Collaborative Proposal: Tracking Hydraulic Mining Sediments from the Sierra Piedmont into Flood Bypasses of the Sacramento Valley, California

加州的内华达州山脉的水力采矿取代了大量的沉积物，这些沉积物是从砂矿砾石中提取黄金的副产品。 在过去的世纪，水力采矿沉积物的改造和洪水旁路沉积的空间分布是相关的污染物的命运，洪水输送，并在加州的下萨克拉门托山谷的土地利用，这是正在经历一个大规模的恢复和发展计划，并对谷底沉积物预算和洪泛区沉积的基础研究。 本研究采用了一套新的技术和数据，调查中央谷洪泛平原沉积和水力采矿沉积物在塞拉利昂皮埃蒙特在过去的世纪侵蚀之间的时间和空间的联系。 最近的现场证据，情节皮埃蒙特侵蚀和旁路沉积要求在下萨克拉门托山谷在过去的世纪的水力采矿沉积物输送问题进行新的调查。 这项研究将跟踪萨克拉门托河谷下游水力采矿尾矿产生的细沉积物的运动。 该研究小组将把萨特河和约洛河（中央谷的防洪平原）沉积的时空模式和过程与最后一个大坝下游的贝尔河、尤巴河和羽毛河下游的皮埃蒙特尾矿的侵蚀联系起来。 它将通过摄影测量、河道变化分析和实地调查相结合，追踪皮埃蒙特水力采矿沉积物的历史侵蚀。 该小组将通过粒度测定法、X射线荧光光谱法、磁学和地质年代学记录中央谷采矿沉积物的历史和来源。 此外，还将仔细研究来自流量测量站网络的记录，以确证分析皮埃蒙特侵蚀与中央谷沉积之间的时间相关性。 该项目将对沿着皮埃蒙特河道的沉积物储存量和侵蚀量及其排空时间进行定量和实地评估。 它将记录采矿和非采矿沉积物的地球化学、粒度和磁性，并制定适当的混合模型，以通过河流系统辨别下游每个来源的相对影响。 它将确定旁路系统中离散沉积物的空间范围和体积，并记录跨越萨特和约洛河流域的沿着各断面的沉积速率和历史。 该研究将建立皮埃蒙特侵蚀和旁路沉积之间的定量联系，这些联系基于历史水文学和旁路沉积过程的精确概念模型。 该项目将为预测未来洪水对中央谷沉积物运动的影响提供基础，为萨克拉门托谷未来的管理决策和方向提供定量基础，并提供一套可应用于其他大型管理河流流域的方法。 从这项研究的数据和解释将是很大的实际用途，河流和环境管理在较低的萨克拉门托河谷和三角洲，我们的结果是最重要的洪水输送，维护岛屿，沉积物的潜在毒性。 这项研究将为新一代地貌学家创造教育机会，包括那些历史上代表性不足的群体。 这项研究的成果将通过万维网作为一个项目网站提供，并通过美国宇航局空间联盟（一个教育资源中心）提供直接的K-12科学宣传。

Hydraulic mining in the Sierra Nevada of California displaced great volumes of sediment as a byproduct of gold extraction from placer gravels. The spatial distribution of hydraulic mining sediment reworking and deposition in flood bypasses over the last century are relevant to the fate of contaminants, flood conveyance, and the land-use in the lower Sacramento Valley of California, which is undergoing a massive program of restoration and development, and to basic research on valley floor sediment budgets and floodplain sedimentation. This research employs a suite of new techniques and data to investigate the temporal and spatial links between Central Valley floodplain sedimentation and erosion of hydraulic mining sediment in the Sierra piedmont over the last century. Recent field evidence of episodic piedmont erosion and bypass deposition calls for a new investigation of the hydraulic mining sediment delivery problem in the lower Sacramento valley over the last century. The research will track the movement of fine sediments derived from hydraulic mining tailings in the lower Sacramento Valley. The research team will link spatial and temporal patterns and processes of deposition in Sutter and Yolo Bypasses (leveed floodplains of the Central Valley) with erosion of piedmont tailings of the lower Bear, Yuba, and Feather Rivers downstream of the last major dam on each. It will track historical erosion of hydraulic mining sediments in the piedmont through a combination of photogrammetry, channel change analysis, and field surveys. The team will document history and provenance of mining sediment deposits in the Central Valley by granulometry, X-ray fluorescence spectroscopy, magnetism, and geochronology. In addition, records from a network of streamflow gauging stations will be perused for corroborative analysis of temporal correlation between piedmont erosion and Central Valley sedimentation. The project will produce quantitative, field-based estimates of volumetric sediment storage and erosion along piedmont channels and the timing of its evacuation. It will document geochemical, grain size, and magnetic properties of mining and non-mining sediment and develop appropriate mixing models for discerning the relative influence of each source downstream through the fluvial system. It will identify the spatial extent and volume of discrete sediment deposits in the bypass system, and document sedimentation rates and histories along various transects spanning Sutter and Yolo Bypasses. The research will develop quantitative links between piedmont erosion and bypass deposition that are based on historical hydrology and refined conceptual models of bypass sedimentation processes. It will provide the basis for predictive modeling of the impact of future floods on sediment movement through the Central Valley.The project will provide a quantitative basis for future management decisions and direction in the Sacramento Valley and a set of methodologies that can be applied to other large, managed river basins. Data and interpretations from this study will be of great practical use to river and environmental management in the lower Sacramento Valley and the Delta, where our results are of utmost importance to flood conveyance, maintenance of islands, and potential toxicity of sediment. This research will create educational opportunities for a new generation of geomorphologists, including those from historically underrepresented groups. The output from this research will be made available as a project website via the World Wide Web and provide direct K-12 scientific outreach through the NASA space consortium, an educator resource center.