Appendix B. DATABASE OF MEASURED FLOWS
The EXCEL spreadsheet “HydData.xls” contains measured values of hydraulic variables
for 931 within-bank flows in 171 natural-channel reaches. The data are taken from the
following sources:
Source
Barnes (1967)
Hicks and Mason (1991)
Coon (1998)
Jarrett (1985)
Number of Reaches
51
78
21
21
Number of Flows
62
559
236
74
The Barnes (1967), Coon (1998), and Jarrett (1985) data were measured by U.S.
Geological Survey (USGS) personnel using standard USGS protocols at reaches within
the conterminous United States; the Hicks and Mason (1991) data were measured by
personnel of the New Zealand Water Resources Survey, National Institute of Water and
Atmospheric Research (NIWAR), using standard NIWAR protocols at reaches on the
north and south islands of New Zealand. Most of the measurements were made at
established discharge-measurement reaches. A few of the flows measured by Barnes were
also included in the tabulations of Coon, but this duplication has been eliminated in the
spreadsheet.
The original sources should be consulted for detailed descriptions of and
additional information about the reaches, and the measurement methods and
precision.
The spreadsheet includes the following information:
Reach ID: Each measurement reach is identified by a letter corresponding to the source
(B = Barnes, H = Hicks and Mason, C = Coon, J = Jarrett) and a number corresponding to
the order in which the data occur in the original source; e.g., “C04” indicates the 4th reach
in Coon (1998).
Flow ID: Each flow is identified by a number from 1 to 931 corresponding to its order in
the spreadsheet listing.
Station ID: This number is the reach identification number in the original source. For the
U.S. data, this is the U.S. Geological Survey gaging-station identification number for the
measurement reach; however, note that the numbering system has changed since the
Barnes (1967) publication.
Reach: This is the reach name as given in the original sources
Discharge, Q: This is the measured discharge as given in the original sources in m3/s.
(The U.S. data have been converted from ft3/s.) Values are given to two decimal places;
however, measurement precision generally does not exceed three significant figures (see
Table A.4).
Surface Slope, SS: For the Hicks and Mason, Coon, and Jarrett data, this is the measured
water-surface slope as given in the original sources. For the Barnes data, this slope has
been calculated from the “Fall between sections” and “Length between sections”. Values
are given to five decimal places; however, measurement precision generally does not
exceed three significant figures, and some of the Jarrett data are reported to only one or
two significant figures.
Friction Slope, Sf: For the Hicks and Mason, Coon, and Jarrett data, this is the computed
friction slope as given in the original sources. (The Coon values are those reported as
“Energy Gradient”.) For the Barnes data, this slope has been calculated from the
Manning equation [Equation (6.40b)] as Sf = nM2∙U 2/R 4/3, where nM is the published
value of Manning’s resistance coefficient, U is reach-average velocity (m/s), and R is
reach-average hydraulic radius (m). Values are given to five decimal places; however,
measurement precision generally does not exceed three significant figures, and some of
the Jarrett data are reported to only one or two significant figures.
Area, A: This is the reach-averaged cross-sectional area of the flow as given in the
original sources in m2. (The U.S. data have been converted from ft2.) Values are given to
two decimal places; however, measurement precision generally does not exceed three
significant figures.
Hydraulic Radius, R: This is the reach-averaged hydraulic radius of the flow as given in
the original sources in m. (The U.S. data have been converted from ft.) Values are given
to two decimal places; however, measurement precision generally does not exceed three
significant figures.
Depth, Y: This is the reach-averaged flow depth in m. (The U.S. data have been
converted from ft.) These values are as given in the Barnes and Jarrett data; they are
computed as A/W for the Coons data. Average depth is not given in the Hicks and Mason
data, but may be approximated by assuming Y = R. Values are given to two decimal
places; however, measurement precision generally does not exceed three significant
figures.
Width, W: This is the reach-averaged water-surface width in m. (The U.S. data have
been converted from ft.) Width is not given in the Hicks and Mason data, but is estimated
here by assuming Y = R and computing W ≈ A/R . Values are given to two decimal
places; however, measurement precision generally does not exceed three significant
figures.
Velocity, U: This is the reach-averaged cross-sectional area of the flow as given in the
original sources in m/s. (The U.S. data have been converted from ft/s.) Values are given
to two decimal places; however, measurement precision generally does not exceed three
significant figures.
d50: This is the reach-averaged median bed-sediment diameter as given in the original
sources in mm. Although some of the values in the Hicks and Mason data are given to
one or two decimal places, all values here are rounded to the nearest mm. For sites where
no value is reported, additional information on the nature of bed and bank material may
be available in the original sources.
d84: This is the reach-averaged 84th-percentile bed-sediment diameter as given in the
original sources in mm. Although some of the values in the Hicks and Mason data are
given to one or two decimal places, all values here are rounded to the nearest mm. For
sites where no value is reported, additional information on the nature of bed and bank
material may be available in the original sources.
References
Barnes, H.H. (1967) Roughness characteristics of natural channels. Water-Supply Paper
1849, U.S. Geological Survey.
Coon, W.F. (1998) Estimation of roughness coefficients for natural stream channels with
vegetated banks. Water-Supply Paper 2441, U.S. Geological Survey.
Hicks, D.M., and P.D. Mason (1991) Roughness Characteristics of New Zealand Rivers.
Wellington, N.Z.: New Zealand National Institute of Water and Atmospheric
Research. (Also published by Water Resources Publications, Highlands Ranch,
CO, 1998).
Jarrett, R.B. (1985) Determination of roughness coefficients for streams in Colorado.
Water-Resources Investigations Report 85-4004, U.S. Geological Survey.