7811

• UCREFRP Catalog Number: 7811
• Author: U.S. Fish and Wildlife Service, U. C. R. B. S.
• Title: Documentation of the Instream Flow Incremental Method Micro Habitat Analysis, Task 6.
• USFW Year: 1984.
• USFW - Doc Type: \
• Copyright Material: NO

INTRODUCTION
The objectives of the Task 6 series included the following:
1. Determine the status and quality of existing Instream Flow Incremental
Method (IFIM) cross sectional locations (here after referred to as
Physical Habitat Simulation System [PHABSIM) sites) and associated data.
2. Determine the needs for additional PHABSIM data using the results of Tasks
4.2 (map and document sensitive area reaches for species being studied)
and 7.2 {identify and map water development projects). Prioritize
locations and document results.
3. Arrange for and implement the collection of additional PHABSIM data
identified in 2 above.
4. Computerize all old and newly collected PHABSIM data and intergrate with
data on existing sites in a format suitable for application with the
PHABSIM approach. Computerize all preference curve data (tasks 5.9 and
5.10). Perform sensitivity analysis. Calibrate the model as needed.
Document the results.
Many other study Upper Colorado River Basin (UCRB) Technical Advisory tasks are
related to the IFIM micro habitat analysis. Task results which serve as
information inputs to task 6 generally include:. 1) the sensitive reach
analysis (Tasks 4.2 and 4.3) which defines, by species and life stage,
important reaches, migration routes and physical barriers; 2) development of
fish suitability index curves (task 5.10) for use with PHABSIM; and 3)
definition of existing and proposed water developments in the basin (Task 7.4)
which may potentially affect important habitat areas occupied by endangered
fishes.
Results of Task 6 also serve as information inputs to other related tasks
including: 1) defining the final HYDROSS node network (Task 7.4) to ensure
that node descriptors also exist for important fish reaches and existing
PHABSIM sites; and 2) linking PHABSIM modeling results with the Stream Network
Habitat Analysis (Task 9.1).
PHABSIM is one of the critical pieces to a network habitat analysis. It is a
microhabitat descriptor and as such is aimed at describing changes in depth,
velocity, and substrate imposed by various flow regimes. These changes may or
may not be the most important habitat consideration for life stages of fish
being studied. Channel form dynamics, temperature, and water quality are the
microhabitat descriptors and are variables of equal consideration in the
current study. Together both micro and macro models are used to describe the
usable habitat for a given species.