•;?:,.:__•?
<br />?
<br />reteasing water stored for 'tr "ition and
<br />powez genecation is a flow ti that was
<br />iateiy grovided under pre-deveiopment
<br />conditions. FurtheRnore, oweng to the
<br />?..,.?:o:^..•,. .,•.-___ lu--??- itt ?8
<br />g
<br />?x75.i1? ,iy., v?... CG;ivi?ivna ai
<br />Platte, teleases from Lake McConaughy
<br />W(juld ?1P.P.f1 !(1 fIP p Patrvr f}ian 40-0 .r.?.c+
<br />because seepage losses and evaporation
<br />between the release noint would occur
<br />between the {ake and Grand Island, where
<br />the 400 cfs flow rate is to be provided.
<br />In same drought years, oniy a small part,
<br />if any, of the released water would reach
<br />vrand island even iT diversions in the
<br />intervening reacti were to be curtai[ed
<br />.. mp:e.ety.
<br />vAt the risk of seeming pedantic, we
<br />SIC a(Id1ItP thP fElllQwing eummWry nFnL;
<br />observations and conciusions about the
<br />Platte River:
<br />t. The quantity of precipitatiot? oa the
<br />area drained by the Platte varies widely
<br />from one to another period but over the
<br />long run now is no more nor no lcss than
<br />ia the past. in ciiect, the annnal average
<br />watcr supply availab)e for use has not
<br />LfS''^.g..^`?... HCwC:Ci, usC Oi ttlZ a?ti2i WeiCI
<br />has increased to the point that the av-
<br />erage flow of the Lriver 1i DiSf:C3S; Uust
<br />beiow the inflow Ezom the L.onp River}
<br />has been reduced as much as 50 nercent.
<br />Ie is necessary, however, to point out that
<br />this large use would not be possible with-
<br />out storage of the high fiows that for-
<br />merly passed cluough the state unused_
<br />in other words, only the high flows have
<br />been decreased (and beneFciatly so)
<br />whereas iire reiurn f'iows and ground-
<br />water seepage into ttie river have aug-
<br />mrnted Lho .' i-^_
<br />.. ei u :?iy'Yreixi11C4 1n1oW.
<br />HistoricaIly, the Platte River in the Big
<br />Bend area was a milc or rnorP Nv,dc cx_
<br />panse of rushing water during tlie hcight
<br />of the snowmett period and then became
<br />a cibbon of dry gravel interspersed with
<br />nazrow rivulecs of water for the remain-
<br />der of tlie year. Auring some summers,
<br />and particutarly during the 1930s drought
<br />periad, even wading poois disappeazed
<br />hom the river bed at Grand lsland. In
<br />fact and accard:r.g to aju:y I980 report
<br />of the Nebraska I3epartment of Water
<br />Resources (DWR}--"in the twe]ve yea:s
<br />ptioc lo consu-uction of Kingsley L?am,
<br />ttie key measuring station on the Platte
<br />Rivcr at Overton was dry for a portion
<br />of each yeu."
<br />2. Whereas periods of no surface flow
<br />were nflt uncommon before the storage
<br />was created. Uiey now are rare. Seepagc
<br />to Ltie ::ve; f;arin i;e ;asge mound of
<br />groundwater that eztends fmm Suther-
<br />land ea5t te M?.^.drn a.^.d :!:2: wa5 C:eQied
<br />by canal Iosses and ircigation seepage
<br />has tended to increase in the 8Et, @end
<br />area and may be even greater in the fn-
<br />htrr W_ PSL' m^o'.v i...ai . . .. '
<br />• ?. ua ic iucrcd.ie i(3
<br />groundwater siocage is aboat 7 to iil-
<br />lion acre-feet and that annual set?agP
<br />retums to the Ptane are as much as
<br />200,000 acce-ieeUyear from that source
<br />alone. Return flaws upstream from t,alce
<br />McCenaughy also hetQ siabilize the #low
<br />of the Platte River_ DWR, in its 1980
<br />rcport, states, "-swruner inflow to Lake
<br />hie?onaughy is oftcn 80 percent return
<br />flow from upstseam developments."
<br />?. F.°..`?'. Y..:.Y.e ::uucis:ni u ii n? i;e
<br />Platte between Kearney and the mouth
<br />of the Loup River naturally ??nds rn tese
<br />Flow by seepage to groundwater on both
<br />sides of the river. Before Europeans ar-
<br />rived lhe wide ezpanse of the va1ley iand
<br />on the north side supported a stand oF
<br />tali grasses that probahly used as mctch
<br />or more groundwater than now is used
<br />by pump-irrigatett croQs. And an the
<br />souch side, seepage loss was, and still
<br />:C L?i? grouudV:aiei Siipyiy fii the nig
<br />B[ue River basin.
