Features of the formation of storm water on highways

06.02.2019
Articles
Features of the formation of storm water on highways

The maximum surface runoff on highways, as a rule, has high flow rates and depends on changes in the intensity and duration of precipitation. A feature of the road drainage system is that the runoff surface is characterized by the absence of a channel on two-sided and often one-sided slopes, or, as it is commonly called, slopes.

The amount of runoff on such surfaces is significantly influenced not only by the design of the road surface, but also by the presence of reinforcement of the slopes, the characteristics of the soil of the slope and adjacent territories. It is also important whether the slope is of artificial or natural origin.

Slopes are characterized and differ in shape: rectangular for an artificial slope and fan-shaped - for a natural one. Features of the forms are regulated by regulatory requirements. Of particular importance is both the category of the road and its location, the proximity to the road of various industrial or domestic facilities. As a result, a decision is made on the conjugation of the systems of these objects and road drainage structures.

Numerous observations and studies carried out in regions with different climatic features have shown that there are several factors that undoubtedly affect the formation of a significant amount of natural precipitation. Factors are classified into several classes. The main ones can be distinguished: meteorological factors, depending on the device of the water conduit, (artificial or natural) and factors associated with the characteristics of water bodies. But regardless of whether the factors belong to a particular group, they can be natural or natural regulation.

Thus, the runoff can be formed as a result of household and industrial activities of the population. In the second variant, natural conditions influence the formation of runoff. In different regions, all these factors have an impact on the formation of maximum water flow rates. Some factors can be recorded only in certain areas that have their own distinctive features, while others, the so-called metrological factors, are inherent in all areas, but with varying degrees of influence. One of the main factors is the unevenness of precipitation in the form of rain and snow at different intervals, as well as the influence of seasonal fluctuations.

It is always necessary to take into account the possibility of changing factors over a long period of intensive operation of wastewater disposal. When calculating increased volumes of water, the criterion of the probability of exceeding should be decisive. Methods for calculating the extreme runoff at the values ​​of the excess probability from 0.1 to 10%. But the actual conditions in this range are poorly understood. To develop reliable methods for calculating maximum rainfall rates, the amount of field data is currently insufficient.

Calculation methods must be universal and, regardless of weather anomalies, provide for approximate calculations with the required degree of reliability. During construction, it should be borne in mind that highways, car parks, junctions and bridges require large areas for surface drainage.

At present, most countries, including Russia, have gained rich experience in carrying out calculations in order to determine the maximum rainfall runoff. The experience of calculating extreme storm runoff in many countries is discussed at international seminars. The results are presented in the reports of the General Conferences of UNESCO and highlight various aspects of constructing the calculated dependencies.

The basic principle when creating methodological materials, allowing to determine the maximum order of rainwater, should take into account the most unfavorable conditions. These are weather anomalies, increased moisture content of surfaces, watering during the operation of transport facilities and a number of other non-standard situations.

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