Modeling the influence of river rehabilitation scenarios on bed material sediment flux in a large river over decadal timescales

摘要: [1] A stochastic flood generator and calibrated sediment transport formulae were used to assess the decadal impact of major river rehabilitation strategies on two fraction bed material flux net storage, first-order indicators aquatic riverine habitat, in a large system. Model boundary conditions modified reflect implementation three being considered Sacramento River Valley: gravel augmentation, setting back levees, flow alteration. Fifty 30-year model simulations compute probabilities response storage these strategies. Total annual average estimates made at six gauged cross sections, ∼60 km reach-scale budgets evaluated between them. Gravel augmentation improve spawning habitat induced accumulation locally and/or downstream, depending added mixture. Levee setbacks recreate corridor reduced stages for most flows hence lowered flux. Flow alteration mimic natural regimes systematically decreased total flux, suggesting that high-magnitude low-frequency events do not affect long-term trends The results indicate each strategy reduces its target reaches modulates imbalances reach scale. Additional risk analysis is necessary identify extreme associated with variable hydrology could over decades. Sensitivity suggests sorting important determinant modeled patterns.