MEAN POROSITY, e

“or
35h

-30f

° 4a
= .176 + .028d,
225 r © a 3 Ig
(r° = .85)
yp a
-20F 7
a
/@
5 aN
© = 1854537
(r? = 193)
.10F
NOTE:
Data —_ taken from Table 2 and
based on Cooper(1965)
-05F
1 2 3 4 5 6 7

GEOMETRIC MEAN PARTICLE DIAMETER rdgs centimeters

Figure 4. Relationship between sediment porosity and

geometric mean sediment particle diameter.

13



REFERENCES

Bogardi, J. 1974. Sediment Transport in Alluvial Streams. Akademiai Kiato
Budapest. 826 pp.

Cooper, A. C. 1965. The effects of transported stream sediments on the sur-
vival of sockeye and pink salmon eggs and alevin. International Pacific
Salmon Fisheries Commission, New Westminster, B.C. Canada.

Corley, Donald R. 1975a. Stream inventory survey of Squaw Creek, Second Fork
and Third Fork. USDA For. Serv. Intermt. Reg., Boise Natl. For., Boise,
ID. 59 pp.

. 1975b. Stream inventory survey of streams in the Fall Creek and
rinity Creek drainages, 1975. USDA For. Serv. Intermt. Reg., Boise
Natl. For., Boise, ID. 53 pp.

- 1978. Fishery habitat survey of the South Fork Salmon River -
1977. USDA For. Serv., Intermt. Reg., Boise Natl. For., Boise, ID. 90
Pp.

Hall, J. D., and R. L. Lantz. 1969. Effects of logging on the habitat of
coho salmon and cutthroat trout in coastal streams. In Symposium on

salmon and trout in streams, T. G. Northcote, Ed., Univ. British
Columbia, Vancouver, B.C., pp. 355-375.

Innman, D. L. 1952. Measures for describing the size distribution of sedi-
ments. Journal of Sedimentary Petrology, 22(3): 125-145.

Iwamoto, R. N., E. 0. Salo, M. A. Madej and R. L. McComas. 1978. Sediment
and water quality: A review of the literature including a suggested ap-
proach for water quality criteria. EPA 910/9-78-048, 1978.

McNei], W. J. 1964. A method of measuring mortality of pink salmon eggs and
larvae. U.S. Fish and Wild). Serv. Fish. Bull. 63(3):575-588.

McNeil, William J., and W. H. Ahnell. 1964. Success of pink salmon spawning
relative to size of spawning bed materials. U.S. Fish and Wild]. Serv.,
Spec. Sci. Rep. Fish., 469, 15 p.

Ortmann, David W. 1968. Particle size of substrate materials in tributaries
and the South Fork Salmon River. Idaho Fish & Game Dep. Addendum to
F-49-R-5, Job. No. 1, Amendment No. 1, Boise, ID, 4p.

Orcutt, D. R., B. R. Pulliam and Arthur Arp. 1968. Characteristics of steel-
head trout redds in Idaho streams. Trans. Amer. Fish. Soc. 97(1):42-45.

31


Only summer chinook use the South Fork Salmon River for spawning; spring

chinook are the primary species using the Middle Fork drainage and the main
Salmon River.


Data obtained by Platts were presented for 3-in (76.2 mm) size particles
and less, i.e., that fraction of the sample passing the 3-in sieve. All
materials above 3 in were grouped into one size class. Corley's 1975 and 1977
data are analyzed only for sediment particles l-in (25.4 mm) and less. The
composition above 1 in and below 3 in was not sorted, except for 1976 data.

17


FOREWORD

Effective regulatory and enforcement actions by the Environmental Protec-
tion Agency would be virtually impossible without sound scientific data on
pollutants and their impact on environmental stability and human health. Re-
sponsibility for building this data base has been assigned to EPA's Office of
Research and Development and its 15 major field installations, one of which is
the Corvallis Environmental Research Laboratory (CERL).

The primary mission of the Corvallis Laboratory is research on the ef-
fects of environmental pollutants on terrestrial, freshwater, and marine
ecosystems; the behavior, effects and control of pollutants in lake and river
systems; and the development of predictive models on the movement of pollu-
tants in the biosphere.

This report addresses a non-point source pollution problem of special
regional interest to the Pacific Northwest. Salmon in this region spawn in
head waters subjected to intensive silvicultural activities. Sediment laden
runoffs from disrupted land surfaces could degrade the spawning habitat in the
adjacent stream. The identification and analysis of such habitats is a sub-
ject of this report.

James C. McCarty
Acting Director, CERL

ii


Continued attempts to characterize the strata of egg pockets resulted in
Table 9 which was obtained from the Poverty area in November 1978. The sample
was collected with a battery of freeze cores and an attempt was made to ex-
tract an entire redd egg pocket soon after spawning. The dry sample weight
was 620 kg and the geometric mean diameter of the redd was 23.3 mm. This is
somewhat large compared with similar measurements taken by other means both in
1978 and previously.

The difference is attributed to two important factors. The first is that
considerable coarsening of the gravel was accomplished by the fish during
spawning. The fish was observed digging deep, and covering the eggs with
relatively coarse substrate. The digging action released considerable fines
thus rendering the texture relatively coarse compared with the surrounding
gravel. The second explanation lies in the bias introduced in wet seiving of
the 1975 through 1978 gravel samples, even though they were obtaind with 12-in
core, which is probably an adequate sample size. In this process, the water
held within the space between small particles is artificially added to the
size fraction. The larger particles do not hold much excess water and thus
are relatively unaffected by wet seiving. The method is therefore unduly
biased toward smaller particles. An estimate was made of this bias on 1977
data in the Poverty area. The average of 40 samples gave d_ = 8.4 mm without
correction. With an approximate correction, d_ = 11.9 mm, GVie., a bias of 42
percent. g

Composition of the egg pocket in the vertical shows that the d_ for top
to 6 inches, for 6 to 12 inches and 12 to 18 inches are respectively%39.2 mm,
20.1 mm, and 35.2 mm.

TABLE 9. ANALYSIS OF A COMPLETE CHINOOK SALMON EGG POCKET
TAKEN IN POVERTY AREA DURING 1978 SPAWNING

Particle size (mm) Percent fines
203.2 100.0
152.4 98.9
127.0 93.4
101.6 82.2
76.2 62.4
50.8 50.6
25.4 37.4
12.5 25.4
6.3 18.48
4.75 14.98

84 2.78
246 0.48
074 0.08
074 0

28


MEAN PERMEABILITY, /3

NOTE:
Data —_ taken from Table 2 and
28h based on Cooper(1965) oO

2ar

&
8
T

s

cs

rn 1 n an
7

GEOMETRIC MEAN PARTICLE DIAMETER, dg» centimeters

Figure 5. Relationship between gravel permeability B, and
geometric mean sediment particle diameter.

14


02

TABLE 5. CHANNEL SUBSTRATE COMPOSITION BY DRAINAGE BY SEDIMENT PARTICLE SIZE IN SAMPLES TAKEN FROM CHINOOK SALMON SPAWNING AREAS.

