"OVERVIEW This glossary is divided into three parts: ? Overview@ ? Glossary@ and ? References. It is not intended that all the terms in this glossary be rigorously accurate or complete. Realistically@ this is impossible. Depending on the circumstance@ a particular term may have several meanings; this can never change. The primary purpose of this glossary is to define the terms found in the Highway Drainage Guidelines and Model Drainage Manual in a manner that makes them easier to interpret and understand. A lesser purpose is to provide a compendium of terms that will be useful for both the novice and the more experienced hydraulics engineer. This glossary may also help those who are unfamiliar with highway drainage design to become more understanding and appreciative of this complex science and facilitate communication between the highway hydraulics engineer and others. Where readily available@ the source of a definition has been referenced. For clarity or format purposes@ cited definitions may have some additional verbiage contained in double brackets [ ]. Conversely@ three ""dots"" (. . .) are used to indicate where some parts of a cited definition were eliminated. Also@ as might be expected@ different sources were found to use different hyphenation and terminology practices for the same words. Insignificant changes in this regard were made to some cited references and elsewhere to gain uniformity for the terms contained in this glossary@ e.g.@ ""groundwater"" vs. ""ground-water"" or ""ground water@"" and ""cross section area"" vs. ""cross-sectional area."""