10.4122/1.1000001347 Pezzaniti, D. Loughlin, G.G.O Argue, J.R. General characteristics of pit inlet capacity relationships DTU Library, Technical University of Denmark (DTU) 2005 stormwater inlets inlet capacity pipe system analysis stormwater drainage design University of South Australia, Urban Water Resources Centre Anstad Pty Ltd en Conference presentation 10.4122/1.1000001348 text/xml 1 The importance of stormwater inlet pits, the types of inlets, and the need for inlet capacity relationships at high flowrates are covered in the first part of this paper. A case study is used to show differences in published inlet relations and the problem of extrapolating relationships that were originally developed for relatively low flows. The US Federal Highway Administration Hydraulic Engineering Circular No. 22 (HEC22) methodology was used as a benchmark for comparisons with Australian laboratory inlet capacity test data and relationships in manuals, with the aim of extrapolating published relationships. It was not possible to establish precise relationships, but qualitative information developed for various kinds of inlets can be used, together with a spreadsheet implementing HEC22 procedures, to develop capacity relations for many kinds of inlets. Brief comments are provided on effects of inlet blockage and on cumulative effects in large pipe networks.