Substrate Particle Size by Groups Representing Percent Volume Passing?
Through Sieve of the Designated Size (mm)

Sample

Drainage Size 76.1 50.8 38.1 25.4 19.0 12.7 9.51 6.35 4.76 2.83 2.28 2.00 1.00 .83 .42 .25  .21 -10 .07 .05
South Fork

Salmon R. 725 91 80 70 59 53 47 42 37 33 29 24 19 14° «210 6 3 1 0.8 0.2 0.2
Middle Fork

Salmon R. 60 7 88 79 66 56 45 40 (34)1 29° (26) (21) «18 =«(13)s 8 3° 0.8 (0.8) 0 0 QO
Main Salmon

River 30 2 75 67 57 4g ay 36 = (29) 24 «(21) (17) +13) (0) 6 2 0.7 (0.7) 0 0 0

1 values in parentheses are interpolated by graphing the particle size distribution curve and selecting the percent passing from
the intersection of the group size with the curve.


PROCEDURES

Three investigators determined the sediment composition of selected
spawning areas from 1966 to 1977 in the Salmon River drainage. They used at
least three different procedures in site selection, method of collection,
equipment and analysis. 1

The data collected by Ortmann (1968) for 1966 and Platts (1968, 1970 and
1972) for 1967-1974 were obtained using the McNeil method with 6-inch (153 mm)
diameter cores. The USDA Forest Service Materials Testing Laboratory, Salt
Lake City, Utah, heat-dried, screened, and weighed the selected particle size
groups of the samples collected by Platts. Platts collected cores along
permanent stratified random transects crossing spawning areas. Two samples
were taken, one each at 1/4 and 3/4 intervals across each transect. Occasion-
ally a third sample was taken mid-point on the transect.

Corley (1975a, 1975b and 1978) collected samples from 1975 through 1977
with a 12-inch (305 mm) core sampler. About 5 gallons (18.9 liters) of sedi-
ment was collected with each sample. The sediment samples of Ortman and
Corley were sieved wet and analyzed in the field using standard sorting
screens for sediment separation. Weights of the selected sediment size groups
were determined using the volumetric water displacement method suggested by
McNeil (1964).

Corley selected gravel areas from 25 x 25 foot (7.63 x 7.63 m) square
grids laid out within known spawning riffles. Ten core samples were selected
randomly within the designated 625 ft? (58.1 m*) square. Four riffles, all
located within the spawning area, were selected to represent the complete
spawning site.

Very fine particle sizes, on the order of .0025 in (63 microns) and less,
were analyzed by Corley using an Imhoff cone and by Platts using a hydrometer.
The mass fraction of these smal] particles per sample was much Jess than 1
percent.

The treatment of very large sediment particles was more difficult and
depended on the core diameters used. Frequently large particles were found
obstructing the 6-in (153 mm) core sampler, in which case they were added to
the sample. The use of a 12-in (305 mm) core sampler may present a smaller
sampling bias. Since the total volume from a 6-in core sampler is smaller
than that taken from a 12-in core sample, the presence of large particles in
the small sample could skew the distribution, biasing it toward coarse compo-
sition. This would cause larger fluctuations in the results. Also, in the
process of digging out the channel materials within the core sampler, fine
sediments are more readily collected than large size particles.

16


DISCUSSION

While there appears to be a slight difference in the procedures discussed
for obtaining samples and presenting data on the description and evaluation of
spawning habitat for salmonids, these are minor indeed, compared with our
inability to relate these procedures to the effects created by different types
of land use, an area of impact evaluation that begs for a better understand-
ing. That goal will be achieved by establishing more unified, scientifically
defensible procedures. The authors know of no place in Idaho, for example,
where the effects of a land use such as logging and road construction have
been accurately related to the reproductive success of a chinook salmon or
steelhead trout population. For proper land use and fishery planning and
management, this degree of predictability should be attained.

29


The positive relationship is unmistakable with these low velocities.
However, as velocities continue to increase above those reported here, there
would be a level where egg survival would start to decrease because of the
pressures or buffeting from surface flows. Cooper conducted numerous tests
with gravels of different compositions and showed that apparent velocity is a

function of gravel porosity and permeability for a given hydraulic head. That
is,

V= f(s, e, B).
where,

V = velocity

s = hydraulic head
e = porosity

B = permeability

Our analysis of Cooper's data demonstrates a strong correlation between
geometric mean diameter of the appropriate gravels used and their respective
measured porosity e and computed permeability B. These results are shown in
Table 2 and Figures 4 and 5. Accordingly, a single measure of gravel composi-

tion, d_, provides the link between apparent subsurface water velocity and egg
survivat.

Alternatively, "percent fines" also are related to porosity with reason-
ably high correlation, but a choice has to be made for a proper definition of
“percent fines". Table ES shows the comparison of porosity as a function of
d_, percent fines, and 5. The latter factor appears in the definition of
p@rmeability fB as reported by Cooper (1965). It is the sum of the fraction P
of particles by weight of diameter d divided by the diameter. The table was
prepared for correlation of e and B with d_, "percent fines", etc. {Linear
correlations were best suited for e but powet functions of the type Ax were
more appropriate for B. This table is not intended for use of these empirical
correlations. The degrees of fit also are not used here to show conclusively
which are the best parameters. We are dealing only with one set of data and
caution should be exercised in reading too much into the result. Table 3,
however, does serve one important function, i.e., to show that for this set of

data the geometric mean particle diameter competes in representativeness with
other measures.

There is also an excellent correlation betwean xf and B, since bea has
been used in the definition and calculation of B. 25 dos appear to be a very
good measure, even though it is less conventional and more difficult to calcu-
late than d.. There is, however, a strong correlation between 35 and d_.
Calculations“are not presented in the table, but the coefficient of Srepresefl-
tation r? of a power function of the type Ax was found to be 0.89.

The high correlation between "percent fines" for the 6.3 mm particle size
and less and B has a curious explanation associated with the specific nature
of gravel used in the work. For the 15 gravel compositions used, "percent
fines" below 6.3 mm averaged 15 percent. This is very closely related to dig
used in calculation of d- The rationale for the strong correlation becomes

11


STUDY AREA

The Salmon River drainage supports most of the chinook salmon that enter
Idaho to spawn. These waters are usually low in mineral content because of
the predominance of granitic bedrock. A major part of the Salmon River water-
shed is within the 16,000-square-mile (6,150 km?) Idaho Batholith, an area of
granitic bedrock much of which is characterized by steep slopes, erosion-prone
soils, and severe climatic stresses. Soil disturbances, such as those associ-
ated with logging and road construction, can accelerate soil erosion many
times over natural rates on such lands. Part of the Salmon River drainage
lies in the Belt Series which is not granitic, and other bedrock types such as
volcanics and sedimentaries occupy relatively small sections.

