ASTM_D_6000_-_D_6000M_-_15e1.pdf

Designation:D6000/D6000M151Standard Guide forPresentation of Water-Level Information from GroundwaterSites1This standard is issued under the fixed designation D6000/D6000M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorially corrected designation to match units of measurement statement in September 2015.1.Scope*1.1 This guide covers and summarizes methods for thepresentation of water-level data from groundwater sites.1.2 The study of the water table in aquifers helps in theinterpretation of the amount of water available for withdrawal,aquifer tests,movement of water through the aquifers,and theeffects of natural and human-induced forces on the aquifers.1.3 A single water level measured at a groundwater sitegives the height of water at one vertical position in a well orborehole at a finite instant in time.This is information that canbe used for preliminary planning in the construction of a wellor other facilities,such as disposal pits.Hydraulic head canalso be measured within a short time from a series of points,depths,or elevation at a common(single)horizontal location,for example,a specially constructed multi-level test well,indicates whether the vertical hydraulic gradient may beupward or downward within or between the aquifer.NOTE1The phrases“short time period”and“finite instant in time”are used throughout this guide to describe the interval for measuringseveral project-related groundwater levels.Often the water levels ofgroundwater sites in an area of study do not change significantly in a shorttime,for example,a day or even a week.Unless continuous recorders areused to document water levels at every groundwater site of the project,themeasurement at each site,for example,use of a steel tape,will be at aslightly different time(unless a large staff is available for a coordinatedmeasurement).The judgment of what is a critical time period must bemade by a project investigator who is familiar with the hydrology of thearea.1.4 Where hydraulic heads are measured in a short period oftime,for example,a day,from each of several horizontallocations within a specified depth range,or hydrogeologic unit,or identified aquifer,a potentiometric surface can be drawn forthat depth range,or unit,or aquifer.Water levels from differentvertical sites at a single horizontal location may be averaged toa single value for the potentiometric surface when the verticalgradients are small compared to the horizontal gradients.Thepotentiometric surface assists in interpreting the gradient andhorizontal direction of movement of water through the aquifer.Phenomena such as depressions or sinks caused by withdrawalof water from production areas and mounds caused by naturalor artificial recharge are illustrated by these potentiometricmaps.1.5 Essentially all water levels,whether in confined orunconfined aquifers,fluctuate over time in response to natural-and human-induced forces.The fluctuation of the water table ata groundwater site is caused by several phenomena.Anexample is recharge to the aquifer from precipitation.Changesin barometric pressure cause the water table to fluctuatebecause of the variation of air pressure on the groundwatersurface,open bore hole,or confining sediment.Withdrawal ofwater from or artificial recharge to the aquifer should cause thewater table to fluctuate in response.Events such as rising orfalling levels of surface water bodies(nearby streams andlakes),evapotranspirationinducedbyphreatophyticconsumption,ocean tides,moon tides,earthquakes,and explo-sions cause fluctuation.Heavy physical objects that compressthe surrounding sediments,for example,a passing train or caror even the sudden load effect of the starting of a nearby pump,can cause a fluctuation of the water table(1).21.6 This guide covers several techniques developed to assistin interpreting the water table within aquifers.Tables andgraphs are included.1.7 This guide includes methods to represent the water tableat a single groundwater site for a finite or short period of time,a single site over an extended period,multiple sites for a finiteor short period in time,and multiple sites over an extendedperiod.1.8 This guide does not include methods of calculating orestimating water levels by using mathematical models ordetermining the aquifer characteristics from data collected1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved April 15,2015.Published May 2015.Originallyapproved in 1996.Last previous edition approved in 2008 as D6000 96(2008).DOI:10.1520/D6000_D6000M-15E01.2The boldface numbers in parentheses refer to a list of references at the end ofthis sta