ASTM_D_4750_-_87_2001.pdf

Designation:D 4750 87(Reapproved 2001)Standard Test Method forDetermining Subsurface Liquid Levels in a Borehole orMonitoring Well(Observation Well)1This standard is issued under the fixed designation D 4750;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes the procedures for measuringthe level of liquid in a borehole or well and determining thestabilized level of liquid in a borehole.1.2 The test method applies to boreholes(cased or uncased)and monitoring wells(observation wells)that are vertical orsufficiently vertical so a flexible measuring device can belowered into the hole.1.3 Borehole liquid-level measurements obtained using thistest method will not necessarily correspond to the level of theliquid in the vicinity of the borehole unless sufficient time hasbeen allowed for the level to reach equilibrium position.1.4 This test method generally is not applicable for thedetermination of pore-pressure changes due to changes instress conditions of the earth material.1.5 This test method is not applicable for the concurrentdetermination of multiple liquid levels in a borehole.1.6 The values stated in inch-pound units are to be regardedas the standard.1.7 This standard does not purport to address all of thesafety problems,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 653 Terminology Relating to Soil,Rock,and ContainedFluids23.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 boreholea hole of circular cross-section made in soilor rock to ascertain the nature of the subsurface materials.Normally,a borehole is advanced using an auger,a drill,orcasing with or without drilling fluid.3.1.2 earth materialsoil,bedrock,or fill.3.1.3 ground-water levelthe level of the water table sur-rounding a borehole or well.The ground-water level can berepresented as an elevation or as a depth below the groundsurface.3.1.4 liquid levelthe level of liquid in a borehole or wellat a particular time.The liquid level can be reported as anelevation or as a depth below the top of the land surface.If theliquid is ground water it is known as water level.3.1.5 monitoring well(observation well)a special welldrilled in a selected location for observing parameters such asliquid level or pressure changes or for collecting liquidsamples.The well may be cased or uncased,but if cased thecasing should have openings to allow flow of borehole liquidinto or out of the casing.3.1.6 stabilized borehole liquid levelthe borehole liquidlevel which remains essentially constant with time,that is,liquid does not flow into or out of the borehole.3.1.7 top of boreholethe surface of the ground surround-ing the borehole.3.1.8 water table(ground-water table)the surface of aground-water body at which the water pressure equals atmo-spheric pressure.Earth material below the ground-water tableis saturated with water.3.2 Definitions:3.2.1 For definitions of other terms used in this test method,see Terminology D 653.4.Significance and Use4.1 In geotechnical,hydrologic,and waste-managementinvestigations,it is frequently desirable,or required,to obtaininformation concerning the presence of ground water or otherliquids and the depths to the ground-water table or other liquidsurface.Such investigations typically include drilling of ex-ploratory boreholes,performing aquifer tests,and possiblycompletion as a monitoring or observation well.The opportu-nity exists to record the level of liquid in such boreholes orwells,as the boreholes are being advanced and after theircompletion.4.2 Conceptually,a stabilized borehole liquid level reflectsthe pressure of ground water or other liquid in the earthmaterial exposed along the sides of the borehole or well.Undersuitable conditions,the borehole liquid level and the ground-water,or other liquid,level will be the same,and the formercan be used to determine the latter.However,when earthmaterials are not exposed to a borehole,such as material whichis sealed off with casing or drilling mud,the borehole water1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Nov.27,1987.Published January 1988.2Annual Book of ASTM Standards,Vol 04.08.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.levels may not accurately reflect the ground-water level.Consequently,the user is cautioned that the liquid level in aborehole does not necessarily bear a relationship to thegro