07. Iso-Q Lines The relationship between flow depth and velocity is important to understanding the hydraulic conditions in a sewer. The addition of flow rates to a scattergraph deepens the operational understanding of these conditions. Flow rates can be scaled within a scattergraph and displayed using iso-Q lines. Simply put, […]
Scattergraph
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06. Constant vs. Varrying Roughness The Manning Equation can be applied using three methods, including the Design Method, the Lanfear-Coll Method, and the Stevens-Schutzbach Method. The roughness coefficient used in these methods is often treated as a constant value. However, historical research has shown that the roughness coefficient actually varies […]
05. Manning Equation Comparison The Manning Equation can be applied using three methods, but which method should be used? Laboratory results have shown that these methods provide similar results under uniform flow conditions. However, only the Stevens-Schutzbach Method describes the relationship between depth and velocity under non-uniform flow conditions caused […]
04. Stevens-Schutzbach Method The Stevens-Schutzbach Method is an iterative regression technique used to fit the Manning Equation to flow monitoring data. This method can be applied to data obtained under non-uniform flow conditions resulting from downstream obstructions or dead dogs. This method is demonstrated here using four iterations. The magnitude […]
03. Lanfear-Coll Method The Lanfear-Coll Method uses a regression technique to fit the Manning Equation to flow monitoring data. This method can be applied to data obtained under uniform flow conditions and requires no direct knowledge of the roughness coefficient (n) or slope (S). This method is demonstrated here and […]
02. Design Method The Design Method is a traditional use of the Manning Equation and requires information regarding the roughness coefficient (n) and the pipe slope (S). These values are obtained from design or as-built records. The resulting pipe curve is then compared to actual flow monitoring data. This method […]