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", Water cout1 l")(''to--r;taminatcd al'KI by radio3ctiH material~ buried in tht': ground. Earth materials lend to atlral:t {"3tl-;orb'" certain radio<llli\'(' su~(an<:cs. and Ihu~ can act as filtcp.; for th~ ~Ilh"tan(("~ <;(J lonl!; as their adsorptive capacity i~ nol cxcccd<"d. Other radinartin- surntanrcs, however, may OlD\(" frrcly through tht" ground .....ith tb(' \\'31('(. Th~ are "'Orne of the Tt'asons wh,", though Ihc nucl('ar..{'n('r~y industry k small, comidcrablc effort i" !x-ing expended in studies of wa!'.te control in relation to water supplies 10 a.s~ure the So1.fety of our future supplies. In the foreseeable (utuft' (:\.D. 2000), many arcas of tb(' CnitNl Stitle" will require complete u<<e of all their walcr H~ourr~. Watn supply is already scarce in :<orne areas where nuclcar facili- ties are imtallcd or are likdy to bt- imtallcd. We cannot ri.,k Io:<ing important sourn~ of walef by radioacti,"c contamination. WHAT ABOUT WELLS? ~Iam' peapl!." today ha'"e never :<-('en a well except in pictures. The wells pictured in books are often the nld-fa..hionl:"d kind wilh a little cupola OHr a bu,kc-t that ,0111('S up wh(.n Ihe crank is wound. Such ",ells W"efe ~elwrally dug hy hand and were 1101 nTY d('cp. HO\~e\'er. cwo a well du~ b,' hand mUM be Enerl, or "cur!-x-d." to keep the side; from fallin~ in. A properly con. structcd dug \\'('11 that taps a pt'rmeable aqllillcf can ha\"e a IargC' yield, hut most dll"~ wdl.. for home :i-upplics arc capable of yiddin~ only I or 2 gallons per minute. when pumped sleadily. .-\ wdl is drilled by mcans of a cable.tool drill- ing rig which chums a bit lip and down in the hol{", or it may !)(' bored with a rotary drill. It is lined with a lon~ mC'tal or pla_"tic pipe called a tas;'l.!!. which support... the walls so that rock... or din won't fall in, and which also might ~r\'(' to seal ofT a Wilt' containing poor-quality .....ater. Th(' pump pipe hang" down insid(' lhe casing below the water le\"("1. ~Iost wells nowadays IJ~ pump; to lift the water in"t('ad of only a bucket on a rop<". The old-fa"hiollcd pitcher or lift pump can ,till be S('en on famls or in village; fig. 12). It_", raucous sound is familiar music to many cin dwdlers who come from homes in the country. It has a long iron handle: raising and lowC'Ting thi." handk forc~ air out of the' pump" Water enter<. 10 fill thl' ('mpl}' ~pace Idt by the air, and eom~ out in spurt~. ~tost modem pump~ arc drin'n by c1crlric motors. To teit a well. you m('asure the water re,"d; then pump the \~ell al a steady rate. Tne water level will drop H'~" fa~t at fir<.t and then more ~Iowly. as tne rate at which wale'T i.~ flowing into the hell approacnC'< the pumping rate. The dif- frrencc ht-tween the original water Ie\.c1 and the water le,"eJ after a period of pumping is called the' drtw'dou"n. The di.'\Char~e rate is deter- mint"d by a me:t~uring de,"ice aHached to the discharg'(' pipe. The ratio between the di.'>Charge rate and the drawdown will provide the well's specific capacity. FaT in~tanc('. if the drawdown i" 10 feet and the di_scharg-e rate is 100 gpm (gal- 10m per minute), the specific capacity of the well will !-x- 10 gpm per II {If drawdown" The hydrol- ogi_~t can take Ihe rcsub of cardully controlled pumpin~ Ie-l" and use them in formula." which ('nable him to predin what will happen to water levels in the future. Pumping: water from a wclllowcrs the water tahl(' around the well and cre:l.lCS a con~ of de- pression (fi~. 13). Around ..mall-yield wells in produnivc aqujfic~ the cone of deprnsion is quite !'mall and shallow. Wdb pumpt"d for irri- gation or indl1~t~.. howevcr. may wilhdraw so much water that the watcr table is lowered and the COtH. of depr('S.~ion may extend for milcs" Locating wells too close to~ether causes more lowering of the '\"atef t3blt" than spacin~ them far apart. This procr.<." i~ called ;nterfrrence. Such interference may draw watn lenls.so low that pumpin~ COSl" will be l!t"eally inere3..<.ed. Thefe' is a ...dde!'pread popular notion that there ha" been a progrf'S'<i\-e lowering of the water table all over the :\'ation. It i." tme that in many places waler lenl.~ in wdls are lower than they u~ed to be'. This may indic31e only that more water is bdng wilhdrawn. 1101 1lC'Ce;."<lrily that it i" being withdrawn too rapidly, The water sit- u3tion which b gra\"t' in a loca13rt'a is not neces- sarily symptomatic of trouhle throu~hout the eounln', For the :'\alion a~ a whoIc Ihl."re i.~ neilher a pronounce'd downtTt"nd nor an upt~nd. Water Je\"ds rise in wet pcriod~ and decline' in d~' periods. 3nd in are3..~ that ar(" not hea,'ily pumped th("y a\"Cra~c alxlUt the s.1me' as they did in Ihe pa..~t. On the other hand, thert' are sizable areas where ground walcr i.~ being taken out fa~tcr than it i... repkni~hed.. and the water lcHb arc lower- [5