红水河阶地与极限洪水

本文用地貌学方法与水文学、气候学、地质学结合起来,综合研究河流极限洪水问题。

A RESEARCH OF THE EXTREME FLOOD OF THE HONGSHUI RIVER DURING THE PAST THIRTY THOUSAND YEARS

In the course of irriagtion and waterpower electrical construction at home and abroad, problems of extreme river flood are very crucial and must be studied and solved, as it affects the cost and the safety of construction.If the designed flood is estimated higer, it may waste the construction investment, otherwise if the designed flood is estimated lower, it may cause dams to collapse and then make heavy, sometimes incalculable loss of property of the State and lives of the people.For many causes, such examples of the failure of construction are nothing new at home and abroad, so the problems of extreme river flood are worth researching and will attract much attention.This article tries to solve the problem of extreme river flood by using geomorphic method and other related methods such as hydrologie, climatalogic, geologic methods and carbon-14 dating techniques.After collecting lots of data and inspecting on-the-spot, we provide five principles of dividing the uppermost valley flat from the first level river ter-race.Using geomorphic method, we have estimated the discharge of extreme flood of Tiane hydrometric station,Yiantan hydrometric station,Dahua hydro-power station, Duan hydrometric station, xincheng Hongdu hydrometric station, Qienjing hydrometric station and No.2 Wuxuan hydrometric station along the Hongshui river.And further more, from the results of the carbon-14 analysis of the Hongshui river we estimated that the reappearing time of the flood is 30,000 years. Comparing the extreme flood estimated by geomorphic method with the flood met per 10,000 years, we got ±1-9% e,g, k=0.91-1.04.This article tries to do synthetical research on the extreme flood by using geomorphologic, hydrologic, climatic and geologic methods.1.In the recent 30,000 years, the earth crust was relatively stable or slightly uplifted.Using geomorphologic method to estimate the extreme flood of a river is quite accurate and reliable.2.In the other region, it can be used that the historical flood aids 50-70% of it as the extreme tlood.3.We suggest that in a major hydro-electric project the extreme flood be used as the design flood or as the upper limit of the discharge curve, and make the result of the f requency calculation match the natural law.ln the case of lacking meteorological data, using this method, it can be avoided that the result calculated by other method is higher or lower, and it can be more reasonable for inrestment arid Can raise the safety of the project.