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-8- Attached algae was Ciadophdra sp, At no time did this algae form large fronds; growth was restricted to strands approximately 1 to 2 inches in length. Filamentous algae taken during the summer months was Spirogyra sp. The sampling site was a small riffle on the west side of the river. The site was apposite the north end of an island which split the river inta two channels. The bottom consisted of rock from 1 to 5 inches in diameter, A light covering of silt was present during the spring and early summer, but was usually gone by July. Diatom growth at this station was not heavy. Collections made with the diatometer showed a predominance of Nir.zschia followed by Tabellaria snd Cymbella. Gomphonema, Navicula and Cocconeis were also present, but in much reduced numbers. Zooplankton populations averaged 2.7 organisms per liter. The organisms were copepods and rotifers. The bottom fauna at this station was not too varied, Representatives from 8 orders were taken and are listed in Table V, page L9• The Ephemeroptera represented the majority of organisms in both numbers and bulk in most of the samples. Samples could have easily been biased at this station. The scattered areas where mosses and attached algae were present contained a considerably larger number of organisms. A square foot sample taken in one of these areas would have given the impression that the fauna populations were heavier than they actually were. Water chemistry data for all stations is presented in Table No. VI, on page 30. Coliform counts were quite low at this station. Of the three plate counts made in November, 1958, only three colonies developed, one per each plate. The area between Stations No. 1 and No. Z is composed of a sandy loam which is highly erosive. Run-off is high and precipitation in the area often causes the Green River to become murky f.or some distance downstream. The dominant plants in this area are: greasewood, Sarcobatus vermi- culatus; rabbitbrush, Chrysothamnus nauseosus; silver sage, Arteznisia frigidia; Aromatic sage, Artemisia dracunculoides; and the saltgrass, Distichlis stricta. Dominant streamside vegetation in this section is the andbar willow. Scattered clumps of narrowleaf cottonwood are found throughout the area.. Three streams enter the Green River between Stations No. 1 and No. 2, they are: Muddy Creek, Fontenelle Creek and Sheep Creek. Muddy Creek and Sheep Creek are intermittan.t and contribute little besides silt and dissolved solids during spring run-off. Fontenelle Creek has a sustained flow although irrigation withdrawals greatly reduce the volume of water in the lower reaches. The majority of water flow in the late summer is a result of return seepage. Stream temperatures range from 3~~ F. in the winter to the high 70's in late summer and early fall,