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<br />, <br /> <br />SENT BY: BOR-WCAOS SDj <br />I I'U;\.o\,Jt'Lui a.la-lfbj 1U:1l1ll""'j <br /> <br />8.16-96 4:48PM; 970 385 6539 -> <br />-> IOR..cAOS IDi '14 <br /> <br />303 866 4474; <br /> <br />#9/22 <br /> <br />SWQBINMED Summary <br />August 12, 1996 <br />Page 11 <br /> <br />La Plata River <br /> <br />Undllf PhaM I, Stage B water pumped from the Animas River at Durango to 1bc Ridies Basin <br />Reservoir will be pumped to the La Plat, River Basin prixnarily for irrigation putposes. Under <br />PM'll! II the Southern Ute Reservoir would be construC1!:d off-stream necr the ColoradolNew Mexicu <br />line to store water for mervation UK, This fiua1 phase of the Project will satisfy. portion of the <br />Colorado Ute Indian water right clllims 8B speci1ied in the 1988 Colorado Ute Indian Water Rights <br />Settlemeo.t Act, Effects on the La Plata River from the Project will be primarily from increa,ed <br />irrigation return flows and from reduced flows downstream from 1lu: Soutbc:m Ute Reservoir. <br /> <br />Under Phase II flows on the La Plata River dov.'IlSlream from the Southern Ute Diversion Dam <br />would be "substantially redueecl by the diversion of up to 375 efs of flow to the Southern Ute <br />~rvoir, An estimated 49 percent of spring meaa daily flow would be diverted under average <br />conditiolU, cl1lSing reductions in overbank flooding and related decreases in hydroperiods and <br />substrate moisture conditions." <br /> <br />j{ater Dullity Appendix <br /> <br />Tablll 10 (page B-23) This table lists the average: to1al values of those water quality samples <br />collected from the La Plata River along with the minimlurl, maximum, standard deviation end the <br />number of observations, The period oftime covered by these slImples is not indicated. All of'"e <br />1Il4ZXitlUllll \IIIlua fDr ItII!rcary fJl 'lie New Meldeo La PfJJtn RIHr SItIItmr., excttd tire New Mexico <br />chrordc wilier flUllity standtud fnr IDIIIl mqcury. All ,,"fln. ValllU for seirnium at tire New <br />Mexko 1.11 Pl/IIG River flfl.tlMIf VtJ:J!e4 tire chro"ic WlIUr 'l1l1ll1ty IlAHw4for total recoverable <br />selenlam, It is not possible from this table to determine the number of exce(',dances of the water <br />qua.lity stand;u:ds, Sampl.sllOlleo;\ed on September IS, 1994, were exclllCled from the statistics <br />b<<~,.. J'98\ll1s _rc high, These samples yielded levels of merclltY from 0.37 10 0.39 ~itL, 31 to <br />33 times the New Mexico chronic IWIdard. These samples )ieldt4levels of selenium ftom 216 to <br />236 !lillI, 10.8 to 11.8 times the New Mexico ~ standard. <br /> <br />Table I I (page B-24) 1bis table lists the maximum values, number of observations and the number <br />of samples above the detection limits for samples collected from the La PlaIa River for dissolved <br />trace elP.lIll!nts. The ma1Iimum dkc;olved vlllut5 at tbru oftbe stations (Allen Anoyo, Jacbon Lake <br />BI1d Farminaton) exceed the ohronic water quality standard for tolaI recov....u.le selenium, Tl is not <br />possible to determine how IlI8I1Y oithe individuai.mples I!l(ceed warer quality standards, It should <br />be kept in mind that the BOR's projecli.oll.5 indicate that significant m:w loads of selenium will be <br />diseharaed to this drainage if the project is implemented, hence the Dumber lIZId severity of standards <br />violatiOlU should be expected to increase. <br /> <br />Table 12 (pa&e B-25) This table lists the fral:tion of the La Plata Rh-er trace element values that are <br />in the dissolved state. For mercury thi~ Tlml!et from 93 to 100 percent. For selenium this ranaes <br /> <br />lilJn <br />