1、Designation: D 4050 96 (Reapproved 2002)Standard Test Method(Field Procedure) for Withdrawal and Injection Well Tests forDetermining Hydraulic Properties of Aquifer Systems1This standard is issued under the fixed designation D 4050; the number immediately following the designation indicates the year
2、 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 field procedure forselec
3、ting well locations, controlling discharge or injectionrates, and measuring water levels used to analyze the hydraulicproperties of an aquifer or aquifers and adjacent confiningbeds.1.2 This test method is used in conjunction with an analyti-cal procedure such as Test Methods D 4105 or D 4106 todete
4、rmine aquifer properties.1.3 The appropriate field and analytical procedures areselected as described in Guide D 4043.1.4 The values stated in SI units are to be regarded asstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
5、ponsibility 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 ContainedFluids2D 2488 Practice for Descripti
6、on and Identification of Soils(Visual-Manual Procedure)2D 4043 Guide for Selection of Aquifer-Test Method inDetermining Hydraulic Properties by Well Techniques2D 4105 Test Method (Analytical Procedure) for Determin-ing Transmissivity and Storage Coefficient of NonleakyConfined Aquifers by the Modifi
7、ed Theis NonequilibriumMethod2D 4106 Test Method (Analytical Procedure) for Determin-ing Transmissivity and Storage Coefficient of NonleakyConfined Aquifers by the Theis Nonequilibrium Method2D 4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (ObservationWell
8、)23. Terminology3.1 Definitions:3.1.1 aquifer, confinedan aquifer bounded above andbelow by confining beds and in which the static head is abovethe top of the aquifer.3.1.2 confining beda hydrogeologic unit of less perme-able material bounding one or more aquifers.3.1.3 control wellwell by which the
9、 head and flow in theaquifer is changed, for example, by pumping, injection, orchange of head.3.1.4 hydraulic conductivity (field aquifer tests)the vol-ume of water at the existing kinematic viscosity that will movein a unit time under a unit hydraulic gradient through a unitarea measured at right a
10、ngles to the direction of flow.3.1.5 observation wella well open to all or part of anaquifer.3.1.6 piezometera device used to measure hydraulic headat a point in the subsurface.3.1.7 specific storagethe volume of water released fromor taken into storage per unit volume of the porous medium perunit c
11、hange in head.3.1.8 storage coeffcient the volume of water an aquiferreleases from or takes into storage per unit surface area of theaquifer per unit change in head. For a confined aquifer, thestorage coefficient is equal to the product of the specific storageand aquifer thickness. For an unconfined
12、 aquifer, the storagecoefficient is approximately equal to the specific yield.3.1.9 transmissivitythe volume of water at the existingkinematic viscosity that will move in a unit time under a unithydraulic gradient through a unit width of the aquifer.3.1.10 For definitions of other terms used in this
13、 testmethod, see Terminology D 653.4. Summary of Test Method4.1 This test method describes the field practices in con-ducting withdrawal and injection well tests. These methodsinvolve withdrawal of water from or injection of water to anaquifer through a control well and measurement of the water-leve
14、l response in the aquifer. The analysis of the data from this1This test method is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Oct. 10, 1996. Published Febru
15、ary 1997. Originallypublished as D 4050 91.2Annual Book of ASTM Standards, Vol 04.08.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.field practice is described in standards such as Test MethodsD 4105 and D 4106.5. Significance and U
16、se5.1 Withdrawal and injection well test field procedures areused with appropriate analytical procedures in appropriatehydrogeological sites to determine transmissivity and storagecoefficient of aquifers and hydraulic conductivity of confiningbeds.6. Apparatus6.1 Various types of equipment can be us
17、ed to withdraw orinject water into the control well, measure withdrawal andinjection rates, and measure water levels. The test proceduremay be conducted with different types of equipment to achievesimilar results. The objectives to be achieved by the use of theequipment are given in this section and
18、 in Sections 7 and 8.6.2 Control WellDischarge or injection well test methodsrequire that water be withdrawn from or injected into a singlewell. This well, known as the control well, must be drilled andcompleted such that it transmits water to or from the aquifer(usually the entire thickness of the
