Centennial-Scale Anthropogeomorphic Change: Legacies of Hydraulic Mining in Greenhorn Creek, California
學年 109
學期 2
發表日期 2021-04-07
作品名稱 Centennial-Scale Anthropogeomorphic Change: Legacies of Hydraulic Mining in Greenhorn Creek, California
作品名稱（其他語言）
著者 L. Allan James; Allison M. Pfeiffer; Chen-Ling J. Hung
作品所屬單位
出版者
會議名稱 AAG Annual Meeting
會議地點 Virtual
摘要 Hydraulic mining in upper Greenhorn Creek, a small mountainous watershed (41.2 km^2) in northwestern Sierra Nevada, was practiced extensively from 1853 until 1884. This is an ideal site to study long-term geomorphic responses to a catchment-scale sediment pulse due to the discrete 31-year period of production, large volume of distinctive clastic sediment produced, and lack of subsequent engineering. Geomorphic responses to mining include mine pits and extreme valley-bottom aggradation below the mines. High-resolution (1m) airborne LiDAR topographic data were used to map geomorphic features, compute volumetric changes by DEM differencing, and develop spatially distributed sediment budgets for the catchment. The 25 hydraulic mine pits produced 41.3×10^6m^3 of hydraulic mining sediment (HMS) by 1884, of which 15.8×10^6m^3 (35% of production) was stored at the time of penultimate aggradation (ca.1884) and 4.8×10^6m^3 (11%) was stored when LiDAR data were acquired (2014). Differences between production and storage volumes indicate that sediment delivery ratios (SDR) were 62% in 1884 and 88% in 2014, documenting persistent storage in the mountains. Bulk densities of mined material (1.78 kg m^-3) and HMS (1.92 kg m^-3) were measured and used to convert volumes to mass and compute long-term HMS flux rates. Specific sediment yields (SSY) were 33,039 t km^-2yr^-1 during mining (1853-1884) and 3,845 t km^-2yr^-1 thereafter (1884-2014). During mining, SSYs were two orders of magnitude higher than globally predicted values for catchments this size. Volumes of production, storage, and flux were much greater than in neighboring Steephollow Creek, a comparable-sized watershed.
關鍵字 sediment budgets;fluvial geomorphology;human impacts;mining
語言 en_US
收錄於
會議性質 國際
校內研討會地點 無
研討會時間 20210407~20210411
通訊作者 L. Allan James
國別 USA
公開徵稿
出版型式
出處 AAG Annual Meeting 2021
相關連結

機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/121196 )

SDGS 優質教育,潔淨水與衛生,產業創新與基礎設施,永續城市與社區,夥伴關係