- The objectives of this study are to revise and reformulate a
previous simulation model of the Calapooia River and proposed
Holley Dam project and to critically investigate the anadromous
fish enhancement function of the project.
The Corps of Engineers proposes a 145,000 acre-foot reservoir
for the Calapooia River at Holley, Oregon. Previously, a
97,000 acre-foot reservoir was proposed. The larger project's
justification is based mainly on anadromous fish enhancement.
Investigation revealed that there is a great deal of uncertainty and
lack of information about: (1) temperature requirements of
anadromous fish in the Calapooia River and whether they can be
met, (2) the affects of high streamflow discharges on spawning,
incubation, and rearing of anadromous fish in the Calapooia River,
(3) the affects of variability in food supply due to fluctuations in
the level of the water in the reservoir, and (4) the survival rates
of salmon eggs to fry, fry to smolts, and ocean survival.
A simulation model in DYNAMO computer language is formulated
and includes the following components: (1) hydrology generator,
(2) reservoir regulation and flood control procedures, (3)
freshwater life cycle of Spring Chinook and Fall Chinook Salmon,
(4) supply of recreation user days, (5) supply of resident fishing
angler days, and (6) supply of irrigation water. The model calculates
the daily, monthly, and yearly variability of various physical,
economic, and intangible outcomes.
The simulation of floods and their regulation corresponds to
historical data and regulation hypothesized by the Corps of Engineers.
The dynamic nature of the Spring and Fall Chinook Salmon populations
are modeled and computer results indicate that the likelihood of
conservation and enhancement is not great enough to justify the
145,000 acre-foot reservoir.
Due to the fluctuations in the reservoir level which accompany
flood control regulation and reflect the variability in the hydrology,
the recreational use and resident fishing angler use is highly
variable and the average use is unlikely to reach the estimated
supply potential. The reservoir, as simulated by the model, has
sufficient capacity to supply water for the proposed irrigation
project. However, it appears that uncertainty remains concerning
the dollar benefits that are obtainable from irrigating soils along
the Calapooia River.
Further study is necessary to determine whether the 97,000
acre-foot reservoir is a feasible alternative to the proposed
145,000 acre-foot reservoir. The computer model is general
in formulation and can be utilized to provide information to decision
makers in determining the feasibility of further dam and reservoir