19、aquifer) at rates such that ameasurable water level change will occur at observation wells.The control well should be as efficient as possible, to reduce thehead loss between the aquifer and the well. Well developmentshould be as complete as possible to eliminate additionalproduction of sand or silt
20、 and consequent changes in wellefficiency and pumping water levels during the test. Thecuttings from the control well should be described and re-corded according to Practice D 2488. The analytical methodselected for analysis of the data may specify certain dimensionsof the control well such as scree
21、n length and depth of screenplacement. Specific requirements for control wells may begiven in standards for specific analytical methods (see, forexample, Test Methods D 4105 and D 4106).6.3 Observation Wells or PiezometersNumbers of obser-vation wells and their distance from the control well and the
22、irscreened interval may be dependent upon the test method to beemployed. Refer to the analytical test method to be used forspecifications of observation wells (see, for example, TestMethods D 4105 and D 4106).6.4 Control Well PumpA pump capable of withdrawal ofa constant or predetermined variable ra
23、te of water from thecontrol well. The pump and motor should be adequately sizedfor the designed pumping rate and lift. The pump or motormust be equipped with a control mechanism to adjust dischargerate. In the case of diesel-, gasoline-, or natural-gas-fueledengines, throttle settings should allow f
24、or small adjustments inpumping rates. Pumps equipped with electric motors areusually controlled by adjusting backpressure on the pumpthrough a gate valve in the discharge line. Take care to selecta discharge rate small enough such that the rate can bemaintained throughout the test without fully open
25、ing the gatevalve. If neither method of control is practical, split thedischarge and route part of the discharge back to the wellthrough a separate discharge line.6.5 Many aquifer tests are made at “sites of opportunity,”that is, using existing production wells as the control well andusing other exi
26、sting wells for observation of water level. Insuch cases the locations and screened intervals of the wellsshould be compatible with the requirements of the method oftest analysis.6.6 Water-Level Measurement EquipmentManual mea-surements can be made with a steel tape or electric tape asdescribed in T
27、est Method D 4750, with a mechanical recorderlinked to a float, or combination of pressure transducer andelectronic data logger.6.6.1 Mechanical RecordersMechanical recorders em-ploy a float in the well to produce a graphic record of waterlevel changes. Early in the test, it may be difficult to dist
28、inguishsmall increments of time on the recorder chart, therefore therecorder should be supplemented with additional early timemeasurements or by marking the trace of an automatic water-level recorder chart and recording the time by the mark. Checkthe mechanical recorder periodically throughout the t
29、est usingthe steel tape.6.6.2 Pressure Transducers and Electronic DataLoggersA combination of a pressure transducer and elec-tronic data logger can provide rapid measurements of water-level change, and can be programmed to sample at reducedfrequency late in the test. Select the pressure transducer t
30、omeasure pressure changes equivalent to the range of expectedwater level changes. Check the transducer in the field byraising and lowering the transducer a measured distance in thewell. Also check the transducer readings periodically with asteel tape.7. Conditioning7.1 Pre-Test Procedures:7.1.1 Sele
31、cting Aquifer-Test MethodDevelop a conceptualmodel of the site hydrogeology and select the appropriateaquifer test method according to Guide D 4043. Observe therequirements of the selected test method with regard tospecifications for the control well and observations wells.7.1.2 Field Reconnaissance
32、Make a field reconnaissanceof the site before conducting the test to include as much detailas possible on depth, continuity, extent, and preliminaryestimates of the hydrologic properties of the aquifers andconfining beds. Note the location of existing wells and water-holding or conveying structures
33、that might interfere with thetest. The control should be equipped with a pipeline orconveyance structure adequate to transmit the water away fromthe test site, so that recharge is not induced near the site. Makearrangements to ensure that nearby wells are turned off wellbefore the test, and automati
34、c pump controls are disabledthroughout the anticipated test period. Alternately, it may benecessary to pump some wells throughout the test. If so, theyshould be pumped at a constant rate, and not started andstopped for a duration equal to that of the test before nor shouldthey be started and stopped
