Land quality – managing ground conditions

4.1

4.1.3Initial Assessment – walkover survey (all sites)

To assess ground conditions, a walkover survey of the site and the surrounding area shall be undertaken by a suitable person.

A walkover survey is a direct inspection of the site and the surrounding area carried out in conjunction with the desk study. Indications of any potential hazards should provide a basis for the investigation. A photographic record of the site can help in the reporting of the walkover survey.

Table 2: Potential hazards

Source of information	Items to be taken into account
Topography	■ abrupt changes in slope ■ valley bottoms or depressions which may be soft or filled ■ evidence of overburden on slopes ■ excavations at the base of the slope ■ signs of landslip, e.g. tilting trees, posts or walls ■ signs of subsidence ■ evidence of imported soil including local surface depressions, tipped material or rubbish, particularly if it is hot or has an odour.
Soils and rocks	■ the basic ground type ■ evidence of peat, silt or other highly compressible material at or below the surface ■ cracking or stickiness of the surface which may indicate a shrinkable sub-soil ■ sudden changes in conditions, e.g. clay to chalk or soil to rock.
Surface water and vegetation	■ a high water table indicated, e.g. by waterlogged ground ■ signs of flooding ■ reeds or water-loving plants ■ springs, ponds, wells, ditches or streams ■ the source of any discoloured water.
Vegetation	■ vegetation which may indicate the nature of the soils ■ sparse dead or dying vegetation ■ type and condition of vegetation on land adjoining the site ■ species, height and condition of the trees ■ species, height, spread and condition of hedges and scrub on clay ■ evidence of former trees, hedges or scrub on clay.
Structural information	■ damage to structures, e.g. cracking in buildings, on or around the site ■ other evidence of movement, e.g. tilting or distortion ■ any structures or services below ground.
Local information	■ local knowledge of the site, e.g. mining, refuse tipping or flooding ■ local industrial history records indicating past and present uses of the site ■ place names and street names that may give clues to previous site usage, e.g. Brickfield Cottage, Water Lane.