<br />4. SOIIIC pePpIg pC3CCEHC ihv pl8!tY'-_c
<br />flowing in a lined conduit. That is, that
<br />the river's ttow at a given locarion should
<br />be no tess than at an upsuream ]ocatian.
<br />Such a concept is unrealistic because the
<br />t'iatte is intimately related to ground-
<br />water in the afluvial deposits over which
<br />it ;ows aad ihe river and floodpiain are
<br />w[nerable to bigh evapotranspiratian
<br />!osses. Q: c reach ..ay be gair?ing from
<br />groundwater and another reach simul-
<br />taneously Iosing to greundw.ater. '!?:e.e
<br />is no guarantee that an addition to flow
<br />at an uDStream npint w}ll stiil hrM ±n rbc
<br />river at a downsiream point. Hisiory pro-
<br />vides sorne insight in this regard. The
<br />to[lowing excerpt is from the Tenth
<br />Siennial Repori of the 5tate Board of
<br />Irmgation, Sept. 1, 1912 to Sept. l, 1914.
<br />['recipiaation during the period covered
<br />vy tj'ie izpon was considereci to be about
<br />average_ We quote, "Thc weather con-
<br />ditio::s ase such o s;raZg €ac:m govern-
<br />ing the amount of watex which is
<br />necessary to have passing t+otlt R:idge_
<br />port and Notth Plattc that even with the
<br />?ecords of the past season it is not pos-
<br />sible to figure accarately the ezact
<br />amounts. For instance, on August 6,
<br />1914, there waz several bundred feet of
<br />vracer passing the headgates of the ICear-
<br />ney Cana] in excess of what they could
<br />use. ?:s .-,ugss. S. u,e ;ver ai iCeatney
<br />was absolutely dry. No water was avail-
<br />able for uce b; die Ke2r.:eJ CA'r.;.l, yei
<br />during this period there had been nine
<br />hundred fifty to twelve hundred cut+ic
<br />feet of water passing our gaging stacion
<br />at North Piatte, and the incervening
<br />ditches between Kearney and Nonh Platte
<br />were using not to exceed three hundred
<br />forry feet. This extreme Qecrease in the
<br />flow of the river is easily accounted for
<br />considering the wide czpanse of the river
<br />bed and the foar days of exceeding3y hot
<br />south winds on August 6th, 7th, 8th and
<br />9th_" Transpiration by vegetation on is-
<br />JancLs and on wetlands border.ng thc ; iver
<br />alsa can account for water ioss from th,
<br />river. Existing models do noi adequatet:
<br />consider these losses in planning rive
<br />reguiation.
<br />5. Despite alI claims to the coatrary
<br />the ct;i-
<br />ieni t,ydrbivgit equiiibriun
<br />reached throagh reguIatioa of river floC
<br />ha,c in,rny:riea E.tie btRLfiw Ci flvw F?I`0
<br />tection, environmentally sound produc
<br />tion of hydropower; water for i?*iga:ion
<br />f1a1-water rccreation, and a signif'tcantl;
<br />enhanced riverine habitat for migrator
<br />waterfowl and indigenous species o
<br />birds, 6sh and mammals.
<br />6. The order for re-regulation of ce
<br />leases from [rake McConaughy is ba8
<br />hyura;ogicaIly and economicaliy un
<br />sound aed unrealisiic.
<br />7. Ir. OL'S fL'dgTi?eni, the l?iaile ZSYC
<br />and its tributary flows aze? very poorl.
<br />undetstood by anyQLne who has ;;o: g:'sd
<br />ied the rivers and their history. Misin
<br />[ormation appeam to be the rvle rathe
<br />than the exception, and that misinfor
<br />mation is being disseminateri widely. Thi
<br />Etow, storage, diversion, and manage
<br />ment o[ the Platte R?ver are exceedingi?
<br />?ouipiex. i.ndeed, many chastges havt
<br />cecuaed over the Qast lUQ yeazs or so
<br />wd these eF.as:g:s, iw, dc corr,piex. Ihi
<br />issue of ee-regulation of water flows fron
<br />those reservoirs licensed b; MRC i;. thi
<br />western states for envirvnmentai pur
<br />poses hopcfully witl be decicled on a fac
<br />tua] scientific basis case by ease. Han
<br />questions should be raised now.
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