35、 during the test.7.1.3 Testing of Control WellConduct a short term pre-liminary test of the control well to estimate hydraulic proper-ties of the aquifer, estimate the duration of the test and establisha pumping rate for the field procedure.7.1.4 Testing Observation WellsTest the observation wellsor
36、 piezometers prior to the aquifer test to ensure that they arehydraulically connected to the aquifer. Accomplish this byadding or withdrawing a known volume of water (slug) andD 40502measure the water-level response in the well. The resultantresponse should be rapid enough to ensure that the water l
37、evelin the piezometer will reflect the water level in the aquiferduring the test. Redevelop piezometers with unusually sluggishresponse.7.1.5 Measuring Pre-Testing Water-Level TrendsMeasurewater levels in all observation wells prior to start of pumpingfor a period long enough to establish the pre-pu
38、mping trend.This period is at least equal to the length of the test. The trendin all observation wells should be similar. A well with anunusual trend may reflect effects of local disturbances in thehydrologic system, or may be inadequately developed.7.1.6 Selecting of Pumping RateSelect the pumping
39、rate,on the basis of the preliminary test (see 7.1.3), at which thewell is to be pumped, such that, the rate can be sustained by thepump for the duration of the test. The rate should not be solarge that the water level is drawn down below the perforationsin the control well, causing cascading water
40、and entrained airin the well. Under no circumstances should the rate be so largethat the water level is drawn down to the water-entry section ofthe pump or tailpipe.8. Procedure8.1 Withdrawing or Injecting Water from the AquiferRegulate the rate at which water is withdrawn from, or injectedinto, the
41、 control well throughout the test. The short-termdischarge should not vary more than 10 % about the meandischarge. For constant-discharge tests, long-term variation ofdischarge from the beginning to end of test generally should beless than 5 %.8.2 Measure discharge frequently, for example every 5 mi
42、n,and if necessary adjust discharge during the beginning of thetest. When the discharge becomes more stable, reduce thefrequency of adjustments and check discharge at least onceevery 2 h throughout the test. Variations in electric line loadthroughout the day will cause variations in discharge of pum
43、psequipped with electric motors. Changes in air temperature andbarometric pressure will likewise affect diesel motors. Late ina lengthy test, measure and adjust discharge much morefrequently than the water levels are measured.8.3 Measuring Water Level; Frequency of MeasurementMeasure water levels in
44、 each observation well at approxi-mately logarithmic intervals of time. Measure at least ten datapoints throughout each logarithmic interval. A typical measure-ment schedule is listed in Table 1.8.4 Duration of Pumping Phase of TestMake preliminaryanalysis of the aquifer-test data during the test us
45、ing theappropriate test method (such as Test Methods D 4105 andD 4106). Continue the test until the analysis shows adequatetest duration.8.5 Measuring Recovery of Water Levels:8.5.1 If the recovery data are to be analyzed completely asa part of the test and used to determine long-term backgroundwate
46、r-level changes, the recovery of water levels followingpumping phase should be measured and recorded for a periodof time equal to the pumping time. Analyze the recovery datato determine the hydraulic parameters of the system. Thefrequency of measuring water levels should be similar to thefrequency d
47、uring the pumping phase (see Table 1).8.5.2 If water level data during the early part of the recoveryphase are to be used from the control well, the pump should beequipped with a foot valve to prevent the column pipe fluidfrom flowing back into the well when the pump is turned off.8.6 Post-Testing P
48、rocedures:8.6.1 Tabulate water levels, including, pre-pumping waterlevels, for each well or piezometer, date, clock time, time sincepumping started or stopped, and measurement point (TestMethod D 4750).8.6.2 Tabulate measurements of the rate of discharge orinjection at the control well, date, clock
49、time, time sincepumping started, and method of measurement.8.6.3 Prepare a written description of each well, describingthe measuring point, giving its altitude and the method ofobtaining the altitude, and the distance of the measuring pointabove the mean land surface.8.6.4 Make plots of water-level changes and dischargemeasurements as follows:8.6.4.1 Plot water levels in the control well and eachobservation well against the logarithm of time since pumpingbegan. Plot the rate of discharge, Q, of the control well onarithmetic paper.8.6.4.2 Prepare a plot of the log
