7934

• UCREFRP Catalog Number: 7934
• Author: Hyra, R.
• Title: Methods of Assessing Instream Flows for Recreation.
• USFW Year: 1978.
• USFW - Doc Type: Instream Flow Information Paper No. 6,
• Copyright Material: NO

physical criteria, recreation activities have certain physical or
absolute limits or requirements which must be met (i. e., a boat requires
a certain minimum depth of water to float). In the case of safety
criteria there are no absolutes; however, it can generally be stated
that certain depths or velocities may be unsafe for the average parti-
cipant. Safety criteria may also be considered a preferred physical
limitation.
Optimum Criteria
Minimum and maximum criteria are used to establish the range of
depths and velocities which provide a usable surface area for river
recreationists. It is also possible to identify a preferred depth or
velocity or range of preferred depths and velocities which could be
called optimum. Obviously, optimum will not be agreed upon by all
recreationists since they represent such a heterogeneous group. How-
ever, the total range can be narrowed and a preferred range established.
An optimum value of depth or velocity or a preferred range of depths and
velocities will be that value or range of values which is usable to the
largest number of potential participants.
There are "psychological" criteria that also might be used for
selecting optimum depths or velocities. Psychological criteria relate
to the quality of the experience. However, in order to evaluate the
quality of the experience, one must determine what experience is sought.
A number of the recreation activities included in this report have
expectations that appear to be unrelated to flow. Therefore, for such
activities only the physical and safety criteria need to be considered.
Other activities have flow-related expectations and it appears that the
experience desired and expected should be a part of the criteria.
According to Schreyer and Nelson (1978) the "white water" activities,
have an "action-excitement" expectation, and certain types of water are
necessary to realize that expectation. Stream depths and/or velocities
which produce action-excitement are not easily identified because of the
differing ski]1 levels and experience of recreationists. Consequently,
psychological criteria, in terms of depth or velocity, are not listed at
this time.
The activities which have action and excitement as an expectation
_ are the last four activities listed under boating (below). However, not
all of the persons who engage in these activities seek action and
excitement. Therefore, a wide range of optimum velocity values is
necessary to include the action excitement expectation as well as the
other expectations. Each of these four activities may be viewed as two
separate activities, one which occurs on tranquil water and one which
occurs on non-tranquil water.
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