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Allan James Geomorphic Continuity (PDF) Geomorphic Continuity: Longterm RfthLYbRiResponses of the Lower Yuba River to Hydraulic Mining Sediment Allan James University of South Carolina 2012 Lower Yuba River Symposium July 11, 2012, Sacramento Introduction • Historical fluvial changes, drawn from and illustrated by examples of newly developed cartographic and aerial photographic data, are examined. • The Lower Yuba River (LYR) is a poster child for anthroppgogenic chang e. It is one of the most heavil y changed rivers known, due to hydraulic mining sediment (HMS), dredging, and engineering works. • KithhitfhiKnowing the history of change is essenti tiltal to understanding river dynamics as responses to a complex of processes and trends. Water canon used for hyygdraulic mining. North Bloomfield, Malkoff Diggings. Objectives • Combine historical map & air photo evidence with stratigraphic, sedimentological, geochemical, field, & hithistori cal ld dat a t o d ocument tLYR LYR ch annel l&fl & flood pl ai n initial (pre-European) conditions and changes over historical period. • Document specific changes caused by hydraulic mining sediment (HMS), gold dredging, and engineering to LYR, especially prior to ca . 1950 . •Many aerial photographs have been rectified and examined for geomorphic change . Most LYR changes occurred before air photos, however, so this presentation emphasizes early chhlllddhanges that are less well documented. Scope • PrePre--settlementsettlement Conditions • Initial Influx of Hydraulic Mining Sediment (HMS) • The River Engineering Era : Channel incision, dredging, & bank protection. • Adjustments to Longitudinal Profile • Base Level Control Below the Feather Confluence Pre-settlement Conditions • LYR had deep, clear water, with abundant salmon and high cohihesive bklidbanks lined wi ihith ripari an vegetation. • Riparian zone on low floodplains, aka, the ‘low bottoms’: • Dark soil with tall trees, brush, and vines. • Away from channels, an older terrace rose above floodplains: • Reddish soil with fewer trees. • “In the early days, all the territory south of the present north channel of the Yuba River at the D Street Bridggfe was a vast wilderness of trees and underbrush, wild grape and blackberry vines, this dense forest extending down to Eliza Bend on the south and upstream on the Yuba River for many miles... The southerly boundary of this forest was the higher ridge of red dirt land…” W.T. Ellis, 1939. Longitudinal Transition: Floodppglain Widening at Colluvial Limit • Late Quaternary terraces dip below historical alluvium near Parks Bar. Earlier terraces and colluvium ((p)with well developed soils) dip beneath historical alluvium in YGF. • Quaternary terraces idddin YGF were dredged. • Valley bottoms widen in YGF where modern alluvium emerge from older surfaces. This i s where levees begin. Generalized from USDA digital soils data. 1844 • Early maps lack details of channels • Sacramento Valley: topographically challenged • Extensive basins and wetlands were sites of flooding and sediment deposition. • In LYR, this was greatly exacerbated by HMS and later engineering works. Sacramento Valley (Bidwell 1844) PrePre--miningmining Channels • Sedimentation in Valley prior to 1862 flood was negligible. • Channels on 1859 map represent pre-mining chlhannels. • Although single channel is shown, other maps indicate a southhlidhern channel existed that was not mapped in 1859. RMSE=43.7 m North half 1859 Von 29 GCPs Schmidt map. Map of Yuba County, Anastomosing channel 1861 (multithread) Of Note: • Two channels from YGF to Simpson FtbiddFerry; not braided. • Former channel to south with slough to north near Marysville • Cutoff to Feather confluence existed prior to dredging Westcoat, 1861, map of Yuba County 5.5 m historic Pre- settlement alluvium LYR at Marysville, right bank exposure. Pre-settlement soil i s d ark b rown silt (f orest soil) b uri ed b y >5 m HMS. Bank Stratigraphy at Marysville Bank exposure • Bank exposure was not on main channel during pre-settlement time. HMS has high Hg concentrations Influx of HMS • Auriferous paleochannel gravels on Foothill ridgetops were washed into canyons below. North Columbia Mine, San Juan Rdg. Photo by A.James, Oct., 2003. Brief History of Hydraulic Mining • 1853 – Invented in upper Yuba basin near Nevada City. • 18621862--1880s1880s – Extreme sedimentation in Valley. • 1884 – Hydraulic mining to navigable rivers enjoined. • 1893 – Caminetti Act creates California Debris Commission (CDC) & legalizes permitted mining . Relatively small volumes mined but actions of CDC and small dams important. • 1917 – Gilbert’s classic treatise on hydraulic mining sediment, b ased on Y ub a Ri ver. AifAuriferous pa leoc hanne ls on rid idtgetops. Placer & River Mining Sediment Produced by Hydraulic Mining (Adapted from Gilbert , 1917) Volume Percent of total River (106 m3) Production Basin 523 49.0 % Yuba River 271* 25.4% Bear River 76.5 7.2% Feather River 871 81.6% SubTotal 197 18. 