The Salmon River drainage (Figures 1 and 2) ranges from over 12,000 feet
(3600 m) above sea level in headwater areas to about 1500 feet (450 m) at its
confluence with the Snake River. Most of the spawning areas occur between
5000 and 7000 feet (1650-2100 m), which corresponds to some important sediment
dumps formed by glaciers during the Pleistocene epoch. These streams formed
themselves in these extensive Pleistocene glacial deposits. This sediment was
transplanted from higher elevations by glaciers and deposited in moraines and
outwash trains. Subsequently, stream channels have reworked this sediment and
evolved to their present morphology in quasi-~equilibrium with climatic change.
Part of the reason chinook salmon and steelhead trout (Salmo gairdneri
Richardson) spawn and rear on these glacial dumps is because of the abundant
supply of suitable sediment particle sizes at elevations creating cool water
temperatures.

The Boise River drainage (Figure 3) ranges from over 10,000 feet (2048 m)
to about 2600 feet (792 m) at its confluence with the Snake River. This river
also drains an area of granitic bedrock.

This study was mainly conducted in the Salmon River drainage including
its two major tributaries, the South Fork Salmon River and the Middle Fork
Salmon River. The South Fork drains a 1,270-square-mile (660 km?) watershed
representative of the forested mountainous terrain found in central Idaho.
The Middle Fork is a larger drainage that depends on its tributaries for the
spawning of chinook salmon and steelhead trout. The South Fork channel con-
tains the necessary sediment particle sizes required for spawning while the
Middle Fork channel does not. The stream power in the Middle Fork is too high
to allow sufficient quantities of gravel and fine sediment to remain in the
channel. Therefore, salmon move into the tributaries to find the size of
channel materials they need for spawning. In the South Fork there are channel
reaches with low enough stream power to allow accumulation and containment of
gravels and fine sediment. However, salmon use the tributaries in the South
Fork much less than in the Middle Fork. The main river has large channel
areas composed of gravel and fine sediments.

3


of particle size distribution, geometric mean diameters for trout areas could
not be calculated. However, to provide a comparison, the particle size dis-
tributions averaged for all chinook spawning areas vs. all samples collected
in trout channels used for rearing and possible spawning are presented in
Figure 8. The coarser substrate in resident trout channels is clearly shown.
Trout often spawn in small niches within the channel that frequently have
finer substrate than the overall riffle areas. Therefore, redds are usually
interspersed among areas of much coarser material. The sampling procedure
does not take this into account.

Table 8 shows the variation of geometric mean diameter for 1976 for
different spawning areas in the South Fork Salmon River. These areas are
arranged in order of increasing channel elevation, showing that fish have used
persistently coarser spawning gravel in the upstream direction, with d_ = .58
in (14.7 mm) in the upstream reaches compared with d_ = .35 in (8.8 mm)*in the
downstream reaches of the South Fork Salmon River. whether this is a reflec-
tion of availability or preference for certain sediments is not determined.

An attempt was made to obtain measurements within egg pockets in the
Poverty area. Fifteen freeze core samples were collected during the 1977
spawning period. The freeze core rods were driven to a depth of 18 inches in
the substrate. Results were analyzed separately for each core sample and in
combination. The geometric mean diameter for the combined 15 core samples was
18.4 mm. The geometric mean diameter for top to 6 inches, 6 to 12 inches, and
12 to 18 inches were respectively 20.3 mm, 22.4 mm, 6.5 mm. Unfortunately,
the individual analysis of separate core samples revealed unusual scatter.
For example, the average d_ for the 15 samples was 34.6 mm with a standard
deviation of 20.6 mm from thiS mean.

TABLE 8. VARIATION OF GEOMETRIC MEAN DIAMETER OF SPAWNING
SEDIMENTS IN SAMPLES COLLECTED FROM CHANNEL REACHES
IN THE SOUTH FORK SALMON RIVER IN 1976

Site dg(mm)

Downstream reaches:

Glory Hole 9.6
Oxbow Area 8.5 Average = 8.8
Poverty Flat Area 8.4
Upstream reaches:
Dollar Creek Area 13.5 =
Stolle Meadow Area 15.8 Average = 47

26


€@

PERCENT SEDIMENT PASSING SIEVE OF
DESIGNATED SIZE

100,

or

70-

South Fork Salmon River.
50r

2or

10F

100.

SIEVE SIZE, millimeters

Figure 7. Particle size distributions for chinook salmon spawning areas.


CONTENTS

Page
Abstract 2. 1. ee iv
Introduction. ©... ee ee 1
Study Areas 2 2 ee eee 3
Methods for Describing Spawning Sediments ...........e0005 8
Procedures. 2. 2... ee 16
Results and Conclusions .. 1... . ee ee es 18
References. 2 2... ee 30


ABSTRACT

The size composition of substrates used by chinook salmon for spawning in
the South Fork Salmon River, the main Salmon River and tributaries of the
Middle Fork Salmon River, Idaho, was determined. Substrates used by resident
trout were analyzed for streams in the Boise and Payette River drainages.
These analyses were made over time to determine particle sizes preferred by
spawning salmon, yearly differences in sizes used by these salmon, the size
differences used by spring and summer chinook salmon, and differences between
channel sediments used by chinook salmon for spawning and those substrates
occupied by trout.

The use of the geometric mean particle diameter method is presented as a
companion measurement to "percent fines" for a more complete analysis of
sediments used for spawning. The geometric mean particle diameter is more
adaptive to statistical analysis than the more common method of using “percent
fines." The geometric mean diameter of the sediment particle size distribu-
tion is used for analyzing channel sediments. The relationship between the
geometric mean particle diameter and "percent fines," substrate permeability,
and substrate porosity is established. The strongest correlation between the
two methods of analysis, "percent fines" and geometric mean diameter, was for
fine sediments below 0.88 in (2 mm) in particle size. :

Chinook salmon selected sediments for spawning that were mainly between
28 and .79 in (7.0 to 20 mm) in geometric mean particle diameter, regardless
of stream selected. This is a narrow range considering that the mean particle
diameters for streambed sediments available for chinook salmon to spawn in
vary from less than 0.02 in (.5 mm) to wel] over 3.94 in (100 mm). The compo=
sition of spawning sediments selected by chinook salmon each year between 1966
and 1976 were quite uniform. Sediments used for spawning in the South Fork
Salmon River decreased in particle size in a downstream direction. Geometric
mean diameters 35 miles below the headwaters averaged .35 in (8.8 mm); parti-
cles 10 miles below the headwaters averaged .58 in (14.7 mm).

iv


ral

TABLE 2. POROSITY AND PERMEABILITY OF SPAWNING GRAVEL AND ITS RELATION TO GRAVEL COMPOSITION?

