Rain Series Research Articles

Methods for Calculation of Annual and Extreme Overflow Events from Combined Sewer Systems

Overflow from combined systems constitute an increasing source of pollution of receiving waters, as compared to daily wastewater discharges which undergo treatment to a still higher extent. The receiving water problems from overflows are significant both in a long term scale (mean annual load) and in a short term scale (extreme event load). A method for computation of both annual and extreme load is presented. It is based on historical rain series and the use of a time-area model and simple pollutant mixing model in runoff calculation. Statistical calculations for both mean annual load and extreme events have been applied to the computed overflow series. Based on the computerized method simple manual calculations methods have been developed, resulting in graphs and tables for annual load and extreme load.

Simulation of the Impact of Combined Sewer Overflow on Rivers

Combined sewer overflows can in some cases cause critical oxygen concentrations in small rivers. The traditional design criteria for the overflow structures is not specificly related to this effect. By combination of a long historical rain series, a runoff model and a river quality model, it has been possible to achieve operational design diagrams for overflow structures. The diagrams are statistically based and relate the independent parameters for the catchment, the overflow structure and the river to the effect in question, the oxygen concentration.

Les crues du Danube et la grande inondation de juin 1965

The Danube in spate, with particular reference to the great flood s of june 1965 (Abstract). — The Danube expériences floods which are very varied in kind. According to our classification the most powerful floods on the lower course of the river, below its confluence with the Save at Belgrade, are Pannonian Carpato-Dinarics, and iheir grea-test sources are the Tisza and the Save. In Austria and again in Hungary, the most impressive floods, except those which owe iheir catastrophic heights to ice-jams (eg the disastrous flood of March 1838 at Budapest), belong to the Central European Alpine type. Thèse occur mainly in the Eastern Alps. The considérable flood of June 1965 was clearly 1. Et les débits records du Dniepr, puis encore plus ceux de la Dvina et la Petchora, l'emportent aussi de beaucoup sur ceux du fleuve de Budapest et d'Orsova. one of this sort This was an outstanding example of flood being caused by many factors that is it was due to whole series of heavy rains and consecutive elementary floods which overlapped and aggravated the situation Throughout almost all of its Hungarian reaches as far as its confluence with the Tisza it broke all known records that at Budapest by 040 that at Novi-Sad by 072 It burst the dykes in Slovakia and in Yugoslavian Vojvodina which brought about real national catastrophes

The relation of hydrographs of runoff to size and character of drainage‐basins

In a previous paper entitled “stream‐flow from rainfall by unit method” (Eng. News‐Record, April 7, 1932), the writer defined a unit graph as the hydrograph of runoff from a given area, due to a one‐inch runoff‐depth applied in one day or in any other convenient unit of time. A procedure for deriving the unit graph from observed rainfall‐ and runoff‐records was presented. After the unit graph has been derived a runoff‐record for the given area, for any rain or series of rains, may be computed by a simple summation process. Figure 1, from the aforesaid paper, graphically illustrates the summation process and it will not be described further here.

In Support of Gardner's Theory of the Origin of Certain Concretions

In an article in the Journal of Geology, Gardner has maintained that certain concretions are formed in supersaturated or overloaded water carrying fine clay particles. He believes that the particles are pressed together and are gathered in lumps just as the finely disseminated particles of butter are gathered together in churning and that these particles grow by accretion and gain their spherical form by being rolled along the bottom. He bases his opinion on observations of aggregations of mud balls in the bed of a stream after a flood in the Rio Chaco region of the San Juan Basin, New Mexico. In the summer of 1921 the writer observed similar phenomena in the bed of the North Fork of the Red River, Beckham County, Oklahoma. As a result of a series of severe rains, this river, which is usually an insignificant stream flowing in sand-choked channels, had been flowing bank full. After the flood had subsided the writer observed on one of the sandy flats in the river bed a remarkable collection of clay aggregations similar to those described by Gardner. They consisted both of clay balls and cylinders, the former being much more numerous. The balls varied from less than an inch to about six inches in diameter. The cylinders were from four to six inches in diameter and a foot or more in length. Both balls and cylinders were composed of fine clay, with a small amount of sand and gravel in them or imbedded in the outer portion. The cylinders were apparently the result of two balls becoming stuck together and being rolled along the bottom, as several cases were observed showing the steps in this process. The considerable