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<br />Purpose and Scope
<br />
<br />This report presents algal data collected by the
<br />USGS for the UCOL-NAWQA Program during water
<br />years 1996-97. Algal data include densities (abun-
<br />dance of cells per square centimeter of substrate) and
<br />biovolumes (cubic micrometers of cells per square
<br />centimeter of substrate) of RTH and DTH samples for
<br />15 sampling sites in the UCOL. Algal community data
<br />are presented in the appendixes of this report. Taxa
<br />and densities of RTH periphyton environmental
<br />samples are presented in Appendix A, and RTH peri-
<br />phyton replicate samples are presented in Appendix B.
<br />Taxa and densities of DTH periphyton environmental
<br />samples are presented in Appendix C. Algal commu-
<br />nity data and taxonomy used in this report are
<br />presented in alphabetical order and are taxonomically
<br />representative (spelling and taxonomic hierarchy) of
<br />data as provided by the Academy of Natural Sciences
<br />of Philadelphia (Frank Acker, Academy of Natural
<br />Sciences of Philadelphia, written commun., 2000).
<br />
<br />Description of Study Unit
<br />
<br />The drainage area of the UCOL study unit is
<br />about 17,800 mi2 with a varied climate, geology,
<br />topography, and hydrology. The primary river in the
<br />study unit, the Colorado River, originates in the moun-
<br />tains of central Colorado and flows about 230 mi
<br />southwest into Utah (fig. 1). Its headwaters and most
<br />of the tributaries originate in the mountains that form
<br />the eastern and southern boundaries of the study unit
<br />(Driver, 1994).
<br />
<br />The UCOL study unit is divided almost equally
<br />into two physiographic provinces: the Southern Rocky
<br />Mountains in the eastern, high-elevation part of the
<br />study unit, and the Colorado Plateaus in the western,
<br />low-elevation part of the study unit. Stream habitats
<br />range from cool, clear, and forested headwater streams
<br />that have crystalline bedrock, high gradients, and
<br />coarse substrates in the Southern Rocky Mountains to
<br />warm, sluggish, less vegetated, and saline streams that
<br />have low gradients and fine substrates in the Colorado
<br />Plateaus. Stream algal communities reflect the
<br />extreme differences in elevation, climate, vegetation,
<br />and geology across the study unit. A more detailed
<br />description of the two physiographic provinces and
<br />their environmental settings in the UCOL study unit is
<br />described in Apodaca and others (1996).
<br />
<br />The NAWQA study design includes fixed moni-
<br />toring sites, which are sites selected to represent
<br />water-quality conditions of streams within designated
<br />major land uses in the basin. Predominant land cover
<br />in the study unit is forest and rangeland. Major human
<br />land uses in the UCOL include agriculture, mining,
<br />urban, and mixed. Agricultural activities include the
<br />production of alfalfa, fruits, grains, hay, and vegeta-
<br />bles (Apodaca and others, 1996). Past and present
<br />mining activities have included the extraction of
<br />metals (copper, gold, lead, molybdenum, nickel, silver,
<br />vanadium, and zinc) and energy fuels (coal, gas, oil,
<br />and uranium). Urban land use represents one of the
<br />smaller land uses in the study unit, spatially. However,
<br />a number of urban areas and associated recreation
<br />activities are experiencing accelerated growth
<br />resulting from the expansion of the ski industry and
<br />from energy development in the 1980s. Mixed land
<br />use consists of a combination of major land uses (agri-
<br />culture, mining, and urban) where no particular land
<br />use dominates the basin.
<br />
<br />Acknowledgments
<br />
<br />The authors thank V. Cory Stephens for assis-
<br />tance in periphyton sampling, Stephen D. Porter
<br />and Cathy M. Tate for their critical review of the
<br />report, and C. Michelle Smith for compilation of data
<br />and appendixes for this report. Appreciation is
<br />extended to Carol A. Anderson for editorial review,
<br />Alene J. Brogan for manuscript and layout, and
<br />Sharon P. Clendening for graphic design.
<br />
<br />METHODS OF DATA COLLECTION
<br />
<br />Algae Sampling
<br />
<br />Algal samples were collected at the 15 sampling
<br />sites, once during low-flow conditions in August of
<br />1996 and then again in August 1997. The collection
<br />and field processing of algal samples followed estab-
<br />lished NAWQA protocols (Porter and others, 1993). A
<br />stream reach that consisted of at least two of each type
<br />of different geomorphic channel unit (riffles, runs, and
<br />pools) and was at least 492 ft (150 m) in length at
<br />wadeable sites and 2,461 ft (750 m) in length at
<br />nonwadeable sites was selected at each site (table 1).
<br />Quantitative periphyton samples were collected within
<br />RTH and DTH environments in the stream reach.
<br />
<br />2 Algal Data from Selected Sites in the Upper Colorado River Basin, Colorado, Water Years 1996-97
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