Stream sorting tool
A. Introduction
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The tool enables sorting of the perennial, trout-bearing streams based on 12 watershed features.
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Those features, or characteristics, are:
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Drainage area, sq mi
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Maximum elevation, ft (x 1,000)
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Stream length, mi
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Slope, mean, %
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Vegetation cover, %
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Precipitation, in, annual
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Flow, cfs, July, mean
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Flow, cfs, August, mean
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Flow, cfs, July-August, mean
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Flow, cfs, annual, mean
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Time of concentration (TOC), hr
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Outfall elevation, ft
B. Approach
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The sorting uses proportional scoring.
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That is, the highest value of a characteristic is given a score of 1.00 (or 100).
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A lower value is scored as a percentage of that highest value.
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For example, Stoner has the highest drainage area, 45.6 sq mi, and is scored 1.00 (or 100) in drainage area.
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Bear has a drainage area of 33.7 sq mi and is scored 0.74 (or 74) in drainage area.
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The scores for each characteristic are summed in a total for each stream, enabling comparison among the streams.
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Highest total scores of favorable characteristics logically would indicate the streams most resilient as trout habitat.
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They would be the streams more likely than others to maintain sufficient flow and habitat volume despite climate change.
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The information source for the characteristics is the U.S. Geological Survey online water-resources program StreamStats.
Protections | Priority | Comparison | Tool
C. Download
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The sorting tool is in the form of an Excel spreadsheet.
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Click here to download it.
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In example applications of the tool, Dolores streams are sorted by:
D. Application
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By default, all streams are included in a sort.
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To narrow the sort to selected streams, replace 1 with 0 in the column labeled Sort, in/out: 1/0.
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To narrow the sort to selected characteristics, replace 1 with 0 in the row labeled Weight.
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The maximum value for each characteristic is given in the row labeled Best and will need to pertain to the selection.
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That is, when a subset is made, inspect the values to ensure the maximums apply to that subset of streams.
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Replace with the correct value when necessary.
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For example, if Stoner is excluded in a sorting and Bear remains, the new Best drainage area is 33.7 sq mi, not 45.6 sq mi.
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So the value of 45.6 is replaced by 33.7 in Best in the Drainage area column.
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For each subset, inspect each column to ensure the applicable maximum value is entered in the row of Best values.
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The tool will automatically recalculate individual scores for the characteristics and total scores for the streams.
Protections | Priority | Comparison | Tool