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WATER RESOURCES RESEARCH,
VOL. 40,
W11301,
doi:10.1029/2004WR003279,
2004
Estimating accumulation rates and physical properties of sediment behind a dam: Englebright Lake, Yuba River, northern California
Noah P. Snyder
Pacific Science Center, U.S. Geological Survey, Santa Cruz, California, USA
David M. Rubin
Pacific Science Center, U.S. Geological Survey, Santa Cruz, California, USA
Charles N. Alpers
U.S. Geological Survey, Sacramento, California, USA
Jonathan R. Childs
U.S. Geological Survey, Menlo Park, California, USA
Jennifer A. Curtis
U.S. Geological Survey, Sacramento, California, USA
Lorraine E. Flint
U.S. Geological Survey, Sacramento, California, USA
Scott A. Wright
U.S. Geological Survey, Flagstaff, Arizona, USA
Abstract
Studies of reservoir sedimentation are vital to understanding scientific and management issues related to watershed sediment
budgets, depositional processes, reservoir operations, and dam decommissioning. Here we quantify the mass, organic content,
and grain-size distribution of a reservoir deposit in northern California by two methods of extrapolating measurements of
sediment physical properties from cores to the entire volume of impounded material. Englebright Dam, completed in 1940, is
located on the Yuba River in the Sierra Nevada foothills. A research program is underway to assess the feasibility of introducing
wild anadromous fish species to the river upstream of the dam. Possible management scenarios include removing or lowering
the dam, which could cause downstream transport of stored sediment. In 2001 the volume of sediments deposited behind Englebright
Dam occupied 25.5% of the original reservoir capacity. The physical properties of this deposit were calculated using data
from a coring campaign that sampled the entire reservoir sediment thickness (6–32 m) at six locations in the downstream ∼3/4
of the reservoir. As a result, the sediment in the downstream part of the reservoir is well characterized, but in the coarse,
upstream part of the reservoir, only surficial sediments were sampled, so calculations there are more uncertain. Extrapolation
from one-dimensional vertical sections of sediment sampled in cores to entire three-dimensional volumes of the reservoir deposit
is accomplished via two methods, using assumptions of variable and constant layer thickness. Overall, the two extrapolation
methods yield nearly identical estimates of the mass of the reservoir deposit of ∼26 × 106 metric tons (t) of material, of which 64.7–68.5% is sand and gravel. Over the 61 year reservoir history this corresponds
to a maximum basin-wide sediment yield of ∼340 t/km2/yr, assuming no contribution from upstream parts of the watershed impounded by other dams. The uncertainties and limitations
of the estimates of overall sediment quantities are discussed. Implications for watershed management and future reservoir
sedimentation studies are also presented.
Received 19
April
2004;
accepted 20
September
2004;
published 18
November
2004.
Keywords: reservoir sedimentation;
river restoration;
dam removal;
sediment transport;
Yuba River.
Index Terms: 1815 Hydrology: Erosion and sedimentation; 1857 Hydrology: Reservoirs (surface); 1824 Hydrology: Geomorphology (1625).
Read Full Article (file size: 1295164 bytes) Cited by
Citation: Snyder, N. P., D. M. Rubin, C. N. Alpers, J. R. Childs, J. A. Curtis, L. E. Flint, and S. A. Wright
(2004),
Estimating accumulation rates and physical properties of sediment behind a dam: Englebright Lake, Yuba River, northern California,
Water Resour. Res.,
40,
W11301,
doi:10.1029/2004WR003279.
This paper is not subject to U.S. copyright. Published in 2004 by the
American Geophysical Union.
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