Managing Water Resources in the West Under Conditions of Climate Uncertainty A Proceedings (1991) / Chapter Skim
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11. Economic Consequences of Climate Variability on Water in the West
11. Economic Consequences of Climate Variability on Water in the West
Pages 217-238
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From page 217... ...
A case study of the Missouri River basin illustrates the possible impacts of a general warming on the availability of water within one of the West's principal river basins and indicates how management changes and a reallocation of supplies would help the region adapt to a sizable reduction in streamflow. Hydrologic extremes have long posed risks to settlements in the western United States.
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From page 218... ...
Water intensive industries such as irrigated agriculture declined in relative importance, and industries in general learned to prosper with less water (National Water Commission, 1973~. The tremendous expansion of the infrastructure to store and transport water and to tap ground water supplies also has tended to reduce the susceptibility of the nation's economy to climate variability.
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From page 219... ...
Second, the rate of construction of reservoirs to assure water supplies has decreased since 1970 and is likely to continue declining. A basic principle of reservoir planning is that the risk of deficiency increases if the storage period (that is, available reservoir storage divided by average daily withdrawals)
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From page 220... ...
The economic consequences of adjusting to any given climate change would depend on the nature of the economy and its dependence on water supplies, the slack in the supply system, and society's ability to anticipate and adapt to hydrologic change. Effective adaptation to drought involves curbing excessive and low-value uses through demand management and transferring scarce supplies to uses for which the losses from inadequate supplies would be greatest.
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From page 221... ...
. The recent decline in the storage period noted above suggests a decline in the overall robustness of the nation's water supplies.
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From page 222... ...
Joint management of water supply systems that are currently managed independently with separate operating rules and objectives may make it possible to improve significantly the supply capabilities of each system. Integration of the three principal water supply agencies in the Washington, D.C.
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Ratio of basin consumptive depletions (including consumptive use, water transfers, evaporation, and ground water overdraft) to total basin annual mean renewable supply as of 1985.
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From page 224... ...
concludes that "the Bureau's mission must change from one based on federally supported construction to one based on effective and environmentally sensitive resource managements" A recent paper by three senior members of the U.S. Army Institute for Water Resources advocates greater emphasis on management measures to meet the problems caused by extreme events and the uncertainties stemming from the prospect of climate change (Hanchey et al., 1987~.
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From page 225... ...
The urban water supply industry usually sets rates lust high enough to cover average costs including a return to capital. Average cost pricing in a rising cost industry such as water results in prices below marginal costs.
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From page 226... ...
If the climate of the 1931-1940 analog period became the norm, runoff and evaporation rates would differ from those of the current climate. Estimates of the impact of these differences on the basin's renewable water supplies are presented in Table 11.2.3 The mean assessed total streamflow represents the renewable supply available before consumptive use.
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From page 228... ...
Under the analog climate, total use exceeds these streamflows by at least seven percent in eight of the subregions; even in the other three subregions, total use is 94 percent or higher of mean assessed total streamflow. When total use exceeds mean assessed total streamflow, then ground water supplies are being mined and/or desired instream flows are not being met.
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From page 229... ...
Table 11.4 shows desired instream flows as a percentage of current streamflow under the current and the analog climates. Under the analog climate, instream flows are generally well below desired levels as estimated in the Second National Water Assessment.
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From page 230... ...
Table 11.5 presents preliminary estimates of the average annual benefits by principal use categories derived from the operations of the Missouri main stem system under existing operating criteria and historical streamflows. The large water flows required to support navigation and the high priority navigation receives in the current operating scheme are in striking contrast to the relatively small contribution navigation makes to the overall benefits from the system.
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From page 231... ...
The guidelines for managing the main stem reservoirs have come under attack during the recent drought and are currently under review. Table 11.6 compares the differences between the preliminary average annual benefits for the various users (power, reservoir recreation, downstream recreation, water supply, navigation on the Missouri, navigation on the Mississippi, and flood control on the Mississippi)
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From page 232... ...
232 V, .5 Ct em ·= so .5 o Ct E Ct lo: I: ._ Ct ~ o o ~ V, ~ A o Ct ~ ~ ._ em ~ a ~ Ct I_ Ct C)
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From page 235... ...
increase the benefits from hydropower production and reservoir recreation in the upper basin. The dollar value of the adverse effects on navigation of increasing the permanent pool and altering other operating criteria that currently favor navigation are overwhelmed by the positive impacts on power, water supplies, and reservoir recreation.
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From page 236... ...
The estimates of "desired" instream flows are from the Second National Water Assessment. The assessment suggests that desired instream flows are "that amount of water flowing through a natural stream channel needed to sustain the instream values at an acceptable level.
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From page 237... ...
1987. Water resources planning under climate uncertainty.
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From page 238... ...
In U.S. Geological Survey, National Water Summary 1985: Hydrologic Events and Surface-Water Resources.
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