7410

• UCREFRP Catalog Number: 7410
• Author: Williams, O. R., S. L. Ponce and A. E. Johns
• Title: Use of Departure Analysis in Decision Making
• USFW Year: 1988
• USFW - Doc Type: American Water Resources Association
• Copyright Material: YES

.. n <, - '. > " ^ . '- - K " ." ( ~ ,-<- "".,.,,, ' ~ ~
. . . .
Ii- ''t... j-,r e

DEPAB1'UBE AHALYSIS STUDIES J:1. ZIOH HAfiOllAL PAn

:'i'

f
t
'."
f.
L
t

The Departure Analysis methodology is being used at Zion to identify the potential
effects of land management decisions which are made for lands outside of the park upon
park water-related resource values. In view of water's critical importance to park
resource values, this approach offers an appropriate method whereby management may
assess potential effects consequent to management decisions made by others.

Beginn1.ng The Analysis - Inventory And Literature leview

The Departure Analysis began with a field inventory designed to identify Park
resource attributes which are related to or dependent upon either surface or subsurface
sources of water. Along with the field effort, an extensive literature review was
conducted which included historic documentation regarding Park resources.

Selection Of Variables For Study

When the inventory and literature search were completed, enough information had been
compiled to allow a selection of response variables to be used in the Departure
Analysis. This step is a distillation of all information specific to the resources of
Zion or related to the scientific disciplines to be employed.

~.'
~.
i
!

A variable was selected for study if it met the following criteria:
1) It can be measured with ease, precision, and accuracy.
2) It will respond to changes in surface and ground water.
3) Its responses can be separated from natural variation within the limits of a
selected level of certainty.
4) Its responses presage broader system responses.
5) It can be measured at reasonable cost.
6) Expertise is available for its measurement.

Numerous water-related resource attributes have been identified as important to the
decision makers of Zion. The effects upon these attributes of water diversion and/or
storage are being estimated using individual studies which, in aggregate, form the basis
of the Departure Analysis. The individual studies predict the nature and magnitude of
departures in selected response variables due to alterations in control variables
associated with hypothetical flow regimes.

Collection of Baseline Data

The assessment of potential departures from existing conditions in water-related
resource attributes requires the measurement of existing conditions. A baseline data
collection effort was, therefore, initiated. This effort, it must be emphasized,
characterizes the existing condition which is then taken to be, for purposes of
departure analysis, baseline. Accomplishing this characterization at Zion involves
several concurrent studies.

A complete description of the Zion studies ia...beyond the scope of this document.

However,

A.
B.
C.
D.
E.
F.
G.

their titles are:
Water and Sediment Discharge.
Channel Processes.
Aquatic Organism and Physical Habitat.
Ephemeral Wash Sediment Supply.
Riparian Physical Habitat and Organisms.
Hanging Gardens.
Ground Water Contribution to Surface Flow.

451