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<br />CONcr~uSIONS
<br />
<br />decreases .yields n.nd increases drawdowns. .:Most of the wells a.r6
<br />drilled.to bedrock, are lined with mato.! casing, and are eqUipped.With
<br />electci.CsJ1y driv.en turbine pumps. .A :few of the ws1ls~ axB dug and
<br />lined With concrete cltSing. Only two welis fll'6 equipped with centrif-
<br />uga.1~pum.ps md only .one 'pump is driven by !1J1 internal-combustion
<br />; engine.
<br />.Hlidson (population'430) is.supplied with 'Waw from two drilled
<br />metal-.ca.sed wells that obtain water' from the vllilley~fi.l1 deposits. 'The
<br />weUa; :which are outside the .city limits, ILte equipped with electrically
<br />driven turbine pumps: that force WlLter'into .11. 4i,OOO~gaJlon elevated
<br />stee!-ta.nk. An avemge ,operating pressure of about 85 psi is main-
<br />tained. in the city distribution system. About 125,000 gpd, or about
<br />: 140 a.cre--Ttper, year, is pumped :fmm. the wells :f<< municipal use:
<br />. Pumping from the irciga.tion wells in this district has- been very
<br />heavy during .recent years. Yields :from the wells thlLt were measured
<br />by .the, U.S. Geologicml. Survey ranged from 85 to 1,0f)Q gpm and
<br />averaged 550 gpm. Dll'lLwdowns ranged: :from 7 to 32.:feet a.nd speeifi.c
<br />capacities r&nged ,from 5 to 135. The .coefficients of permeability [l,ud
<br />transmissibility a.r0 relatively low ~ tiLbleo). oomplLl'Sd to those in tb.s
<br />. -rest or the report:n.rea.. The water levels in'many of the wells BOutb.
<br />of Hudson.declined ,td the pump intakes during .the 1957 pumping sea-
<br />. son., and some 'Wells were not. used. The largest .yia1l1s genel'ally lU'e
<br />obtained irom wells nellir. the' o.xinl pa.rt. of the. voJ1ey; the slope':wash
<br />. depositsn.long the. edges of the vnl.1ey :fill are poor producers. The
<br />. comparatively small EIoverage yields of ,wells in the district proba;bly
<br />. are due' to the dec:llining water table' and to:the lower permea.bi.1ity
<br />,of the valley-fill depositsJ w.bich conto.in n. large petcentage of alay
<br />and Silt, Heavy pumping eventually. could lower the regional water
<br />tll;ble below: the intakes af soroe pumps.
<br />It, is .estimated thll:t abaut 20JOOO acre-feet of ground wo.ter is
<br />.pumped from the valley-flU deposita. (luring a' nermal yenr. The
<br />estimo.ted qunrttity of recoverable ground water in storage in:Novem-
<br />. ber 1957 was about 320,000 acre-ft. Declining water. levels, indicate
<br />that ground ;Water is being tnken from stollage; that. is,. recharge' is not
<br />. buJn.ncing disch.o.l.'ge. The decline of the' water" tabla in this matI'ict
<br />is the most mo.rh.-ed in the report area.
<br />In the .southern part of this district, the water generally has a spe-
<br />cific. conductance of less than 1,400 micl1omhos per em and is or the
<br />co1eium bicarbonate ,type. ; In the northern part, the water generally
<br />has [I. spec:rlfic conductnnce of mOl'e .th(lJll,800 micl'omhcs ,pel' em and
<br />is of ,tile calcium sulfate type.
<br />
<br />CONCLUSIONS
<br />
<br />123
<br />
<br />122 GROt1ND WATER) SOUT.E:.PLATTE
<br />
<br />about 23 xeet per mile south of ,Hudson, but it decreases to. n.bout~18
<br />feet-per mile and is nearly uniform northward from'Hudson. In the
<br />vicinity'of sae. ll,'T. 4; N., R. 64 W., however, there: is a flattening of
<br />the slope, probably dUB to BJ.l increDSB in the permeability of the
<br />Bsdimento.ry rock. Depths to water nnd the shape of the water table
<br />.show tl~t Bqx Elder Creek was: not. gainb;1g wnter' from the ground-
<br />water reServoir in November 1957'. The creek is dry rllll'ing much of
<br />the year but is a source of recha.rge to the ground-water reservoir when
<br />it flows and especially 50 when it i$ at. flood stage. Ot1ler ~Oul'ces of
<br />reclu\rge aTe surface water ,that is' spread for irrigation'lUid prooipita.
<br />tion that falls within t11e bn.sin. Immediately after It Hood, when
<br />witter from Box' Elder Creek is racl1arging tIle ground-WAter reservoir,
<br />II; ridge probably is fonned on the water table benelLth the bed of the
<br />creek:. The uontouTS around Horse Creek, however, indicate that the
<br />creek 1s gaining ground water, probably by seepage from' Horse Greek
<br />Reservoir. Reehnrge from t118 Ireland Reservoir. No.5 api:llLren.t1y is
<br />causing.the mound in the wa.ter table downstream from the reservoir.
<br />The contourain the area where the valleys of the Beebe Draw and Box
<br />Elder Greek valley merge show tllO,t some of the ground water in Box
<br />Elder Creek valley is mov:ing into the vnney~fi.ll deposits in Beebe
<br />.Draw. . The slight inward movement of ground wn.te-r along the
<br />edges or tl1B valley probably is caused, by tIle' slope of the bedrock
<br />surface.
<br />'Depths to water in the. voJley range from less thlm 5 feet.to ohout
<br />40 feet and o.vern.ge 22 feet. Hydrographs of the U~S. Geological
<br />"Surveytel observation wells (figs. 11, 12, and 13) show tho.t.the.man-
<br />'mum &nnuo.lftuctuation in weLl Bl-65.,.12aed2 w.a.s about 18. :feet~ part
<br />of which was due to the pumping of [I, neo.rby irrigation well. The
<br />records of the long-term nbserva.tion wells, except well B2-64.-BOcbc,
<br />show n. pronounced downward trend in the' wn.ter levels.. since 1950
<br />(fig. 10). In,the vioi:nity.of this well, ground-water underflow from
<br />IreltLnd Reservoir No.5 probably.reeho.rgeathe ground-water reservoir.
<br />Although. the w&ter'}evels :!lad l'isen by _the spring of 19l58~ they stU1
<br />were far below -the average of .recDrd- in, most of the wells. The only
<br />SurfOOB 'Water ~vaila.ble .for.' irrigation in the district is tbat diverted
<br />from the few reservoirs nnd from Box Elder Creek when it is at flood
<br />stage. Therefore, irriga.tion. is. largely dependent on wa.ter pumped
<br />:from wells. All the large withdraiwals' of ground water nom the
<br />. v.alley-fill deposits, except from the;H.udson municipa.l wel:1sJ are used
<br />for irrigation. Codo's. well-location map (1943) shows only 70 irri-
<br />gation wells in 1940 j by the end of 1951 tItere were 210. . The number
<br />of weHs per section rn:nges from 0 in several to 12 in sacs. 12 lmd 13,
<br />T. 1 N., R. 65 W., and the ILvera;ge is three. Loaa.lly, however~ the ir-
<br />rigation wells n.re 'too closely spaced, and as a. result mutual interference
<br />
<br />RIVER' :BASIN
<br />
<br />Unconsolidated valley-fill deposits 'of sand, gravel,. cobblesJ and
<br />bo.uldersof Quaternary age are. the important water-bearing forma.-
<br />
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