 * Critical Findings * DEFORESTATION IN THE MID-1800s RESOURCE USE: CHANGING NEEDS THROUGH TIME * Social and Economic Analysis Community Well-Being in the Sierra Management Scenarios and Strategies
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Cumulative Major Reservoir Capacity in the Sierra Nevada
Excluding the hard-to-quantify public good value of flood control and reservoir-based
recreation, the hydroelectric generating, irrigation, and urban use values of water
are far greater than the combined value of all other commodities produced in the
Sierra Nevada. Since 1980 there has been very little increase in the number of reservoirs
in the Sierra Nevada (figure 2.10). Increased concern about the ecological impacts
of diversions as well as the social decisions about who should bear the financial
burdens of plans to reduce, or at least stop the growth of, these impacts requires a greater
understanding of how diversions, economic benefits, and ecological impacts are linked.  FIGURE 2.10 (ACTUAL VIEW 6K) Cumulative capacity of reservoirs at the date when the reservoir was installed, 1910-89. Reservoirs in the foothills are shown separately from those upstream due to differences in pattern of capacities. (From volume III, chapter 23.) The rivers of the northern Sierra Nevada have been extensively diverted in both the upstream and the foothill stretches. The central rivers draining the western side have been moderately diverted upstream and heavily diverted in the foothills (only one small river is allowed to flow into the Central Valley without a major dam and reservoir). The southernmost rivers have been moderately diverted in both the upstream and the foothill stretches. The dominant purpose of the dams varies by location. Two-thirds of foothill reservoir capacity is managed to provide irrigation water to the Central Valley. Conversely, two-thirds of upstream reservoirs are managed to provide municipal water supplies and hydroelectric power. This difference suggests that efforts to reduce the negative ecological impacts of upstream diversions will need participation by quite different institutions from those involved in similar issues downstream. Current Status and Future Directions Resource utilization is permitted across most of the land and water resources in the Sierra Nevada. In contrast to largely agricultural or urban landscapes such as the Central Valley or the Los Angeles Basin, the prevailing land cover types of the Sierra Nevada are managed forests, rangeland, and alpine ecosystems that sustain many if not most elements of native biodiversity while also supporting activities based on natural resources. The history of the Sierra Nevada and recent ecological assessments suggest that Sierran biodiversity could be maintained by ecologically sound management of lands designated for renewable resource extraction, in combination with a moderate system of areas specifically reserved for native biodiversity. Table 2.1 summarizes the economic value of different resource uses as well as the financial reinvestment and local employment associated with them. The economic value of the basic resource is much less than the total revenue of the sectors that use the resources because the total revenue is based on other inputs in addition to the basic commodities and services. Employment figures, however, are based on full revenues of each sector and are not tied only to the basic commodity or service. The key conclusion is that different patterns of resource utilization will lead to relatively large economic and employment changes. The degree to which these different sectors are complementary or competing can be assessed only at scales smaller than the whole Sierra Nevada region.  TABLE 2.1 (ACTUAL VIEW 128K) Estimated annual resource values and reinvestment for major ecosystem commodities and services. (From volume III, chapter 23.) The relative importance of the major resources in terms of employment, resource values, and reinvestments varies considerably. The benefits of water use accruing outside the Sierra Nevada region account for more than half the total value of basic goods and services but provide limited employment or funds for reinvestment. The historic allocation of water rights benefits those who made the large investments in the dams, canals, and power plants that impact many of the rivers and streams of the Sierra Nevada. Most of the value of timber stumpage, forage, and other agricultural output comes from private rather than public lands in the Sierra Nevada. Federal revenue sharing of timber receipts is the largest single source of reinvestment funds, but it is partially canceled out by the effective subsidy provided through low grazing fees on public lands. Conservative estimates of the ecosystem value or rent for the large recreation and tourism industry as well as new construction are estimated at 10% of total revenue for the two sectors. The remaining 90% of the actual revenues are assigned to services over and above the estimated ecosystem value or rent. Taxes on overnight visitors and property constitute a significant source of funds to county governments. The 1990 censusbased estimates of employment overestimate the impact of many seasonal jobs in the recreation and construction industries. After correcting for seasonality and wage differentials, commodity-related employment and service-related employment each constitute a little more than 10% of the total employment for the Sierra Nevada as a whole. In terms of reinvestments, the commodity and service sectors each provided around $20 million per year over the past decade. Each region within the Sierra Nevada exhibits a different mix of sectors in terms of relative size and trends over time. Management practices for many forms of resource utilization have been altered over the past few decades to specifically improve the complementarity between the resource extraction and ecological conditions. Management of forests under many new guidelines will require modified silvicultural approaches (figure 2.11). For instance, the focus may be on density management of stands to reduce the potential for insect epidemics, to reduce fuel, to maintain a diverse species composition, and to stimulate growth of larger trees. This general approach can be used in both general purpose forestlands and areas managed for late successional structure. Carefully thought out and implemented, site-specific prescriptions may be needed on all harvested lands. These prescriptions may employ both prescribed fire and mechanical removal of wood. Regeneration may occur by natural and artificial means to maintain species composition and restock stands after fire or timber harvest. The purpose of management may be to reduce fire and insect potential on general-purpose timberlands, while maintaining stands that produce both wood and wildlife habitat. In areas emphasizing biodiversity and forest structure, the focus may be on reducing fire and insects, while providing the characteristics and habitats of old forests; wood production may be a by-product.  FIGURE 2.11 (ACTUAL VIEW 83K) Schematic diagram showing how different silvicultural treatments in mixed conifer stands can lead to different structural conditions. Initial stands are uneven-aged forests. (From volume II, chapter 15.) Alterations in schedules of water release from dams, closer management of grazing animals in meadows and riparian areas, and new silvicultural techniques to preserve specific forest ecosystem characteristics reduce the conflict between resource utilization and the protection of native biodiversity. Monitoring of individual sites and the larger landscape may be required to determine the net impacts of these new approaches to resource utilization in the Sierra Nevada. 
 
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