% Finer than Porosity, e Permeability, B Gravel Sample!
P
dg 2G -83 6.3 Loose Compact Mean Loose Compact Mean ID Symbol
(cm) (cm 2) (mm) (mn) bed bed e bed bed B used in
Figures
4 and 5
1.61 2.66 2.0 19.4 0.278 0.200 0.244 0.025 0.015 0.020 1
1.73 1.88 3.5 20.9 0.298 0.232 0.265 0.037 0.025 0.031 2 @
3.24 3.84 7.9 27.6 0.233 0.117 0.172 0.013 0.005 0,009 3
3.35 0.77 1.0 9.2 0.305 0.254 0.280 0.093 0.069 0.081 4
6.90 0.41 0.4 4.4 0.412 0.382 0.397 0.283 0.238 0.261 5
1.60 4.35 6.7 25.9 0.235 0.186 0.211 0.012 0.008 0.010 A
2.09 3.93 5.2 18.8 0.269 0.235 0.252 0.015 0.012 0.014 B A
2.97 1.54 3.5 12.6 0.295 0.248 0.272 0.045 0.089 0.067 Cc
4.60 0.58 1.7 7.4 0.316 0.283 0.300 0.130 0.106 0.118 3)
6.26 0.40 0.2 4.9 0.371 0.334 0.353 0.238 0.193 0.216 E
6.57 0.40 0.2 5.0 0.327 0.200 14
4.13 1.12 2.4 9.0 0.278 0.053 15 io}
3.12 1.93 4.0 12.5 0.240 0.027 16
2.12 3.07 5.2 17.5 0.217 0.014 W7
1.30 4.67 6.7 27.5 0.206 0.009 18

based on data from Cooper (1965); ID column allows data in this table to be related to that of Cooper.


ual spawning areas. Although there may be some minor changes in riffle loca-
tion from year to year they are usually slight enough to cause no problems to
salmon homing. Thus, each year salmon usually seek a predetermined area for
deposition of their eggs. Salmon usually select areas where the hydraulic
controls on the stream channel provide a substrate almost devoid of boulders
because fish can't move them, low in fine sediments because of the need for
subsurface water permeability, and high in gravel and small rubble which they
can form into a cover that protects the eggs and alevins. This particle size
distribution provides an egg cover that will withstand most of the velocities
the stream exerts without sediment movement damaging the embryos. It is
interesting that the fish do not choose channel substrates completely devoid
of fine sediments, even though such areas exist. Thus, it is possible that
fine sediments in the correct amounts can be important to embryo survival.
Possibly, and this is based only on intuitive thinking, proper amounts of fine
sediments could protect the eggs from predators, keep organic materials in the
stream flow from settling on the eggs, keep eggs from being buffeted by high
sub-surface flows, and help keep eggs and alevins in the substrate during
floods until time for their emergence.

A confounding factor to us in determining why salmon choose a certain
spawning area is that the quality of the surrounding rearing environment that
guarantees survival of their young must also be a major factor in spawning
site selection. We believe salmon select spawning sites by ocular selection
of desirable sediment size classes, a feel for the required surface water
velocities to drive the needed subsurface flows for the embryos and alevins,
and a strong homing instinct that places them in an area in which their young
have a good chance to survive.

Although salmonids have survived sedimentation from the watershed over
the past million years, the literature indicates that their ability to cope
with sudden increases in channel sedimentation may not be very good. Thus
certain questions relating to watershed management need better answers: Have
stream channel sediment size classes changed because of man's influences? Has
there been a resulting change in the spawning success of salmonids? Can
salmonids adjust to changes in the quality of channel sediments over time?
Have fish evolved to survive only within narrow ranges of channel sedimenta-
tion or can they survive under wide variations? Do we know what channel
sediment particle sizes and particle size composition fish need for good
health and survival? If so, how closely do we need to be able to measure this
composition for optimum fisheries management?

This report contributes some answers for these questions by describing
channel sediment particle size mixtures chinook salmon (Oncorhynchus
tshawytscha Walbaum) use for spawning over broad streambed areas. Methods for
the analysis and evaluation of those sediments selected are discussed.


RESULTS AND CONCLUSIONS

Data describing the particle size distributions for various spawning
areas are summarized in Tables 4-7. Because of the differences in screen size
selection by the different authors, the tables do not show directly-measured
data for all sieve sizes. Instead, interpolated values (shown within paren-
theses) are inserted for convenience. The interpolations were made by graph-
ing the particle size frequency distribution curve for each sample and taking
the interpolated number from its respective place on the curve.

The substrate compositions of chinook spawning areas located in the South
Fork Salmon River, Middle Fork Salmon River tributaries, and the Salmon River
and one of its tributaries are shown in Tables 4 and 5. Each spawning area
listed represents from 5 to 130 core samples collected from that site. In
addition, averages for all chinook spawning areas located within each of the
three river drainages are presented, and, finally, a grand average for all
chinook salmon spawning areas is given. The preference for the sediment
composition chosen by spawning salmon is reflected by the d_ averages of .28
to .79 in (7 to 20 mm), depending on the river reaches samfled. The narrow
range salmon find acceptable for spawning becomes apparent when the average
sediment particle size found in spawning areas is compared with other channel
reaches of similar size they could have selected for spawning, e.g., they
could have selected fine sand with d_ less than 0.04 in (1 mm) or areas of
predominant rubble with d, greater than%.99 in (100 mm).

Orcutt et al. (1968) listed the preferred substrate size used by spawning
steelhead trout in Idaho as between .25 in (6.7 mm) and 4.0 in (101.6 mm).

Based on the 815 samples taken from the 12 most important salmon spawning
areas in Idaho, channels used for spawning averaged only 8 percent fine sedi-
ments below .03 in (.83 mm) in particle size. However, these areas averaged
30 percent in sediment particle size less than .19 in (4.7 mm). This indi-
cates that entrapment of alevins by fine sediments may be more of a problem in
the Salmon River drainage than embryo or alevin mortality caused by low dis-
solved oxygen in the subsurface flows. About 93 percent of the sediments are
less than 3 in (76.1 mm) in particle diameter, which shows salmon are not
looking for large sediments for spawning. Actually, the majority of the
sediments they are using are less than .75 in (19 mm) in particle size.

There are differences in sediment sizes used for spawning between streams
or areas within streams, but these are not major differences. The change in
procedures from year to year and person to person may have some effect on
these differences.

In comparing particle sizes used by salmon between the three major drain-
ages, the differences were again not substantial. There was a difference of 4

18


United States Environmental Research EPA-600/ 3-79-043
rt

Environmental Protection Laboratory April 1979
Agency Corvallis OR 97330

Research and Development

SEPA Sediment Particle
Sizes Used by
Salmon for
Spawning with
Methods for
Evaluation



almon River

Secesh
River

South)Fork

Loon Creek

Glory

E. Fork South Fork

Salmon River

Oxbow

Middle Fork
Salmon River
Poverty

Johnson Creek

Dollar 1k Creek

S Marsh Creek

Stolle
Bear Valley
Meadows Creek
South} Fork

Salmon’ River

Study Area

*& Boise

Figure 2. Streams studied in the Salmon River drainage.

5


¢ Obsidian

Decker Creek
Salmon River

Pettit Lake

Alturas Lake ,
Creek

B study Area Perkins Lake

Reise

Alturas Lake

Miles

Figure 1. Study sites in the headwaters area of the Salmon River.

