Verification of drainage channels receiving urban sewer flows
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In the Italian tradition the verification of artificial hydraulic networks, whether drainage or sewer channels, is carried out by the classic „Italian method", that considers analytically the influence of the water volume held by the network on the channel flow. This method allows us to determine the time necessary to fill the channel, as long as the in-flow to the channel network is known, when this is taken as constant and proportional to the in-flow from rainfall. If the filling time does not exceed the length of computed rainfall, the channel can be considered verified. Mathematical elaboration leads to two different expressions of filling time, depending on whether they are trapezoidal drainage channels or covered sewer channels (circular or polycentric). When drainage channels receive urban sewer flows, which is a frequent occurrence in urbanised flat zones, the above- mentioned relationships cannot be used, in that they are not able to compute the water volume held by both networks. When the incidence of the urbanised area is considerable, it is impossible to estimate the hydraulic risk of the zone caused by land modifications, if we do not consider the effects of the sewer network on the channel flow. The present work supplies a first contribution to solving this problem mathematically. We notice that the drainage channel flow can be approximately expressed by means of a relationship with the wet section of the last sewer trunk line, as follows: q = µ ω ²
-  Dwight H.B. 1961. Tables of integrals and. other mathematical data The Macmillan company: 336.
-  Milano V., Pagliara S., Venturelli M. 1996. A comparison between a varied „italian method" and distributed models in urban drainan
-  7th International conference on urban storm drainage. Hannover: 311-316.
-  Ruggiero C. 1955. Costruzioni idrauliche. Pisa. 814.
-  Supino G. 1965. Le reti idrauliche. Patron. Bologna. 806.