Method for improving water temperature stratification characteristic of channel reservoir tributary bay by internal wave

Abstract

The invention belongs to the technical field of improvement and restoration of reservoir water ecology, and relates to a method for improving water temperature stratification characteristic of a channel reservoir tributary bay by internal wave. During a water temperature stratification period of the tributary bay, fluctuation is generated from letdown flow, and water level of a reservoir fluctuates, so that tide is formed at the estuary of the tributary bay. Tide type inflow and outflow are formed between the bay and a trunk reservoir and have shear effect at the thermocline, so that tide interval wave is generated near the thermocline. Water of the thermocline flows reversely since the tide internal wave transmits along the thermocline, so that alternate flow is generated, water temperature fields are mixed, and then water temperature stratification is improved. Deepwater reservoir equal-density stratification water is aroused to generate internal wave under reservoir regulation, andthus natural underwater stirring movement is formed. The method is easy to implement, has influence to large-scope water, improves water dynamic strength remarkably, suppresses water temperature stratification and achieves the purposes of improving water ecological environments.

Description

technical field [0001] The invention belongs to the technical field of water ecology improvement and restoration of lakes and reservoirs, and specifically relates to a method for improving the water temperature stratification characteristics of tributary reservoir bays of channel-type reservoirs by using internal waves. Background technique [0002] After the river channel reservoir is completed, the tributaries are supported by the water level of the main stream to form a reservoir bay. The water flow velocity is very slow (only on the order of millimeters), and the water depth is large (up to 100 meters or more). Its hydrodynamic characteristics are similar to those of deep-water lakes. It is divided into thermocline layer, thermocline layer and hysteresis layer. Water temperature is the main factor affecting the growth of algae. The thermocline formed by water temperature stratification will cause the concentration of pollutants and nutrients to appear in a thermocline, ...

AI Technical Summary

Problems solved by technology

The dissolved oxygen content in the lower part of the thermocline decreases and the concentration of carbon dioxide increases, forming a reducing environment, causing changes in the types, quantities, and distribution of plankton and aquatic plants. The release of low-temperature water may also cause delays in the spawning period of fish and lower spawning rates. The lowering will slow down the metabolism of crops in the irrigation area and reduce the yield, which will bring many disadvantages to the water ecology and water environment in the downstream of the dam site.

[0003] As for the ecological environment problems caused by water temperature stratification and low-temperature water discharge, engineering measures are mainly adopted at present, such as stratified water intake, stacking gates, dynamic stirring, aeration and other methods for local water intakes. The water temperature is appropriately increased, but these measures cannot change the temperature stratification of the large-volume water area in the reservoir area, and cannot improve the ecological environment of the large-scale water body in the reservoir area.

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