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1 A 8 radius rK should bt taken a% the radial distance j from the. center of the wtl) to the outer surface of tht gra%cl pact. %hcrc the double straight line I% due to a naturall% dc%clopcd znnc around the well, rN is harder to e%aluatc and an "intelligent" rear- mate must be mads It ma) also be possible to esti- - i i mate rpt from the value of at point B in Figure 4 t omidcring the %olume of Hater in the wc1l be t%%tcn % % and K in Figure 4 to be due to the € drainage of the gra%cl pack or dc•%eloped zone, and i GR VEL PA K i + ].nos%Ing or estimating tht drainable porosity of OR € + the gra%cl pack or dc%eloped zone, the radial DEVELOPED i cxtcnt of this zone can be calculated for e%aluation ZONE of ret (_apillar) fringe effects do not has a to be considered, since the capillar) fringe was also I Fig Slug test for borehole with ground water level below presc nt in the pack or in the dei eloped zone before the eater let c] was lowered Because the using QA1,and above (B1 top of screen or perforated rection water Ic%el in the hole during the slug test will also fill up the drained port. space of the gra%cl pack or dc%cloped -one, the value of r, in the equation for calculation of K should be adjusted to take thi. I the drawdow n around the holt httonx-c significant cffcct into account, as discussed earlier in this relati%t to %, 7 he. first straight lint portion in article Figure 4 is probabl% due to a highly permt:ibit t'onccnah]) , a well Could hast. a gravel pat{. zone around the Stell (gra%el pick or dt%elope•d surrounded b) a les, pe.rmeablr de►elopcd zorn zone?, which quick]% ands %+atcr into ilii te.eE1 bcfort the original aquifer material is reached 7 hiti ' tmmcdiatcl) after the eater Ic►tl u, the ►Sell hiti could Iced to a triple straight line effect, with an been lowered (1 figure SA) ]lien %then the %%.ne.r intermediate straight lint. portion at point H. or a Jc%cl in the permcaU]t cont ,ire:end ilii vte.11 has tuned transition tour at B if the hydraulic con- drained to the %Safer ]c%el In the "ill itself, ilii ductnit) of the developed zone gradually decreases flow into the %%eI] s1o%%s dn%%n and ilii point% begin until )\ of the original aquafer material is reached to form a second, less etcrp, str.iii*ht line (Win B% the same token, portion AB to Figure 4 could i Figure 4) This second straight lira i• imirt mdua also be cutitd i! ilii hydraulic conductnir) of the tivc of ilii Clo%% from flit uncir.rii�l+c <' t, • is si,t�� gra%cl pick or dc%c]npcd cant immcdiatcl%• around the w�cll lienee, segment !t( .h•'" + flit still decreases with radial distance from the culattng k of the ayuif e r %t ith t, € w e11 original 1976 articlt gra%t I t -j� t ' l+t d zones were assumed to d' .1 int r tilt � ` Watcr It%tl in the bort lit-1, 11 ,i 1. lim.,.,i iter FALLING WATER LEVEL TEST the slug test, i c ,cs%cmi jl.ti t%t +mtainmr,l% litm !hc slug tt%t was de%cloped for a rising water ever, sonic gra%cl pack% tri tltttlop(d iont,, It.%el in tht borehole, a% obtained In quick rcnio%a] appartntl) arc not permcabIt enough to gni %uth of a certain %olume or slug of water Ihis can he Instantaneous drarriagc achic%td In bailing (quick)pumping, or h) If the ground %%ater tel It t% alimc tht screened immersing a action of pips filled %t ith sand or or open section of tht borehole anil the .%.i ter othtr lrallisi and closed with cap-.on both end% or Jet el in the hole I. not lo"tred so far that it drops other %ubmcrvbIt oli)cct, in tht borchok, Jetting belctiw the top of the open section (1 igurt 511), the the %%aier le%cl in the bortholc return to cquilib gra%el cn%clopt or dc%elopcd lone around the opt num, and quick]) retuning the submerged object section cannot drain The inflow into tht hole then The question I% often raiud can the method al%o is immediately controlled b% the aquifer, and the bt used %%hen a %olumc of wattr is quickh addtd double straight lint effect should not occur If it to the holt and the subsequent rate of fall of the still occurs, it could indicate leakage around the wattr It%el in the hole is measured for calculation casing or grouting above the gravel pack of K= the ans%%t-r is yes, pro%idcd that tht equilIli Where the double straight lint. I%duc to a rium water lc%-cl is abo%c the screened or open gravel pack around the well, the cffccti%c wc11 section of the borehole. (rigures 1 and SB) In thi% a4k