WSP02129

• File Number: 8441.600
• Description: Colorado Big Thompson Project - Studies
• Basin: South Platte
• Water Division: 1
• Date: 5/1/1951
• Title: Recreational Use and Water Requirements of the Colorado River Fishery Below Granby Dam Colorado
• Water Supply Pro - Doc Type: Report/Study

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50. Habitat. Studies. The productivity of tIDY trout stream depends

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W upon both the amount, ~Ji.d quality of the aquatic habitat it provides. The
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...J amount of habitat is determined by the volume of stream flow in relation

to the topography and character of the stream bed. The quality depends
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upon the chemical content of the water, upon water temperatures, upon food

production, upon shelter available for fish, upon the interspersion of food

and shelter areas, and upon conditions favorable or unfavorable to reproduo-

tion. It is obvious tha.t not only the amount of he.bitat but many of its
quality factors are dependent upon the number of cubic feet per second of

11!at,er flowing in the stream..

51. Eight habitat study sections were established on the Colorado

River below Granby Dam, each of which was one~quarter of a mile in length.

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The location of these sections is shown on the aerial mosaics, Plates I and

II. The aquati,c habitat factors of each section 'Were studied in detail

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under, many different conditions of stream flow both in 1948Bnd 1949.

Va-riation in the stream flow volume under which studies

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were maderan~d
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of water and aii"
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from 8 to 650 cubic feet per second. Records were made

temperatures, water depths and velocities, chemical qualities, turbidity,

food organisms, and the area of various habitat types.

52. In order to compare the amount of aqu~rl:.ic habita.t which pr~-
vailed at various stages of stream now, each section was carefully mapped

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to show the normal bank lines and the water is edge.. The dry portion of the
stream bed was designated as "dry rock. n That portion which actuall.y:
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supplied the aquatic habitat waS further broken down to show the areas of
the following habitat types~ ltpools,1I tlriffles91t udeep-fast water," and
"slow-shallow water. It Maps were prepared to show the distribution and
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extent of the various types. A system of permanent control lines along
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