4


se

TABLE 7. CHANNEL SUBSTRATE COMPOSITION BY YEARLY AVERAGES BY SEDIMENT PARTICLE SIZE CLASS IN SAMPLES TAKEN FROM TROUT SPAWNING AND REARING AREAS.

Substrate Particle Size by Groups Representing Percent Volume Passing? Through
Sieve of the Designated Size (mm)

Drainage Sample

Stream Size Year 76.1 50.8 38.1 25.4 19.0 12.7 9.51 6.35 4.76 2.83 2.38 2.00 1.00 .83 .42 .25 .21 .10 .07 .05
South Fork Boise River 70 1975 44 (39) (35) (31) 27 24 (20) (17) (13) (10) 6 (5) (3) 1 40) Q) 1

Fall Creek 10 (1975 40 (37) (34) (31) 28 26 (22) (19) (15) (12) 8 (7) G) 3 (3) @) 2
E.F. Fall Creek 5 1975 32 (28) (24) (20) 16 14 (12) (10) (8) (6) 3 (2) GQ) 0
W.F. Fall Creek 5 1975 50 (47) (43) (40) 36 33° (28) (23) (18) (13) 8 (7) (5) 3) (3) (2) 2
Bear Hole Creek 1S 1975 58 (53) (47) (41) 35 32 (27) (23) (18) (14) 9 (7) (5) 3 (3) (2) 2
Trinity Creek 15 1975 35 (30) (26) (22) 18 1 6(13) (11) (8) (5) 2 (2) Q) 0
Spring Creek 5 1975 55 (49) (44) (39) 34 30 (25) (20) (15) (10) 5 (4) (3) 2 (2) G@) 1
See reek 5 1975 37 (33) (29) (25) 21 19 (15) (12) (9) (6) 3 G3) (2) 1 @) (@) oO
Steel Creek 10 1975 36 (33) (29) (25) 21 18 (15) (12) (9) (6) 4 (3) (2) 1 G) @) 90

North Fork Boise River

N.F. Boise River 45 1976 81 (72) (63) 54 (48) 43 (37) 32 29° (24) «19 (15) (11) 7 (5) (3) 1 ) (0) 0

Payette River 40 1974 60 (53) (46) (40) (33) 27 (25) (22) 19 (18) (17) 16 (14) (12) (9) (7) (4) (2)
Squaw Creek 15 1974 54 (47) (40) (34) (27) 21 (19) (16) 13° (11) (10) 8 (6) (5) (4) (3) (2) ()

Second Fk. Creek 10 1974 59 (51) (43) (36) (28) 21 (19) (17) 15 (13) (12) 10 (9) (7) «(6) (4) (3) G)
Third Fk. Creek 15 1974 66 (60) (54) (48) (42) 36 (34) (31) 28 (26) (24) 22 (18) (15) (12) (9) (6) (3)

ooo oO

Combined Average by Stream 65 (58) (50) 43 (38) 33 (29) 25 23° (19) (16 13 10 6 (5) (4) 2 (2) 0.6 0.6
Total Sample Size 155

1 Values in parentheses are interpolated by graphing the particle size distribution curve and selecting the percent passing from the intersection
of the group size with the curve.


It is difficult to provide a systematic comparison showing substrate
composition differences between the streams, spawning areas and stream reaches
sampled. The main difficulty arises because of the change in procedures and
equipment from year to year and person to person. Therefore, some of the
variability and differences indicated by the data might be procedural in
nature and not a reflection of the true situation. Taking into consideration
this problem, an attempt is made to compare these variabilities. Thus, the
data sets are selected to avoid some of the more obvious problems.

A detailed look at a single spawning area (Poverty area) on the South
Fork Salmon River is given in Table 6. Four sites were sampled and five
samples were taken at each site. The geometric mean particle diameter and to
some extent "percent fines" within each site as well as between sites varies
by a two-fold magnitude. Thus, there is some variability between each site
within the spawning area. This was expected as the upper end of the Poverty
spawning area is composed mainly of rubble with gravel in the downstream
direction to gravel mixed with fine sediments at the lower end of the spawning
area.

TABLE 6. VARIATION OF GEOMETRIC MEAN PARTICLE DIAMETER OF SPAWNING SEDIMENTS
IN THE POVERTY AREA AMONG SAMPLES COLLECTED IN 1976.

Percent fines d_ mm
<6.3 mm 9
Site Point Average Average
1 1 6.7 8.5
2 7.7 1.7
3 6.7 7.8
4 8.3 8.5
5 9.0 6.9
7.7 8.4
2 All points 10.6 6.4
3 " 8.3 8.1
4 " 10.8 12.0
9.4 8.4

Particle: size distributions for sediment collected from areas used by
trout spawning and rearing are listed in Table 7. These sample areas were
distributed over a much larger portion of the stream channel than were the
samples collected in the salmon spawning areas discussed earlier. Each hori-
zontal line in Table 7 represents the average for several individual samples
taken from each stream. Overall averages for tributaries within the three
major rivers and a grand average for all three areas are presented. Because
of the lack of the upper portion (i.e., particles larger than 1 in (25.4 mm))

24


INTRODUCTION

Most stream fishes require channel sediments having a variety of particle
size mixes for survival. This is especially true for salmonids which deposit
their eggs in sediments of a particular size class. However, studies have
demonstrated that the redd sediments must be of the proper particle size class
and composition for high embryo survival. Large increases in fine sediment
loads into stream channels can create intolerable channel modifications in
salmonid spawning areas (Platts and Megahan 1975). Hall and Lantz (1969), in
their Alsea, Oregon logging studies, found that an increase of 5 percent in
fine sediment smaller than 0.033 in (.83 mm) in diameter in redds decreased
survival of emergent coho salmon fry (Oncorhynchus kisutch Walbaum). Other
authors have demonstrated that fine sediment particles deposited in the
streambed reduce permeability and thus cause higher egg-to-fry mortality
(McNeil and Ahnell 1964). The literature supports the statement that fine
sediments can limit fish productivity. However, there is a dearth of litera-
ture identifying and evaluating the effect of different mixtures of sediment
sizes on fish health and survival in the actual stream environment.

During their evolutionary period salmon and trout adapted to the natural
channel sediments. Salmonids need sediment for spawning, rearing their young,
and providing for their food. However, the mix of sediment particle sizes for
optimum fish productivity is not clear. Probably no single particle size
group (i.e., boulder, rubble, gravel or fine sediment) will create the type of
environment salmonids require for growth and survival. More likely, a complex
mixture of sediment sizes is needed in combination with certain hydraulic
conditions to provide the ideal channel environment.

Since streams offer a wide variety of sediment sizes, salmon entering
virtually any river area can select any particle size for spawning. Stream
channel substrates are available from 100 percent fine sediments to channels
that are all boulder or rubble. The fish seldom find channels composed en-
tirely of gravel because gravels are usually mixed with fine sediment and
smal] rubble. However, some hydraulic environments such as heads of riffles
may sort out most of the fine sediments. Throughout their evolution, it is
probable that those salmon that spawned in fine sediments, rubble or boulders
failed to survive as well as salmon that spawned in predominantly gravel.
Somewhere between the extremes of fine sediment and rubble is the optimum
composition composed mainly of gravel mixed with smaller amounts of fine
sediment and small rubble.

