Examination of stormwater drainage by the conventional methods in urban street

Stormwater management system in today's world that attracts all the attention because of difficulties in stormwater drainage and increasing costs, by using the conventional methods have been discussed in this study. Before the studies as a sub-structure of entry into the subject, rainfall-recurrence-time graphs and tables are also given which will be used in design according to road types. According to this precipitation accepted in design, permissible spread of runoff water on the street surface and velocities-depth charts are given. The maximum longitudinal and transverse slope values that can be tolerated by the road type are given. Cross-sections and water collection capacity of the gutters on the streets is shown with examples. The social and economic damages of poor or inadequate stormwater drainage have been mentioned. For this purpose, to be able to drain of runoff water in the urban streets, the four main storm drain inlets have been mentioned. These inlets are especially widely used in developed countries and theirs names are curb inlets, grate inlets, combination inlets (curb and grate), and slotted drain inlets. (The use of curb inlets and combination inlets is not common except in developed countries). The shapes of drain inlets are also given and their characteristic features against the clogging, safety of bicycles and children are discussed. The hydraulic behaviors of these inlets on grade and in sag locations at the street have been examined with examples according to the formulas of Hec-22 (Hydraulic Engineering Circular No.22, third edition). In conclusion, their advantages and disadvantages compared to each other are shown. The main subject of this study is to examine the issues affecting the hydraulic efficiency of these inlets. Within the concept of this study, it was used the experiment data and observations which is done by KU (The University of Kansas). The hydraulic efficiency of storm drain inlets in variable longitudinal slopes was investigated in these experiments. In this study, two dimensionless values (F, dTLg / VQ) were obtained using these data. After these dimensionless values have been obtained, their relationship to hydraulic efficiency of inlets have been tabulated and charted. As seen from these graphs and tables, the efficiency decreases with the increasing Froude dimensionless coefficient whereas the efficiency increases with the increase of the other dimensionless coefficients. The rates vary depending on the varying longitudinal slope ratios and inlet types while the interaction is the same direction. xviii Apart from the experimental data, it is seen that, the inlets work much more efficiently when the gutter with composite cross section is selected instead of gutter with uniform cross section. And also clogging factor has a negative effect on the hydraulic efficiency have been observed.