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<br />Stream Temperatures
<br />
<br />Pre$ently there is one steam~generating power plant in the Yampa River
<br />basin, The plant is located at Hayden, Colo., and produces about 150 MW (meg-
<br />awatts) of e1ec,trical power annually. Currently an expansion of this plant (a
<br />unit with a generating capacity of 250 MW) is under construction, A new plant
<br />at Craig, Colo" having two generator units of 380 MWeach, Is also under con-
<br />struction, The present plant at Hayden uses water from the Yampa River for
<br />cooling; this also will be the case for the plant under construction at Craig,
<br />
<br />Although the Hayden power plant has discharged cool ing waters to the Yam-
<br />pa River by way of a creek, starting in November 1975, a recycling evaporation-
<br />pond system was scheduled to be In operation, resulting in no thermal wastes
<br />discharging into the' Yampa River (Robert Heard" oral commun, , 1975),
<br />
<br />Existing environmental controls which forbId thermal discharges may be
<br />modified in the future. To help, assess the impact of possible thermal load-
<br />ings on the Yampa River, a procedure developed by Bauer, Jobson, and Jennings
<br />(1973) may be used. 'This procedure can pred'ict both the dispel's Ion and decay
<br />of a thermal waste. The model simulates water temperature' in excess of the
<br />normal water temperature without the thermal loading for a' specified number of
<br />reaches below the thermal-input source,
<br />
<br />
<br />After cal ibration and verification have been completed, the model can be
<br />used to project other thermal loading,s for an expanded Hayden plant or the
<br />thermal effects of the impending Craig plant, The results of this analysis
<br />wi'llbehypothetica.1 because of deficiencies in existing,pJant data to cali-
<br />brate the model.
<br />
<br />Trace Elements, and S,tream Biota
<br />
<br />Studies on tra'ce-element CO~ltent and, st,ream biota of the Yampa River, the
<br />Little, Snake Rive,r" and major tributaries will be continued, Results of the
<br />basJnwlde streamf1owrreconnaissance survey (Steele and others, 1976) aided in
<br />dectermining the' s,e:lectlon of stream sites for quarter:ly sampl ing over a 12-
<br />month per lod,
<br />
<br />C'oncentrations of selected trace, elements will b'e, date,rmined on fi I tered
<br />and, w,ho1e'wa:ter samples to asse$:s the d:istr:iblJtJon between,' d,i ssol ved and sus-
<br />pende:;;! phases. Tra'Ce el emen ts a1 so' wi I r be dete I'm ined on the less than 210-
<br />mJcrometre sl,ze, haction of stream,..bottrom sediments a.t s:itlls where sediment
<br />can' be Co.l1 ected,. De'ta ils of the, speeJ,fi c I abara tory analyses are. given in
<br />Stee:l'e, B'auer, Wen,U, and Warner (19-76),
<br />
<br />'periphyton anod'benthi,c Inve,rtebrates will b.e identIfied during summer
<br />low".flow condit:ioo'Sc at the quarterly samp,l!:ng sites. In a,dd'ltion, total num-
<br />bers::arrd total weightt of organisms: will, be measured, These studies wi 11 be
<br />coordinated with a.related project at Colorado State University (Elizabeth
<br />Ames, oral commun. ,1975) ,
<br />
<br />Periphyton Identification,. biomass, and chlo,rophyll content will be eval-
<br />uatedat a.11 sta-,tJans included, i,n the Dtl,..BOD,modeling effort. In addition,
<br />benthic, inve'rteb.ra,tes wi 11 be sampled: at these stations, This effort, which
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