and degree of weathering)

  • Description of discontinuties (as much detail as possible on the nature, frequency, inclination and orientation of all joints, bedding, cleavage, etc.)

  • Structural geological data (folding, faulting, etc.)

  • Tectonic activity (notably neotectonics, including rates of uplift)

Engineering geology data
  • Engineering soil and rock units (based on their engineering geological properties)

  • Subsurface conditions (provision of subsurface information if possible, e.g. rockhead isopachytes)

  • Geotechnical data of the engineering soil and rock units

  • Location of previous site investigations (i.e. the sites of boreholes, trial pits, and geophysical surveys)

  • Location of mines and quarries, including whether active or abandoned, dates of working, materials extracted and whether or not mine plans are available

  • Contaminated ground (waste tips, landfill sites, old industrial sites)

  • Man-made features, such as earthworks (with measurements of design slope angles, drainage provision, etc.), bridges and culverts (including data on waterway areas), tunnels and dams

Hydrological and hydrogeological data
  • Availability of information (reference to existing maps, well logs, abstraction data, rainfall and evaporation)

  • General hydrogeological conditions (notes on groundwater flow lines, piezometric conditions, water quality, artesian conditions, potability and sources of recharge)

  • Hydrogeological properties of rocks and soils (aquifers aquicludes and aquitards, permeabilities, yields, storage)

  • Springs and seepages (flows to be quantified wherever possible, perched water tables, and water levels with depth, both phreatic (water table) and piezometric)

  • Streams, rivers, lakes and estuaries (with data on flows, stage heights and tidal limits)

  • Man-made features (canals, leats, drainage ditches, reservoirs)

Geomorphological data
  • General geomorphological features (ground morphology, landforms, processes, Quaternary deposits)

  • Ground movement features (e.g. landslides, subsidence, solifluction lobes, cambering)

Geohazards
  • Mass movement (extent and nature of landslides, type and frequency of landsliding, possible estimates of runout hazard, snow avalanche tracks)

  • Swelling and shrinking, or collapsible, soils (soil properties)

  • Areas of natural and man-made subsidence (karst, areas of mining, over-extraction of groundwater)

  • Sand and dust hazard, mainly but not solely in areas of limited vegetation cover

  • Flooding (areas at risk, flood magnitude and frequency, coastal or river flooding)

  • Coastal erosion (cliff form, rate of coastal retreat, coastal processes, types of coastal protection)

  • Seismicity (seismic hazard assessment)

  • Vulcanicity (volcanic hazard assessment)

  • After Griffiths (2004).