Most salmon become riffle spawners because embryo survival requires
specific conditions such as water velocities, water depths, sufficient dis-
solved oxygen and embryo metabolic waste removal. The hydraulic conditions
that build and maintain these spawning riffles are widespread and persistent
enough so that through time and over space, salmon were able to develop habit-

1


obvious if we recall] the definition of dyg, i.e., the size below which 16
percent of the gravel is finer. Naturally we should not always expect that
6.3 mm and dig coincide as it did in this case.

TABLE 3. COEFFICIENT OF DETERMINATION BETWEEN PERMEABILITY AND POROSITY AND
INDICES OF GRAVEL COMPOSITION dy, ba AND PERCENT FINES USING
LINEAR AND POWER FITTING FUNCTIONS

P

Sediment d G Percent fines less than
property 9 83 mm 6.3 mm
Porosity, e .85 7 -79 -77
Permeability, B -90 .97 82 +93

In summary, the geometric mean diameter is recommended as a standard

measure for substrate characterization in fisheries work for the following
reasons:

(1) d, is a conventional statistical measure being used by several
d¥sciplines to represent sediment composition.

(2) d, is a convenient standard measure that enables comparison of
s@diment sample results between two studies.

(3) d, is calculated fron dgq and dig, two parameters that can be used
+8 calculate the standard deviation.

(4) d, relates to the permeability and porosity of channel sediments and
9 embryo survival, at least as well as "percent fines".

(5) dis a more complete description of total sediment composition than

"Bercent fines" and sediment composition evaluations in many cases

involve less sampling error using qd:

(6) Because d_ relates to porosity and permeability, it is potentially a

suitable Suni fying measure of channel substrate condition as it
impacts embryo survival.

15


TECHNICAL REPORT DATA .
(Please read Instructions on the reverse before completing)

1, REPORT NO. 2. 3, RECIPIENT’S ACCESSION NO.
EPA-600/3-79-043
4, TITLE AND SUBTITLE 5. ford] oF
pril 1979
Sediment Particle Sizes Used by Salmon for
Spawning with Methods for Evatuation 6. PERFORMING ORGANIZATION CODE
7, AUTHOR(S) 18, PERFORMING ORGANIZATION REPORT NO.

William S. Platts, Mostafa A. Shirazi and
Donald H. Lewis

ig. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
Env.Res.Lab.-Corvallis and Intmtn For. and Range ExSta
lOff.of Res. and Dev. Forest Service TT, CONTRACT/GRANT NO.
Envirn. Prot. Agency U.S. Dept of Agriculture
Corvallis, OR 97330 Ogden, Utah 84401
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
Environmental Research Laboratory--Corvallis inhouse
14, SPONSORING AGENCY CODE

Office of Research and Development
Environmental Protection Agency

Corvallis, Oregon 97330 EPA/600/02 _

75. SUPPLEMENTARY NOTES

Contact: Mostafa A. Shirazi, Corvallis, OR 97330 503-757-4751 (FTS 420-4751)
" fze' Composition of substrates used by chinook salmon for spawning in the South Fork
Salmon River, the main Salmon River and tributaries of the Middle Fork Salmon River, ID
was determined. Substrates used by resident trout were analyzed for streams in the Bois®
and Payette River drainages. These analyses were made over time and space to determine
particle sizes preferred by spawning salmon, yearly differences in sizes used by these
salmon, the size differences used by spring and summer chinook salmon, and differences
between channel sediments used by chinook salmon for spawning and those substrates
occupied by trout. Use of the geometric mean particle diameter method is presented as a
companion measurement to "percent fines" for an easier and more complete analysis of
sediments used for spawning. The geometric mean particle diameter is more adaptive to
statistical analysis than the more common method of using "percent fines." The geometri
mean diameter of the sediment particle size distribution is used for analyzing channel
sediments and its relationship to “percent fines," substrate permeability, and substrate
porosity is established. For sediments used by spawning salmon, the strongest correla-
tion between the two methods of analysis, "percent fines" and geometric mean diameter,
was for fine sediments below 0.08 in (2mm) in particle size. Chinook salmon selected
sediments for spawning that were mainly between .28 and .79 in (.7 to 20 mm) in geome-
tric mean particle diameter, regardless of stream selected. The composition of spawn-
ing sediments selected by chinook salmon each year between 1966-76 were quite uniform.

17. KEY WORDS AND DOCUMENT ANALYSIS
la. DESCRIPTORS Ib, IOENTIFIERS/OPEN ENDED TERMS |c. COSATI Field/Group
substrate sediment particle sizes
sediments
salmon
spawning

gravelbed stream

78. DISTRIBUTION STATEMENT 19, SECURITY CLASS (This Report) 21. NO, OF PAGES
‘ unclassified
Release to public 20. SECURITY CLASS (This page) 22. PRICE
unclassified

EPA Form 2220-1 (Rev. 4-77)

33


percent at .03 in (.83 mm) and less in particle size, 9 percent at the .19 in
(4.7 mm) particle size, and 6 percent at the 3 in (76.1 mm) particle size.
Salmon are not searching out major differences in sediment particle sizes for
spawning regardless of the drainage, stream or stream area. However, studies
have shown that an increase from 5 percent to 15 percent in fine sediments
less than .03 in (.83 mm) in particle size can result in a change from low
mortality to high mortality. Therefore, salmon have to search out sediments
within narrow particle size distribution limits because the survival require-
ments of the embryo and alevin are so demanding.

In an attempt to find a best correlation between various definitions of
"percent fines" and geometric mean diameter for chinook spawning substrate in
the Salmon River, a power curve fitting procedure of the form

(percent < d) = ad)?

was used, where d is the appropriate particle diameter below which the mass
fraction percentile is finer, and A and b are constants. This formula was

repeatedly applied to the core data and the coefficient of determination, r?
was calculated.

"Percent fines" less than .08 in (2 mm) provides the best fit (Figure 6).
Possibly this is because .08 in (2 mm) coincides with the mean of the 16

percentiles of the entire data sample for the spawning substrate in the Salmon
River drainage.

The curves in Figure 6 might be used as a summary and as rough estimates
of "percent fines" in spawning areas in the Salmon River drainage. The figure
provides a good illustration of the value of d_ in synthesizing apparently
unrelated results. A vertical line drawn throug ad_ of .24 in (6 mm), for
example, shows that this d_ is equivalent to each of~the following "percent
fines" specifications: 22 ‘percent less than .04 in (1 mm), 26 percent less
than .08 in (2 mm), 31 percent less than .09 in (2.38 mm), 36 percent less
than .1] in (2.83 mm), and 39 percent less than .19 in (4.76 mm). It should
be emphasized, however, that use of Figure 6 is restricted to obtaining an
estimate of fine sediments for this specific data set. Figure 6 should not be
used to determine a general relationship for other spawning substrates.

