Sensitivity Analysis Method of Human-induced Riverbed Evolution to River Water Level Change

Abstract

A sensitivity analysis method for the change of a river level caused by river bed evolution due to human intervention comprises the following steps: collecting runoff data in a riverway area to be evaluated since hydrological records, determining the dominant discharge, and selecting the dominant formative runoff date according to the type of a tide to actually measure tide level processes at the river mouth; acquiring actually measured natural river bed topographic maps before and after the dominant formative runoff date; acquiring natural river bed geological data, determining burial depths and widths of sand beds on cross sections; determining the characteristic parameters of bed load and suspended load through a soil test; establishing a flow and sediment mathematics calculation model according to the basis data; determining the bed roughness of the natural river bed according to water level validation, sand content validation of the suspended load, and erosion and deposition validation of a terrain; dividing the river bed area into four areas according to the river sand reserves and the river sand distribution of the natural river bed; forecasting the influence of artificially dredging on a future riverway level change rule in different areas.

Description

【Technical field】 [0001] The invention relates to the field of water conservancy engineering technology development, in particular to a method for analyzing the sensitivity of artificially induced river evolution to river water level changes. 【Background technique】 [0002] The natural phenomenon that the natural riverbed is deformed under the action of natural hydrodynamic forces such as runoff and ocean tide, or due to human intervention such as dredging and damming, is called riverbed evolution. The evolution of natural riverbed is closely connected with river sand and gravel. River sandstone has two properties. First, river sandstone is an important part of the riverbed, which is related to the stability of the river regime, the safety of flood control and navigation, the normal operation of river-related projects, and ecological and environmental protection. Secondly, river sand is a limited resource. Sand mining is an activity that artificially changes the natural sh...

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Problems solved by technology

The influence of riverbed evolution involves a wide range of areas, and "one hair affects the whole body". Due to riverbed evolution, Shuikou Hydropower Station, the largest hydropower station in East China on the Minjiang River in Fujian Province, the Jinji large-scale sluice on the Jinjiang River, the Beiyin large-scale sluice on the Jiulong River, and the Xixi River Some of the functions of important water conservancy facilities such as large sluices have been lost, or have been severely damaged, or even rebuilt, causing huge economic losses; not only that, due to the evolution of the riverbed, there are Wanshou Bridge, Hongshan Ancient Bridge, and Jiangdong Ancient Bridge with hundreds of years of history on the Minjiang and Jiulong Rivers and Shiwuhubei were destroyed one after another. The evolution of the river bed also changed the hydrodynamic conditions. The estuary shrinks, the wetland disappears, and the salt tide goes up. Some water intakes in Fuzhou, the capital city of Fujian Province, change the flow conditions due to the evolution of the river bed. Chloride ions The concentration once exceeded ten times the standard, Zhangzhou Baoxin Water Diversion Project and Zhangzhou No. 2 Waterworks were scrapped due to changes in hydrodynamic conditions, seriously affecting farmland irrigation and urban drinking water safety

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