This part of ISO 22282 establishes the general rules and principles for geohydraulic testing in soil and rock as part of the geotechnical investigation services in accordance with EN 1997-1 and EN 1997-2. It defines concepts and specifies requirements relating to permeability measurement in soil and rock. The different purposes of geohydraulic testing are to obtain information on the permeability of soil or rock in natural or treated states, transmissivity and storage coefficient, and hydrodynamic parameters of aquifers. Geohydraulic testing is used for many purposes, such as: a) absorption capacity and effectiveness of grouting in rock mass; b) assessment of seepage and drainage; c) assessment of groundwater lowering work; d) effects of cut-offs for dams; e) effects of tunnels and shaft sinking; f) checking fill or cover tightness; g) assessment of the flow of fluids and suspensions in the ground; h) planning for remedial measures. NOTE 1 Geohydraulic testing for water supply is covered by ISO 14686. NOTE 2 For most types of ground, field permeability tests yield more reliable data than those carried out in the laboratory, because a larger volume of material is tested, and because the ground is tested in situ, thereby including effects resulting from the structure of the ground mass but avoiding the disturbance associated with sampling. This part of ISO 22282 deals with the execution of tests with groundwater and does not explicitly consider other fluids and suspensions. The flow of other fluids and suspensions can be considered by applying the different viscosities and relations between transmissivity, permeability coefficient and intrinsic permeability.