The average substrate composition for spawning areas located in each of
the three drainages listed in Table 4 is plotted using semi-log axes in Figure
7. The consistently coarser structure of substrates used by spawning salmon
in the Salmon River and its tributary, Alturas Creek, relative to those areas
used in its two major tributaries, the Middle Fork Salmon River and the South
Fork Salmon River, is clearly shown, The upper Salmon River as well as the
Middle Fork Salmon River are used mainly by spring chinook salmon. There is
some indication that spring chinook salmon spawning areas in Idaho consist of
a coarser substrate. However, the data alone cannot be used to substantiate
this because the South Fork Salmon River (used by summer chinook) may stil] be
affected by past logging operations.


DISCLAIMER

This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.

ii


METHODS FOR DESCRIBING SPAWNING SEDIMENTS

Sediments with different particle size compositions can be compared using
the respective particle size-cumulative distribution curves. Data for these
curves can be obtained through standard particle size analysis with percent of
sediment by weight that is finer or coarser than a given sieve size plotted
against that opening size. The use of logarithmic abscissa is desirable
because natural sediments have an extremely wide range of grain sizes spread-
ing over three or more cycles (i.e., factors of 10). Furthermore, natural
sediments frequently exhibit lognormal distributions, i.e., when the logarithm
of the particle size (instead of the particle size itself) is used, the dis-
tribution is nearly normal. Such nearly lognormal distributions show more
symmetrical patterns on semi-log papers and their cumulative distributions are
close to straight lines on log probability papers.

Following a conventional statistical approach, it is possible to compare
two different sediment samples by some representation of the particle size-
cumulative distribution curves in place of the entire curves. For example, if
the curves were truly lognormal, the means and variances of the cumulative
distributions could be the only information needed to define the curve. If
the curves are skewed, additional information is required to show. the skewed
effects. The use of mean and variance simplify the comparison considerably,
even when the distributions are not truly lognormal.

Numerical integration procedures for calculation of the mean, variance or
skewness are available and can be applied to the data once the particle size
cumulative distribution is known. Because this is tedious, graphical ap-
proaches are better suited for estimating such standard parameters as the mean
and variance. For example, the median particle size, dso, is picked up from
the graph of the cumulative distribution curve directly to represent the
particle diameter for which 50 percent dry weight of the sediment is coarser
or finer. If the distribution is lognormal, this jis exactly equal to the
geometric mean of the distribution. For normal distributions, one standard
deviation on either side of the mean diameter is approximately dyg and dg,
respectively, and the 2.5 and 97.5 percentiles are two standard deviations on
either side of the mean. Once the cumulative distribution curve of a sediment
composition is plotted, al] such parameters can be directly picked up from the
curves with no further calculation.

When the distribution is not symmetrical or lognormal, Innman (1952)
following the classic work of Otto, recommended using the geometric mean of
the particle diameters corresponding to the 16th and 84th percentiles (i.e.,
dig and dgg). This has now become a standard procedure (Vanoni 1977). That
is, the geometric mean diameter obtained from dig and dg, is used even if the
distribution deviates from lognormal. The geometric mean diameter, d, is
obtained from dig and dg4 as follows: g


For example, the channel .substrate in the Dollar and Poverty spawning
areas on the South Fork Salmon River contains 5 and 14 percent, respectively,
“percent fines" less than .03 in (.83 mm). Therefore, because of smaller
"percent fines" in the Dollar area, the sampling error associated with its
determination is expected to be greater than for the Poverty area. To attain
comparable accuracies while using the same sampling procedures in the two
areas, "percent fines" in the Dollar area must be based on .08 in (2 mm)
particles where 14% of the substrate is finer. This presents an intolerable
paradox; how do we know in advance what basis (i.e., particle diameter) for
percent fines to choose? Measures based on geometric mean avoid this particu-
lar difficulty because the independent variable, i.e., the particle size, is
not predetermined and it may vary, as it actually would from one sediment
sample to another. Also, if it is desirable to determine the smaller particle
sizes, thereby placing more emphasis on the amount of fines, then such quanti-
ties as dig, ds, dg,5 etc., are more suitable than "percent fines". These d
levels can then be used to determine degree and causes of mortality in embryos
and alevins.

The intuitive appeal of "percent fines" in fisheries studies stems from
its long association with impacts on egg survival (Iwamoto et al. 1978). As
stated earlier, it has been verified that intergravel flow of water and oxygen
is strongly related to percent fines and thus to spawning success. This is a
very important and legitimate argument. Our studies show that as a measure of
intergravel flow, the geometric mean is at least as good a measure as "percent
fines".

Cooper (1965), presents data relating survival of eyed sockeye salmon
(Oncorhynchus nerka Walbaum) eggs with intragravel water flow (Table 1).

TABLE 1. RELATION BETWEEN RATE OF WATER FLOW THROUGH A GRAVEL BED
AND THE SURVIVAL OF EYED SOCKEYE EGGS IN THE GRAVEL?.

Apparent velocity (cm/sec)? Percent egg
through spawning sediments survival
- 0338 89.3
.0112 78.3
00542 68.3
-00261 59.0
- 00136 36.3
-000945 26.5
- 000668 15.6
- 000389 1.9

1 Taken from Cooper (1965).

2 Apparent velocity equals discharge divided by total cross
sectional area of voids and solids.

10


EPA-600/3-79-043
April 1979

SEDIMENT PARTICLE SIZES USED BY SALMON FOR
SPAWNING WITH METHODS FOR EVALUATION

by

William S. Platts
Intermountain Forest and Range Experiment Station
Forest Service
U.S. Department of Agriculture
Ogden, Utah 84401

and

Mostafa A. Shirazi and Donald H. Lewis
Freshwater Systems Division
Corvallis Environmental Research Laboratory
U.S. Environmental Protection Agency
Corvallis, Oregon 97330

CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330


Platts, William S. 1968. South Fork Salmon River, Idaho, aquatic habitat
survey with evaluation of sediment accurement, movement and damages.
USDA For. Serv. Intermt. Reg. , Ogden, UT, 137 p.

. 1970. The effects of logging and road construction on the aqua-
tic habitat of the South Fork Salmon River, Idaho. Proc. Fiftieth Annual
Conf. of the Western Assoc. of State Game and Fish Comm., p. 182-185.

1972. Aquatic environment and fishery study South Fork Salmon
River, Idaho, with evaluation of sediment influences. USDA For. Serv.
Intermt. Reg. , Ogden, UT, 106 p.

Platts, William S. and Walter F. Megahan. 1975. Time trends in riverbed
sediment composition in salmon and steelhead spawning areas: South Fork
Salmon River, Idaho. Trans. of the 40th North Am. and Natl. Resources
Conf. , Wildl. Manage. Inst., Washington, D.C. pp. 229-239.

Vanoni, V. A. 1977. Sedimentation Engineering. American Society of Civil
Engineers, 345 East 47th St. , New York.

