7924

• UCREFRP Catalog Number: 7924
• Author: Loar, J. M. and M. J. Sale.
• Title: Analysis of Environmental Issues Related to Small-Scale Hydroelectric Development, V. Instream Flow Needs for Fishery Resources.
• USFW Year: 1981.
• USFW - Doc Type: TM-7861, ‎(contract no. W-7405-eng-26)‎,
• Copyright Material: NO

LIST OF FIGURES
10

W,

Figure Page
1-1 Variation in daily mean discharge from.a
TVA reservoir during a one-month period of
the flood season . . . . . . . . . . . . . . . . . . 12
1-2 Diagram of a generalized, small-scale hydro-
electric project showing the important
project characteristics . . . . . . . . . . . . . . 14
2-1 Example of instream flow requirements based
on flow duration data for two seasons with
different hydrologic patterns . . . . . . . . . . . . 23
2-2 Examples of habitat-discharge relationships
developed from U.S. Forest Service procedures . . . . 26
2-3 Example of variable weighting factors used
in calculating Weighted Usable Width . . . . . . . . 34
2-4 Example of preferred area calculations using
the Washington Method . . . . . . . . . . . . . . . . 37
2-5 Organization and information processing in
the Incremental Methodology for instream flow
assessment . . . . . . . . . . . . . . . . . . . . . 39
2-6 Subdivision of a stream reach into transects
and mapping cells for computational purposes
with the Incremental Methodology . . . . . . . . . . 42
2-7 Univariate suitability curves for rainbow
trout (Salmo gairdneri) . . . . . . . . . . . . . . . 44
2-8 Nomograph calculation of an instream flow
recommendation using habitat duration data and
assuming a decision criterion to retain the
80 percentile habitat condition . . . . . . . . . . . 46
3-1 Conceptual basis for instream flow assessment . . . . 51
3-2 Flow duration curves calculated on different
flow statistics for Cherry Creek near Hetch
Hetchy, California, 1941-1950 . . . . . . . . . . . . 66
xiii