7923

• UCREFRP Catalog Number: 7923
• Author: Carter, J. G. and V. A. Lamarra.
• Title: An Ecosystem Approach To Environmental Management, Chapter 17.
• USFW Year: n.d.
• USFW - Doc Type: 261-287
• Copyright Material: YES

Tab)e 11. Th(' m.1jor intl'rncd phystc;.c.l fa~tors affecting the White
R iv(~r Syst em.

A. Channel geomorpnology

(1) Elevational chang!: (slope).
(2) Cross S(>ctiofla) dertr. distributions.
(3) Cross sectional waLer velocity distributions.

(a) Current.
(b) Turbu) ence.

(4) Substrate.

(a) Size.
(b) Texture.
(c) Chemical composition.
Cd) Stability.

(5) Channel meander rate.
(6) Pool to riffle ratio.

B. Fluvitile ('Water) cha't"acteristics

(1) Heat (temperature)
(2) Chemistry.

(a) Dissolved gases.
(b) Dissolved substances.
(e) pH.

(3) Turbidity and silt load.

ambient physical system was predictably modified, with
concurrent effects on the biological community.

Changes in current and turbulence can shift and
restabilize the bed in the White River. This dynamic
process can produce molar action that may physically
damage animals and modify habitat types (pools, runs,
riffles). Periods of high discharge or storm events will
produce greater habitat modifications than normal,
baseline water level currents. It should be noted that in
sections of the White River where shifting stream bottoms
are encountered, the configuration of canyon walls or
large boulders may be important in creating permanency in
deflecting currents in a predictable manner.

Substrate stability is dependent on current velocity
(Bull, 1981). Biologically, substrate stability relates
to the organisms which use the benthic region for
attachment (periphyton, macroinvertebrates). The
current-determined substrate size also determines the size
of organic particles (food for higher organisms) caught
within pore spaces (Farnworth, 1979). The substrate type
(size, texture, and chemistry) may at times influence the
distribution of benthic algae and invertebrates in streams
(Whitton, 1975). Large, stable, rocky substrates have

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