Walkotten, William J. 1976. An improved technique for freeze sampling

streambed sediments. USDA For. Serv. Res. Note PNW-281, 11 pp. Pacific
Northwest For. and Range Exp. Stn., Portland, Oreg.

32


6L

TABLE 4.

CHANNEL SUBSTRATE COMPOSITION BY YEARLY AVERAGES BY SEDIMENT PARTICLE SIZE IN SAMPLES TAKEN FROM CHINOOK SALMON SPAWNING AREAS.

Substrate Particle Size by Groups Representing Percent Volume Passing?
Through Sieve of the Designated Size (mm)

Sample Time

Stream or Area Size Period 76.1 50.8 38.1 25.4 19.0 12.7 9.51 6.35 4.76 2.83 2.38 2.00 1.00 .83 .42 .25 .21 .10 .07 .05
South Fork Salmon River

Stolle Meadows 145 (1966 9279 71 53 48 42 #38 #34 30 26 (23) #19 15 11 6 2 1 6 10

Area to 1975

Dollar Area 40 1975 w- == == 49) (44) (40) (35) 31 28 (23) (19) (14) (10) 5 (4) (2) .5) (6.5) 6.4) 0.4

Poverty Area 310 =—-1966 93 84 #%77 68 60 52 47 42 37 33 28 23 18 14 7 4 2 1 0 i)

to 1976
Oxbow Area 50 «1975 o> ss == 74) (68) (63) (58) 53 48 (ay (33) (25) 17) 9 (7) (4) 1 qd) (0) 0
Glory Area 80 61966 93 82 70 57 52 46 41 36 31 (28) (24) 20 (15)12 5 2 1 1 5.5
to 1975

Johnson Creek 100 1966 6 86 74 (63) 51 (44) 38 (33) 28 25 21 17 (14) 10 8 (5) (3) 1 qa) (0) 0
Middle Fork Salmon River

Bear Valley Creek 20 «(1968 98 90 82 72 63 53 48 (42) 37 (33) (28) 24 (18) 12 5 1 (1) 0 tt) 0

Elk Creek 20 «1968 wo 698 «6897 58 «45039 (34) 28 «(24) (19) 15 (10) 5 3 .5(.5) 0 0 0

Loon Creek 20 1969 94 76 67 55 47 38 32 (27) 22 (20) (17) 15 (11) 7 2 1 (1) 0 0 0
Salmon River

Lower Decker Area 5 1969 82 62 56 49 43 37 32 (26) 21 (18) (15) 12 (9) 6 3 1 (1) ti) 0 0

Upper Decker Area 5 1969 96 85 78 67 59 49 42 (35) 28 (23) (19) 14 (102) 5 1 0 0 0 (3) 0

Alturas Creek 20 1969 95 77 66 S54 46 38 33 (27) 24 (22) (17) 14 (10) 6 3 1 (1) 0 0 0
Combined Average 93 81 72 60 53 45 40 34 30 2 22 7 13 8 4 2 «0.9 0.4 0.1 0.7

Total Sample Size 815

1 Values in parentheses are interpolated by graphing the particle size distribution curve and selecting the percent passing from the

intersection of the group size with the curve.


RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
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The nine series are:

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ODMNONSE WN

This report has been assigned to the ECOLOGICAL RESEARCH series. This series
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for setting standards to minimize undesirable changes in living organisms in the
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.


l@

PERCENT SEDIMENT PASSING SIEVE OF

DESIGNATED SIZE

70

60

SOF

40-

30F

20-

Chinook Spawning Areas

Resident Trout Channels

on Ses aaweert| ees |

100.

F

SIEVE SIZE, millimeters

igure 8. Comparison of particle size distributions for resident
trout channels and chinook salmon spawning areas.


NOTE:
1.Data for these curves are the
yearly averages used in
calculating the longer term
averages of Table 4.
2.Data points shown for d = 2.00mm
only.

d= 4.76mm (r?= .79)
d= 2.83nm (r2= ,82)
d= 2,38nm (r2= .84)
d= 2.0mm (r@= .86)

d= 1.00mm (r2= .85)

PERCENT SEDIMENT LESS THAN d

rn foo n yo 1 1 1 n 1

1 1 1 l 1 L
4 6 8 10 iY 14 16 18 20 22

GEOMETRIC MEAN DIAMETER, dg, centimeters

Figure 6. Relationship between geometric mean diameter and percent fines.

22


( /
| Third Fork
/
| /
| Squaw Greek / river
I /

/ e
{ /
| / W. Fork,

{ Fall Creek

@ Study area

Anderson Ranch
Reservoir

Miles Z

Figure 3. Study areas in the Squaw Creek and South Fork Boise River drainages.

6


d= die dea

g
An estimate of the standard deviation, Og» is obtained by:
Og = Wde47dz6

The mean diameter d_ is a useful measure, since it can be manipulated
algebraically (Innman 1952). For example, the mean particle size of several
combined samples is equal to the average of the means of those samples; this
is not true for the median, i.e., dso.

It is interesting to note that small values of o, are usually associated
with small d_ values, frequently in large streams. Sin the case of coarse
sediments, i.@., when d jis relatively large, the geometric standard deviation
is also relatively latye (Bogardi 1974). This suggests that d_ is both a
convenient and sufficient way to describe substrate composition.

Innman (1952) reported on Yule and Kendall's calculations showing that,
for a normal curve, sampling error is greatly increased below 5 and above 95
percentiles of the distribution. The errors are tolerable for 16 and 84
percentiles. This is an important practical consideration when sampling for
substrate composition and will be discussed further.

Fishery scientists have characterized stream channel sediments by “per-
cent fines", which is defined as the mass fraction below a suitable selected
particle size. There has been considerable debate (Iwamoto et al. 1978) on
the choice of the suitable particle size as it relates to egg and alevin
mortality. Common particle sizes fishery scientists use to identify "percent
fines" are .03 in (0.83 mm), .13 in (3.3 mm), .19 in (4.7 mm), and .25 in (6.3
mm). This has rendered comparison of research results difficult if not impos-
sible. There are reasons why fishery scientists have used different particle
size limits to define fine sediments. One reason is that salmon spawning
areas in the Pacific Northwest exhibit different particle size graduations and
researchers concerned with these areas observe different dominant features
affecting embryo survival. A second reason is that mortality has been intrin-
sically associated with excess fine particles because of (a) the adverse
effects very fine particles have on permeability and (b) the entrapment of
embryos that can be caused by presence of particles of intermediate fineness,
say, 2 mm-6 mm.

Note the difference in emphasis between the “percent fines" and the
percentile approach. With the "percent fines" the particle diameter is se-
lected and then the fraction of the sample which is finer is determined. With
the percentile method, the percent passing is selected and the sample analyzed
to find the corresponding particle diameter. The inherent disadvantages of
the "percent fines" approach is that the probability of occurrence of these
quantities, e.g., percent by weight less than .03 in (.83 mm), etc., vary from
one composition to another. This means that if the sediment composition is
coarse, it would be more difficult to evaluate its "percent fine" by sampling
than if the sediment composition is fine. The percentile approach always
results in the same sample size.