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IV. Scientific Information Required for Lake and Watershed Management Research Applied to Environmental Needs During the last two decades research and monitoring efforts of the Tahoe Research Group have been guided by the following: (1) the growing awareness that the Tahoe ecosystem is fragile and in danger of irreparable damage, (2) concerns on the part of state and federal resource agencies to implement water quality policy at the watershed level, and (3) the University of California's commitment to addressing basic and applied questions in land, air and water science in the Tahoe basin. |
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Summary of Current Research Projects Sediment Budgets - Identification of sources of sediment to Lake Tahoe are fundamental to watershed management. It is important to know exactly where in the watershed this material originates, e.g. stream bank erosion, disturbed land, naturally unvegetated parcels, etc. Phosphorus Loading - Results of long-term algal growth bioassay experiments show that the lake has experienced a fundamental shift in its response to nitrogen and phosphorus inputs. Since phosphorus is typically transported along with the suspended solids load, these findings have highlighted the importance of sediment control and erosion mitigation. Monitoring phosphorus loading and studies on bioavailability are important to determineing impacts on algal growth. Watershed Yield - Multiple Stress - The LTIMP watersheds were selected, in part, because they differ with respect to natural geomorphic and human-use factors such as amount of urbanization and land disturbance, road density, tributary density, slope, elevation, parent geology, precipitation, stream channel morphology, aspect, etc. These conditions provide a natural experiment to determine the most important factors regulating nutrient and sediment load from each under a variety of hydrologic conditions. Atmospheric Deposition - Current research builds on previous analysis of our long-term air quality data base to determine the ultimate source of these airborne pollutants and the role of in-basin versus out-of-basin generated material. Erosion Control - In partnership with the UCD Department of Civil and Environmental Engineering, the TRG is developing a scientific basis for erosion control management and project selection in the basin. With guidance from a technically-based model, mitigation dollars can be allotted in the most cost-effective manner. The potential application of these new models to watershed management not only at Tahoe but elsewhere in the mountainous United States is significant. Treatment of Surface Runoff - Some amount of erosion in inevitable in urbanized, high-mountain watersheds. A second line of defense to erosion control, for the purpose of reducing nutrient load to Lake Tahoe is treatment of surface runoff. Ongoing research is now allowing for the quantification of BMP (Best Management Practices) effectiveness. Fisheries Ecology - Current work focuses on nearshore fish ecology and an evaluation of artificial reefs to increase available fish habitat. The recent finding that prized lake trout extensively utilize submerged macrophyte beds for spawning raises additional concern as to the fate of these fish should clarity decline to a point where deep submerged plant growth is affected. Lake Optical Properties - The optical properties of Lake Tahoe have been a focal point in the concern over the continued degradation of this waterbody. Studies quantifying the contribution of in-lake produced organic matter and watershed-derived terrestrial material, and the contribution of each in lake optics, are underway. Paleolimnology - Studying deep lake sediments provides a method of reconstructing historical sediment transport to the lake and algal growth. New work being done using these long-term sedimentary records is aimed at investigating historical patterns of fire disturbance and the role of global climate change on the lake environment. Wetland Ecology - Wetland studies at Tahoe have all indicated the importance of these ecosystems with respect to removal of nutrients, flood control, groundwater recharge, and species habitat. Continuing work addresses the response of wetland flora to ecological stress with emphasis on the use of remote-sensing to for this evaluation. | ||
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Future Program Needs Much of the anticipated work of the Tahoe Research Group will focus on continued research and monitoring to protect water quality, with specific attention to applied research in the areas of watershed management, airshed management, lake management, water quality protection and land use policy. Significant emphasis will be placed on collaborative scientific efforts and the ultimate goal of much of this work is to incorporate findings into regulatory processes within the Tahoe basin. The TRG has presented a comprehensive outline for future research at Tahoe which also has broad applicability in the entire Sierra Nevada ecoregion - this outline is referred to as Lake Tahoe Agenda 2000: Programmatic Goals. Major topics included in the TRG's Agenda 2000 are:
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