||Storm Sewer Design - An Evaluation of the RRL Method.
Stal, John B. ;
Terstrie, Michael L. ;
||Illinois State Water Survey, Urbana.
||EPA-11030-FLN; 03519,; R2-72-068
( Storms ;
Surface water runoff) ;
( Storm sewers ;
Structural design) ;
Surface drainage ;
Urban areas ;
Fluid flow ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
Storm rainfall and runoff data were assembled from 10 urban basins in the U.S.A. ranging in size from 14 acres to 8 sq mi. The British RRL method of storm drainage design was applied to the 10 basins. The RRL method considers the urban basin to be comprised of the paved area of the basin which is directly connected to the artificial storm drainage system. In 3 of the 10 basins the RRL procedure was deemed to be appropriate and suitable for the design of a storm drainage system within the normal range of frequency of design rainfall events, from 2 to 20-year events. For greater storms and for certain cases within this frequency range, the RRL method breaks down because the runoff coming from the grassed area of the basin is significant. If the basin is highly steep or if the paved area comprises less than 15% of the total basin, this breakdown occurs. An example is given of the use of the RRL method in the re-design of an existing storm drainage system, as is current practice in Great Britain. (Author)