4% AiRiAmerican River 1,067 100% Total *Pro duct ion in Bear rev ised up to Gilbert’s original estimate (James, 1989). Patterns of Sediment Storage Two Storage Zones: • Near mines on flat ridges • Little storage in steep canyons. • Most sediment delivered to Sacramento Valley. Valley storage was reported by Gilbert. View up James, 2006, ESPL Middle Yuba Storage of Hydraulic Mining Sediment in Valley Fans Storage Storage as % Production (million m3) Individual Basin Lower Yuba 253 48. 4 Feather River below Yuba 24.6 32.2 >1 billion m3 produced in Yuba, Bear, Feather & American Rivers, 1853-1884. Yuba drainage area: 3499 km2. Data from Gilbert, 1917. First accurate survey and map in 1880 1880 paleo-channel is 1859 pre-miiining ch annel . South bend levee failed in 1997. 1859 Marysville, 1880. Channel & Floodplain Morphogenesis to 1880s Mendell, 1882 • Max aggradation occurred at most LYR sites by 1900. Previously, little if any dre dg ing or v iabl e d ams. • Multi-thread channel system with braided main channel and secondary channels to north and south. 1891 USGS Quad sheet The River Engineering Era: Channe l Inc is ion, Dre dg ing, Levees & Bank Protection Brief history of Federal funding for river improvements: • Began for Sacramento & Feather Rivers in 1875 – Dredging, snag removal & construction of ‘brush jetties’ • Modified by River and Harbor Act of 1882 - construction of brush dams on lower Yuba, Bear & American Rivers. • River and Harbor Act of 1892 – funds for LYR near Marysville and for dredging a cut-off of Shanghai Bend on Feather River . • Caminetti Act (1893) created CDC with broad environmental & flood mgt powers. Powers not used until 20th century but early studies, maps, and flood mgt. coordination important. History of LYR Needs Updating • The LYR was made famous as an example of extreme river alteration byy()y G.K. Gilbert’s classic (1917) study of HMS. • Since Gilbert, many changes: – Channel incision & return to a single-thread system in response to lowering sediment loads, – Mining: • Blue Pt. hydraulic mine ( Smartville) produced sediment below Englebright; • Dredggging for g old g reatly altered channels in the Yuba Gold Fields (YGF) – Engineering works: dams, levees, wing dams, training walls, d red gi ng, and b ank revet ment . Contrasting Styles of 19th Century River Mgt & Response: Feather vs. Yuba Rivers Earliest case of large river-basin mgt West of Miss. R: • Early engineering Goals: – Arrest sediment in Yuba with dams – Protect navigable Feather & Sacramento Rivers • Broad levee setbacks & dams in Yuba contrasted with narrow setbacks and dredging in Feather. • After brush dams in Bear and Yuba failed (1880s) and Barrier dam failed in LYR (()1907) plans for LYR resorted to wide levee setbacks with boulder wing dams on main channel. • Apparent manipulations of designed inlets encouraged moderate floods to disperse from YGF onto floodplain. Barrier No.1 Dam Site • Built 1904; filled with sediment first winter. • Dam raised 2.4 m but also filled quickly. • Filled with ~1.3 x 106 m3 HMS • 20-ft d rop over d am i n 1906 • Failed in 1907 flood. • Channel from here to DPD has not incised or returned to pre- mining levels. Excerpt from CDC 1906 map; 1:9600; 0.6-m contours. RMSE ~12 m; ~12 GCPs Distributary Channel System Multi-thread channel system from mining period persists as high- water chlhannel system. Wing dams & revetment in main channel protected banks & encouraged incision. Inlet structures controlled inflows to distributary systems. Mapping the Distributary Channel System • High-water channels have very sandy soils. • Soil maps distinguish these soils as Xero-psamments. • Other HMS soil units mapped as Xero-fluvents and Riverwash . Generalized soil units from digital USDA map data. Mapping Distributary Channels Digitized geomorphic fblYGFfeatures below YGF: • Dark blue: main channel • Light blue: high -water channels • Brown: stable terrace surfaces (former floodplain deposits during peak aggradation period. When & How were Distributary Channels Abandoned by Moderate Flows? Distributary channels (red arrows) north of main channel below YGF. Development suggests flood risks are decreasing by 1938. • Broad channel abuts north levee (brown line) . 1938 • (A&B) Large islands with young orchards. • (C ) Road incroaches on channel suggesting flood hazards were no longer an issue. • These channels fed by inlets in next two figures. 1938 airphoto; USACE film archives DaGuerre Pt Before Extensive Dredging DPlifdiihlhdhfDaguerre Pt was loci of diversionary channels north and south of main channel. Single channel flows
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