AU2003212018A1 - Technology for the prevention of river flooding with particular application to the case of a proposal for the suspended lower course of the Yellow River - Google Patents

Description

AUSTRALIA

Patent Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Technology for the Prevention of River Flooding with Particular Application to the Case of a Proposal for the Suspended Lower Course of the Yellow River The following statement is a full description of this invention, including the best method of performing it known to me: Technology for the Prevention of River Flooding with Particular Application to the Case of a Proposal for the Suspended Lower Course of the Yellow River 1 Introduction Floods, with particular reference to those caused by the over flowing of rivers, have been the cause of tragic calamitiesin the world's history since time immemorial, inflicting untold damage to humans, other living beings, as well as the environment.

As a consequence, since ancient times man has in various countries endeavored to find means of preventing or mitigating floods.

The particular case of a river whose flooding has been especially disastrous over the ages is that of the Yellow River in China, known as China's "mother river" and the cradle of Chinese civilisation,. but due to the catastrophes that it brought to China over thousands of years of its history, it is also symbolized as China's frustration and sorrow. Particularly in its lower reaches, it is like a runaway horse: shifting and uncontrollable, the turbulent and silt-laden stream often overflows its banks and sends floodwaters across the North China plain.

The extremely high silt content combined with the radical topographic changes from the mountainous upper reaches to the flat plains of its lower course have become the legend of the Yellow River. Because of the resulting decrease in stream gradient and reduced velocity in the lower course, the Yellow River deposits an enormous amount of silt, sand and gravel in its riverbed, which in turn builds up ata rate of 10 centimeters every year.

Through the centuries, hundreds of kilometres of levees have been built to stabilize the course of the river and to protect the population against flooding. However, the building-up of levees could only delay the floods and has resulted in elevating the riverbed continuously. Consequently, the lower course of the Yellow River is now a suspended river: in many places, its riverbed lies above the surrounding land, its level being up to metres higher than the land. There is thus the potential for disaster to erupt in the lower course of the Yellow River. The resolution of this suspension crisis has become the most urgent task in the control and reclamation of the Yellow River, with various proposals having been advanced over the past decade, such as: re-opening the old river course (to the south of Shandong Peninsula) in addition to the current course which is north of Shandong; or transporting water to add to the river's upper stream in order to increase the flow rate in the lower course, etc. Many of them do have some good features, but lack overall strategy and/or feasibility.

2: Proposed technology A new technological scheme is proposed for the purpose of achieving complete prevention of flooding by rivers especially, but not exclusively, due to the silting up and raising of their river beds, thus resulting in overflowing with or without protection by dykes.

The technology consists in essence of the construction of one or more canal courses which are generally in line with to and alongside the existing course of the river* but, depending on circumstances, may be diverted to a different route.

Ultilisation of the existing river course is discontinued and it is converted to useful productive dry land. The canal courses are provided with water resistant beds and walls, their depth and width may be varied according to the requirements of each case, with much less resulting deposition of silt, but which nonetheless can periodically be removed by "cleaning" with much greater facility than is the case with the existing river course.

The application of this technology has been studied more thoroughly with a view to its application to the Yellow River. This is demonstrated in detail in the example submitted hereunder.

*The river course is defined as the space between the dykes constructed on either side of the river, determining the maximum width of the river when it normally attains its peak level.